Abstract:
A power management apparatus includes a first electrical lead and a second electrical lead. The first electrical lead routes electrical current at a first electrical lead electrical potential level and the second electrical lead route electrical current at a second current port electrical potential level. The power management apparatus further includes a first electrical parameter sensor configured to measure a first electrical lead electrical parameter and a second electrical parameter sensor configured to measure a second electrical lead electrical parameter. The power management apparatus further comprises a buck boost converter electrically coupled to both the first electrical lead and the second electrical lead. The buck boost converter is configured to convert electrical current between the first electrical lead electric potential level and the second electrical lead electric potential level at a controlled potential conversion level. The power management apparatus further comprises a controller is configured to receive operating current from either one of the first electrical lead and the second electrical lead. The controller is configured to monitor the first electrical parameter sensor and the second electrical parameter sensor and being configured to output control signals to the buck boost converter.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 11/739,742 filed on Apr. 25, 2007, which claims priority to U.S. Provisional Patent Application Ser. No. 60/795,006 filed Apr. 26, 2006, the entire contents of both are herein incorporated by reference. 
    
    
     GOVERNMENT INTERESTS 
     This invention was made with government support under contract number W909MY-08-C-0025, awarded by the Department of Defense. The government has certain rights in this invention. 
    
    
     TECHNICAL FIELD 
     The invention relates to an electric power management apparatus. 
     BACKGROUND 
     The material presented in this section merely provides background information to the present disclosure and may not constitute prior art. A power management apparatus can manage electrical parameters such as electrical voltage, electrical current and electrical power levels when transferring electrical energy among multiple devices. 
     The power management apparatus can include a buck boost converter to convert electrical parameters. Buck boost converters are DC-DC converter that can provide an output voltage that is a selected conversion magnitude greater than or less than an input voltage. The selected conversion magnitude can be determined by a control system based on sensed inputs and selected electrical parameter outputs to thereby accommodate devices having differing electrical parameter requirements. The control system can utilize an internal power device, such as an internal battery, to provide operating power. However, utilizing an internal battery provides a system failure mode when the internal battery is inoperable or discharged. Further, the internal battery adds costs, weight, and energy management inefficiency to the power management apparatus. 
     Power management apparatuses can measure an input electrical current level or an input electrical voltage level to convert the electrical current level or the electrical voltage level to a desired output electrical current level or output electrical voltage level. A controller can be utilized to monitor the input electrical current and voltage levels and to determine buck boost converter commands based on the input electrical current and electrical voltage levels. 
     When the controller is not receiving operating power, the controller does not provide buck boost converter commands to the buck boost converter and therefore, the buck boost converter is unable to control output electrical current and electrical voltage levels to desired levels. 
     Therefore, improved power management apparatuses are needed. 
     SUMMARY 
     A power management apparatus includes a first electrical lead and a second electrical lead. The first electrical lead routes electrical current at a first electrical lead electrical potential level and the second electrical lead routes electrical current at a second electrical lead electrical potential level. The power management apparatus further includes a first electrical parameter sensor configured to measure a first electrical lead electrical parameter and a second electrical parameter sensor configured to measure a second electrical lead electrical parameter. The power management apparatus further comprises a buck boost converter electrically coupled to both the first electrical lead and the second electrical lead. The buck boost converter is configured to convert electrical current between the first electrical lead electric potential level and the second electrical lead electric potential level at a controlled electrical potential conversion level. The power management apparatus further comprises a controller configured to receive operating current from either one of the first electrical lead and the second electrical lead. The controller is configured to monitor the first electrical parameter sensor and the second electrical parameter sensor and is configured to output control signals to the buck boost converter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of a buck boost converter module in accordance with an exemplary embodiment of a present disclosure; 
         FIG. 2  is a schematic diagram of a power management apparatus including the buck boost converter module of  FIG. 1  in accordance with an exemplary embodiment of the present disclosure; 
         FIG. 3  is a schematic diagram of a power management apparatus in accordance with another exemplary embodiment of the present disclosure; and 
         FIG. 4  is a schematic diagram of a power management apparatus in accordance with another exemplary embodiment of the present disclosure; and 
         FIG. 5  is a front view of a power management apparatus of  FIG. 2  in accordance. 
     
    
    
     It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various preferred features illustrative of the basic principles of the invention. The specific design features of the power management apparatus will be determined in part by the particular intended application and use environment. Certain features of the illustrated embodiments have been enlarged or distorted relative to others for visualization and understanding. In particular, thin features may be thickened for clarity of illustration. 
     DETAILED DESCRIPTION OF THE EMBODIMENTS 
     The schematics diagrams of  FIG. 1-4 , depict schematic diagrams wherein power paths are generally depicted as solid lines and wherein data paths are generally depicted as dashed lines. Referring to  FIG. 1 , a buck boost converter module  10  is provided to convert voltage between a first voltage level at a first electrical lead  14  and a second voltage level at a second electrical lead  16 . The buck boost converter module  10  includes first and second electrical leads  14  and  16 , diodes  18  and  20 , a DC-DC converter (‘DC-Converter’)  22 , a controller (‘Controller’)  24 , a buck boost converter (‘Buck Boost’)  26  and voltage and current sensors ‘voltage and current sensors’  28  and  30 . 
     The electrical leads  14  and  16  are portions of the buck boost converter module  10  routing electric power to and from the buck boost converter  26  can generally be considered as electrical inlet and electrical outlet portions of the buck boost converter module  10 . The diodes  18  and  20  each selectively allow current flow in one directional while preventing current flow in the opposite direction. In particular, the diode  18  allows current flow in a direction from the first electric lead  14  to the DC-DC converter  22  while prevent current flow in the opposite direction and the diode  20  allows current flow in a from the second lead  16  to the DC-DC converter  22  while preventing current flow in the opposite direction. Therefore, the diodes  18  and  20  enable current flow to the DC-DC Converter  22  and to the controller  24  from only the electrical lead  14 ,  16  having the voltage level. 
     The DC-DC converter  22  is provided to receive electric current at an input voltage level and output electric current to the controller  24  at a desired voltage level for operating the controller  24 . 
     The voltage and current sensor  28  measures voltage levels and current levels at the electrical lead  14  and the voltage and current sensor  30  measures voltage levels and current levels at the electrical lead  16 . The voltage and current sensor  28  can comprises a single sensor assembly or multiple sensor assemblies, i.e., a separate voltage sensor assembly and current sensor assembly. 
     The controller  24  monitors voltage levels and current levels from each of the voltage and current sensors  28  and  30 . The controller  24  determines control commands for controlling the buck boost converter  26  based on the monitored voltage levels and current levels. The controller  24  provides output signals comprising control commands to the buck boost converter  26 . 
     The buck boost converter  26  can adjust the voltage difference between the first electrical lead  14  and the second electrical lead  16 . In an exemplary embodiment, the buck boost converter utilizes a switching transistor to provide a voltage difference between the first electrical lead and the second electrical lead. The duty cycle of the switching transistor is controlled by the controller  24  utilizing closed-loop feedback control. 
     Although in an exemplary embodiment, the controller  24  determines control commands for controlling the buck boost converter  26  based on both the monitored voltage levels and current levels, in alternate embodiments, a controller can control a buck boost converter utilizing only signals indicative of current, only signals indicative of voltage, or combinations of signals indicative of current and voltage. For example, in one embodiment, the controller controls the buck boost converter based on voltage levels measured on opposite sides of a buck boost converter. In alternate embodiment, a controller controls the buck boost converter based on electric current levels measured on opposite sides of the buck boost converter. 
       FIG. 1  depicts power level (‘P 1 ’) and voltage level (‘V 1 ’) of the first electrical lead  14  and power level (‘P 1 ’) and voltage level (‘V 5 ’) of the second electrical lead  16 . The difference in power levels between P 1  and P 1 ′ represents resistive power losses, power losses associated with voltage conversion within the buck boost converter modules  10 , and power utilized to operate components of the buck boost converter module  10  such as the controller  24 . 
       FIG. 2  depicts a power management apparatus  100  including the buck boost converter module  10 , a buck boost converter module  30 , a buck boost converter module  50 , a buck boost converter module  70 , a power bus  96 , a master controller  92 , and a communications bus  94 . 
     The buck boost converter modules  30 ,  50 , and  70  comprise substantially similar components to those of the buck boost converter module  10 . The buck boost converter modules  10 ,  30 ,  50  and  70  each allow for bi-direction transmission of electric power between the power bus  96  and an external device. 
     The buck boost converter module  30  comprises electrical leads  34  and  36 , diodes  38  and  40 , a DC-DC Converter (‘DC-Converter’)  42 , a controller (‘Controller’)  44 , a buck boost converter (‘Buck Boost’)  46  and voltage and current sensors (‘Voltage and Current Sensors’)  48  and  49 . 
     The buck boost converter module  50  comprises electrical leads  54  and  56 , diodes  58  and  59 , a DC-DC Converter (‘DC-Converter’)  52 , a controller (‘Controller’)  54 , a buck boost converter (‘buck boost’)  56  and voltage and current sensors (‘voltage and current sensors’)  68  and  69 . 
     The buck boost converter module  70  comprises electrical leads  74  and  76 , diodes  78  and  70 , a DC-DC Converter ‘DC-Converter’  82 , a controller (‘Controller’)  84 , a buck boost converter ‘buck boost’  86  and voltage and current sensors ‘voltage and current sensors’  88  and  89 . 
     The power bus  96  transmits electrical energy to components of the power management system  100  including the buck converting modules  10 ,  30 ,  50 , and  70 , and the master controller  92 . The power bus  96  is maintained at a nominal voltage (‘V 5 ’) or within a nominal voltage range. 
     The master controller  92  receives power (‘P 5 ’) from the power bus  96 . Further, the master controller  92  receives input signals from and sends output signals to the controllers  24 ,  44 ,  64 , and  84  via the communications bus  94 . The master controller  92  includes a central processing unit (CPU) (not shown) that includes a real-time operating system and programs actively controlling a power usage. The CPU can determined control commands based on the input signals and send output signals comprising the control commands to each of the controllers  24 ,  44 ,  64 , and  84 . 
     The master controller  92  can actively manage power to and from external devices having differing priorities. For example, when an energy source such as a battery having a limited amount of stored energy is coupled to power management apparatus  10 , the master controller  92  can actively manage input and output power to other devices to provide desired battery operating life. Further, the master controller  92  can continuously provide electric power to a first device having a highest priority, for example a radio, while providing power only intermittently to a second device having a lower priority than the first power device, for example, a light source. 
     Each priority can be assigned by master controller  92  or can be directly inputted by a user through a graphic user interface  400  ( FIG. 5 ). Additionally, the master controller  92  can determine mutually exclusive activities of the external devices and adjust a power or current to at least one of the devices. In this manner, devices that may not be operable at the same time are regulated by the power management apparatus to prevent current from being delivered to one or more of the external devices to preserve an amount of power of a storage device coupled to the power management apparatus. 
     As stated above, the power management apparatus  100  automatically identifies external devices that are connected to the ports and automatically adjusts one or more parameters appropriate for the external connected device. In this manner, various devices may be connected to the power management apparatus  100  wherein the power management apparatus automatically determines the type of device connected and provides a necessary power to the device. Additionally, the power management apparatus through the use of the real-time operating system and programs can allow a user to select from a desired energy management mode. The energy management modes may be stored in the memory of the CPU or may be custom tailored by a user for customizing devices that may be connected to the power management apparatus  100 . 
       FIG. 3  depicts a power management apparatus  200  having a buck boost converter module  210 , a buck boost converter module  230 , and a buck boost converter module  250 . The buck boost converters  210 ,  230 , and  250  are substantially similar to the buck boost converter  10  described above. The buck boost converter module  210  is electrically connected to a fuel cell  202  wherein the buck boost converter  210  converts a voltage level V 1  of the fuel cell  202  to a voltage level V 4  of the power bus  296 . The buck boost converter module  230  is electrically connected to a battery  204 , wherein the buck boost converter module  230  provides bi-directional power flow between power bus  296  and the battery  204 . The buck boost converter module therefore can adjust voltage (‘V 4 ’) to receive current from the power bus  296 , thereby charging the battery  204  or to provide current to the power bus  296 , thereby charging the battery  204 . 
     The buck boost converter module  250  is electrically connected to a power consuming device  206  wherein the buck boost converter  210  converts a power bus voltage V 4  to the desired operating voltage (V 3 ) of the power consuming device  206 . 
     Each of the controller  224 , the controller  244 , and the controller  264  can transmit and receive control signals from the communications bus  294 . Therefore, each of the controllers  224 ,  244 ,  264  can receive voltage and current measurement levels from the other two controllers and determine control commands based on the voltage and current measurements of the other control modules along with the voltage and current measurements within their respective control modules. In an alternate embodiment, the buck boost converter module  200  can have a master controller in addition to or instead of the distributed controllers  224 ,  244 , and  264 . 
       FIG. 4  depicts a power management system  300 . The power management system  300  comprises a buck boost converter module  310 , a buck boost converter module  330 , and a buck boost converter module  350 . 
       FIG. 4  depicts a power management apparatus  300  having a buck boost converter module  310 , a buck boost converter module  330 , and a buck boost converter module  350 . The buck boost converter module is substantially similar to the buck boost converter module  310  described above. The buck boost converter module  310  is electrically connected to a fuel cell  302 , wherein the buck boost converter  310  converts a voltage level (‘V 1 ’) of the fuel cell  302  to a voltage level V 4  of the power bus  396 . 
     The buck boost converter module  350  is substantially similar to the buck boost converter module  230  described above. The buck boost converter module  330  is electrically connected to a power consuming device, wherein the buck boost converter  310  converts a voltage level V 1  of the fuel cell  330  to a voltage level V 4  of the power bus  396 . 
     The battery  304  is directly electrically coupled to the power bus  396  and therefore, the battery voltage is approximately equal to the power bus voltage. Further, battery charges and discharges based on the power bus voltage. When the power bus voltage is greater than the battery charging voltage, the battery accepts charge. When the battery bus voltage is greater than the battery charging voltage, the battery discharges. The battery charging voltage depends on the battery state of charge. 
       FIG. 5  shows a front view of the exemplary power management apparatus  100 . The power management apparatus  100  comprises a graphical user interface  400 . The graphically user user interface can be selected from various types of interfaces including aural, tactile or optical interfaces. The master controller  92  can send and receive information from the graphical user interface  400  and receive user inputs from the graphical user interface  400 . 
     The graphical user interface  400  depicts graphical indicia indicating the hybrid power levels P 1 , P 2 , P 3 , and P 4 . In  FIG. 5  the power P 1  represents power transferred between the power bus  96  and the fuel cell  402 , P 2  represents power transferred between the power bus  96  and the battery  204 , P 3  represents power transferred between the power bus  96  and the radio  406 , and P 4  represent power transferred between the power bus  96  and the  408 . Each indicia comprises a plurality of triangles, and the number of triangles filled is indicative of power transfer rate, wherein upper triangles being filled-in indicates power being provided from the external device to the power bus and lower triangles being filled-in indicates power being provided from the power bus to the external device. For example, when the power transferred from the external device to the power bus  96  is a high power level (as shown by Fuel Cell  402  power (‘P 1 ’)), all three upper triangles are filled-in, there from. When power transferred between the external device and the power bus  96  is low only one of the three triangles is filled. When the hybrid power level is substantially zero or negative, none of the triangles is filled. When the external device comprises a rechargeable battery (e.g., battery  404 ) the number of triangle filled-in is indicative of charging rate or discharging rate of the battery. 
     The invention has been described in an illustrative manner. It is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than limitation. Many modifications and variations of the invention are possible in light of the above teachings. Therefore, within the scope of appended claims, the invention may be practiced other than specifically described. 
     From the foregoing disclosure and detailed description of certain preferred embodiments, it will be apparent that various modifications, additions and other alternative embodiments are possible without departing from the true scope and spirit of the invention. The embodiments discussed were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to use the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.