Abstract:
An example power management arrangement includes a motor controller configured to communicate power to a motor drive bridge to drive a motor. The motor controller is configurable to selectively receive power from each of a first power supply and a second power supply. The voltage of the power from the first power supply is different than a voltage of the power from the second power supply. An example power adjusting method includes receiving power at a motor controller, adjusting a voltage of the received power using the motor controller, communicating the power with the adjusted voltage from the motor controller to a motor drive bridge to drive a motor.

Description:
BACKGROUND 
       [0001]    This application relates generally to adjusting power. More particularly, this application relates to adjusting a voltage of power. 
         [0002]    Power conversion products, such as servo position-control drives, motor speed-control drives, power supplies, etc., typically utilize relatively unmodified power. The power moves directly from a single bus power source to a servo position-control drive, for example. The power may be processed to protect the quality of the provided power. The processing does not significantly change the power. The processing is typically limited to filtering electromagnet interference from the power or to a factor correction of the power. 
         [0003]    In a prior art arrangement, a motor assembly includes a servo motor portion and a motor controller portion. The motor assembly is configured to actuate a fuel valve or other engine components within a gas turbine engine, such as bleed valves or compressor variable geometries. The motor controller receives unaltered power directly from a single bus. The motor controller communicates the power to the servo motor. The prior art motor assembly is not able to receive power from another bus having another bus voltage. The servo motor assembly typically includes heat sinks that are used to communicate thermal energy away from the servo motor. The heat sinks undesirably increase the size of the servo motor assembly. The motor is unitary electric motor, for example, and includes an actuator assembly having an explosion-proof construction that facilitates use in explosive gas environments. 
       SUMMARY 
       [0004]    An example power management arrangement includes a motor controller configured to communicate power to a motor drive bridge to drive a motor. The motor controller is configurable to selectively receive power from each of a first power supply and a second power supply. The voltage of the power from the first power supply is different than a voltage of the power from the second power supply. 
         [0005]    An example power adjusting method includes receiving power at a motor controller, adjusting a voltage of the received power using the motor controller, communicating the power with the adjusted voltage from the motor controller to a motor drive bridge to drive a motor. 
         [0006]    Another example method of powering a motor includes receiving power at a motor controller, using the motor controller to adjust a voltage of the received power, powering components of a motor using the power having the adjusted voltage. 
         [0007]    These and other features of the example disclosure can be best understood from the following specification and drawings, the following of which is a brief description: 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  shows a schematic view of an example gas turbine engine having a power management arrangement. 
           [0009]      FIG. 2  shows a schematic view of the  FIG. 1  power management arrangement. 
           [0010]      FIG. 3  shows a flow of an example power adjusting method. 
       
    
    
     DETAILED DESCRIPTION 
       [0011]    Referring to  FIGS. 1 and 2 , an example gas turbine engine  10  includes (in serial flow communication) an inlet section  14 , a centrifugal compressor  18 , a combustor section  26 , a turbine wheel  30 , and a turbine exhaust  34 . The gas turbine engine  10  is circumferentially disposed about an engine centerline X. During operation, air is pulled into the gas turbine engine  10  by the inlet section  14 , pressurized by the centrifugal compressor  18 , mixed with fuel, and burned in the combustor section  26 . The turbine wheel  30  extracts energy from the hot combustion gases flowing from the combustor section  26 . 
         [0012]    The turbine wheel  30  utilizes the extracted energy from the hot combustion gases to power the centrifugal compressor  18 . The examples described in this disclosure are not limited to the radial turbine type auxiliary power units described, however, and may be used in axial architectures. The examples also may be used in gas turbine engines that are single-spool designs, two-spool designs, and three-spool designs. That is, there are various types of engines and engine architectures that could benefit from the examples disclosed herein, which are not limited to the radial turbine design shown. 
         [0013]    The combustor section  26  of the gas turbine engine  10  is configured to receive fuel from a fuel supply  42 . In this example, the fuel is sprayed from an injector  44  into the combustor section  26 . 
         [0014]    A motor assembly  46  has motor components  48  controlled by a motor controller  58 . The motor assembly  46  is a servo motor assembly in this example. The motor components  48 , such as rotors and coils, are configured to actuate a valve  50  to control the flow of fuel between the fuel supply  42  and the combustor section  26 . In another example, the motor components  48  are configured to actuate a bleed valve or to vary geometries of the compressor  18 . 
         [0015]    The motor assembly  46  also includes a heat sink  68  that helps remove thermal energy from the motor assembly  46  that is generated during operation. 
         [0016]    The examples described in this disclosure are not limited to the motor assembly  46  that controls the valve  50  of the gas turbine engine  10 . That is, other types of motors in other environments would benefit from teachings of the examples described in this disclosure. In other examples, the motor assembly  46  is used in factory automation, process control (fluids, gases, etc.), structural testing, aircraft simulators, etc., which use electric actuators with motor controllers and single power buses. 
         [0017]    The example motor assembly  46  is powered by a power supply  54  having a bus voltage of about 120 V. Other examples of the gas turbine engine  10  utilize power supplies having different bus voltages, such as 12 V, 24 V, 48 V, etc. 
         [0018]    In this example, the motor controller  58  includes a power management section  62  and a motor drive bridge section  66 . Power moves from the power supply  54  through the power management section  62  before moving to the motor drive bridge section  66 . The motor controller  58  is part of the motor assembly  46  in this example. In another example, the motor controller  58  is separate from the motor assembly  46 . 
         [0019]    The example power management section  62  has a buck boost portion that adjusts the voltage of power from the power supply  54  to a level appropriate for driving the motor components  48 . In one example, the power management section  62  adjusts the voltage of the received power downward from 120 V to 60 V before the power reaches the motor drive bridge section  66 . That is, the power enters the power management section  62  at 120 V and exits the power management section  62  at 60 V. Adjusting the voltage allows the motor assembly to be powered by bus voltages ranging from 60 V to 120 V. 
         [0020]    The example power management section  62  includes at least one switch  74 , at least one diode  78 , and an inductor  82 . A person skilled in the art and having benefit of this disclosure would understand how to reduce a voltage of the power provided by the power supply  54  using the power management section  62 . As can be appreciated, the adjustments to the voltage by the power management section  62  are more substantial than the prior art arrangements that processed power. 
         [0021]    The example motor drive bridge section  66  includes a plurality of switches  70   a - 70   f  that are used to regulate current to the motor assembly  46 . One or more of phases A-C are typically energized to hold the motor assembly  46  in a given position. The switches  70   a - 70   f  control which phases A-C are energized. In one example, phases A and B are energized by pulse width modulating the switch  70   a  while allowing current to move through a reverse diode of the switch  70   b . Example switches  70   a - 70   f  include insolated gate bipolar transistors (IGBTs) and field effect transistors (FETs) or some combination of these. 
         [0022]    In one example, the motor assembly  46  is driven at  20 A with a terminal winding resistance of 0.25 ohms. The motor assembly  46  utilizes IGBTs as switches  70   a - 70   f  that have a forward voltage of 1.6 V, a switching time (T sw ) of 150 nsec, an inverse diode forward voltage of 1.5 V and a switching frequency of 15 kHz. Such an example generates about 73 Watts of thermal energy (motor drive bridge loss), which is calculated as follows: 
         [0000]    
       
         
           
             
               Motor 
                
               
                   
               
                
               drive 
                
               
                   
               
                
               bridge 
                
               
                   
               
                
               loss 
             
             = 
             
                 
               
                 
                   [ 
                   
                     Upper 
                      
                     
                         
                     
                      
                     IGBT 
                      
                     
                         
                     
                      
                     Switching 
                      
                     
                       
                           
                       
                        
                       
                           
                       
                     
                      
                     Loss 
                   
                   ] 
                 
                 + 
                 
                   [ 
                   
                     Upper 
                      
                     
                         
                     
                      
                     IGBT 
                      
                     
                         
                     
                      
                     DC 
                      
                     
                         
                     
                      
                     Loss 
                   
                   ] 
                 
                 + 
                 
                     
                   
                     
                       [ 
                       
                         Lower 
                          
                         
                             
                         
                          
                         Drive 
                          
                         
                           
                               
                           
                            
                           
                               
                           
                         
                          
                         IGBT 
                          
                         
                             
                         
                          
                         DC 
                          
                         
                             
                         
                          
                         Loss 
                       
                       ] 
                     
                     + 
                     
                         
                       
                         
                           [ 
                           
                             Lower 
                              
                             
                                 
                             
                              
                             Free 
                              
                             
                               - 
                             
                              
                             Wheeling 
                              
                             
                                 
                             
                              
                             IGBT 
                              
                             
                                 
                             
                              
                             Diode 
                              
                             
                                 
                             
                              
                             Loss 
                           
                           ] 
                         
                         = 
                         
                           
                             
                               2 
                               * 
                               
                                 ∫ 
                                 
                                   
                                     
                                       T 
                                       SW 
                                     
                                      
                                     
                                       [ 
                                       
                                         
                                           V 
                                           IGBT 
                                         
                                         * 
                                         
                                           I 
                                           IGBT 
                                         
                                       
                                       ] 
                                     
                                   
                                    
                                   
                                      
                                     t 
                                   
                                 
                               
                             
                             + 
                             
                               ∫ 
                               
                                 
                                   
                                     T 
                                     on 
                                   
                                    
                                   
                                     [ 
                                     
                                       
                                         V 
                                         IGBT 
                                       
                                       * 
                                       
                                         I 
                                         IGBT 
                                       
                                     
                                     ] 
                                   
                                 
                                  
                                 
                                    
                                   t 
                                 
                               
                             
                             + 
                             
                               
                                 V 
                                 IGBT 
                               
                               * 
                               
                                 I 
                                 IGBT 
                               
                             
                             + 
                             
                               ∫ 
                               
                                 
                                   
                                     T 
                                     off 
                                   
                                    
                                   
                                     [ 
                                     
                                       
                                         V 
                                         IGBTDiode 
                                       
                                       * 
                                       
                                         I 
                                         IGBT 
                                       
                                     
                                     ] 
                                   
                                 
                                  
                                 
                                     
                                 
                                  
                                 
                                    
                                   t 
                                 
                               
                             
                           
                           = 
                           
                               
                             
                               
                                 [ 
                                 
                                   2 
                                   * 
                                   
                                     V 
                                     rail 
                                   
                                   * 
                                   
                                     I 
                                     m 
                                   
                                   * 
                                   
                                     
                                       T 
                                       SW 
                                     
                                     / 
                                     T 
                                   
                                 
                                 ] 
                               
                               + 
                               
                                 [ 
                                 
                                   
                                     V 
                                     IGBT 
                                   
                                   * 
                                   
                                     I 
                                     m 
                                   
                                   * 
                                   
                                     
                                       T 
                                       on 
                                     
                                     / 
                                     T 
                                   
                                 
                                 ] 
                               
                               + 
                               
                                   
                                 
                                   
                                     
                                       [ 
                                       
                                         
                                           I 
                                           m 
                                         
                                         * 
                                         
                                           V 
                                           IGBT 
                                         
                                       
                                       ] 
                                     
                                     + 
                                     
                                       [ 
                                       
                                         
                                           I 
                                           m 
                                         
                                         * 
                                         
                                           V 
                                           IGBTDiode 
                                         
                                         * 
                                         
                                           
                                             T 
                                             off 
                                           
                                           / 
                                           T 
                                         
                                       
                                       ] 
                                     
                                   
                                   = 
                                   
                                       
                                     
                                       
                                         [ 
                                         
                                           2 
                                           * 
                                           120 
                                           * 
                                           20 
                                           * 
                                           150 
                                            
                                           e 
                                            
                                           
                                             - 
                                           
                                            
                                           
                                             9 
                                             / 
                                             66.7 
                                           
                                            
                                           
                                               
                                           
                                            
                                           e 
                                            
                                           
                                             - 
                                           
                                            
                                           6 
                                         
                                         ] 
                                       
                                       + 
                                       
                                           
                                         
                                           
                                             [ 
                                             
                                               1.6 
                                               * 
                                               20 
                                               * 
                                               2.78 
                                                
                                               
                                                   
                                               
                                                
                                               e 
                                                
                                               
                                                 - 
                                               
                                                
                                               
                                                 6 
                                                 / 
                                                 66.7 
                                               
                                                
                                               e 
                                                
                                               
                                                 - 
                                               
                                                
                                               6 
                                             
                                             ] 
                                           
                                           + 
                                           
                                             [ 
                                             
                                               
                                                 20 
                                                 2 
                                               
                                               * 
                                               1.6 
                                             
                                             ] 
                                           
                                           + 
                                           
                                               
                                             
                                               
                                                 [ 
                                                 
                                                   20 
                                                   * 
                                                   1.5 
                                                   * 
                                                   63.9 
                                                    
                                                   e 
                                                    
                                                   
                                                     - 
                                                   
                                                    
                                                   
                                                     6 
                                                     / 
                                                     66.7 
                                                   
                                                    
                                                   e 
                                                    
                                                   
                                                     - 
                                                   
                                                    
                                                   6 
                                                 
                                                 ] 
                                               
                                               ≈ 
                                               
                                                 73 
                                                  
                                                 
                                                     
                                                 
                                                  
                                                 Watts 
                                               
                                             
                                           
                                         
                                       
                                     
                                   
                                 
                               
                             
                           
                         
                       
                     
                   
                 
               
             
           
         
       
     
         [0023]    In another example, 250 V FETs are used as switches  70   a - 70   f  in place of the IGBTs. The 250 V FETs have an inverse diode forward voltage of 1.5V and a terminal winding resistance (Rdson) of 40 mOhms at 100 degrees C. Such an example generates about 43 Watts of thermal energy (motor drive bridge loss), which is calculated as follows: 
         [0000]    
       
         
           
             
               Motor 
                
               
                   
               
                
               drive 
                
               
                   
               
                
               bridge 
                
               
                   
               
                
               loss 
             
             = 
             
               
                 [ 
                 
                   Upper 
                    
                   
                       
                   
                    
                   FET 
                    
                   
                       
                   
                    
                   Switching 
                    
                   
                       
                   
                    
                   Loss 
                 
                 ] 
               
               + 
               
                   
                 
                   
                     [ 
                     
                       Upper 
                        
                       
                           
                       
                        
                       FET 
                        
                       
                           
                       
                        
                       DC 
                        
                       
                           
                       
                        
                       Loss 
                     
                     ] 
                   
                   + 
                   
                     [ 
                     
                       Lower 
                        
                       
                           
                       
                        
                       Drive 
                        
                       
                           
                       
                        
                       FET 
                        
                       
                           
                       
                        
                       DC 
                        
                       
                           
                       
                        
                       Loss 
                     
                     ] 
                   
                   + 
                   
                       
                     
                       
                         [ 
                         
                           Lower 
                            
                           
                               
                           
                            
                           Free 
                            
                           
                             - 
                           
                            
                           Wheeling 
                            
                           
                               
                           
                            
                           FET 
                            
                           
                               
                           
                            
                           Switching 
                            
                           
                               
                           
                            
                           Loss 
                         
                         ] 
                       
                       + 
                       
                           
                         
                           
                             [ 
                             
                               Lower 
                                
                               
                                   
                               
                                
                               Free 
                                
                               
                                 - 
                               
                                
                               Wheeling 
                                
                               
                                   
                               
                                
                               FET 
                                
                               
                                   
                               
                                
                               DC 
                                
                               
                                   
                               
                                
                               Loss 
                             
                             ] 
                           
                           + 
                           
                               
                             
                               
                                 [ 
                                 
                                   Lower 
                                    
                                   
                                       
                                   
                                    
                                   Free 
                                    
                                   
                                     - 
                                   
                                    
                                   
                                       
                                   
                                    
                                   Wheeling 
                                    
                                   
                                       
                                   
                                    
                                   FET 
                                    
                                   
                                       
                                   
                                    
                                   Diode 
                                    
                                   
                                       
                                   
                                    
                                   Dead 
                                    
                                   
                                     - 
                                   
                                    
                                   
                                       
                                   
                                    
                                   Time 
                                    
                                   
                                       
                                   
                                    
                                   Loss 
                                 
                                 ] 
                               
                               = 
                               
                                 
                                   2 
                                   * 
                                   
                                     ∫ 
                                     
                                       
                                         
                                           T 
                                           SW 
                                         
                                          
                                         
                                           [ 
                                           
                                             
                                               V 
                                               FET 
                                             
                                             * 
                                             
                                               I 
                                               FET 
                                             
                                           
                                           ] 
                                         
                                       
                                        
                                       
                                          
                                         t 
                                       
                                     
                                   
                                 
                                 + 
                                 
                                   ∫ 
                                   
                                     
                                       
                                         T 
                                         on 
                                       
                                        
                                       
                                         [ 
                                         
                                           
                                             R 
                                             DSon 
                                           
                                           * 
                                           
                                             I 
                                             FET 
                                             2 
                                           
                                         
                                         ] 
                                       
                                     
                                      
                                     
                                        
                                       t 
                                     
                                   
                                 
                                 + 
                                 
                                   
                                     R 
                                     DSon 
                                   
                                   * 
                                   
                                     I 
                                     FET 
                                     2 
                                   
                                 
                                 + 
                                 
                                   2 
                                   * 
                                   
                                     
                                       ∫ 
                                       TSW 
                                     
                                      
                                     
                                       
                                         [ 
                                         
                                           
                                             V 
                                             FET 
                                           
                                           * 
                                           
                                             I 
                                             FET 
                                           
                                         
                                         ] 
                                       
                                        
                                       
                                          
                                         t 
                                       
                                     
                                   
                                 
                                 + 
                                 
                                   ∫ 
                                   
                                     
                                       T 
                                       off 
                                     
                                      
                                     
                                         
                                       
                                         
                                           
                                             
                                               [ 
                                               
                                                 
                                                   R 
                                                   DSon 
                                                 
                                                 * 
                                                 
                                                   I 
                                                   FET 
                                                   2 
                                                 
                                               
                                               ] 
                                             
                                              
                                             
                                                
                                               t 
                                             
                                           
                                           + 
                                           
                                             ∫ 
                                             
                                               
                                                 
                                                   T 
                                                   dead 
                                                 
                                                  
                                                 
                                                   [ 
                                                   
                                                     
                                                       V 
                                                       FETDiode 
                                                     
                                                     * 
                                                     
                                                       I 
                                                       FET 
                                                     
                                                   
                                                   ] 
                                                 
                                               
                                                
                                               
                                                   
                                               
                                                
                                               
                                                  
                                                 t 
                                               
                                             
                                           
                                         
                                         = 
                                         
                                             
                                           
                                             
                                               [ 
                                               
                                                 2 
                                                 * 
                                                 
                                                   V 
                                                   rail 
                                                 
                                                 * 
                                                 
                                                   I 
                                                   m 
                                                 
                                                 * 
                                                 
                                                   
                                                     T 
                                                     SW 
                                                   
                                                   / 
                                                   T 
                                                 
                                               
                                               ] 
                                             
                                             + 
                                             
                                               [ 
                                               
                                                 
                                                   R 
                                                   DSon 
                                                 
                                                 * 
                                                 
                                                   I 
                                                   m 
                                                   2 
                                                 
                                                 * 
                                                 
                                                   
                                                     T 
                                                     on 
                                                   
                                                   / 
                                                   T 
                                                 
                                               
                                               ] 
                                             
                                             + 
                                             
                                                 
                                               
                                                 
                                                   [ 
                                                   
                                                     
                                                       I 
                                                       m 
                                                       2 
                                                     
                                                     * 
                                                     
                                                       R 
                                                       dson 
                                                     
                                                   
                                                   ] 
                                                 
                                                 + 
                                                 
                                                   [ 
                                                   
                                                     2 
                                                     * 
                                                     
                                                       V 
                                                       FETDiode 
                                                     
                                                     * 
                                                     
                                                       I 
                                                       m 
                                                     
                                                     * 
                                                     
                                                       
                                                         T 
                                                         SW 
                                                       
                                                       / 
                                                       T 
                                                     
                                                   
                                                   ] 
                                                 
                                                 + 
                                                 
                                                     
                                                   
                                                       
                                                     
                                                       
                                                         [ 
                                                         
                                                           
                                                             I 
                                                             m 
                                                             2 
                                                           
                                                           * 
                                                           
                                                             R 
                                                             dson 
                                                           
                                                            
                                                           
                                                             
                                                             T 
                                                             off 
                                                             
                                                             / 
                                                             T 
                                                           
                                                         
                                                         ] 
                                                       
                                                        
                                                       
                                                           
                                                       
                                                        
                                                       
                                                           
                                                         
                                                           + 
                                                           
                                                               
                                                             
                                                             
                                                             [ 
                                                             
                                                             
                                                             V 
                                                             FETDiode 
                                                             
                                                             * 
                                                             
                                                               
                                                             
                                                              
                                                             
                                                             I 
                                                             m 
                                                             
                                                             * 
                                                             
                                                               
                                                             
                                                              
                                                             
                                                             
                                                             T 
                                                             DeadSW 
                                                             
                                                             / 
                                                             
                                                               
                                                             
                                                              
                                                             T 
                                                             
                                                             
                                                             ] 
                                                             
                                                             = 
                                                             
                                                               
                                                             
                                                             
                                                             [ 
                                                             
                                                             2 
                                                             * 
                                                             120 
                                                             * 
                                                             20 
                                                             * 
                                                             150 
                                                              
                                                             e 
                                                              
                                                             
                                                             - 
                                                             
                                                              
                                                             
                                                             9 
                                                             / 
                                                             66.7 
                                                             
                                                              
                                                             
                                                               
                                                             
                                                              
                                                             e 
                                                              
                                                             
                                                             - 
                                                             
                                                              
                                                             
                                                               
                                                             
                                                              
                                                             6 
                                                             
                                                             ] 
                                                             
                                                             + 
                                                             
                                                               
                                                             
                                                             [ 
                                                             
                                                             .008 
                                                             * 
                                                             
                                                             20 
                                                             2 
                                                             
                                                             * 
                                                             2.78 
                                                              
                                                             e 
                                                              
                                                             
                                                               
                                                             
                                                              
                                                             
                                                             - 
                                                             
                                                              
                                                             
                                                               
                                                             
                                                              
                                                             
                                                             6 
                                                             / 
                                                             
                                                               
                                                             
                                                             66.7 
                                                              
                                                             e 
                                                              
                                                             
                                                             - 
                                                             
                                                              
                                                             6 
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             ] 
                                                             
                                                             + 
                                                             
                                                               
                                                             
                                                               
                                                             
                                                             
                                                             [ 
                                                             
                                                             
                                                             20 
                                                             2 
                                                             
                                                             * 
                                                             .008 
                                                             
                                                             ] 
                                                             
                                                             + 
                                                             
                                                               
                                                             
                                                               
                                                             
                                                             [ 
                                                             
                                                             
                                                             2 
                                                             * 
                                                             1.5 
                                                             * 
                                                             20 
                                                             * 
                                                             150 
                                                              
                                                             e 
                                                              
                                                             
                                                             - 
                                                             
                                                              
                                                             
                                                             9 
                                                             / 
                                                             
                                                               
                                                             
                                                             66.7 
                                                              
                                                             e 
                                                              
                                                             
                                                             - 
                                                             
                                                              
                                                             6 
                                                             
                                                             ] 
                                                             
                                                             
                                                             
                                                             + 
                                                             
                                                               
                                                             
                                                             
                                                             
                                                             [ 
                                                             
                                                             
                                                             20 
                                                             2 
                                                             
                                                             * 
                                                             .008 
                                                             * 
                                                             63.9 
                                                              
                                                             e 
                                                              
                                                             
                                                             - 
                                                             
                                                              
                                                             
                                                             6 
                                                             / 
                                                             66.7 
                                                             
                                                              
                                                             e 
                                                              
                                                             
                                                             - 
                                                             
                                                              
                                                             6 
                                                             
                                                             ] 
                                                             
                                                             + 
                                                             
                                                             [ 
                                                             
                                                               
                                                             
                                                              
                                                             
                                                             1.5 
                                                             * 
                                                             20 
                                                             * 
                                                             300 
                                                              
                                                             e 
                                                              
                                                             
                                                             - 
                                                             
                                                              
                                                             
                                                             9 
                                                             / 
                                                             66.7 
                                                             
                                                              
                                                             e 
                                                              
                                                             
                                                             - 
                                                             
                                                              
                                                             6 
                                                             
                                                             ] 
                                                             
                                                             
                                                             ≈ 
                                                             
                                                             43 
                                                              
                                                             
                                                               
                                                             
                                                              
                                                             Watts 
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                           
                                                         
                                                       
                                                     
                                                   
                                                 
                                               
                                             
                                           
                                         
                                       
                                     
                                   
                                 
                               
                             
                           
                         
                       
                     
                   
                 
               
             
           
         
       
     
         [0024]    In another example, 100 V FETs are used as switches  70   a - 70   f  in place of the IGBTs. The 100 V FETs have an inverse diode forward voltage of 1.5V and a terminal winding resistance (Rdson) of 8.0 mOhms at a junction temperature of 100 degrees C. Such an example generates about 18 Watts of thermal energy or motor drive bridge loss, which is calculated as follows: 
         [0000]    
       
         
           
             
               Motor 
                
               
                   
               
                
               drive 
                
               
                   
               
                
               bridge 
                
               
                   
               
                
               loss 
             
             = 
             
               
                 [ 
                 
                   Upper 
                    
                   
                       
                   
                    
                   FET 
                    
                   
                       
                   
                    
                   Switching 
                    
                   
                       
                   
                    
                   Loss 
                 
                 ] 
               
               + 
               
                   
                 
                   
                     [ 
                     
                       Upper 
                        
                       
                           
                       
                        
                       FET 
                        
                       
                           
                       
                        
                       DC 
                        
                       
                           
                       
                        
                       Loss 
                     
                     ] 
                   
                   + 
                   
                     [ 
                     
                       Lower 
                        
                       
                           
                       
                        
                       Drive 
                        
                       
                           
                       
                        
                       FET 
                        
                       
                           
                       
                        
                       DC 
                        
                       
                           
                       
                        
                       Loss 
                     
                     ] 
                   
                   + 
                   
                       
                     
                       Lower 
                        
                       
                           
                       
                        
                       Free 
                        
                       
                         - 
                       
                        
                       Wheeling 
                        
                       
                           
                       
                        
                       FET 
                        
                       
                           
                       
                        
                       Switching 
                        
                       
                           
                       
                        
                       Loss 
                     
                     ] 
                   
                   + 
                   
                       
                     
                       
                         [ 
                         
                           Lower 
                            
                           
                               
                           
                            
                           Free 
                            
                           
                             - 
                           
                            
                           Wheeling 
                            
                           
                               
                           
                            
                           FET 
                            
                           
                               
                           
                            
                           DC 
                            
                           
                               
                           
                            
                           Loss 
                         
                         ] 
                       
                       + 
                       
                           
                         
                           
                             [ 
                             
                               Lower 
                                
                               
                                   
                               
                                
                               Free 
                                
                               
                                 - 
                               
                                
                               
                                   
                               
                                
                               Wheeling 
                                
                               
                                   
                               
                                
                               FET 
                                
                               
                                   
                               
                                
                               Diode 
                                
                               
                                   
                               
                                
                               Dead 
                                
                               
                                 - 
                               
                                
                               
                                   
                               
                                
                               Time 
                                
                               
                                   
                               
                                
                               Loss 
                             
                             ] 
                           
                           = 
                           
                             
                               2 
                               * 
                               
                                 ∫ 
                                 
                                   
                                     
                                       T 
                                       SW 
                                     
                                      
                                     
                                       [ 
                                       
                                         
                                           V 
                                           FET 
                                         
                                         * 
                                         
                                           I 
                                           FET 
                                         
                                       
                                       ] 
                                     
                                   
                                    
                                   
                                      
                                     t 
                                   
                                 
                               
                             
                             + 
                             
                               ∫ 
                               
                                 
                                   
                                     T 
                                     on 
                                   
                                    
                                   
                                     [ 
                                     
                                       
                                         R 
                                         DSon 
                                       
                                       * 
                                       
                                         I 
                                         FET 
                                         2 
                                       
                                     
                                     ] 
                                   
                                 
                                  
                                 
                                    
                                   t 
                                 
                               
                             
                             + 
                             
                               
                                 R 
                                 DSon 
                               
                               * 
                               
                                 I 
                                 FET 
                                 2 
                               
                             
                             + 
                             
                               2 
                               * 
                               
                                 
                                   ∫ 
                                   TSW 
                                 
                                  
                                 
                                   
                                     [ 
                                     
                                       
                                         V 
                                         FET 
                                       
                                       * 
                                       
                                         I 
                                         FET 
                                       
                                     
                                     ] 
                                   
                                    
                                   
                                      
                                     t 
                                   
                                 
                               
                             
                             + 
                             
                               ∫ 
                               
                                 
                                   T 
                                   off 
                                 
                                  
                                 
                                     
                                   
                                     
                                       
                                         
                                           [ 
                                           
                                             
                                               R 
                                               DSon 
                                             
                                             * 
                                             
                                               I 
                                               FET 
                                               2 
                                             
                                           
                                           ] 
                                         
                                          
                                         
                                            
                                           t 
                                         
                                       
                                       + 
                                       
                                         ∫ 
                                         
                                           
                                             
                                               T 
                                               dead 
                                             
                                              
                                             
                                               [ 
                                               
                                                 
                                                   V 
                                                   FETDiode 
                                                 
                                                 * 
                                                 
                                                   I 
                                                   FET 
                                                 
                                               
                                               ] 
                                             
                                           
                                            
                                           
                                               
                                           
                                            
                                           
                                              
                                             t 
                                           
                                         
                                       
                                     
                                     = 
                                     
                                         
                                       
                                         
                                           [ 
                                           
                                             2 
                                             * 
                                             
                                               V 
                                               rail 
                                             
                                             * 
                                             
                                               I 
                                               m 
                                             
                                             * 
                                             
                                               
                                                 T 
                                                 SW 
                                               
                                               / 
                                               T 
                                             
                                           
                                           ] 
                                         
                                         + 
                                         
                                           [ 
                                           
                                             
                                               R 
                                               DSon 
                                             
                                             * 
                                             
                                               I 
                                               m 
                                               2 
                                             
                                             * 
                                             
                                               
                                                 T 
                                                 on 
                                               
                                               / 
                                               T 
                                             
                                           
                                           ] 
                                         
                                         + 
                                         
                                             
                                           
                                               
                                             
                                               
                                                 [ 
                                                 
                                                   
                                                     I 
                                                     m 
                                                     2 
                                                   
                                                   * 
                                                   
                                                     R 
                                                     dson 
                                                   
                                                 
                                                 ] 
                                               
                                               + 
                                               
                                                 [ 
                                                 
                                                   2 
                                                   * 
                                                   
                                                     V 
                                                     FETDiode 
                                                   
                                                   * 
                                                   
                                                     I 
                                                     m 
                                                   
                                                   * 
                                                   
                                                     
                                                       T 
                                                       SW 
                                                     
                                                     / 
                                                     T 
                                                   
                                                 
                                                 ] 
                                               
                                               + 
                                               
                                                   
                                                 
                                                   
                                                     [ 
                                                     
                                                       
                                                         I 
                                                         m 
                                                         2 
                                                       
                                                       * 
                                                       
                                                         R 
                                                         dson 
                                                       
                                                        
                                                       
                                                         
                                                           T 
                                                           off 
                                                         
                                                         / 
                                                         T 
                                                       
                                                     
                                                     ] 
                                                   
                                                    
                                                   
                                                       
                                                   
                                                    
                                                   
                                                       
                                                     
                                                       + 
                                                       
                                                           
                                                         
                                                           + 
                                                           
                                                               
                                                             
                                                             
                                                             [ 
                                                             
                                                             
                                                             V 
                                                             FETDiode 
                                                             
                                                             * 
                                                             
                                                               
                                                             
                                                              
                                                             
                                                             I 
                                                             m 
                                                             
                                                             * 
                                                             
                                                               
                                                             
                                                              
                                                             
                                                             
                                                             T 
                                                             DeadSW 
                                                             
                                                             / 
                                                             
                                                               
                                                             
                                                              
                                                             T 
                                                             
                                                             
                                                             ] 
                                                             
                                                             = 
                                                             
                                                               
                                                             
                                                             
                                                             [ 
                                                             
                                                             2 
                                                             * 
                                                             120 
                                                             * 
                                                             20 
                                                             * 
                                                             150 
                                                              
                                                             e 
                                                              
                                                             
                                                             - 
                                                             
                                                              
                                                             
                                                             9 
                                                             / 
                                                             66.7 
                                                             
                                                              
                                                             
                                                               
                                                             
                                                              
                                                             e 
                                                              
                                                             
                                                             - 
                                                             
                                                              
                                                             
                                                               
                                                             
                                                              
                                                             6 
                                                             
                                                             ] 
                                                             
                                                             + 
                                                             
                                                               
                                                             
                                                             [ 
                                                             
                                                             .008 
                                                             * 
                                                             
                                                             20 
                                                             2 
                                                             
                                                             * 
                                                             2.78 
                                                              
                                                             e 
                                                              
                                                             
                                                               
                                                             
                                                              
                                                             
                                                             - 
                                                             
                                                              
                                                             
                                                               
                                                             
                                                              
                                                             
                                                             6 
                                                             / 
                                                             
                                                               
                                                             
                                                             66.7 
                                                              
                                                             e 
                                                              
                                                             
                                                             - 
                                                             
                                                              
                                                             6 
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             ] 
                                                             
                                                             + 
                                                             
                                                               
                                                             
                                                               
                                                             
                                                             
                                                             [ 
                                                             
                                                             
                                                             20 
                                                             2 
                                                             
                                                             * 
                                                             .008 
                                                             
                                                             ] 
                                                             
                                                             + 
                                                             
                                                               
                                                             
                                                               
                                                             
                                                             [ 
                                                             
                                                             
                                                             2 
                                                             * 
                                                             1.5 
                                                             * 
                                                             20 
                                                             * 
                                                             150 
                                                              
                                                             e 
                                                              
                                                             
                                                             - 
                                                             
                                                              
                                                             
                                                             9 
                                                             / 
                                                             
                                                               
                                                             
                                                             66.7 
                                                              
                                                             e 
                                                              
                                                             
                                                             - 
                                                             
                                                              
                                                             6 
                                                             
                                                             ] 
                                                             
                                                             
                                                             
                                                             + 
                                                             
                                                               
                                                             
                                                             
                                                             
                                                             [ 
                                                             
                                                             
                                                             20 
                                                             2 
                                                             
                                                             * 
                                                             .008 
                                                             * 
                                                             63.9 
                                                              
                                                             e 
                                                              
                                                             
                                                             - 
                                                             
                                                              
                                                             
                                                             6 
                                                             / 
                                                             66.7 
                                                             
                                                              
                                                             e 
                                                              
                                                             
                                                             - 
                                                             
                                                              
                                                             6 
                                                             
                                                             ] 
                                                             
                                                             + 
                                                             
                                                             [ 
                                                             
                                                               
                                                             
                                                              
                                                             
                                                             1.5 
                                                             * 
                                                             20 
                                                             * 
                                                             300 
                                                              
                                                             e 
                                                              
                                                             
                                                             - 
                                                             
                                                              
                                                             
                                                             9 
                                                             / 
                                                             66.7 
                                                             
                                                              
                                                             e 
                                                              
                                                             
                                                             - 
                                                             
                                                              
                                                             6 
                                                             
                                                             ] 
                                                             
                                                             
                                                             ≈ 
                                                             
                                                             18 
                                                              
                                                             
                                                               
                                                             
                                                              
                                                             Watts 
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                             
                                                           
                                                         
                                                       
                                                     
                                                   
                                                 
                                               
                                             
                                           
                                         
                                       
                                     
                                   
                                 
                               
                             
                           
                         
                       
                     
                   
                 
               
             
           
         
       
     
         [0025]    As can be appreciated from the above calculations, the example incorporating the 100 V FETs generates less thermal energy than the other examples. The power management section  62  in this example reduces the voltage from a 120 VDC source to a level suitable for using with the 100 V FETs, such as reducing the 120 V to 60 V. As less thermal energy is generated, the motor assembly  46  can have a smaller area devoted to the heat sink  68  and a smaller enclosure. Reducing the voltage of the power sent to the motor assembly  46  thus facilitates selecting the motor assembly  46  having a relatively small spatial envelope. 
         [0026]    In another example, the motor assembly  46  was previously used in another application where the motor assembly  46  was provided power by another power supply (not shown) having a bus voltage of 24 V. The input voltage to the motor assembly  46  is increased from 24 V to 60 V using the buck boost power management section  62  in such an example for use by the motor assembly  46 . The buck boost power management section  62  may utilize a switch  90  and a diode  94  to increase the voltage in this manner. The buck boost power management section  62  is thus configured to adjust the voltage upward in some examples. 
         [0027]    Referring now to  FIG. 3  with continuing reference to  FIG. 2 , an example method  100  of adjusting power includes a step  104  of selecting desired motor assembly  46 . The selection is based on the available spatial envelope for the motor assembly  46  within the gas turbine engine  10  in one example. In another example, the selection is based on the cost of the motor assembly  46 . 
         [0028]    At step  108 , the method  100  sends power to the motor controller  58  from the power supply  54 , which supplies power at 120 V in this example 
         [0029]    At step  112 , the voltage of the power is adjusted using the power management section  62  of the motor controller  58 . The voltage is adjusted to a level appropriate for use with the motor assembly  46  selected in the step  104 . In some examples, the voltage is adjusted downward. In other examples, the voltage is adjusted upwards the adjustments to the voltage are greater than 10% in this example. 
         [0030]    At step  116 , the adjusted power from step  112  is communicated from the power converter  58  to the motor assembly  46  selected in the step  104 . The motor assembly  46  powers the valve  50 , for example. 
         [0031]    Features of the disclosed examples include adjusting the voltage of power provided by a bus to match the voltage requirements of a desired motor assembly. The motor assembly is selected based on the spatial envelope available for mounting the motor or based on the availability of the motor assembly, for example. 
         [0032]    Although a preferred embodiment has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.