Electric power system for an electric vehicle

Abstract

The present application provides a motor drive integrated on-board charger for electric vehicles that reduces the number of components in the electric power system. The reduction in the number of components is achieved by using the motor and the motor drive inverter as part of the on-board charger in the charging mode. By controlling the relays, the electrical connections in the system can be reconfigured depending on its operating state. In one aspect, the motor and the motor drive inverter function as a boost PFC and / or current regulator.

Description

Technical Field

[0001] This case relates to an on-board charger that utilizes components of a motor drive circuit to reduce the cost and size of the electrical system in an electric vehicle. Background Technology

[0002] Electric vehicles are powered by electric motors, not internal combustion engines. In contrast, electric motors do not emit greenhouse gases, while internal combustion engines do, contributing to air pollution and global warming. As environmental protection becomes increasingly important, public interest in electric vehicles has surged.

[0003] Figure 1A This is a conceptual schematic diagram of the electric power system 10 for an electric vehicle. The electric power system 10 includes a motor 11, a motor driver 12, a battery 13, an on-board charger 14, and an AC input 15. The electric motor 11 can be connected to the mechanical system of the electric vehicle. The electric motor 11 converts electrical energy in the electric power system 10 into mechanical energy to rotate the wheels of the electric vehicle. The motor driver 12 transfers electrical energy from the battery 13 to the motor 11. The on-board charger 14 transfers electrical energy from the external AC input 15 to the battery 13. It can be seen that the electric power system 10 needs to include the components of the motor driver 12 and the on-board charger 14.

[0004] Figure 1B and Figure 1C The direction of electrical energy flow in the power system 10 is shown in both drive mode and battery charging mode. In drive mode, as shown... Figure 1B As shown, electrical energy is transferred from battery 13 to motor 11, battery 13 is discharged, and onboard charger 14 does not operate. In battery charging mode, as... Figure 1C As shown, electrical energy is transferred from AC input 15 to battery 13, which is then charged. Motor driver 12 does not operate. It can be noted that in electrical system 10, motor driver 12 and on-board charger 14 do not operate simultaneously; that is, only motor driver 12 operates in drive mode, while only on-board charger 14 operates in battery charging mode. Because motor driver 12 and on-board charger 14 do not operate simultaneously, motor 11 and / or motor driver 12 can be used as part of on-board charger 14 to reduce the number of components in electrical system 10.

[0005] Figure 2A This is a schematic diagram of the circuit structure of a conventional power system 20 for an electric vehicle with a three-phase motor. The power system 20 includes a three-phase motor 21, a motor drive inverter 22, a battery 23, an on-board charger 24, and an AC input 25. The three-phase motor 21 and the motor drive inverter 22 are connected to the right side of the battery 23 via relay R2. For safety reasons, relays R1 and R2 are necessary so that the battery 23 can be physically disconnected from the power system 20 when it is not in operation.

[0006] The three-phase motor 21 has three windings embedded in the stator assembly. Each stator winding can be represented electrically by an inductor. The motor drive inverter 22 includes three identical half-bridge arms, each containing switches S1, S2, ..., S6. The switching node of each half-bridge arm is connected to one end of the stator winding of the motor 21. The other ends of the stator windings are connected to a single node (i.e., the neutral point). The motor drive inverter 22 controls the phase current and torque of the motor by adjusting the duty cycle of the half-bridge arms. The on-board charger 24 has a two-stage architecture: an AC / DC PFC (power factor correcting) stage 241 and an isolated DC / DC conversion stage 242. The AC / DC PFC stage 241 regulates the waveform shape of the input current, enabling the charger to achieve a high power factor and low total harmonic distortion of the input current.

[0007] Because boost converters are easy to control and have continuous input current, they are commonly used in AC / DC PFC stage 241. In this example, AC / DC PFC stage 241 includes rectifier diodes D1, D2, D3, and D4, and PFC inductor L. PFC Boost switch S B1 and boost diode D5. PFC inductor L PFC Includes a boost inductor. In the chain capacitor C O,PFC The output voltage of the AC / DC PFC stage 241 is quasi-DC with low-frequency ripple, which is caused by the high-power ripple typical of single-phase systems. When the input voltage V... AC When the input voltage V is zero, the input power is zero; conversely, when the input voltage V is zero, the input power is zero. AC At its maximum, the power is also at its maximum. Therefore, the power flow of the AC / DC PFC stage 241 fluctuates during the line cycle. Due to the two zero-crossing points in the AC voltage, the power of the AC / DC PFC stage 241 fluctuates at twice the grid frequency.

[0008] The DC / DC conversion stage 242 is connected after the AC / DC PFC stage 241 and provides isolation and a fixed DC charging current to the battery 23. For isolated DC / DC converters, the LLC resonant converter topology is widely used today because it can achieve high efficiency with a small number of components. Figure 2A An isolated half-bridge LLC resonant converter is shown, which includes a main switch S INV1 and S INV2 Resonant inductor L R Resonant capacitor C R1 and C R2 Transformer TR, rectifier diode D R1 and DR2 and capacitor C IN2 It can be seen that the three main functions of an on-board charger are power factor correction, isolation, and DC charging current regulation.

[0009] Figures 2B and 2C respectively show Figure 2A The diagram illustrates the traditional electric system's drive mode and battery charging mode. Figure 2B shows the operating state in drive mode, where relay R2 is on and relay R1 is off, so that battery 23 is only connected to motor 21 and motor drive inverter 22, and on-board charger 24 is off and not operating. The energy stored in battery 23 is gradually consumed during the process of using electric system 20 to drive the electric vehicle. Figure 2C shows the operating state in battery charging mode, where relay R2 is off and relay R1 is on, so that battery 23 is only connected to on-board charger 24, motor drive inverter 22 is off and motor 21 is not operating.

[0010] References:

[0011] [1]SRMeher, S.Banerjee,BTVankayalapati,and RKSingh, "AReconfigurable On-Board Power Converter for Electric Vehicle With ReducedSwitch Count," IEEE Trans.on Vehicular Technology, vol.69, no.4, Apr.2020.

[0012] [2] M.Tong, M.chenc, W.Hua, and S.Ding, "A Single-Phase On-Board Two-StageIntegrated Battery Charger for EVs Based on a Five-Phase Hybrid-ExcitationFlux-Switching Machine," IEEE Trans.on Vehicular Technology, vol.69, no.4, Apr.2020.

[0013] [3] Khan, Mehnaz Akhter, Iqbal Husain, and Yilmaz Sozer. "Integrated electric motor drive and power electronics for bidirectional power flow between the electric vehicle and DC or AC grid." IEEE Transactions on PowerElectronics28.12(2013):5774-5783.

[0014] [4] Subotic, Ivan, and Emil Levi. "A review of single-phase on-boardintegrated battery charging topologies for electric vehicles." 2015IEEEWorkshop on Electrical Machines Design, Control and Diagnosis (WEMDCD). IEEE, 2015. Summary of the Invention

[0015] This invention provides a motor-driven integrated on-board charger that reduces the number of components in the power system of an electric vehicle. In an electric vehicle, the power system includes a motor, a motor driver, and an on-board charger. In charging mode, the on-board charger performs three main functions: power factor correction (PFC), isolation, and current regulation. In conventional systems, each part of the power system performs only an individual function. Therefore, the motor and motor drive inverter cannot be used in charging mode, and conversely, the on-board charger cannot be used in driving mode. The converter topology of this invention utilizes the motor and motor drive inverter as part of the on-board charger in charging mode, thereby reducing the number of components in the power system. In the embodiments of this invention, by refactoring the topology with relays, the motor and motor drive inverter can provide power factor correction and current regulation functions in charging mode. Therefore, the motor-driven integrated on-board charger of this invention reduces the number of components in the on-board charger, thereby improving the cost-effectiveness of the power system.

[0016] According to one aspect of the concept, this invention provides an electric power system for an electric vehicle, comprising an AC / DC converter, a motor driver, a PFC inductor, a chain capacitor, a first relay, and a second relay. The motor driver includes a motor and an inverter. The PFC inductor is electrically connected between the AC / DC converter and the motor driver. The chain capacitor is connected in parallel to the motor driver. The first relay is connected between the PFC inductor and the motor driver. The battery is connected to the chain capacitor via the second relay.

[0017] In one embodiment, the motor includes multiple phases, and the inverter includes multiple phase arms, with the first end of each phase connected to the corresponding phase arm.

[0018] In one embodiment, the second ends of all phases are connected at the neutral point.

[0019] In one embodiment, the PFC inductor is connected to one of the phase bridge arms via a first relay.

[0020] In one embodiment, each phase bridge arm includes two switches, and a PFC inductor is connected via a first relay to a node between the two switches in one of the phase bridge arms.

[0021] In one embodiment, in drive mode, the first relay is turned off, the second relay is turned on, and the battery releases electrical energy to the motor.

[0022] In one embodiment, in charging mode, both the first relay and the second relay are turned on, and the battery is charged by AC power.

[0023] In one embodiment, the AC / DC converter includes an LLC series resonant converter, which receives AC power and generates DC power at its input and output terminals, respectively.

[0024] In one embodiment, the AC / DC converter includes an isolated AC / DC rectifier having a half-bridge inverter and a full-bridge rectifier, an isolated AC / DC rectifier having a full-bridge inverter and a full-bridge rectifier, an isolated AC / DC rectifier having a half-bridge inverter and a voltage doubler rectifier, or an isolated AC / DC rectifier having a full-bridge inverter and a voltage doubler rectifier.

[0025] According to another aspect of this invention, a power system for an electric vehicle is provided, comprising an AC / DC converter, a motor driver, a PFC inductor, a chain capacitor, a first relay, and a second relay. The motor driver includes a motor and an inverter, wherein the motor includes multiple phases, and the inverter includes multiple phase arms, each phase connected to a corresponding phase arm. The PFC inductor is electrically connected between the AC / DC converter and the motor driver. The chain capacitor is connected in parallel to the motor driver. The first relay is configured to switchably connect a first phase arm of the multiple phase arms to either a first phase of the multiple phases or the PFC inductor. The second relay is configured to switchably connect a battery to either the positive terminal of the inverter or the first phase.

[0026] In one embodiment, each phase arm of the inverter includes two switches, a node is provided between the two switches of the first phase arm, and a first relay is connected between the PFC inductor and the node of the first phase arm.

[0027] In one embodiment, one end of all phase arms of the inverter is connected to a neutral point.

[0028] In one embodiment, the first and second relays comprise single-pole double-throw relays.

[0029] In one embodiment, in drive mode, a first relay connects a first phase bridge arm to a first phase of the motor, and a second relay connects a battery to the positive terminal of the inverter, with the battery releasing electrical energy to the motor.

[0030] In one embodiment, in charging mode, a first relay connects a first phase bridge arm to a PFC inductor, and a second relay connects a battery to a first phase of the motor, with the battery being charged by an AC power source.

[0031] In one embodiment, the AC / DC converter includes an LLC series resonant converter, which is adapted to receive AC power and generate DC power at its input and output terminals, respectively.

[0032] In one embodiment, the AC / DC converter includes an isolated AC / DC rectifier having a half-bridge inverter and a full-bridge rectifier, an isolated AC / DC rectifier having a full-bridge inverter and a full-bridge rectifier, an isolated AC / DC rectifier having a half-bridge inverter and a voltage doubler rectifier, or an isolated AC / DC rectifier having a full-bridge inverter and a voltage doubler rectifier.

[0033] According to another aspect of this invention, a power system for an electric vehicle is provided, comprising an AC / DC converter, a motor driver, a PFC inductor, a chain capacitor, a first relay, a second relay, and a third relay. The motor driver includes a motor and an inverter, wherein the motor includes multiple phases, and the inverter includes multiple phase arms, each phase connected to a corresponding phase arm. The PFC inductor is electrically connected between the AC / DC converter and the motor driver. The chain capacitor is connected in parallel to the motor driver. The first relay is connected between the first phase arm of the multiple phase arms and the first phase of the multiple phases. The first phase arm and the PFC inductor are interconnected or disconnected via the second relay, and the first phase and the buffer capacitor are interconnected or disconnected via the second relay. The battery is connected to the chain capacitor via the third relay.

[0034] In one embodiment, the second relay includes a double-pole double-throw switch.

[0035] In one embodiment, in drive mode, the first and third relays are turned on, the second relay is turned on, and the battery releases electrical energy to the motor.

[0036] In one embodiment, in charging mode, the second and third relays are turned off, the first relay is turned on, and the battery is charged by AC power.

[0037] According to another aspect of this invention, a power system for an electric vehicle is provided, comprising an AC / DC converter, a first relay, a motor, a motor drive inverter, a chain capacitor, and a second relay. The AC / DC converter is adapted to receive AC power and generate DC power at its input and output terminals, respectively. The first relay is electrically connected to the output terminal of the AC / DC converter. The motor is connected to the AC / DC converter via the first relay. The motor drive inverter is connected to the motor. The chain capacitor is connected in parallel to the motor drive inverter. The chain capacitor is connected to the battery via the second relay.

[0038] In one embodiment, in drive mode, the first relay is turned off, the second relay is turned on, and the battery releases electrical energy to the motor.

[0039] In one embodiment, in charging mode, both the first relay and the second relay are turned on, and the battery is charged by AC power.

[0040] In one embodiment, the motor includes multiple phase bridge arms, one end of all phase bridge arms being connected to a neutral point, and a first relay being connected to the neutral point.

[0041] In one embodiment, the power system further includes a third relay, wherein the third relay is electrically connected to the first relay, the motor, and the motor drive inverter.

[0042] In one embodiment, the motor includes multiple phases, and the motor drive inverter includes multiple phase bridge arms. One phase of the motor is connected to the corresponding phase bridge arm of the motor drive inverter via a third relay. In drive mode, the first relay is off, and the second and third relays are on, allowing the battery to release electrical energy to the motor. In charging mode, the first and second relays are on, and the third relay is off, allowing the battery to be charged by AC power.

[0043] The following detailed description and diagrams will make the technology in this case easier to understand. Attached Figure Description

[0044] Figure 1A This is a schematic diagram of a traditional electric vehicle's power system.

[0045] Figure 1B and Figure 1C Show each Figure 1A The direction of electrical energy flow in the power system under driving mode and battery charging mode.

[0046] Figure 2A This is a schematic diagram of the circuit structure of a traditional electric power system for an electric vehicle with a three-phase motor.

[0047] Figures 2B and 2C show the driving mode and battery charging mode, respectively. Figure 2A The power system.

[0048] Figure 3A This is a schematic diagram of the power system architecture of the electric vehicle with a motor-driven integrated on-board charger in this case.

[0049] Figure 3B and Figure 3C Show each Figure 3A The direction of electrical energy flow in the power system under driving mode and battery charging mode.

[0050] Figure 4A The first embodiment of this invention illustrates the power system of an electric vehicle with a motor-driven integrated on-board charger.

[0051] Figure 4B and Figure 4C Show each Figure 4A The driving modes and battery charging modes of the motor-driven integrated vehicle charger are shown.

[0052] Figure 5A The second embodiment of this invention illustrates the power system of an electric vehicle with a motor-driven integrated on-board charger.

[0053] Figure 5B and Figure 5C Show each Figure 5A The driving modes and battery charging modes of the motor-driven integrated vehicle charger are shown.

[0054] Figure 6A The third embodiment of this invention illustrates the power system of an electric vehicle with a motor-driven integrated on-board charger.

[0055] Figure 6B and Figure 6C Show each Figure 6A The driving modes and battery charging modes of the motor-driven integrated vehicle charger are shown.

[0056] Figure 6D for Figure 6C A simplified version.

[0057] Figure 7A The fourth embodiment of this invention illustrates the power system of an electric vehicle with a motor-driven integrated on-board charger.

[0058] Figure 7B and Figure 7C Show each Figure 7A The driving modes and battery charging modes of the motor-driven integrated vehicle charger are shown.

[0059] Figure 7D for Figure 7C A simplified version.

[0060] Figure 7E In response to Figure 7C and Figure 7D A schematic diagram of the control architecture of the converter in the diagram.

[0061] Figure 8A , Figure 8B , Figure 8C and Figure 8D Various topology variations of isolated AC / DC rectifiers in the power system of an electric vehicle with an integrated on-board charger for motor drive are shown.

[0062] Figure 9A The fifth embodiment of this invention illustrates the power system of an electric vehicle with a motor-driven integrated on-board charger.

[0063] Figure 9B and Figure 9C Show each Figure 9A The driving modes and battery charging modes of the motor-driven integrated vehicle charger are shown. Detailed Implementation

[0064] Some typical embodiments embodying the features and advantages of this invention will be described in detail in the following description. It should be understood that this invention can have various variations in different forms, all of which do not depart from the scope of this invention, and the descriptions and illustrations herein are for illustrative purposes only and not intended to limit this invention. For example, if the following disclosure describes forming a first feature on or above a second feature, it indicates that it includes embodiments where the formed first feature and the second feature are in direct contact, and also includes embodiments where additional features can be formed between the first feature and the second feature, so that the first feature and the second feature may not be in direct contact. Furthermore, different embodiments in the description of this invention may use repeated reference numerals and / or words; these repeated numerals or words are for simplification and clarity purposes and are not intended to limit the relationships between the various embodiments and / or the described appearance structures. Furthermore, to facilitate the description of the relationship between one element or feature element and another element(s) or feature elements(s) in the diagrams, spatially related terms such as "beneath," "below," "lower," "above," "upper," and similar terms may be used. It is understood that, in addition to the orientations shown in the diagrams, spatially related terms encompass different orientations of the device in use or operation. The device may also be otherwise positioned (e.g., rotated 90 degrees or located in other orientations), and the descriptions using the spatially related terms will be interpreted accordingly. When an element is referred to as "connected" or "coupled" to another element, it may be a direct connection or coupling to the other element, or the presence of an additional element. Although the numerical ranges and parameters of the broad scope of this disclosure are approximate, values ​​are stated as precisely as possible in specific examples. While it is understood that terms such as “first,” “second,” “third,” etc., may be used in the claims to describe various elements, these elements should not be limited by these terms, and the elements accordingly described in the embodiments are used to express different reference numerals. These terms are only used to distinguish one element from another; for example, a first element may be referred to as a second element, and similarly, a second element may be referred to as a first element, without departing from the scope of the embodiments. The term “and / or” as used herein includes any or all combinations of one or more of the related listed items. Furthermore, numerical ranges or parameters inherently contain errors present in individual test measurements. And, as appears herein, the terms “approximately” or “substantially” generally mean within 10%, 5%, 1%, or 0.5% of a given value or range. Alternatively, the terms “approximately” or “substantially” may mean within an error acceptable to a person skilled in the art.Except in instances of operation / work, or unless expressly stated otherwise, all numerical ranges, quantities, values, and percentages disclosed herein (such as quantities of materials, times, temperatures, operating conditions, proportions of dosages, and the like) should be understood to be modified by the terms “approximately” or “substantially” in all embodiments. Accordingly, unless indicated to the contrary, the numerical parameters set forth in this disclosure and the appended claims are approximate values ​​that may vary as necessary. For example, each numerical parameter should be interpreted at least according to the number of significant figures stated and by applying ordinary rounding principles. Ranges may be expressed herein as from one endpoint to another or between two endpoints. All ranges disclosed herein include endpoints unless otherwise specified.

[0065] Figure 3A This is a schematic diagram of the power system 30 of an electric vehicle with a motor-driven integrated on-board charger 34, according to an embodiment of this invention. To reduce the number of components, the motor-driven integrated on-board charger 34 provides both the functions of a motor driver and an on-board charger. This integrated structure is feasible because the motor driver and the on-board charger do not operate simultaneously. In drive mode, the power system 30 operates as a motor driver, while in battery charging mode, the power system 30 operates as an on-board charger.

[0066] Figure 3B and Figure 3C Show each Figure 3A The direction of electrical energy flow in the power system 30 in drive mode and battery charging mode. In drive mode, such as... Figure 3B As shown, electrical energy is transferred from battery 33 to motor 31. At this time, battery 33 is discharged, and AC input 35 is disconnected. In battery charging mode, as... Figure 3C As shown, electrical energy is transferred from the external AC input 35 to the battery 33, at which time the battery 33 is charged. This function is the main difference between the conventional approach and the motor-driven integrated vehicle charger approach of this embodiment. In this embodiment, for the motor-driven integrated vehicle charger, the motor 31 and the components in the motor-driven integrated vehicle charger 34 operate as part of the vehicle charger, thereby reducing the number of components in the vehicle charger.

[0067] Figure 4A The diagram illustrates the power system 40 of an electric vehicle with a motor-driven integrated on-board charger according to the first embodiment of this invention. For example... Figure 4A As shown, the power system 40 includes a motor 41, a motor drive inverter 42, a battery 43, an isolated AC / DC converter 44, and an external AC power input 45. In one embodiment, the motor 41 includes three motor windings (i.e., a three-phase motor), and all motor windings are connected to the neutral point.

[0068] The isolated AC / DC converter 44 includes rectifier diodes D1, D2, D3, and D4, and an input capacitor C. IN1 and LLC converter. The LLC converter contains two switches S INV1 and S INV2 Resonant inductor L R Resonant capacitor C R1 and C R2 Transformer TR, rectifier diode D R1 and D R2 and capacitor C IN2 Capacitor C IN2 The motor drive inverter 42 is connected to the neutral point of motor 41 via relay R1. It may include switches S1, S2, S3, S4, S5, and S6. Each end of the motor winding of motor 41 opposite the neutral point is connected to two of the switches S1, S2, S3, S4, S5, and S6 of the motor drive inverter 42. The motor drive inverter 42 is connected in parallel to the link capacitor C. O Battery 43 is connected to capacitor C via relay R2. O The two ends. Compared to Figure 2A Traditional systems in China Figure 4A The isolated AC / DC converter 44 in the illustrated embodiment may not include, for example, Figure 2A The boost inductor L in the conventional system shown PFC Boost switch S B1 Diode D5 and capacitor C O,PFC This can reduce system costs.

[0069] Figure 4B and Figure 4C Show each Figure 4A The diagram shows the drive mode and battery charging mode of the motor-driven integrated on-board charger. In drive mode, as... Figure 4B As shown, relay R1 is off and relay R2 is on, so battery 43 can be connected only to motor 41 and motor drive inverter 42, and isolated AC / DC converter 44 is off. It can be noted that... Figure 4B The electrical connections in the power system 40 are essentially the same as those in Figure 2B. In battery charging mode, such as... Figure 4C As shown, both relays R1 and R2 are turned on, allowing electrical energy to be transferred from the AC power input 45 to the battery 43. It can be noted that both the motor 41 and the motor drive inverter 42 are part of the charging system. Conversely, in the power system 20 of Figure 2B, the motor 41 and the motor drive inverter 42 do not operate in battery charging mode.

[0070] In this embodiment, during battery charging mode, the LLC converter in the isolated AC / DC converter 44 is used as an AC / DC rectifier and provides isolation and scaling for the AC power input 45. The switching frequency of the LLC converter can vary between half and five times the resonant frequency, where the resonant frequency is determined by the resonant cavity elements (including L... R C R1 and C R2 This is determined by the switching frequency, which is much higher than the AC input line frequency (e.g., 60Hz). Therefore, the capacitor C... IN2 The voltage on is the AC input voltage V. AC The scaled absolute value. The three windings of the motor drive inverter 42 and the motor 41 can be considered as three independent and parallel-connected boost converters, operating as a composite boost power factor correction circuit. In this way, Figure 4C The circuitry described above can provide isolation and power factor correction with a relatively small number of components. However, in this embodiment, it is affected by the output voltage ripple of the PFC circuit. Figure 4C The charging current in the power system 40 may have significant ripple. Therefore, in some embodiments, Figure 4C The power system 40 can be applied to systems where battery current ripple is acceptable.

[0071] Figure 4C One advantage of the motor-driven integrated on-board charger shown is its simple control. This is due to the input capacitor C... IN1 The voltage across it is relatively small, therefore the voltage across it is the rectified input voltage V. AC Input capacitor C IN1 The voltage across the LLC resonant converter was established. The LLC resonant converter operates with a 50% duty cycle and a fixed switching frequency. Because the number of turns in the secondary winding of the transformer TR is less than the number of turns in the primary winding, the LLC resonant converter will input capacitor C... IN1 The voltage across the terminals is reduced to a lower value. The switching frequency of the LLC resonant converter is based on the battery voltage, battery current, and input voltage V. AC The decision was made to transfer the capacitor C. IN2 Provide an appropriate AC voltage. (This is related to the input capacitor C.) IN1 Similarly, capacitor C IN2 The value of is also relatively small. Therefore, the capacitance C IN2 The voltage at both ends is the rectified and slashed input voltage V. AC Since there is no significant energy storage in the AC / DC converter 44, the voltages of both capacitors follow the input voltage V. AC The waveform shape. Compared to systems that use large capacitance values ​​to maintain the DC link at a quasi-fixed value (e.g., Figure 2A The power system 20), which can be considered as having a soft DC link.

[0072] The phase arms of the three-phase motor drive inverter are controlled to ensure that the current flowing through each motor winding is equal. The reference value of the current flowing through the motor winding follows the capacitor C. IN2 The voltage waveform shape on the capacitor C. As mentioned above, the voltage waveform shape on the capacitor C. IN2 The voltage across the capacitor is a rectified sine wave. Therefore, if capacitor C... IN2 If the voltage across the grid is zero, no current will be drawn from it. The voltage and current waveforms on the output side of the AC / DC converter 44 are rectified sine waves with the same frequency and relatively uniform. Since there is no significant energy storage in the AC / DC converter 44, the input power equals the output power, making the input current of the AC / DC converter 44 also a rectified sine wave. Therefore, the input current drawn from the grid is related to the input voltage V. AC With identical waveform shape and angle, this converter exhibits power factor correction characteristics. The magnitude of the current reference value for each phase winding depends on the battery charging algorithm. When the battery is depleted, the current reference value is the maximum value supported by the converter's power handling capacity. As the battery level gradually approaches its maximum, the current reference value gradually decreases to zero.

[0073] Furthermore, since the current flowing through all windings is the same, even if the windings carry currents that vary over time, Figure 4C The circuit architecture of the illustrated embodiment also does not generate pulsating torque. This is feasible due to the neutral connection of the external motor. When the current flowing through all three windings is equal, the motor can carry only zero-sequence current, which does not generate steady-state or low-frequency torque that would cause motor vibration. The torque component that may be generated in the system is only the small switching frequency ripple torque caused by the winding ripple current, which is inversely proportional to the motor inductance and the switching frequency.

[0074] Figure 5A The second embodiment of this invention illustrates the power system 50 of an electric vehicle with a motor-driven integrated on-board charger. Figure 5A The power system 50 and Figure 4A The power system 40 is basically the same as that in the previous one, except that the power system 50 also includes an external PFC inductor L. PFC (56), and the power system 50 utilizes an external PFC inductor L PFC (56) Self-capacitance C- IN2 It draws current from the circuit instead of utilizing three motor windings connected in parallel. Furthermore, the connection method of the three-phase motor 51 is different from... Figure 4A Unlike motor 41, three-phase motor 51 is considered part of motor drive inverter 52, which includes three-phase motor 51, switches S1, S2, S3, S4, S5 and S6, and chain capacitor C.O In this architecture, the first phase arm of the motor drive inverter 52 includes switches S1 and S2, and is connected only by the first phase arm through an external PFC inductor L. PFC To regulate the current. In this embodiment, the PFC inductor L PFC Includes a boost inductor. Since the phase bridge arm remains connected to the three-phase motor 51, the other two phase bridge arms operate with the same duty cycle to maintain the current flowing through the motor windings at zero. Compared to Figure 4A The method shown is as follows. Figure 5A The advantage of the approach shown is that it eliminates the need for a motor neutral terminal. In some embodiments, an additional inductor may be required.

[0075] Figure 5B and Figure 5C Show each Figure 5A The diagram shows the drive mode and battery charging mode of the motor-driven integrated on-board charger. In drive mode, as... Figure 5B As shown, relay R1 is off and relay R2 is on, allowing the battery to be connected only to motor 51 and motor drive inverter 52, while the isolated AC / DC converter is off. It can be noted that... Figure 5B The electrical connections in the power system 50 are essentially the same as those in Figure 2B. In battery charging mode, such as... Figure 5C As shown, both relays R1 and R2 are turned on, allowing electrical energy to be transferred from the AC power input to the battery.

[0076] In drive mode, such as Figure 5B As shown, the power system 50 operates as a motor drive (and Figure 3B and Figure 4B (Same as shown). In battery charging mode, Figure 5C The motor-driven integrated on-board charger shown provides easy control. Due to the input capacitor C... IN1 The voltage across it is relatively small, therefore the voltage across it is the rectified input voltage V. AC Input capacitor C IN1 The voltage across the LLC resonant converter was established. The LLC resonant converter operates with a 50% duty cycle and a fixed switching frequency. Because the number of turns in the secondary winding of the transformer TR is less than the number of turns in the primary winding, the LLC resonant converter will input capacitor C... IN1 The voltage across the terminals is reduced to a lower value. The switching frequency of the LLC resonant converter is based on the battery voltage, battery current, and input voltage V. AC The decision was made to transfer the capacitor C. IN2 Provide an appropriate AC voltage. (This is related to the input capacitor C.) IN1 Similarly, capacitor C IN2 The value of is also relatively small. Therefore, the capacitance C IN2The voltage at both ends is the rectified and slashed input voltage V. AC Since there is no significant energy storage in the AC / DC converter, the voltages of both capacitors follow the input voltage V. AC The waveform shape. Compared to systems that use large capacitance values ​​to maintain the DC link at a quasi-fixed value (e.g., Figure 2A The power system 20), which can be considered to have a soft DC link.

[0077] The first phase bridge arm of the motor-driven inverter is controlled to make the PFC inductor L- PFC The current drawn follows the capacitance C IN2 The voltage waveform shape across the capacitor. Therefore, if capacitor C IN2 If the voltage across the grid is zero, no current will be drawn from it. The voltage and current waveforms on the output side of the AC / DC converter are rectified sine waves with the same frequency and relatively uniform. Since there is no significant energy storage in the AC / DC converter, the input power equals the output power, making the input current of the AC / DC converter also a rectified sine wave. Therefore, the input current drawn from the grid is related to the input voltage V. AC Having the same waveform shape and angle, this converter produces power factor correction characteristics.

[0078] Furthermore, the first motor winding remains connected to the first phase arm of the motor drive inverter. To maintain zero current flowing through the motor winding, the second and third phase arms of the motor drive inverter can be operated with the same duty cycle as the first phase arm, or the switches in the second and third phase arms can be turned off. Since the current flowing through the motor winding is zero, Figure 5C The circuit architecture shown does not generate torque.

[0079] Figure 6A This illustration shows the power system 60 of an electric vehicle with a motor-driven integrated on-board charger according to a third embodiment of this invention. In this embodiment, the power system 60 uses a single-pole double-throw relay R1 to connect the AC terminal (point A) of the first phase bridge arm (including switches S1 and S2) of the motor-driven inverter to the first motor winding of the motor 61 or an external PFC inductor L. PFC The second single-pole double-throw relay R2 is used to connect the positive terminal of battery 63 to the positive terminal (point B) of the DC link of the motor drive inverter or the first motor winding of motor 61.

[0080] Figure 6B and Figure 6C Show each Figure 6A The diagram shows the drive mode and battery charging mode of the motor-driven integrated on-board charger. In drive mode, as... Figure 6BAs shown, relay R1 connects the AC terminal (point A) of the first phase bridge arm of the motor drive inverter to the first motor winding, and relay R2 connects the positive terminal of battery 63 to the positive terminal (point B) of the DC link of the motor drive inverter, thus shutting down the isolated AC / DC converter 64. This circuit configuration is electrically and functionally equivalent to... Figure 3B , Figure 4B and Figure 5B The circuit configuration shown.

[0081] In battery charging mode, such as Figure 6C As shown, relay R1 connects the AC terminal (point A) of the first phase bridge arm (including switches S1 and S2) of the motor drive inverter to the external PFC inductor L. PFC Relay R2 connects the positive terminal of battery 63 to the first motor winding of motor 61. To clearly illustrate the circuit configuration at this point, this circuit is configured as follows: Figure 6D Redrawn in the middle. This circuit configuration is... Figure 4C and Figure 5C The main difference in the circuit configurations shown is that Figure 6C and Figure 6D The circuit shown is configured in the DC link to absorb voltages originating from the input voltage V. AC The pulsating input power of the voltage source.

[0082] The switching frequency of the LLC converter is based on battery voltage, battery current, and input voltage V. AC The decision was made to transfer the capacitor C. IN2 Provide an appropriate AC voltage. For example... Figure 6C and Figure 6D As shown, the first phase arm of the motor drive inverter operates as a boost PFC. In this circuit configuration, the first phase arm of the motor drive inverter includes switches S1 and S2, and only the first phase arm is used to regulate the current flowing through the external PFC inductor L. PFC The current. Inductance L PFC The current reference value follows the capacitance C IN2 The voltage waveform shape on the capacitor C. As mentioned above, the voltage waveform shape on the capacitor C. IN2 The voltage across the capacitor is a rectified sine wave. Therefore, if capacitor C... IN2 When the voltage across the capacitor is zero, the current drawn from the capacitor is zero. The voltage and current waveforms on the output side of the AC / DC converter are rectified sine waves with the same frequency and relatively uniform. Since there is no significant energy storage in the AC / DC converter, the input power of an isolated AC / DC converter equals its output power, making the input current of the AC / DC converter also a rectified sine wave. Therefore, the input current drawn from the grid is related to the input voltage V. AC Having the same waveform shape and angle, this converter produces power factor correction characteristics.

[0083] Furthermore, the second and third phase arms of the motor drive inverter are connected to the second and third motor windings of motor 61, while the first motor winding is connected to the positive terminal of battery 63. All three motor windings remain connected to their neutral point. Thus, the second and third phase arms of the motor drive inverter and motor 61 form an interleaved buck converter. Since the inductive components are all connected to the output side, the buck converter has a continuous output current, making it easy to regulate the battery charging current to a fixed current value with minimal ripple. Figure 6C and Figure 6D The circuit configuration shown provides PFC functionality on the input side and DC current regulation on the output side. The difference between fluctuating input power and fixed output power arises from the chain capacitance C. O .

[0084] exist Figure 6C and Figure 6D In the circuit configuration shown, the currents flowing through the motor windings connected to the second and third phase arms of the motor drive inverter have the same magnitude and polarity, while the currents flowing through the remaining motor windings have twice the magnitude and opposite polarity. Even so, because the DC current flowing through the motor windings has extremely small and high-frequency ripple, the motor windings used do not generate low-frequency pulsating torque. The ripple current is inversely proportional to the motor inductance and the switching frequency.

[0085] Figure 7A This illustration shows the power system 70 of an electric vehicle with a motor-driven integrated on-board charger according to a fourth embodiment of this invention. In this embodiment, the AC terminal (point A) of the first phase bridge arm (including switches S1 and S2) of the motor-driven inverter is interconnected or disconnected from the first motor winding of the motor 71 via a single-pole single-throw relay R1. Furthermore, the AC terminal (point A) of the first phase bridge arm is connected to an external PFC inductor L. PFC The components are interconnected or disconnected via a double-pole double-throw relay R2. The first motor winding is connected to the buffer capacitor C. B The two devices are connected or disconnected via double-pole double-throw relays R2.

[0086] Figure 7B and Figure 7C Show each Figure 7A The diagram shows the drive mode and battery charging mode of the motor-driven integrated on-board charger. In drive mode, as... Figure 7B As shown, relays R1 and R3 are both on, while relay R-2 is off. The AC terminal (point A) of the first phase bridge arm of the motor drive inverter is connected to the first motor winding of motor 71, and the isolated AC / DC converter is turned off. This circuit configuration is electrically and functionally equivalent to... Figure 3B , Figure 4B , Figure 5B and Figure 6B The circuit configuration shown.

[0087] In battery charging mode, such as Figure 7C As shown, relay R1 is off, while relays R2 and R3 are on. Relay R2 connects the AC terminal (point A) of the first phase bridge arm of the motor drive inverter to the external PFC inductor L. PFC Furthermore, relay R2 also connects the first motor winding of motor 71 to buffer capacitor C. B To clearly illustrate the current circuit configuration, this circuit is configured as follows: Figure 7D Redrawn in the middle. This circuit configuration is... Figure 4C , Figure 5C and Figure 6C The main difference in the circuit configurations shown is that Figure 7C and Figure 7D The circuit configuration shown utilizes a buffer capacitor C B Absorption originates from input voltage V AC The pulsating input power of the voltage source.

[0088] The switching frequency of the LLC converter is based on battery voltage, battery current, and input voltage V. AC The decision was made to transfer the capacitor C. IN2 Provide an appropriate AC voltage. For example... Figure 7C and Figure 7D As shown, the first phase arm of the motor drive inverter operates as a boost PFC. In this circuit configuration, the first phase arm of the motor drive inverter includes switches S1 and S2, which are responsible for regulating the current flowing through the external PFC inductor L. PFC The current. PFC inductor L PFC The current reference value follows the capacitance C IN2 The voltage waveform shape on the capacitor C. As mentioned above, the voltage waveform shape on the capacitor C. IN2 The voltage across the capacitor is a rectified sine wave. Therefore, if capacitor C... IN2 When the voltage across the capacitor is zero, the current drawn from the capacitor is zero. The voltage and current waveforms on the output side of the AC / DC converter are rectified sine waves with the same frequency and relatively uniform. Since there is no significant energy storage in the AC / DC converter, the input power of an isolated AC / DC converter equals its output power, making the input current of the AC / DC converter also a rectified sine wave. Therefore, the input current drawn from the grid is related to the input voltage V. AC Having the same waveform shape and angle, this converter produces power factor correction characteristics.

[0089] Furthermore, the second and third phase bridge arms of the motor drive inverter are connected to the second and third motor windings of motor 71, while the first motor winding is connected to the buffer capacitor C.B The three motor windings remain connected to their neutral point. This allows the second and third phase arms of the motor drive inverter and motor 71 to form an interleaved buck converter. Since all inductive components are connected to the output side, the buck converter has a continuous output current. This buck converter, along with the buffer capacitor C... B This forms an active power filter (APF).

[0090] By definition, an active power filter can only provide AC power. Therefore, an active power filter can provide AC power of the same magnitude but opposite polarity as the AC power provided by a PFC circuit, which provides both DC and AC power. In this way, the AC power provided by the PFC circuit can be canceled on the battery side, thereby reducing or eliminating battery current ripple. When the energy provided by the boost PFC is excessive, energy can self-chain through capacitor C- O It is drawn and stored in the buffer capacitor C B On the other hand, when the energy provided by the boost PFC is insufficient, the energy can be self-buffered by the buffer capacitor C. B Draw and transfer to chain capacitor C- O Therefore, Figure 7C and Figure 7D The circuit configuration shown can simultaneously provide input-side PFC functionality and low battery current ripple.

[0091] It should be noted that, Figure 7C and Figure 7D The circuit configuration shown does not disconnect the DC link from battery 73, therefore the capacitor and switch do not need to be loaded, for example... Figure 6C and Figure 6D A slightly elevated voltage level. Furthermore, in Figure 6C and Figure 6D In the circuit configuration shown, the currents flowing through the windings of phases A and B have the same magnitude and polarity, while the current flowing through the winding of phase C has twice the magnitude and opposite polarity. Even so, because the DC current flowing through the motor windings has extremely small and high-frequency ripples, the motor windings used do not generate low-frequency pulsating torque. The ripple current is inversely proportional to the motor inductance and the switching frequency.

[0092] Figure 7E In response to Figure 7C and Figure 7D A schematic diagram of the control architecture of the converter in the diagram. (See diagram below.) Figure 7E As shown, for Figure 7C and Figure 7D The circuit control is based on two current loops and one voltage loop. The first current loop regulates the current flowing through the PFC inductor L- PFC The current causes it to follow the capacitance C IN2The waveform shape of the voltage across the circuit enables it to perform PFC (Power Factor Correction) functionality. A second current loop regulates the APF current to effectively eliminate AC ripple generated by the PFC circuit. A voltage loop balances the APF capacitor voltage at the nominal point, allowing the APF circuit to supply or absorb the necessary power. The voltage loop is designed with a low crossover frequency (e.g., 10Hz) so that it does not interfere with the higher-frequency APF current loop.

[0093] Figure 8A , Figure 8B , Figure 8C and Figure 8D Various topology variations of the isolated AC / DC rectifier in the power system of an electric vehicle with an integrated on-board charger for motor drive are shown. For simplicity, only the series resonant converter topology is shown in this example. However, it should be noted that any resonant topology can be used as the isolated AC / DC rectifier stage, and the corresponding motor and motor-driven inverter can be any of the configurations shown in Figures 4 through 7.

[0094] exist Figure 8A In the motor-driven integrated on-board charger shown, the isolated AC / DC rectifier includes a half-bridge inverter and a full-bridge rectifier. Figure 8B In the motor-driven integrated on-board charger shown, the isolated AC / DC rectifier includes a full-bridge inverter and a full-bridge rectifier. Figure 8C In the motor-driven integrated on-board charger shown, the isolated AC / DC rectifier includes a half-bridge inverter and a voltage doubler rectifier. Figure 8D In the motor-driven integrated on-board charger shown, the isolated AC / DC rectifier includes a full-bridge inverter and a voltage doubler rectifier.

[0095] Figure 9A The fifth embodiment of this invention illustrates the power system of an electric vehicle with a motor-driven integrated on-board charger. For example... Figure 9A As shown, the power system includes a motor, a motor-driven inverter, a battery, an isolated AC / DC converter, and an external AC power input. In one embodiment, the motor is a three-phase motor with three motor windings, and all motor windings are connected to the neutral point.

[0096] An isolated AC / DC converter includes rectifier diodes D1, D2, D3, and D4, and an input capacitor C. IN1 and LLC converter. The LLC converter contains two switches S INV1 and S INV2 Resonant inductor L R Resonant capacitor C R1 and C R2 Transformer TR, rectifier diode D R1 and D R2 and capacitor CIN2 Capacitor C IN2 The first motor winding is connected to the motor via relay R1. The first motor winding is connected to the first phase bridge arm of the motor drive inverter via relay R2. The motor drive inverter may include switches S1, S2, S3, S4, S5, and S6. Each end of the motor winding opposite the neutral point is connected to two of the switches S1, S2, S3, S4, S5, and S6 of the motor drive inverter. The motor drive inverter is connected in parallel to the link capacitor C. O The battery is connected to the chain capacitor C via relay R2. O The two ends. Compared to Figure 2A Traditional systems in China Figure 9A The isolated AC / DC converter in the illustrated embodiment does not include a PFC inductor L. PFC Boost switch S B1 Diode D5 and capacitor C O,PFC This can reduce system costs.

[0097] Figure 9B and Figure 9C Show each Figure 9A The diagram shows the drive mode and battery charging mode of the motor-driven integrated on-board charger. In drive mode, as... Figure 9B As shown, relay R1 is off while relays R2 and R3 are on, ensuring the battery is connected only to the motor and the motor drive inverter, and the isolated AC / DC converter is off. It can be noted that... Figure 9B The electrical connections in the power system are essentially the same as those in Figure 2B. In battery charging mode, such as... Figure 9C As shown, relays R1 and R2 are both on, and relay R3 is off, allowing electrical energy to be transferred from the AC power input to the battery. It can be noted that the motor and motor drive inverter are both part of the charging system. Conversely, in the power system of Figure 2B, the motor and motor drive inverter do not operate in battery charging mode.

[0098] In this embodiment, during battery charging mode, the LLC converter in the isolated AC / DC converter is used as an AC / DC rectifier, providing isolation and scaling for the AC power input. The switching frequency of the LLC converter can vary between half and five times the resonant frequency, where the resonant frequency is determined by the resonant cavity elements (including L... R C R1 and C R2 This is determined by the switching frequency, which is much higher than the AC input line frequency (e.g., 60Hz). Therefore, the capacitor C... IN2 The voltage on is the AC input voltage V. ACThe scaled absolute value. The three windings of the motor drive inverter and the motor can be considered as two independent boost converters connected in parallel and operating as a composite boost power factor correction circuit, wherein the first motor winding is connected in series with the second and third motor windings respectively. Because relay R3 is off, the first phase bridge arm does not operate. Therefore, Figure 9C The circuitry described above can provide isolation and power factor correction with a relatively small number of components. However, in this embodiment, it is affected by the output voltage ripple of the PFC circuit. Figure 9C The charging current in a power system may have significant ripple. Therefore, Figure 9C This type of power system can be applied to systems that accept battery current ripple. Compared to Figures 4A to 4C The power system shown in this embodiment also uses a relay R3, wherein the relay R3 does not need to be directly connected to the neutral point of the motor winding.

[0099] Figure 9C One advantage of the motor-driven integrated on-board charger shown is its simple control. This is due to the input capacitor C... IN1 The voltage across it is relatively small, therefore the voltage across it is the rectified input voltage V. AC Input capacitor C IN1 The voltage across the LLC resonant converter was established. The resonant converter operates with a 50% duty cycle and a fixed switching frequency. Because the number of turns in the secondary winding of the transformer TR is less than the number of turns in the primary winding, the resonant converter will input capacitor C... IN1 The voltage across the terminals is reduced to a lower value. The switching frequency of the LLC converter is based on the battery voltage, battery current, and input voltage V. AC The decision was made to transfer the capacitor C. IN2 Provide an appropriate AC voltage. (This is related to the input capacitor C.) IN1 Similarly, capacitor C IN2 The value of is also relatively small. Therefore, the capacitance C IN2 The voltage at both ends is the rectified and slashed input voltage V. AC Since there is no significant energy storage in the AC / DC converter, the voltages of both capacitors follow the input voltage V. AC The waveform shape. Compared to systems that use large capacitance values ​​to maintain the DC link at a quasi-fixed value (e.g., Figure 2A The power system 20) can be considered as having a soft DC link.

[0100] The second and third phase arms of the motor drive inverter are controlled to make the currents flowing through the second and third motor windings equal, wherein the sum of the currents flowing through the second and third motor windings equals the current flowing through the first motor winding. The reference value of the current flowing through the motor windings follows the capacitor C. IN2 The voltage waveform shape on the capacitor C. As mentioned above, the voltage waveform shape on the capacitor C.IN2 The voltage across the capacitor is a rectified sine wave. Therefore, if capacitor C... IN2 If the voltage across the grid is zero, no current will be drawn from it. The voltage and current waveforms on the output side of the AC / DC converter are rectified sine waves with the same frequency and relatively uniform. Since there is no significant energy storage in the AC / DC converter, the input power equals the output power, making the input current of the AC / DC converter also a rectified sine wave. Therefore, the input current drawn from the grid is related to the input voltage V. AC With identical waveform shape and angle, this converter exhibits power factor correction characteristics. The magnitude of the current reference value for each phase winding depends on the battery charging algorithm. When the battery is depleted, the current reference value is the maximum value supported by the converter's power handling capacity. As the battery level gradually approaches its maximum, the current reference value gradually decreases to zero.

[0101] To facilitate the explanation and definition of the technical content of this application, terms such as "substantially," "approximately," "slightly," and "relatively" are used to indicate an inherent degree of uncertainty, which may be caused by quantitative comparisons, numerical values, sensing, and other factors. These terms generally mean a deviation from a given value or range within 10%, 5%, 1%, or 0.5%, and that such deviation does not affect the basic function of the corresponding technical feature. Unless otherwise specifically stated, the numerical parameters stated in this application are values ​​that can be considered specific values ​​or values ​​within their error range.

[0102] It should be noted that the above are merely preferred embodiments for illustrating this case, and this case is not limited to the described embodiments. The scope of this case is determined by the appended claims. Furthermore, this case can be modified in various ways by those skilled in the art, but all modifications shall not depart from the protection sought by the appended claims.

[0103] List of reference numerals

[0104] 10: Power System

[0105] 11: Motor

[0106] 12: Motor driver

[0107] 13: Battery

[0108] 14: Car charger

[0109] 15: AC Input

[0110] 20: Power System

[0111] 21: Three-phase motor

[0112] 22: Motor-driven inverter

[0113] 23: Battery

[0114] 24: Car charger

[0115] 25: AC input

[0116] R1, R2: Relays

[0117] S1, S2, S3, S4, S5, S6: Switches

[0118] 241: AC / DC PFC level

[0119] 242: DC / DC conversion stage

[0120] D1, D2, D3, D4: Rectifier diodes

[0121] L PFC Boost inductor

[0122] S B1 Boost switch

[0123] D5: Boost diode

[0124] C O,PFC :capacitance

[0125] V AC Input voltage

[0126] S INV1 S INV2 :switch

[0127] L R Resonant inductor

[0128] C R1 C R2 Resonant capacitor

[0129] T R :transformer

[0130] D R1 D R2 : Rectifier diode

[0131] C IN2 :capacitance

[0132] 30: Power System

[0133] 31: Motor

[0134] 33: Battery

[0135] 34: Motor-driven integrated vehicle charger

[0136] 35: AC input

[0137] 40: Power System

[0138] 41: Motor

[0139] 42: Motor-driven inverter

[0140] 43: Battery

[0141] 44: AC / DC converter

[0142] 45: AC power input

[0143] C IN1 Input capacitor

[0144] C O Chain capacitor

[0145] 50: Power System

[0146] 51: Motor

[0147] 52: Motor-driven inverter

[0148] 56: PFC inductor

[0149] 60: Power System

[0150] 61: Motor

[0151] 63: Battery

[0152] 64: AC / DC converter

[0153] 70: Power System

[0154] 71: Motor

[0155] 73: Battery

[0156] 74: AC / DC converter

[0157] C B Buffer capacitor

[0158] R3: Relay

[0159] D R3 D R4 :diode

[0160] C D1 C D2 :capacitance

[0161] S INV3 S INV4 :switch

Claims

1. An electric vehicle's power system, comprising: An AC / DC converter; A motor driver, comprising a motor and an inverter; A power factor correcting (PFC) inductor is electrically connected between the AC / DC converter and the motor driver; A capacitor chain is connected in parallel to the motor driver; A first relay is connected between the PFC inductor and the motor driver; and A second relay, wherein a battery is connected to the chain capacitor via the second relay. The motor includes multiple phases, the inverter includes multiple phase bridge arms, and regardless of the switching state of the first relay, the first end of the phase is connected to the corresponding phase bridge arm.

2. The power system of claim 1, wherein the second ends of the plurality of phases are connected to a neutral point.

3. The power system of claim 1, wherein the PFC inductor is connected to one of the phase bridge arms via the first relay.

4. The power system of claim 1, wherein the phase arm comprises two switches, and the PFC inductor is connected via the first relay to a node between the two switches of one of the phase arms.

5. The power system of claim 1, wherein in drive mode, the first relay is turned off, the second relay is turned on, and the battery is adapted to release electrical energy to the motor.

6. The power system of claim 1, wherein in the charging mode, both the first relay and the second relay are turned on, and the battery is charged by an AC power source.

7. The power system of claim 1, wherein the AC / DC converter includes an LLC series resonant converter adapted to receive AC power and generate DC power at its input and output terminals, respectively.

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