Abstract:
An electric architecture for use on a vehicle has a collector bus for receiving power from a plurality of power sources. The collector bus distributes power to at least a pair of subsystems which are operable at different frequency levels. Each subsystem is provided with a global bus and a local bus, and is utilized to power at least one motor.

Description:
BACKGROUND 
     This application relates to hybrid electric power architecture for use on a vehicle, wherein there are subsystems operating at distinct frequencies. 
     Many modern vehicles are being provided with complex electric power architectures. One particular example is battlefield vehicles for use in military operations. 
     Such vehicles consume significant amounts of fuel, and have any number of electric components that require power. Electric generators and diverse loads are often decentralized on the vehicle, and each require distinct and dedicated controllers for each component. 
     The requirements of all of the separate motor controllers increases the size and weight of the power architecture associated with the vehicle. 
     SUMMARY 
     An electric architecture for use on a vehicle has a collector bus for receiving power from a plurality of power sources. The collector bus distributes power to at least a pair of subsystems which are operable at different frequency levels. Each subsystem is provided with a global bus and a local bus, and is utilized to power at least one motor. 
     These and other features of the present invention can be best understood from the following specification and drawings, the following of which is a brief description. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  schematically shows a power system for use on a vehicle. 
         FIG. 2  shows a subsystem associated with a portion of the  FIG. 1  schematic. 
         FIG. 3  is a chart showing the operation of the  FIG. 2  embodiment. 
         FIG. 4  shows another portion of the  FIG. 1  schematic. 
     
    
    
     DETAILED DESCRIPTION 
     A vehicle  19 , which may be a battlefield land vehicle is illustrated in  FIG. 1  having an electric power architecture  20 . A collector bus  22  distributes power to each of a 400 Hz subsystem  24 , which is better illustrated in  FIG. 2 , a 60 Hz subsystem  26 , which is better illustrated in  FIG. 4 , and a 28 volt DC subsystem  28 . 
     Energy management dispatch units  30  communicate with pre-processing units  32 . Feeding into the pre-processing units  32  are a number of power supplies  34 ,  36 ,  38 ,  40 ,  42 , and  44 . Elements  34  may be various types of generators. Element  36  may be a solar array. Element  38  may be a wind generator. Element  40  may be fuel cells. Element  42  may be a battery. Element  44  may be another type of energy storage device. 
     Any number of other energy sources can feed into the pre-processing units  32 , and architectures which come within the scope of this application could also have fewer. All of these sources feed into the pre-processing units  32 , which tailor the power such that it is uniform when it reaches collector bus  22 . The energy management dispatch units  30  serve to connect or disconnect any one of the power supplies  34 ,  36 ,  38 ,  40 ,  42 , and  44 . This may be used if a power supply is corrupted, the component is otherwise inoperative, or for any number of other reasons. 
     As shown in  FIG. 2 , the subsystem  24  includes a first inverter  60  which is a constant voltage, constant frequency inverter feeding through a 400 Hz filter  62 . A number of contactors R 1 -R 13  are illustrated. These contactors are each effectively switches which can be opened or closed by a central controller; therefore, the contactors are also referred to as switches. Any number of switches may be utilized as the contactors. Further, a control is associated with the contactors R 1 -R 13  and is operable to control them to open and close as will be disclosed below. 
     When the switches R 1 , and R 3 , are closed, then power flows through the inverter  60  to a 400 Hz global motor bus  64 . This bus is operable to provide power for components off the vehicle  19 . That is, this would allow the user of the vehicle  19  to plug in components, etc., which are not mounted on the vehicle  19  but which are to be powered by the vehicle  19 . 
     At the same time, a local motor bus  66  provides power to motors  68 ,  70  and  72 . During start-up operation, power flows from the collector bus  22  through a second inverter  74 , filter  76 , to power the bus  66 , and the motors  68 ,  70 , and  72 . 
     As also shown, further contactors R 2 , R 4 , R 5 , R 6 , R 7 , R 8 , and R 9 -R 13  are all placed at various locations within the circuit. 
     In operating the subsystem  24  as illustrated in  FIG. 2 , the chart as shown in  FIG. 3  is utilized to control the  13  contactors R 1 -R 13  to be opened and closed. As shown, for example, at the start-up of the induction motor  1  (motor  68 ), the inverter  2  (inverter  74 ) is utilized to start up the induction motor  1 . Once the induction motor  1  reaches a synchronous speed, then the contactor R 5  is closed, contactor R 11  is open, and the induction motor  68  is driven off the global bus  64 . As can be seen in the  FIG. 3  table, the induction motors  2  and  3  (motors  70  and  72 ) are started in a similar manner, while being powered from the variable voltage, variable frequency inverter  74 . As can also be appreciated from  FIG. 3 , during certain times, the inverter  74  will operate as a constant voltage, constant frequency inverter. However, at start-up, it is operable as a variable voltage, variable frequency inverter. 
     Thus, by utilizing the two inverters  60 ,  74 , the subsystem  24  is operable to start the motors  68 - 72  up with the variable voltage, variable frequency inverter, and then switch to the global bus  64 , and powered by inverter  60  while the inverter  74  supplies power to the local bus  66 . 
     In a sense, the local bus  66  is utilized to start the motors  68 ,  70  and  72 , and they are then powered from the global bus  64  once steady state operation is achieved. 
     In addition, as can be appreciated from  FIG. 3 , the use of the redundant inverters  60 ,  74  allows the subsystem  24  to operate even if one of the inverters has failed. In addition, the use of the combined inverters  60 ,  74  eliminates the need for separate motor controls for each of the motors  68 ,  70 , and  72 . 
       FIG. 4  shows a subsystem  26  for powering a 60 Hz subsystem. Again, a pair of inverters  174  and  78  provide power to a micro-grid global bus  170  through a filter  76 , and to a local bus  172  through the filter  80 . Contactors R 1 -R 17  are operated in a manner similar to that disclosed in  FIG. 3  to power induction motors  82 ,  84 , and  86  to start and then run. In addition, non-linear loads  88  may be powered directly from the inverter  174 . Similarly, the lighting loads  90  can be powered directly from the inverter  174  or the global bus  170 . 
     Although embodiments of this invention have 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.