PATENT DOCUMENT

Publication Number: US-11424640-B2
Application Number: US-202017032656-A
Country: US
Kind Code: B2

Title: Integrated high-voltage-low-voltage DC-DC converter and charger with active filter

Abstract:
A high voltage battery system can receive power from an AC grid and deliver power to a low voltage battery system. Embodiments can include an active filter and high voltage to low voltage (HVLV) DCDC converter to reduce harmonics associated with the charger reaching the low voltage battery system and further to stabilize the voltage presented to the HVLV DCDC converter to improve its operating efficiency.

Claims:
The invention claimed is: 
     
       1. A high voltage battery system comprising:
 a charger circuit comprising:
 a first input switching bridge having an input and an output, the input configured to be coupled to an AC input source, the first input switching bridge being further configured to convert an AC input voltage to an AC voltage having a selected voltage and frequency; 
 a first transformer having a primary winding coupled to the output of the input switching bridge and a secondary winding; and 
 a first rectifier charger circuit having an input coupled to the secondary winding of the first transformer and an output coupled to a high voltage DC bus; 
 
 a high voltage battery coupled to an output of the charger circuit; 
 an active filter circuit comprising a filter switching bridge and a filter circuit, having an input coupled to the output of the charger circuit and an output, the active filter circuit being operable to reduce harmonics associated with operation of the charger circuit and to provide a filtered DC voltage output; and 
 a high voltage to low voltage DC-DC converter circuit comprising:
 an inverter having an input configured to be coupled to the output of the active filter circuit and an output, the inverter being further configured to convert a received filtered high DC voltage to an AC voltage having a selected voltage and frequency; 
 a second transformer having a primary winding coupled to the output of the inverter and a secondary winding; and 
 a second rectifier charger circuit having an input coupled to the secondary winding of the second transformer and an output coupled to a low voltage DC bus and being configured to produce a low DC voltage for the low voltage DC bus. 
 
 
     
     
       2. The high voltage battery system of  claim 1  wherein at least one of the first switching bridge and the first rectifier charger circuit comprise a stacked half bridge. 
     
     
       3. The high voltage battery system of  claim 1  wherein the filter switching bridge comprises a stacked half bridge. 
     
     
       4. The high voltage battery system of  claim 1  wherein the filter circuit is a second order low pass filter. 
     
     
       5. A high voltage battery system comprising:
 a charger circuit comprising:
 a first input switching bridge having an input and an output, the input configured to be coupled to an AC input source, the first input switching bridge being further configured to convert an AC input voltage to an AC voltage having a selected voltage and frequency; 
 a first transformer having a primary winding coupled to the output of the input switching bridge and a secondary winding; and 
 a first rectifier charger circuit having an input coupled to the secondary winding of the first transformer and an output coupled to a high voltage DC bus; 
 
 an active filter circuit comprising a filter switching bridge and a filter circuit, the active filter circuit having an input coupled to the output of the charger circuit and an output coupled to the high voltage DC bus, wherein the active filter circuit is operable to reduce harmonics associated with operation of the charger circuit and to provide a filtered DC voltage output; 
 a high voltage battery coupled to the high voltage DC bus; and 
 a high voltage to low voltage DC-DC converter circuit comprising:
 an inverter coupled to the active filter circuit and an output, the inverter being further configured to convert a high DC voltage to an AC voltage having a selected voltage and frequency; 
 a second transformer having a primary winding coupled to the output of the inverter and a secondary winding; and 
 a second rectifier charger circuit having an input coupled to the secondary winding of the second transformer and an output coupled to a low voltage DC bus and being configured to produce a low DC voltage for the low DC voltage bus. 
 
 
     
     
       6. The high voltage battery system of  claim 5  wherein at least one of the first switching bridge and the first rectifier charger circuit comprise a stacked half bridge. 
     
     
       7. The high voltage battery system of  claim 5  wherein the filter switching bridge comprises a stacked half bridge. 
     
     
       8. The high voltage battery system of  claim 5  wherein the filter circuit is a second order low pass filter. 
     
     
       9. A high voltage battery system comprising:
 a charger circuit having an input configured to receive power from an AC input source and an output coupled to a high voltage DC bus configured to provide output DC power to a high voltage battery, wherein one or more switching converters of the charger circuit are operable to convert the received power into the output DC power; 
 an active filter circuit having an input coupled to the output of the charger circuit and an output, wherein the active filter circuit is operable to reduce harmonics associated with operation of the charger circuit and to provide a filtered DC voltage output; and 
 a high voltage to low voltage DC-DC converter circuit having an input coupled to the output of the active filter circuit and an output configured to be coupled to one or more low voltage loads, wherein the high voltage to low voltage DC-DC converter is operable to convert a filtered DC voltage received from the active filter to a lower DC voltage provided to a low voltage DC bus. 
 
     
     
       10. The high voltage battery system of  claim 9  wherein the charger circuit comprises:
 a first input switching bridge having an input configured to be coupled to the AC input source and an output, the first input switching bridge being further configured to convert the received power to an AC voltage having a selected voltage and frequency; 
 a first transformer having a primary winding coupled to the output of the input switching bridge and a secondary winding; and 
 a first rectifier charger circuit having an input coupled to the secondary winding of the first transformer and an output coupled to the high voltage DC bus. 
 
     
     
       11. The high voltage battery system of  claim 10  wherein at least one of the first input switching bridge and the first rectifier charger circuit comprise a stacked half bridge. 
     
     
       12. The high voltage battery system of  claim 9  wherein the active filter circuit comprises a filter switching bridge and a filter circuit. 
     
     
       13. The high voltage battery system of  claim 12  wherein the filter switching bridge comprises a stacked half bridge. 
     
     
       14. The high voltage battery system of  claim 12  wherein the filter circuit is a second order low pass filter. 
     
     
       15. The high voltage battery system of  claim 9  wherein the high voltage to low voltage DC-DC converter circuit comprises:
 an inverter having an input configured to be coupled to the output of the active filter circuit and an output, the inverter being further configured to convert a received filtered high DC voltage to an AC voltage having a selected voltage and frequency; 
 a second transformer having a primary winding coupled to the output of the inverter and a secondary winding; and 
 a second rectifier charger circuit having an input coupled to the secondary winding of the second transformer and an output coupled to the low voltage DC bus. 
 
     
     
       16. A high voltage battery system comprising:
 a charger circuit having an input configured to receive power from an AC input source and an output, wherein one or more switching converters of the charger circuit are operable to convert the received power into output DC power; 
 an active filter circuit having an input coupled to the output of the charger circuit and an output, wherein the active filter circuit is operable to reduce harmonics associated with operation of the charger circuit and to provide a filtered DC voltage output and wherein an output of the active filter circuit is coupled to a high voltage DC bus configured to provide output DC power to a high voltage battery; and 
 a high voltage to low voltage DC-DC converter circuit having an input coupled to the active filter circuit and an output configured to be coupled to one or more low voltage loads, wherein the high voltage to low voltage DC-DC converter is operable to convert a DC voltage to a lower DC voltage provided to a low voltage DC bus. 
 
     
     
       17. The high voltage battery system of  claim 16  wherein the charger circuit comprises:
 a first input switching bridge having an input configured to be coupled to the AC input source and an output, the first input switching bridge being further configured to convert the received power to an AC voltage having a selected voltage and frequency; 
 a first transformer having a primary winding coupled to the output of the input switching bridge and a secondary winding; and 
 a first rectifier charger circuit having an input coupled to the secondary winding of the first transformer and an output coupled to the high voltage DC bus. 
 
     
     
       18. The high voltage battery system of  claim 17  wherein at least one of the first input switching bridge and the first rectifier charger circuit comprise a stacked half bridge. 
     
     
       19. The high voltage battery system of  claim 16  wherein the active filter circuit comprises a filter switching bridge and a filter circuit. 
     
     
       20. The high voltage battery system of  claim 19  wherein the filter switching bridge comprises a stacked half bridge. 
     
     
       21. The high voltage battery system of  claim 19  wherein the filter circuit is a second order low pass filter. 
     
     
       22. The high voltage battery system of  claim 16  wherein the high voltage to low voltage DC-DC converter circuit comprises:
 an inverter having an input configured to be coupled to the active filter circuit and an output, the inverter being further configured to convert a received DC voltage to an AC voltage having a selected voltage and frequency; 
 a second transformer having a primary winding coupled to the output of the inverter and a secondary winding; and 
 a second rectifier charger circuit having an input coupled to the secondary winding of the second transformer and an output coupled to the low voltage DC bus.

Description:
BACKGROUND 
     There has recently been increased proliferation of high voltage battery systems. Such systems may find applications in hybrid and fully electric vehicles, solar power systems, electrical grid storage systems, and the like. In each of these applications, the high voltage battery system may be charged by connecting to the AC power grid. In the case of fully electric vehicles, such connections may be present only when the vehicle is parked and a charger is available. In the case of hybrid electric vehicles an AC generator may be available whenever the internal combustion engine is running or when parked and connected to a charger, as with plug in hybrid electric vehicles (PHEVs). In the case of solar systems, grid batteries, and other applications an AC power source may always or nearly always available. 
     In at least some of the foregoing applications, it may be desirable to provide a single stage charger, which converts AC power received from an AC power source (such as the power grid) and into a DC voltage suitable for charging the battery. One potential disadvantage of such arrangements is the coupling of harmonics of the AC voltage (current) into the battery system. This disadvantage may be addressed by including suitable filter circuits, including active filter circuits, that can reduce this harmonic coupling. Likewise, in at least some of the foregoing applications, it may be desirable to have one or more low voltage systems that can be powered by the high voltage battery system. For example, in automotive applications, the electrical drive system may be powered by the high voltage system, while the remainder of the vehicle&#39;s electrical systems, including, climate control, infotainment, etc., may be powered by the lower voltage system. In such embodiments, a DC-DC converter may be provided to reduce the voltage of the high voltage system to a lower voltage suitable for the lower voltage systems. 
     SUMMARY 
     For applications in which it is desirable to provide both active filtering and high voltage to low voltage DC-DC (HV-LV-DC-DC) the device count and circuit complexity may increase to undesirable levels. For at least some of these applications, it may therefore be desirable to provide an integrated active filter and HVLVDCDC converter as shown and described herein. 
     A high voltage battery system can include a charger circuit, which can include an input switching bridge having an input and an output, the input configured to be coupled to an AC input source, the first switching bridge being further configured to convert an AC input voltage to an AC voltage having a selected voltage and frequency; a first transformer having a primary winding coupled to the output of the input switching bridge and a secondary winding; and a first rectifier charger circuit having an input coupled to the secondary winding of the first transformer and an output coupled to the high voltage DC bus. The high voltage battery system can further include a high voltage battery coupled to an output of the charger circuit. The high voltage battery system can further include an active filter circuit comprising a filter switching bridge and a filter circuit, having an input coupled to the output of the charger circuit and an output, the active filter circuit being operable to reduce harmonics associated with operation of the charger circuit and to provide a filtered DC voltage output. The high voltage battery system can also include a high voltage to low voltage DC-DC converter circuit including: an inverter having an input configured to be coupled to the output of the active filter circuit and an output, the inverter being further configured to convert a received filtered high DC voltage to an AC voltage having a selected voltage and frequency; a second transformer having a primary winding coupled to the output of the inverter and a secondary winding; and a second rectifier charger circuit having an input coupled to the secondary winding of the second transformer and an output coupled to the low voltage DC bus and being configured to produce a low DC voltage for a low DC voltage bus of the high voltage battery system. At least one of the first switching bridge and the first rectifier charger circuit can include a stacked half bridge. The filter switching bridge can include a stacked half bridge. The filter circuit can be a second order low pass filter. 
     A high voltage battery system can include a charger circuit, the charger circuit including: an input switching bridge having an input and an output, the input configured to be coupled to an AC input source, the first switching bridge being further configured to convert an AC input voltage to an AC voltage having a selected voltage and frequency; a first transformer having a primary winding coupled to the output of the input switching bridge and a secondary winding; and a first rectifier charger circuit having an input coupled to the secondary winding of the first transformer and an output coupled to the high voltage DC bus. The high voltage battery system can further include an active filter circuit comprising a filter switching bridge and a filter circuit, the active filter circuit having an input coupled to the output of the charger circuit and an output coupled to a high voltage DC bus, wherein the active filter circuit is operable to reduce harmonics associated with operation of the charger circuit and to provide a filtered DC voltage output. The high voltage battery system can also include a high voltage battery coupled to the high voltage DC bus. The high voltage battery system can also include a high voltage to low voltage DC-DC converter circuit, which can include: an inverter coupled to the active filter circuit and an output, the inverter being further configured to convert a high DC voltage to an AC voltage having a selected voltage and frequency; a second transformer having a primary winding coupled to the output of the inverter and a secondary winding; and a second rectifier charger circuit having an input coupled to the secondary winding of the second transformer and an output coupled to the low voltage DC bus and being configured to produce a low DC voltage for a low DC voltage bus of the high voltage battery system. At least one of the first switching bridge and the first rectifier charger circuit can include a stacked half bridge. The filter switching bridge can include a stacked half bridge. The filter circuit can include a second order low pass filter. 
     A high voltage battery system can include: a charger circuit having an input configured to receive power from an AC input source and an output coupled to a high voltage DC bus configured to provide output DC power to a high voltage battery, wherein one or more switching converters of the charger circuit may be operable to convert the received power into the output DC power; an active filter circuit having an input coupled to the output of the charger circuit and an output, wherein the active filter circuit may be operable to reduce harmonics associated with operation of the charger circuit and to provide a filtered DC voltage output; and a high voltage to low voltage DC-DC converter circuit having an input coupled to the output of the active filter circuit and an output configured to be coupled to one or more low voltage loads, wherein the high voltage to low voltage DC-DC converter may be operable to convert a filtered DC voltage received from the active filter to a lower DC voltage provided to a low DC voltage bus. The charger circuit can include: an input switching bridge having an input configured to be coupled to the AC input source and an output, the first switching bridge being further configured to convert the received power to an AC voltage having a selected voltage and frequency; a first transformer having a primary winding coupled to the output of the input switching bridge and a secondary winding; and a first rectifier charger circuit having an input coupled to the secondary winding of the first transformer and an output coupled to the high voltage DC bus. At least one of the first switching bridge and the first rectifier charger circuit can include a stacked half bridge. The active filter circuit can The filter switching bridge can include a stacked half bridge. The filter circuit can be a second order low pass filter. The high voltage to low voltage DC-DC converter circuit can include: an inverter having an input configured to be coupled to the output of the active filter circuit and an output, the inverter being further configured to convert a received filtered high DC voltage to an AC voltage having a selected voltage and frequency; a second transformer having a primary winding coupled to the output of the inverter and a secondary winding; and a second rectifier charger circuit having an input coupled to the secondary winding of the second transformer and an output coupled to the low voltage DC bus. 
     A high voltage battery system can include: a charger circuit having an input configured to receive power from an AC input source and an output, wherein one or more switching converters of the charger circuit are operable to convert the received power into the output DC power; an active filter circuit having an input coupled to the output of the charger circuit and an output, wherein the active filter circuit is operable to reduce harmonics associated with operation of the charger circuit and to provide a filtered DC voltage output and wherein an output of the active filter circuit is coupled to a high voltage DC bus configured to provide output DC power to a high voltage battery; and a high voltage to low voltage DC-DC converter circuit having an input coupled to the active filter circuit and an output configured to be coupled to one or more low voltage loads, wherein the high voltage to low voltage DC-DC converter is operable to convert a DC voltage to a lower DC voltage provided to a low DC voltage bus. The charger circuit can include: an input switching bridge having an input configured to be coupled to the AC input source and an output, the first switching bridge being further configured to convert the received power to an AC voltage having a selected voltage and frequency; a first transformer having a primary winding coupled to the output of the input switching bridge and a secondary winding; and a first rectifier charger circuit having an input coupled to the secondary winding of the first transformer and an output coupled to the high voltage DC bus. At least one of the first switching bridge and the first rectifier charger circuit comprise a stacked half bridge. The active filter circuit can include a filter switching bridge and a filter circuit. The filter switching bridge can include a stacked half bridge. The filter circuit can include a second order low pass filter. The high voltage to low voltage DC-DC converter circuit can include: an inverter having an input configured to be coupled to the active filter circuit and an output, the inverter being further configured to convert a received DC voltage to an AC voltage having a selected voltage and frequency; a second transformer having a primary winding coupled to the output of the inverter and a secondary winding; and a second rectifier charger circuit having an input coupled to the secondary winding of the second transformer and an output coupled to the low voltage DC bus. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a block diagram of a high voltage battery system that can receive power from an AC grid and deliver power to a low voltage battery system. 
         FIG. 2  illustrates a schematic of a high voltage battery system that can receive power from an AC grid and deliver power to a low voltage battery system incorporating an active filter to reduce harmonics associated with the charger reaching the low voltage battery system. 
         FIG. 3  illustrates a schematic of a first embodiment of a high voltage battery system that can receive power from an AC grid and deliver power to a low voltage battery system incorporating an integrated active filter and HVLV DCDC converter to reduce harmonics associated with the charger reaching the low voltage battery system. 
         FIG. 4A  illustrates a block diagram of the high voltage battery system of  FIG. 3 . 
         FIG. 4B  illustrates operation of the high voltage battery system of  FIG. 4A  in a battery discharging mode. 
         FIG. 4C  illustrates operation of the high voltage battery system of  FIG. 4A  in a battery charging mode. 
         FIG. 5  illustrates a schematic of a second embodiment of a high voltage battery system that can receive power from an AC grid and deliver power to a low voltage battery system incorporating an integrated active filter and HVLV DCDC converter to reduce harmonics associated with the charger reaching the low voltage battery system. 
         FIG. 6A  illustrates a block diagram of the high voltage battery system of  FIG. 5 . 
         FIG. 6B  illustrates operation of the high voltage battery system of  FIG. 6A  in a battery discharging mode. 
         FIG. 6C  illustrates operation of the high voltage battery system of  FIG. 6A  in a battery charging mode. 
     
    
    
     DETAILED DESCRIPTION 
     In the following description, for purposes of explanation, numerous specific details are set forth to provide a thorough understanding of the disclosed concepts. As part of this description, some of this disclosure&#39;s drawings represent structures and devices in block diagram form for sake of simplicity. In the interest of clarity, not all features of an actual implementation are described in this disclosure. Moreover, the language used in this disclosure has been selected for readability and instructional purposes, has not been selected to delineate or circumscribe the disclosed subject matter. Rather the appended claims are intended for such purpose. 
     Various embodiments of the disclosed concepts are illustrated by way of example and not by way of limitation in the accompanying drawings in which like references indicate similar elements. For simplicity and clarity of illustration, where appropriate, reference numerals have been repeated among the different figures to indicate corresponding or analogous elements. In addition, numerous specific details are set forth in order to provide a thorough understanding of the implementations described herein. In other instances, methods, procedures and components have not been described in detail so as not to obscure the related relevant function being described. References to “an,” “one,” or “another” embodiment in this disclosure are not necessarily to the same or different embodiment, and they mean at least one. A given figure may be used to illustrate the features of more than one embodiment, or more than one species of the disclosure, and not all elements in the figure may be required for a given embodiment or species. A reference number, when provided in a given drawing, refers to the same element throughout the several drawings, though it may not be repeated in every drawing. The drawings are not to scale unless otherwise indicated, and the proportions of certain parts may be exaggerated to better illustrate details and features of the present disclosure. 
       FIG. 1  illustrates a block diagram of a high voltage battery system  100  that can receive power from an AC source  102  (such as the electrical grid) and deliver power to a low voltage battery system  109 . High voltage battery system  100  includes a high voltage battery  106 . High voltage battery  106  may be charged from AC source  102  via a charger  104 . Various embodiments of charger  104  are possible depending on the particular embodiment. 
     In the illustrated embodiment, charger  104  includes input filter  141 , which may serve to minimize electromagnetic interference. Input filter  141  is illustrated as pair of inductors or chokes in series with the supplied AC voltage, but it will be appreciated that any of a variety of input filter arrangements are possible. 
     Charger  104  may also include a rectifier  142  that receives the AC input voltage and converts it to a DC voltage, which may be supplied to DC bus  144 , which may be supported by capacitor(s)  143 . Various rectifier topologies may be used, including half bridge and full bridge designs. Additionally, depending on the configuration of the input AC voltage, the rectifier may be a single phase, split phase, or polyphase (e.g., three phase) rectifier. 
     Depending on the configuration, a variety of rectifier devices may be used including diodes, silicon controlled rectifiers (SCRs) a/k/a thyristors, or transistors, including, for example, bipolar transistors, insulated gate bipolar transistors, field effect transistors such as junction field effect transistors (JFETs) or metal-oxide-semiconductor field effect transistors (MOSFETs), etc. In each of the embodiments discussed herein, MOSFETs are illustrated, although it is to be understood that other switching devices could be substituted as appropriate for a given embodiment. Additionally, the aforementioned semiconductor devices may be use any suitable semiconductor technology including silicon, silicon carbide (SiC), gallium nitride (GaN), etc. Depending on how high the “high voltage” is, SiC devices may be warranted. Additionally or alternatively, for higher power levels and/or higher switching frequencies, GaN devices may be preferred. 
     As noted above, the output DC voltage produced by rectifier  142  may appear across a DC bus  144 , which may be supported by capacitor(s)  143 . This DC voltage may further be provided to an inverter  145  that converts the DC voltage into an AC voltage that may be provided to transformer  147 , which may include leakage inductance (or other series inductance  146 ). The Ac voltage produced by inverter  145  may have different voltage and/or frequency properties than the AC input voltage  102 . As an example, using an inverter output voltage higher than the AC input voltage may allow for reduced current and therefore higher operating efficiency. As another example, using an inverter output frequency higher than the AC input frequency may allow for smaller magnetic components, such as transformer  147 . As was the case with rectifier  142 , various inverter topologies may be used, including half bridge and full bridge configurations configured as either single phase, split phase, or polyphase systems. Likewise, various switching devices using any suitable semiconductor technology may also be used. 
     Transformer  147  may receive the AC output voltage form inverter  147  and convert it into a high voltage that is in the general range of the high voltage battery  106 . The degree of voltage conversion may be determined by the turns ratio of the transformer. For example, transformer  147  may convert the inverter output voltage to a level that is slightly above the full charge voltage of high voltage battery  106 , so that charger  148  (discussed in greater detail below) may operate as a step-down converter. As another example, transformer  147  may convert the inverter output voltage to a level that is approximately equal to the full discharge voltage of high voltage battery  106  so that charger  148  (discussed in greater detail below) may operate as a step up converter. As still another example, transformer  147  may be a 1:1 transformer, in which case it serves only to provide galvanic isolation between high voltage battery  106  (and the associated systems) and the AC grid. Galvanic isolation is provided regardless of the transformer turns ratio (unless an autotransformer configuration is used). 
     As alluded to above, charger  148  may be a switching converter that converts the AC voltage on the secondary side of transformer  147  into a voltage suitable for high voltage battery  106 . In some embodiments, this voltage may be the charging target voltage of the battery. Thus, when the battery is substantially discharged, and is at a relatively lower voltage (but still a “high voltage” for the purposes herein), charger  148  may produce a relatively low output voltage to regulate the charging current delivered to high voltage battery  106 . Alternatively, when the battery is substantially charged, and is therefore at a relatively higher voltage, charger  148  may produce a relatively higher output voltage to charge the battery at a relatively slower rate. As with rectifier  142  and inverter  145  discussed above, charger  148  may have a variety of configurations (i.e., full bridge, half bridge, single phase, polyphase, etc.) and may be constructed from semiconductor switching devices of any suitable type or semiconductor technology. In any case, the output voltage of charger  148  may be provided to a high voltage bus  105  that is provided to high voltage battery  106  as well as to high voltage to low voltage DC to DC (HVLV DCDC) converter  108 , which is discussed in greater detail below. High voltage bus may be supported by one or more capacitors CHV as illustrated. Finally, one or more high voltage loads (not shown) may be coupled to high voltage battery  106  and/or high voltage bus  105 . 
     HVLV DCDC converter  108  may be employed to convert the high voltage appearing on high voltage bus  105  to a lower level suitable for a low voltage power system, illustrated as low voltage battery  109 . In some embodiments, there may be additional or alternative loads appearing on the low voltage bus (i.e., bus  185 ), which may be supported by low voltage battery  109  and/or capacitor CLV. These additional or alternative loads are omitted here for sake of clarity. HVLV DCDC converter  108  may include an inverter  181  that converts the DC voltage of high voltage DC bus  105  into an AC voltage that may be applied to the input of transformer  183  (which may also include leakage or other series inductance  182 ). As above, inverter  181  may be constructed in a variety of configurations and using a variety of semiconductor devices and technologies. Transformer  183  may be configured to step down the rectified high DC voltage to a voltage more suitable for the low voltage bus  185 . Transformer  183  may also serve to provide galvanic isolation between the low voltage system and high voltage bus  105 /battery  106 . 
     The AC voltage appearing at the secondary of transformer  183  may be provided to a rectifier  184  that may produce a suitable low voltage for low voltage bus  185  and low voltage battery  109 . In some embodiments, rectifier/regulator  184  may be configured to produce a relatively constant low voltage DC bus voltage that is suitable for the attached low voltage loads. In other embodiments, rectifier regulator  184  may be configured to produce a variable DC voltage suitable for charging low voltage battery  109 . In any case, rectifier/regulator  184  may be constructed using any suitable configuration, switch type, and semiconductor technology, including the examples discussed above with respect to various other converter stages. 
     As noted above, in at least some embodiments, the arrangement described above can result in the undesirable coupling of AC grid harmonics into the high voltage bus  105  and thus to both high voltage battery  106  and the HVLV DCDC converter  108 . Thus,  FIG. 2  illustrates a schematic of a high voltage battery system  200  that can receive power from an AC grid  202  and deliver power to a low voltage battery system  209 . The system includes an active filter  270  to reduce harmonics associated with the high voltage charger reaching the low voltage battery system. In  FIG. 2 , reference numerals that correspond to the same/similar devices in  FIG. 1  are as an aid to understanding. As in  FIG. 1 , the system receives power from an AC source  202 , such as the power grid. This input power may be filtered by an input filter  241 . The resulting filtered voltage appears across an AC input bus  244 , supported by input capacitors  243   a  and  243   b.    
     Coupled to input bus  244  is a switching bridge  249 , which in the illustrated embodiment is a stacked half bridge that effectively replaces both rectifier  142  and inverter  145  discussed above. Switching bridge  249  includes four switching devices SaP, SaN, SbN, and SbQ, with the inputs of the stacked half bridge (terminals P, N, and Q) coupled to DC bus  244  and the outputs (terminals a and b) coupled to transformer  247  (via blocking capacitor Cp). Operation of these switches selectively couples the AC voltage appearing at input terminals P, N, and Q to the output terminals a and b. Control of the switching frequency and/or duty cycle of these switches, using for example a pulse width modulation (PWM) control technique, can produce a controllable AC voltage at output terminals a and b. Switching bridge  249  thus takes the filtered AC input voltage appearing on bus  244  and converts it to an AC voltage that may have a different voltage and/or frequency. This converted voltage may then be applied to the primary winding transformer  247 . As above, transformer  247  serves both to provide galvanic isolation between the AC input and the high voltage bus (discussed in greater detail below) as well as optionally providing either a step-up or step-down of the voltage. The AC voltage appearing across the secondary winding of transformer  247  may then be converted into a DC voltage by rectifier/charger  248 . 
     In the illustrated embodiment, rectifier/charger  248  is a full bridge switching arrangement including switches SuM, SvM, SuN, and SvN. The inputs of the full bridge (terminals u and v) are coupled to the secondary winding of transformer  247 . The outputs of the full bridge (terminals R and S) may then be coupled to an active filter  247 , discussed in greater detail below. The outputs of rectifier/charger  248  are also coupled to high voltage bus  205 , to which high voltage battery  206  is also coupled. As described above, rectifier/charger  248  may be operated to produce a target voltage for high voltage battery  206  so as to control charging of the battery. More specifically, operation of these switches selectively couples the AC voltage appearing at input terminals u and v to the output terminals R and S. Control of the switching frequency and/or duty cycle of these switches, using for example a pulse width modulation (PWM) control technique, can produce a controllable DC voltage at output terminals R and S. High voltage bus  205  may also optionally be supported by one or more capacitors Co. High voltage bus  205  may also be coupled to the HVLV DCDC converter as described in greater detail below. 
     The HVLV DCDC converter may include inverter  281 , illustrated as a full bridge inverter made up of switching devices SuM, SvM, SuN, and SvN, with the input terminals coupled across high voltage bus  205  and the output terminals (u and v) coupled to the primary winding of transformer  283 . These switching devices may be any suitable device type or semiconductor technology, as described above. Operation of these switches selectively couples the high voltage DC bus voltage on bus  205  to output terminals u and v. Control of the switching frequency and/or duty cycle of these switches, using for example a pulse width modulation (PWM) control technique, can produce an AC voltage having desired voltage and frequency characteristics at output terminals u and v. Inverter  281  may be thus operated to convert the high voltage DC bus voltage  205  into an AC voltage with voltage and frequency suitable for input into transformer  283 . 
     As above, transformer  283  may serve to provide galvanic isolation between high voltage bus  205  and the low voltage battery system. Additionally, transformer may provide a desired degree of voltage conversion (e.g., step-down), depending on the turns ratio of the transformer. The voltage appearing at the secondary winding of transformer  283  may be coupled to the input terminals (u′ and v′) of rectifier/regulator  284 . Rectifier/regulator  284  may be a full bridge made up of switching devices SuR, SuS, SvR, and SvS. These switching devices may be any suitable device type or semiconductor technology, as described above. Operation of these switches selectively couples the AC voltage appearing at input terminals u′ and v′ to the output terminals coupled to low voltage DC bus  285 . Control of the switching frequency and/or duty cycle of these switches, using for example a pulse width modulation (PWM) control technique, can produce a controllable DC voltage on the low voltage DC bus. Rectifier/regulator  284  may thus be operated to convert the AC voltage appearing at the secondary of transformer  283  into a DC voltage suitable for low voltage DC bus  285 , which may power one or more low voltage loads  209 , including charging a low voltage battery. 
     As noted above, an active filter  270  may be provided. Active filter  270  may be configured and/or operated to minimize undesirable coupling of harmonics associated with the operation of charger stages  248 / 249  onto high voltage bus  205  and thereby into high voltage battery  206  and HVLV DCDC converter input stage  281 . Active filter  270  may take a variety of configurations. In the illustrated embodiment, active filter  270  includes a half bridge made up of switches  271  and  272 , with the half bridge coupled across the high voltage DC bus  205  (also the output terminals R and S of rectifier charger  248 ). These switching devices may be any suitable device type or semiconductor technology, as described above. The central node of the half bridge, i.e., terminal x, may be coupled to a low pass filter. Various filter configurations are possible. In the illustrated embodiment, the low pass filter is a 2 nd  order low pass filter made up of filter inductor Lf,  273  and filter capacitor Cf,  274 . By selective operation of switching devices  271  and  272 , active filter  270  may be operated to minimize coupling of harmonics associated with switching of converters  248  and  249  onto high voltage DC bus  205 . 
     As noted above, the addition of active filter  270  results in the inclusion of additional switching devices that increase the cost and complexity of the system. To that end,  FIG. 3  illustrates a schematic of a first embodiment of a high voltage battery system  300  that can receive power from an AC grid and deliver power to a low voltage battery system incorporating an integrated active filter and HVLV DCDC converter to reduce harmonics associated with the charger reaching the low voltage battery system. High voltage battery system  300  includes a single stage charger  304  that receives AC input power, for example from an AC grid  302  and converts it to a high voltage DC that is supplied via high voltage DC bus  305   a  to a high voltage battery  306 . Also coupled to high voltage bus  305   a  is an active filter  370 , described in greater detail below. The output of active filter  370  may be provided to HVLV DCDC converter  308 , which converts the filtered high DC voltage into a lower DC voltage suitable for low voltage loads  309 . 
     Returning to charger  304 , and similar to the systems described above, an AC voltage from an AC power source, such as an AC grid  302  may be passed through an input filter  341 . This filtered AC voltage may appear across an AC input bus  344  (corresponding to terminals P, Q, and N). AC input bus  344  may be supported by capacitors  343   a  and  343   b . This filtered AC input bus  344  is also connected to the input of a switching bridge  349 . In the illustrated embodiment, switching bridge  349  is a stacked half bridge made up of four switches SaP, SaN, SbN, and SbQ. However, other switching bridge configurations could be used. Likewise, as with all converters described herein, different types of semiconductor devices based on different semiconductor technologies may be used depending on the particular application. Operation of these switches selectively couples the AC voltage appearing at input terminals P, N, and Q to the output terminals a and b. Control of the switching frequency and/or duty cycle of these switches, using for example a pulse width modulation (PWM) control technique, can produce a controllable DC voltage at output terminals a and b. Switching bridge  349  may thus be operated to convert the filtered AC input voltage appearing across AC input bus  344  to an AC voltage having different voltage and/or frequency characteristics at the output of switching bridge  349 , i.e., terminals a and b. This voltage may be provided to the primary winding of transformer  347 , which may provide galvanic isolation between the AC input and the DC voltage bus, as well as providing a suitable step up or step down of the voltage, depending on the turns ratio of the transformer. 
     As a result, a transformed AC voltage appears across the secondary winding of transformer  347 . This voltage may be provided to the input terminals (u, v) of switching bridge  348 , which may act as a rectifier/charger to produce the high voltage DC for DC bus  305   a . In the illustrated embodiment, rectifier/charger  348  includes a stacked half bridge of switches SuR, SuO, SvO, and SvS. Operation of these switches selectively couples the AC voltage appearing at input terminals u and v to the output terminals R,  0 , and S. Control of the switching frequency and/or duty cycle of these switches, using for example a pulse width modulation (PWM) control technique, can produce a controllable DC voltage at output terminals R,  0 , and S. As with the other converter embodiments described herein, different topologies (e.g., bridge configurations), switching devices, and/or semiconductor technologies may be used as appropriate for a particular application. 
     The DC voltage appearing across high voltage DC bus  305   a  (corresponding to terminals R and S) may be provided to high voltage battery  306 . Additionally, operation of switching bridge  348  may be used to control this DC voltage, to provide a suitable battery charging target voltage. As alluded to above, the operation of the preceding converter stages may produce undesirable harmonics of the AC grid frequency on this DC bus. Additionally, the changing voltage requirements of the battery throughout the charging cycle may cause the voltage appearing across high voltage bus  305   a  to vary substantially. This voltage variation may adversely impact the operating efficiency of the converters associated with the HVLV DCDC converter  308 , discussed in greater detail below. To alleviate these issues, active filter  370  may be provided. 
     Active filter  370  includes a stacked half bridge of switches Sf 1 , Sf 2 , Sf 3 , and Sf 4  coupled to a filter circuit made up of inductor Lf,  373  and capacitor Cf,  374 . As with the other converters discussed herein, differing bridge configurations, switch types, and semiconductor technologies may be used as appropriate for a given application. The input of the switch bridge (terminals R, O, and S) are coupled to the high voltage DC bus  305   a  (and the neutral/common terminal O of rectifier charger  348 , discussed above). The outputs of the switch bridge (terminals w and x are coupled to the filter circuit. The filter circuit is a 2 nd  order low pass filter, as described above. Switches Sf 1 , Sf 2 , Sf 3 , and Sf 4  may be operated to selectively couple the high voltage DC bus voltage to the filter circuit. By controlling the switching frequency and duty cycle of these switches, a controlled and filtered DC voltage may be delivered at the output of the filter circuit, forming filtered high voltage DC bus  305   b , which is coupled to the input of HVLV DCDC converter  308 . 
     HVLV DCDC converter  308  receives the filtered high voltage DC bus  305   b  and converts that high voltage to a low voltage suitable for low voltage loads  309 . In the illustrated configuration, HVLV DCDC converter  308  may include inverter  381 , illustrated as a full bridge inverter made up of switching devices SuM, SvM, SuN, and SvN, with the input terminals coupled across filtered high voltage bus  305   b  and the output terminals (u and v) coupled to the primary winding of transformer  383 . These switching devices may be any suitable device type or semiconductor technology, as described above. Operation of these switches selectively couples the high voltage DC bus voltage on bus  305   b  to output terminals u and v. Control of the switching frequency and/or duty cycle of these switches, using for example a pulse width modulation (PWM) control technique, can produce an AC voltage having desired voltage and frequency characteristics at output terminals u and v. Inverter  381  may be thus operated to convert the filtered high voltage DC bus voltage  305   b  into an AC voltage with voltage and frequency suitable for input into transformer  383 . 
     As above, transformer  383  may serve to provide galvanic isolation between high voltage bus  305   b  and the low voltage battery system. Additionally, transformer may provide a desired degree of voltage conversion (e.g., step-down), depending on the turns ratio of the transformer. The voltage appearing at the secondary winding of transformer  383  may be coupled to the input terminals (u′ and v′) of rectifier/regulator  384 . Rectifier/regulator  384  may be a full bridge made up of switching devices SuR, SuS, SvR, and SvS. These switching devices may be any suitable device type or semiconductor technology, as described above. Operation of these switches selectively couples the AC voltage appearing at input terminals u′ and v′ to the output terminals coupled to low voltage DC bus  385 . Control of the switching frequency and/or duty cycle of these switches, using for example a pulse width modulation (PWM) control technique, can produce a controllable DC voltage on the low voltage DC bus. Rectifier/regulator  384  may thus be operated to convert the AC voltage appearing at the secondary of transformer  383  into a DC voltage suitable for low voltage DC bus  385 , which may power one or more low voltage loads  309 , including charging a low voltage battery. 
       FIG. 4A  illustrates a block diagram of the high voltage battery system  300  described above with respect to  FIG. 3 . Each of the converters/switching bridges has been replaced with a correspondingly numbered functional block. Notably, active filter  370  is denoted as a DC-DC converter. In all material respects, the connections and operation are as described above with respect to  FIG. 3 . 
       FIG. 4B  illustrates the high voltage battery system  300  (represented by the block diagram of  FIG. 4A ) operating in a first battery discharging mode. In this operating mode, AC grid  302  is disconnected. Converters  348  and  349  are not operating and are de-energized, as is transformer  347  are deenergized. DC bus  305   a  is supported by high voltage battery  306 . As a result, as high voltage battery  306  discharges, the voltage appearing on high voltage bus  305   a  will decrease, as indicated by plot  475   a , which illustrates the voltage of high voltage bus  305   a  versus time during a series of states: (1) during discharge (declining voltage), (2) an off time in which the battery is discharged, (3) a charging time (increasing portion), and finally (4) a time in which the battery is fully charged (level portion). 
     Also in this mode, active filter/DCDC converter  370  will be operating to provide a filtered/substantially constant DC voltage to bus  305   b . The voltage across bus  305   b  is illustrated by plot  476   a , which shows the filtered DC bus voltage as substantially constant over time. This substantially constant voltage may be achieved by varying the switching frequency and/or duty cycle as described above to provide suitable output voltage regulation. As a result of the substantially constant voltage appearing at the input of inverter  381 , the efficiency of inverter  381  may be improved. In all other material respects, operation of the HVLV DCDC converter is as described above. 
       FIG. 4C  illustrates the high voltage battery system  300  (represented by the block diagram of  FIG. 4A ) operating in a second mode corresponding to battery charging. In this mode, an AC power source, such as AC grid  302  provides power to the charger stage, including converters  349  and  348  and transformer  347 , which are energized and operate as described above with respect to  FIG. 3 . This produces a controlled DC voltage on high voltage bus  305   a  that may be used to charge high voltage battery  306 . The voltage on high voltage bus  305   a  is illustrated by voltage plot  477 . In general, when high voltage battery  306  is in a discharged state (2), the voltage on high voltage bus  305   a  will be at a relatively lower level, increasing (3) as the battery is charged, to the fully charged battery voltage (4). The voltage of high voltage battery  306  will also correspond to the voltage of high voltage bus  305   a , as illustrated by plot  475   b . In this mode of operation, active filter  370  will operate as described above to produce the filtered high voltage appearing on filtered high voltage bus  305   b . Operation of filter/converter  370  can reduce, but not entirely eliminate coupling of harmonics of the AC power frequency onto the bus, so there will still be some, although substantially reduced harmonics appearing at the input of the HVLV DCDC converter, as illustrated by the undulating voltage  476   b  of the filtered high voltage DC bus. 
       FIG. 5  illustrates a schematic of a second embodiment of a high voltage battery system  500  that can receive power from an AC grid and deliver power to a low voltage battery system incorporating an integrated active filter and HVLV DCDC converter to reduce harmonics associated with the charger reaching the low voltage battery system. High voltage battery system  500  includes a single stage charger  504  that receives AC input power, for example from an AC grid  502  and converts it to a high voltage DC that is supplied via high voltage DC bus  505   a  to a high voltage battery  506 . Also coupled to high voltage bus  505   a  is an active filter  570 , described in greater detail below. The output of active filter  570  may be provided to HVLV DCDC  508 , which converts the filtered high DC voltage into a lower DC voltage suitable for low voltage loads  509 . 
     Returning to charger  504 , and similar to the systems described above, an AC voltage from an AC power source, such as an AC grid  502  may be passed through an input filter  541 . This filtered AC voltage may appear across an AC input bus  544  (corresponding to terminals P, Q, and N). AC input bus  544  may be supported by capacitors  543   a  and  543   b . This filtered AC input bus  544  is also connected to the input of a switching bridge  549 . In the illustrated embodiment, switching bridge  549  is a stacked half bridge made up of four switches SaP, SaN, SbN, and SbQ. However, other switching bridge configurations could be used. Likewise, as with all converters described herein, different types of semiconductor devices based on different semiconductor technologies may be used depending on the particular application. Operation of these switches selectively couples the AC voltage appearing at input terminals P, N, and Q to the output terminals a and b. Control of the switching frequency and/or duty cycle of these switches, using for example a pulse width modulation (PWM) control technique, can produce a controllable DC voltage at output terminals a and b. Switching bridge  549  may thus be operated to convert the filtered AC input voltage appearing across AC input bus  544  to an AC voltage having different voltage and/or frequency characteristics at the output of switching bridge  549 , i.e., terminals a and b. This voltage may be provided to the primary winding of transformer  547 , which may provide galvanic isolation between the AC input and the DC voltage bus, as well as providing a suitable step up or step down of the voltage, depending on the turns ratio of the transformer. 
     As a result, a transformed AC voltage appears across the secondary winding of transformer  547 . This voltage may be provided to the input terminals (u, v) of switching bridge  548 , which may act as a rectifier/charger to produce the high DC voltage that is provided to active filter  570  for production of high voltage DC busses  505   a  (for charging high voltage battery  506 ) and  505   b  (for conversion to low voltage for the low voltage system). In the illustrated embodiment, rectifier/charger  548  includes a stacked half bridge of switches SuR, SvR, SuS, and SvS. Operation of these switches selectively couples the AC voltage appearing at input terminals u and v to the output terminals R and S. Control of the switching frequency and/or duty cycle of these switches, using for example a pulse width modulation (PWM) control technique, can produce a controllable DC voltage at output terminals R and S. As with the other converter embodiments described herein, different topologies (e.g., bridge configurations), switching devices, and/or semiconductor technologies may be used as appropriate for a particular application. 
     The DC voltage appearing across terminals R and S) may be provided to active filter  570 . Active filter  570  includes a stacked half bridge of switches Sf 1 , Sf 2 , Sf 3 , and Sf 4  coupled to a filter circuit made up of inductor Lf,  573  and capacitor Cf,  574  (illustrated as two parallel capacitors). As with the embodiment discussed above, other filter circuit configurations could also be employed. Similarly, as with the other converters discussed herein, differing bridge configurations, switch types, and semiconductor technologies may be used as appropriate for a given application. The input of the switch bridge (terminals w and x) are coupled to output terminals R and S of rectifier charger  548  by the filter circuit. The outputs of the switch bridge may be coupled to high voltage bus  505   a , which may be coupled to high voltage battery  506 . Switches Sf 1 , Sf 2 , Sf 3 , and Sf 4  may be operated to selectively couple high voltage bus  505   a  to the filter circuit. By controlling the switching frequency and duty cycle of these switches, a controlled and filtered DC voltage may be delivered to high voltage bus  505   a  as well as high voltage DC bus  505   b , which is coupled to the input of HVLV DCDC converter  508 . 
     HVLV DCDC converter  508  receives the filtered high voltage DC bus  505   b  and converts that high voltage to a low voltage suitable for low voltage loads  509 . In the illustrated configuration, HVLV DCDC converter  508  may include inverter  581 , illustrated as a full bridge inverter made up of switching devices SuM, SvM, SuN, and SvN, with the input terminals coupled across filtered high voltage bus  505   b  and the output terminals (u and v) coupled to the primary winding of transformer  583 . These switching devices may be any suitable device type or semiconductor technology, as described above. Operation of these switches selectively couples the high voltage DC bus voltage on bus  505   b  to output terminals u and v. Control of the switching frequency and/or duty cycle of these switches, using for example a pulse width modulation (PWM) control technique, can produce an AC voltage having desired voltage and frequency characteristics at output terminals u and v. Inverter  581  may be thus operated to convert the filtered high voltage DC bus voltage  505   b  into an AC voltage with voltage and frequency suitable for input into transformer  583 . 
     As above, transformer  583  may serve to provide galvanic isolation between high voltage bus  505   b  and the low voltage battery system. Additionally, transformer may provide a desired degree of voltage conversion (e.g., step-down), depending on the turns ratio of the transformer. The voltage appearing at the secondary winding of transformer  583  may be coupled to the input terminals (u′ and v′) of rectifier/regulator  584 . Rectifier/regulator  584  may be a full bridge made up of switching devices SuR, SuS, SvR, and SvS. These switching devices may be any suitable device type or semiconductor technology, as described above. Operation of these switches selectively couples the AC voltage appearing at input terminals u′ and v′ to the output terminals coupled to low voltage DC bus  585 . Control of the switching frequency and/or duty cycle of these switches, using for example a pulse width modulation (PWM) control technique, can produce a controllable DC voltage on the low voltage DC bus. Rectifier/regulator  584  may thus be operated to convert the AC voltage appearing at the secondary of transformer  583  into a DC voltage suitable for low voltage DC bus  585 , which may power one or more low voltage loads  509 , including charging a low voltage battery. 
       FIG. 6A  illustrates a block diagram of the high voltage battery system  500  described above with respect to  FIG. 5 . Each of the converters/switching bridges has been replaced with a correspondingly numbered functional block. Notably, active filter  570  is denoted as a DC-DC converter. In all material respects, the connections and operation are as described above with respect to  FIG. 5 . 
       FIG. 6B  illustrates the high voltage battery system  500  (represented by the block diagram of  FIG. 6A ) operating in a first battery discharging mode. In this operating mode, AC grid  502  is disconnected. Converters  548  and  549  are not operating and are de-energized, as is transformer  547  are deenergized. DC bus  505   a  is supported by high voltage battery  506 . As a result, as high voltage battery  506  discharges, the voltage appearing on high voltage bus  505   a  will decrease, as indicated by plot  675   a , which illustrates the voltage of high voltage bus  505   a  versus time during a series of states: (1) during discharge (declining voltage), (2) an off time in which the battery is discharged, (3) a charging time (increasing portion), and finally (4) a time in which the battery is fully charged (level portion). 
     Also in this mode, active filter/DCDC converter  570  will be operating to provide a filtered/substantially constant DC voltage to bus  505   b , with the energy being supplied by high voltage battery  306  via high voltage bus  305   a . The voltage across bus  505   b  is illustrated by plot  676   a , which shows the filtered DC bus voltage as substantially constant over time. This substantially constant voltage may be achieved by varying the switching frequency and/or duty cycle as described above to provide suitable output voltage regulation. As a result of the substantially constant voltage appearing at the input of inverter  581 , the efficiency of inverter  581  may be improved. In all other material respects, operation of the HVLV DCDC converter is as described above. 
       FIG. 6C  illustrates the high voltage battery system  500  (represented by the block diagram of  FIG. 6A ) operating in a second mode corresponding to battery charging. In this mode, an AC power source, such as AC grid  502  provides power to the charger stage, including converters  549  and  548  and transformer  547 , which are energized and operate as described above with respect to  FIG. 5 . This produces a controlled DC voltage that may be provided to active filter/DCDC converter  570 , which in turns produces high voltage bus  505   a  that may be used to charge high voltage battery  506 . The voltage produced by converter  548  is illustrated by voltage plot  677 , which includes harmonic components of the AC grid voltage and thus has the illustrated sinusoidal form. Also illustrated is the voltage appearing on DC bus  505   a  (and supplied to high voltage battery  506 ) by active filter  570 . In general, when high voltage battery  506  is in a discharged state (2), the voltage on high voltage bus  505   a  will be at a relatively lower level, increasing (3) as the battery is charged, to the fully charged battery voltage (4). The voltage of high voltage battery  506  will also correspond to the voltage of high voltage bus  305   a . In this mode of operation, active filter  570  will operate as described above to produce the high voltage appearing on high voltage bus  505   b . Operation of filter/converter  570  can reduce, but not entirely eliminate coupling of harmonics of the AC power frequency onto the bus, so there will still be some, although substantially reduced harmonics appearing at the input of the HVLV DCDC converter, as illustrated by the undulating voltage  676   b  of the filtered high voltage DC bus. 
     The foregoing describes exemplary embodiments of high voltage battery systems that can receive power from an AC grid and deliver power to a low voltage battery system incorporating an integrated active filter and HVLV DCDC converter to reduce harmonics associated with the charger reaching the low voltage battery system. Such systems may be used in a variety of applications but may be particularly advantageous when used in conjunction with Such systems may be used in a variety of applications but may be particularly advantageous when used in conjunction with relatively high voltage and/or high power systems, such as may be used in electric vehicles, grid storage batteries, photovoltaic systems, and the like. Although numerous specific features and various embodiments have been described, it is to be understood that, unless otherwise noted as being mutually exclusive, the various features and embodiments may be combined various permutations in a particular implementation. Thus, the various embodiments described above are provided by way of illustration only and should not be constructed to limit the scope of the disclosure. Various modifications and changes can be made to the principles and embodiments herein without departing from the scope of the disclosure and without departing from the scope of the claims.

Metadata:
Filing Date: 20200925
Publication Date: 20220823
Grant Date: 20220823
Priority Date: 20200925
Inventors: Sahoo, Ashish K.
PIERQUET, BRANDON
Assignee: APPLE INC
CPC Classifications: [{"code": "H02J1/02", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J2207/20", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02J2207/40", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02J7/342", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02M1/10", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02M1/007", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02M3/33584", "inventive": false, "first": false, "tree": "[]"}, {"code": "B60L53/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02M1/15", "inventive": true, "first": false, "tree": "[]"}, {"code": "B60L2210/10", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02M3/01", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02M3/158", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02J7/342", "inventive": true, "first": false, "tree": "[]"}, {"code": "Y02T10/92", "inventive": false, "first": false, "tree": "[]"}, {"code": "B60L50/60", "inventive": true, "first": false, "tree": "[]"}, {"code": "B60L53/14", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/06", "inventive": true, "first": true, "tree": "[]"}, {"code": "B60L53/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "B60L50/60", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02M1/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "B60L53/50", "inventive": false, "first": false, "tree": "[]"}, {"code": "B60L2210/10", "inventive": false, "first": false, "tree": "[]"}, {"code": "B60L1/00", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J2207/20", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02M3/33573", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02M3/33576", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02M1/12", "inventive": true, "first": false, "tree": "[]"}, {"code": "B60L53/50", "inventive": false, "first": false, "tree": "[]"}, {"code": "H02M3/33576", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J7/06", "inventive": true, "first": true, "tree": "[]"}, {"code": "H02J7/342", "inventive": true, "first": false, "tree": "[]"}, {"code": "B60L2210/10", "inventive": false, "first": false, "tree": "[]"}, {"code": "B60L53/20", "inventive": true, "first": false, "tree": "[]"}, {"code": "H02J2207/20", "inventive": false, "first": false, "tree": "[]"}, {"code": "B60L50/60", "inventive": true, "first": false, "tree": "[]"}]
Family ID: 80821511