Electrical system with step-up conversion function

Abstract

An exemplary electrical system is disclosed. The electrical system may include a rechargeable energy storage system (RESS) and a power inverter connected to the RESS. The power inverter may be configured to supply power to a traction motor. The electrical system may include multiple motor windings connected between the power inverter and a switch. The switch may be configured to switch between a closed state and an open state, wherein a closed state allows current to flow from an off-board power source through the multiple motor windings to the RESS, and an open state prevents current from flowing between the off-board power source and the multiple motor windings.

Description

Technical Field

[0001] This disclosure relates to a vehicle electrical system with a boost converter function. Background Technology

[0002] Hybrid electric or battery electric vehicle transmissions typically include one or more high-voltage machine motors in the form of electric generator units or traction motors. The motors supply / charge rechargeable direct current (DC) battery packs or draw power from them. The energized motors regulate the torque of the transmission's gear sets for optimal system efficiency. Voltage converters are typically used to convert the voltage to a suitable level for use by the vehicle's motors and / or accessory loads.

[0003] The semiconductor switches of the power inverter module are controlled by pulse width modulation or other switching control signals to convert the battery output voltage into an alternating current (AC) output voltage. The AC output voltage from the power inverter module is ultimately transmitted to the individual phase windings of the motor. The energized motor provides power to the vehicle's drivetrain. Summary of the Invention

[0004] An exemplary electrical system is disclosed. The electrical system may include a rechargeable energy storage system (RESS) and a power inverter connected to the RESS. The power inverter may be configured to supply power to a traction motor. The electrical system may include multiple motor windings of the traction motor connected between the power inverter and a switch. The switch may be configured to switch between a closed state and an open state, wherein a closed state allows current to flow from an off-board power source through the multiple motor windings to the RESS, and an open state prevents current from flowing between the off-board power source and the multiple motor windings.

[0005] Among other features, the electrical system includes an inductor connected in series between a plurality of motor windings and an accessory load, wherein the inductor is configured to mitigate at least one of current ripple or torque ripple.

[0006] Among other features, the power inverter includes a set of semiconductor switches configured to convert direct current (DC) into alternating current (AC).

[0007] Among other features, each of the semiconductor switches in this group includes a voltage-controlled switching device.

[0008] Among other features, the voltage-controlled switching device includes at least one of an insulated-gate bipolar transistor (IGBT), a metal-oxide-semiconductor field-effect transistor (MOSFET), or a wide-bandgap device (WBG).

[0009] Among other features, the power inverter includes multiple phase arms, each of the multiple phase arms including a pair of semiconductor switches in the set of semiconductor switches, wherein each phase arm is connected to a corresponding phase terminal of multiple motor windings of the traction motor.

[0010] Among other features, at least one semiconductor switch of the first phase bridge arm and the second phase bridge arm is pulse-width modulated such that current flows through at least one of the first phase bridge arm and the second phase bridge arm.

[0011] Among other features, current flows through at least two phases of multiple motor windings to increase the voltage from an off-board power source from a first voltage to a second voltage.

[0012] Among other features, the switch includes at least one of a contactor or a solid-state relay.

[0013] An exemplary electrical system is disclosed. The electrical system may include a rechargeable energy storage system (RESS) and a power inverter connected to the RESS. The power inverter may be configured to supply power to a traction motor. The electrical system may include multiple motor windings of the traction motor connected between the power inverter and a switch. The electrical system includes a controller connected to the switch and the power inverter. The controller is configured to transmit control signals to the power inverter and the switch such that current flows from the off-board power supply through the multiple motor windings to the RESS during a first operating state, and prevents current from flowing between the off-board power supply and the multiple motor windings during a second operating state.

[0014] Among other features, the electrical system includes an inductor connected in series between multiple motor windings and an off-board power supply, wherein the inductor is configured to mitigate at least one of current ripple or torque ripple.

[0015] Among other features, the power inverter includes a set of semiconductor switches configured to convert direct current (DC) into alternating current (AC).

[0016] Among other features, each of the semiconductor switches in this group includes a voltage-controlled switching device.

[0017] Among other features, the voltage-controlled switching device includes at least one of an insulated-gate bipolar transistor (IGBT), a metal-oxide-semiconductor field-effect transistor (MOSFET), or a wide-bandgap (WBG) semiconductor power device (WBG), such as a SiC MOSFET, a SiC JFET, or a GaN FET.

[0018] Among other features, the power inverter includes multiple phase arms, each of which includes a pair of semiconductor switches from a set of semiconductor switches, wherein each phase arm is connected to a corresponding phase terminal of a plurality of motor windings of a traction motor.

[0019] Among other features, at least one semiconductor switch of the first phase bridge arm and the second phase bridge arm is pulse-width modulated such that current flows through at least one of the first phase bridge arm and the second phase bridge arm.

[0020] Among other features, current flows through at least two phases of multiple motor windings to increase the voltage from an off-board power source from a first voltage to a second voltage.

[0021] Among other features, the controller receives software updates via over-the-air programming.

[0022] Among other features, the controller is configured to transmit control signals to control current flow in order to mitigate torque disturbances and achieve the desired voltage rise.

[0023] A method is disclosed that includes determining whether a connection to an off-board power source has been established, and transmitting at least one control signal to a power inverter and a switch to allow current to flow from the off-board power source through multiple motor windings to a rechargeable energy storage system (RESS) during a first operating state, and to prevent current from flowing between the off-board power source and the multiple motor windings during a second operating state when the connection has been established.

[0024] Further areas of application will become apparent from the description provided herein. It should be understood that these descriptions and specific examples are for illustrative purposes only and are not intended to limit the scope of this disclosure. Attached Figure Description

[0025] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of this disclosure in any way.

[0026] Figure 1A This is a schematic diagram of an exemplary motor vehicle connected to a non-vehicle DC fast charging station;

[0027] Figure 1B This is a schematic diagram of an exemplary motor vehicle connected to another motor vehicle;

[0028] Figure 2 It is a block diagram of an exemplary electrical system according to an exemplary embodiment;

[0029] Figure 3 It is a block diagram of an exemplary electrical system according to an exemplary embodiment;

[0030] Figure 4It is a circuit diagram of an exemplary electrical system according to an exemplary embodiment;

[0031] Figure 5 This is a circuit diagram of an exemplary electrical system showing a first operating state according to an exemplary embodiment;

[0032] Figure 6 This is a circuit diagram of an exemplary electrical system illustrating a second operating state according to an exemplary embodiment;

[0033] Figure 7 This is a circuit diagram of an exemplary electrical system according to another exemplary embodiment;

[0034] Figure 8 This is a flowchart illustrating an exemplary process for supplying power to the RESS of a vehicle via a non-vehicle power source, according to an exemplary embodiment. Detailed Implementation

[0035] The following description is merely exemplary in nature and is not intended to limit this disclosure, its application, or its uses.

[0036] Some hybrid electric or battery electric vehicles may include a local onboard rechargeable energy storage system (RESS) that stores a voltage higher than that available for charging the vehicle's RESS. In these cases, the vehicle may require an additional DC-DC converter to increase the voltage from the offboard power source to the RESS during charging. An additional DC-DC converter increases the vehicle's cost, weight, and size.

[0037] This disclosure describes an electrical system that provides boost conversion functionality via inverter switches and motor windings during vehicle charging. For example, a controller, such as an inverter controller, can selectively switch one or more switches from an open state to a closed state, or vice versa, to direct power from off-board power to the RESS. Power can be diverted through one or more motor windings via the inverter, causing the voltage to be boosted relative to the off-board power supply.

[0038] Figure 1A An exemplary direct current (DC) charging circuit 10 as part of a motor vehicle 20 is shown. The vehicle 20 is depicted undergoing DC fast charging operation, wherein the DC charging circuit 10 is electrically connected to an off-board DC fast charging station 30 via a charging port 11 and a charging cable 15, for example, using an SAE J1772 charging connector, a CHAdeMO, or another suitable regional or national standard charging plug or connector. This teaching is independent of the specific charging standard ultimately employed in the DC fast charging operation involving the DC fast charging station 30, and therefore the above example is merely illustrative.

[0039] The DC charging circuit 10 can be used as part of the motor vehicle 20 and other electrical systems, such as stationary or mobile power supply equipment, robots, or platforms. For vehicle applications, non-motorized vehicles, such as aircraft, ships, and rail vehicles, may enjoy similar benefits. In an exemplary embodiment, the DC charging circuit 10 can be used as part of the powertrain of a mobile system such as the exemplary vehicle 20. For consistency of illustration, the application of the DC charging circuit 10 as a component of the vehicle 20 in a motor vehicle environment will be described below, but this disclosure is not limited to such embodiments.

[0040] Figure 1A The vehicle 20 includes a body 12 and drive wheels 14. The body 12 may define or include a charging port 11 in a location accessible to a user. The vehicle 20 may be implemented in various ways as a plug-in electric vehicle, having, for example... Figure 2 The on-board rechargeable energy storage system (RESS) 115 shown and described below can, for example, use Figure 1A The off-board DC fast charging (DCFC) station 30 shown selectively recharges multi-cell lithium-ion, zinc-air, nickel-metal hydride, or lead-acid DC battery packs. The DC charging circuit 10 integrates the powertrain / traction drive components of the vehicle 20, and its general functions may include powering the traction motor 114 to generate motor torque and transmit it to the drive wheels 14 to propel the vehicle 20 or perform other useful work on the vehicle 20. Figure 1B An exemplary implementation of vehicle-to-vehicle (V2V) charging is illustrated. As shown, a first vehicle 20-1 can be used to at least partially charge a second vehicle 20-2, and vice versa. The first vehicle 20-1 and / or the second vehicle 20-2 may include electrical systems as described herein.

[0041] Figure 2 and Figure 3 A block diagram of the electrical system 100 of the DC charging circuit 10 of vehicle 20 according to various embodiments is shown. As shown, the electrical system 100 includes an on-board rechargeable energy storage system (RESS) 115 adapted to store high-voltage electrical energy for propelling an electrically driven vehicle (e.g., vehicle 20 of FIG. 1). The RESS 115 may be a deep-cycle, high-ampere-capacity battery system with a rated voltage of approximately 400 to approximately 800 volts direct current (VDC) or higher, depending, for example, on the desired vehicle range, the vehicle's gross weight, and the rated power of the various loads drawing power from the RESS 115. Figures 4 to 6 As shown, the DC link capacitor Co can be connected between the positive and negative terminals.

[0042] RESS 115 may include one or more high-voltage, independent rechargeable battery packs. RESS 115 can be connected to DCFC station 30 via high-voltage DC connector 160 and power inverter 162 to control the transfer of electrical energy to and from traction motor 114.

[0043] Vehicle 20 may also include one or more accessory loads 170. In an exemplary embodiment, accessory loads 170 may include various loads that draw power from electrical system 100. In an exemplary embodiment, RESS 115 may be adapted to store voltage at a first voltage, such as approximately 800 (800) volts DC. However, off-board power sources, such as off-board DC fast charging station 30 or another vehicle, may be configured to provide voltage at a second voltage, such as 400 (400) volts DC, which is less than the first voltage. As discussed in more detail below, electrical system 100 may be configured to boost the voltage provided by off-board power sources.

[0044] refer to Figure 2 The electrical system 100 also includes a controller 150, a first switch 102, a second switch 103, and a third switch 104 to control boost DC-DC operation to deliver power from an off-board power source to the RESS 115. Although the off-board power source shown includes the DC fast charging station 30, it should be understood that the off-board power source may also include another vehicle.

[0045] Switches 102, 103, and 104 may include contactors or solid-state relays adapted to close under electrical load to ensure instantaneous or near-instantaneous power delivery to the vehicle propulsion system and to drive any number of onboard accessories. Figure 3 As shown, the electrical system 100 may include a single-pole double-throw (SPDT) switch 105. In this embodiment, the SPDT 105 may replace... Figure 2 The switches 102 and 104 are shown and can be controlled by the controller 150.

[0046] Controller 150 may include at least one processor and sufficient memory for storing computer-readable instructions. The memory includes tangible, non-transitory memory, such as read-only memory, whether optical, magnetic, flash memory, or other types. Controller 150 also includes a sufficient number of random access memories, electrically erasable programmable read-only memories, etc., as well as high-speed clocks, analog-to-digital and digital-to-analog circuits, input / output circuits and devices, and suitable signal conditioning and buffering circuitry. Controller 150 may receive charging request signals from one or more electronic control units (ECUs) of vehicle 20. For example, an ECU associated with a vehicle-to-charging station or vehicle-to-vehicle communication system may provide a signal indicating that RESS 115 needs to be charged from a power source with a voltage lower than the RESS voltage, and controller 150 may initiate boost DC-DC operation as described below. If DC fast charging station 30 is able to directly provide the required charging voltage to RESS 115, switches 102 and 103 may be closed, and switch 104 may be open, for example, in non-boost mode operation.

[0047] like Figures 2 to 7 As shown, the electrical system 100 also includes an inverter controller 180, which controls the operation of the semiconductor switches S1 to S6 of the power inverter 162, as will be described below. Figures 4 to 6 A more detailed description follows. The inverter controller 180 may include at least one processor and sufficient memory for storing computer-readable instructions. The memory includes tangible, non-transitory memory, such as read-only memory, whether optical, magnetic, flash memory, or other types. The inverter controller 180 also includes a sufficient number of random access memories, electrically erasable programmable read-only memories, etc., as well as high-speed clocks, analog-to-digital and digital-to-analog circuits, input / output circuits and devices, and suitable signal conditioning and buffering circuitry.

[0048] In an exemplary embodiment, the inverter controller 180 may receive signals from the controller 150 and / or from sensors within the traction motor 114. For example, the traction motor 114 may include a phase current sensor and / or a rotor position sensor, providing signals indicating the phase current and / or rotor position, respectively. The inverter controller 180 may control semiconductor switches S1 to S6 by providing signals to one or more gates to switch semiconductor switches S1 to S6 between an open state and a closed state, as will be discussed in more detail below.

[0049] Figures 4 to 6An exemplary schematic diagram of electrical system 100 is shown. Power inverter 162 may include a bidirectional DC-to-AC and AC-to-DC power converter, which may be part of a traction power inverter module (TPIM) that connects off-vehicle power, such as an off-vehicle DC fast charging station 30 or the vehicle, to RESS 115 via motor windings 166. Motor windings 166 may include windings of traction motor 114, shown as motor windings La, Lb, and Lc. For example, during vehicle 20 operation, motor windings 166 may provide three-phase power to generate a rotating magnetic field to rotate the rotor of traction motor 114. Although illustrated with only three motor windings 166, it should be understood that, depending on the motor configuration, traction motor 114 may include additional motor windings 166. Power inverter 162 may include multiple phases and corresponding operable motor control modules to receive motor control commands from and control inverter states to provide motor drive or regenerative functions.

[0050] The power inverter 162 may include a switch group 164 consisting of semiconductor switches S1 to S6 (also referred to herein as “inverter switches”) that cooperatively convert direct current (DC) from RESS 115 into alternating current (AC) for powering the traction motor 114 via high-frequency switching during vehicle operation, for example, in motor operation mode. Each semiconductor switch S1 to S6 may be implemented as a voltage-controlled switching device in the form of a silicon insulated-gate bipolar transistor (IGBT), a silicon carbide (SiC) metal-oxide-semiconductor field-effect transistor (MOSFET), a silicon (Si) superjunction MOSFET, a gallium nitride (GaN) field-effect transistor (FET), a silicon carbide junction-gate field-effect transistor (JFET), other wide-bandgap (WBG) or ultra-wide-bandgap semiconductor power switching device (UWBG), or other suitable switches with a corresponding gate to which a gate signal is applied to change the on / off state of a given switch. Each phase of the three-phase traction motor 114 typically has at least one pair of semiconductor switches. Each pair of switches, such as switches S1 and S2 (phase A), switches S3 and S4 (phase B), and switches S5 and S6 (phase C), may be referred to as a phase bridge arm of power inverter 162. For example, in an exemplary embodiment, power inverter 162 may include at least three (3) phase bridge arms. Each phase bridge arm of power inverter 162 is connected to a corresponding motor phase terminal, such as one of the motor windings 166.

[0051] refer to Figure 5 and Figure 6The off-board power supply can be adapted to provide converted power to RESS 115 during charging. For example, electrical system 100 can boost the voltage provided by the off-board power supply. Battery pack 116 can be adapted to store voltage at a first voltage, which is higher than a second voltage; for example, the first voltage could be 800 volts DC and the second voltage could be 400 volts DC. During this operating state, switches S1 and S2 connected to the off-board power supply (400 volts DC in this example) are open to prevent current from flowing out of the first voltage (battery pack). During this period, switch S3 of phase B and switch S5 of phase C ( Figure 5 (Middle) remains in the open state. Phase B switch S4 and Phase C switch S6 ( Figure 6 The (middle) can receive pulse width modulation at a duty cycle and a phase shift between the two arms, so as, for example, in the case of V2V charging, to provide an increased voltage to the load or battery of the receiving vehicle 20 across the vehicle DC bus filter capacitor C0.

[0052] Switches S4 and S6 can be pulse-width modulated using programmable duty cycles and phase shifts relative to each other. The pulse-width modulation frequency, duty cycle, and / or phase shift between phases B and C can be functions of the charging power and / or rotor position of the traction motor 114.

[0053] During charging operation, the inductive elements of the motor windings La, Lb, and Lc, and switches S4 and / or S6, as well as the freewheeling diodes and / or S5 of the series inductors L1 and S3, can be used as an interleaved two-phase boost converter. It should be understood that the controller 150 can select an optimal phase selection mode to mitigate interference with torque and boost conversion functions. For example, the controller 150 can use a lookup table based on one or more vehicle parameters (e.g., torque, charging, etc.) and output a PMW signal corresponding to the vehicle parameters to cause one or more inverter switches S1 to S6 to operate as described above. For example, based on switch selection, the desired boost conversion function can be selected to charge the RESS 115 and mitigate torque disturbances.

[0054] In some implementations, the software of controller 150 can be updated via over-the-air programming. For example, software updates can be transmitted from a data source, such as an original equipment manufacturer (OEM), to controller 150 via one or more suitable communication networks. Over-the-air updates can provide the necessary parameters to adjust the charging power by regulating inverter control signals of one or more switches S1 to S6, such as current commands, frequency, duty cycle, phase shift, etc., according to the charging power level via inverter controller 180.

[0055] In boost mode PWM operation, switches S5 and S3 for phases B and C are open. In PWM operation with phase B on, switches S6 and 104 are closed, allowing current to flow from the off-board power supply to the motor windings Lb and La and the filter inductor L1. To increase or boost the voltage from the off-board power supply, the inverter controller 180 is in the closed state (…). Figure 5 ) and open state ( Figure 6 Switch S6 is used to switch between phases B and S3, causing electrical system 100 to perform boost conversion. During the PWM closed state of phase B, energy stored in inductors L1, La, and Lb is transferred to RESS 115 via the freewheeling diode of S5. Similarly, switch S4 can be modulated on and off to allow boost operation via the freewheeling diodes of L1, La, Lc, and S3. The PWM operation of S6 and S4 can have phase shifts to minimize current / torque ripple in the motor and current ripple in the power supply and RESS. Therefore, the motor phase winding 166, in conjunction with the inverter phase bridge arm switch, can boost the first voltage to a second voltage, for example, performing boost conversion.

[0056] In use, the filter inductor L1 can be positioned in series with the motor winding 166 to reduce, for example, current ripple and motor torque ripple. It should be understood that in some embodiments, the filter inductor may be optional. In the example shown, switch S6 can accept a pulse-width modulated signal from controller 180 to switch switch S6 between an open and closed state, such that the electrical system 100 converts the voltage supplied to RESS 115 from a first voltage to a second voltage. In embodiments where the inverter switches consist of metal-oxide-semiconductor field-effect transistors, during boost converter operation, when the lower switch is off, the complementary switch in each phase can be turned on to minimize freewheeling diode losses.

[0057] Figure 7 Another exemplary embodiment of the electrical system 100 is shown. As shown, the electrical system 100 may include switches 182 and 184. Similar to switch 104, switches 182 and 184 may include contactors or solid-state relays. Switches 182 and 184 may be controlled by controller 150 such that current can be selectively directed based on a specific operating phase. For example, controller 150 may selectively control switches S1 to S6 and / or switches 104, 182, and 184 based on a desired vehicle charging operation, for example, to mitigate torque disturbances during boost operation. In some embodiments, controller 150 may include a lookup table that associates the charging input with a vehicle charging standard. In one or more embodiments, a single-pole three-position relay or three separate relays, such as switches 104, 182, and 184 (see...), are used. Figure 7It can be used to select the optimal phase to be connected to the DC fast charging station 30, and modulate the remaining phase as described above.

[0058] Figure 8 This is a flowchart of an exemplary process 700 for supplying power to the RESS 115 of vehicle 20 via an off-board power source. The blocks of process 700 can be executed by controller 150 and / or inverter controller 180. At block 705, it is determined whether boost charging is required (in this exemplary case, charging the 800V RESS from a 400V DC fast charging station 30) and whether an electrical connection has been established between the off-board power source and the high-voltage DC bus connector 160. For example, controller 150 may receive an input signal indicating the start of charging via a suitable handshake protocol and / or a signal from the off-board power source controller, and establish the electrical connection. If no electrical connection has been established, 700 returns to block 705.

[0059] If an electrical connection has been established, in block 710, controller 150 sends one or more control signals to inverter 162 and / or switches 102, 103, 104 and / or 105. Based on the input from controller 150, switches 102, 103, 104 and / or 105 switch to the desired operating state, such as an open or closed state, and inverter controller 180 outputs a voltage signal that causes switches S1 to S6 of inverter 162 to provide a boost function. For example, switch 102 may switch to the open state to prevent current from flowing from off-board power to RESS 115, and switch 104 may switch to the closed state to allow current to flow from off-board power to motor winding 166, thereby increasing the voltage supplied to RESS 115. As described above... Figure 5 and 6 As discussed, switch S6 can be modulated to increase the voltage at RESS 115 due to the characteristics of the boost converter that allow current to flow through the motor windings 166 via the inverter controller 180. While this disclosure describes the modulation of switch S6, it should be understood that, in order to increase the voltage, it is also possible to adjust the voltage according to the description above and... Figure 5 and Figure 6 The operation shown is to modulate switch S4 via inverter controller 180.

[0060] In block 715, controller 150 determines whether the electrical connection between the non-vehicle power supply and the electrical system has been disconnected. If controller 150 does not determine that the electrical connection has been disconnected, process 700 returns to block 715. Otherwise, process 700 ends.

[0061] The descriptions in this disclosure are merely exemplary in nature, and any changes that do not depart from the spirit and scope of this disclosure fall within its scope. Such changes should not be considered as departing from the spirit and scope of this disclosure.

Claims

1. An electrical system comprising: Rechargeable Energy Storage System (RESS); A power inverter connected to the RESS, the power inverter being configured to provide power to the traction motor; as well as Multiple motor windings of the traction motor connected between the power inverter and the switch group; The switch group includes a first switch, a second switch, and a third switch, and the plurality of motor windings include a first motor winding, a second motor winding, and a third motor winding; The power inverter includes multiple phase bridge arms, including a first phase bridge arm, a second phase bridge arm, and a third phase bridge arm. Each phase bridge arm includes a pair of semiconductor switches in a set of semiconductor switches configured to convert direct current (DC) into alternating current (AC). One end of the first motor winding is connected to the first phase bridge arm and the first switch, respectively. One end of the second motor winding is connected to the second phase bridge arm and the second switch, respectively; One end of the third motor winding is connected to the third phase bridge arm and the third switch respectively, and the other end of the third motor winding is connected to the other end of the first motor winding and the other end of the second motor winding respectively. The first switch, the second switch, and the third switch are configured to be controlled by a controller such that current can be selectively directed according to the operating phase to select the optimal phase to be connected to a DC fast charging station; In this configuration, one of the first switch, the second switch, and the third switch is configured to switch between a closed state and an open state. The closed state allows current to flow from the off-board power supply through two of the plurality of motor windings connected in series during a first operating state to transfer energy stored in two of the plurality of windings to the RESS. The open state prevents current from flowing between the off-board power supply and the plurality of motor windings.

2. The electrical system of claim 1, further comprising inductors connected in series between two of the plurality of motor windings and the off-board power supply, wherein, The inductor is configured to mitigate at least one of current ripple or torque ripple.

3. The electrical system as claimed in claim 1, wherein, Each of the semiconductor switches in the set includes a voltage-controlled switching device.

4. The electrical system as claimed in claim 3, wherein, The voltage-controlled switching device includes at least one of the following: silicon insulated gate bipolar transistor (IGBT), silicon carbide metal oxide semiconductor field-effect transistor (MOSFET), silicon superjunction MOSFET, gallium nitride (GaN) field-effect transistor (FET), silicon carbide junction gate field-effect transistor (JFET), wide bandgap (WBG) device, or ultra-wide bandgap (UWBG) device.

5. The electrical system as claimed in claim 1, wherein, At least one semiconductor switch of the first phase bridge arm and the second phase bridge arm is pulse-width modulated so that current flows through at least one of the first phase bridge arm and the second phase bridge arm.

6. The electrical system as claimed in claim 5, wherein, During the first operating state, when the first semiconductor switch in the third phase bridge arm connected to two of the plurality of motor windings is closed and the remaining semiconductor switches in the first phase bridge arm, the second phase bridge arm, and the third phase bridge arm are open, current flows through two of the plurality of motor windings to increase the voltage from the off-board power supply from a first voltage to a second voltage and then flows to the RESS.

7. The electrical system as claimed in claim 1, wherein, During boost operation, when one of the first, second, and third switches is closed, and when the second semiconductor in the third phase arm connected to two of the plurality of motor windings is closed and the remaining semiconductor switches in the first, second, and third phase arms are open, current flows through two of the plurality of motor windings but not to the RESS.

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