Inverter circuit for electric vehicle and electric vehicle

Abstract

Provided in the present disclosure is an inverter circuit for an electric vehicle comprising an alternating current motor. The inverter circuit comprises: a first relay, the first relay being connected after a first phase of the alternating current motor; a second relay, the second relay being connected after a second phase of the alternating current motor, and an end, away from the first phase, of the first relay being electrically connected to an end, away from the second phase, of the second relay; a first output end and a second output end, the first output end and the second output end being used for outputting an alternating current; a first capacitor, the first capacitor being arranged between the first output end and the second output end; and a third relay and a fourth relay, the third relay being arranged between the first output end and a first connection point, the first connection point being located between the second relay and the second phase, and the fourth relay being arranged between the second output end and a second connection point, and the second connection point being located between the first relay and the first phase.

Description

Inverter circuit for electric vehicle and electric vehicle

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on November 15, 2023, with application number CN 202311519569.4 and application name “Inverter Circuit for Electric Vehicle and Electric Vehicle”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present disclosure relates to the field of vehicle discharge technology, and more specifically, to a system and vehicle for converting direct current (DC) power from a vehicle battery pack into civilian 220V AC power. More specifically, it relates to an inverter circuit for an electric vehicle including an AC motor and an electric vehicle including the inverter circuit. Background Art

[0003] With the continuous development of new energy vehicles, their technology is also developing rapidly. Vehicle to Load (V2L) discharge technology is designed to meet the diverse needs of car users in outdoor camping scenarios.

[0004] The existing technology implements V2L discharge technology through the inverter of the vehicle charger, which has a complex system, increases the risk of electromagnetic interference (EMC), and has disadvantages such as high cost.

[0005] As shown in Figure 1, existing V2L discharge technology converts the battery pack's DC power into civilian 220V AC power through an inverter within the on-board charger (OBC). Specifically, existing V2L discharge technology uses the inverter within the on-board charger to convert the battery pack's DC power into civilian 220V AC power. This technology cannot reuse the electric vehicle's internal components to achieve this technical goal, but requires the design of a separate dedicated inverter circuit (such as the one included in the on-board charger shown in Figure 1). This complicates the system design, increases the risk of electromagnetic interference (EMC), and increases costs.

[0006] Summary of the Invention

[0007] In order to solve the above problem, that is, when existing electric vehicles need to be connected to ordinary civilian household appliances, they need a dedicated on-board charger to use the inverter circuit set therein to achieve the purpose of converting direct current into civilian alternating current required by household appliances. The inventors of the present disclosure innovatively thought of using the timing of two switching tubes and relays associated with each electric drive bridge arm of the electric vehicle and the AC motor to achieve the desired alternating current. This can not only reuse existing components to reduce costs, but also simplify the structure of the charger to avoid unnecessary electromagnetic compatibility problems, which can be said to kill two birds with one stone.

[0008] Based on this, the first aspect of the present disclosure provides an inverter circuit for an electric vehicle, the electric vehicle including an AC motor, the inverter circuit including: a first relay, the first relay connected after the first phase of the AC motor; a second relay, the second relay connected after the second phase of the AC motor, the end of the first relay away from the first phase being electrically connected to the end of the second relay away from the second phase; a first output terminal and a second output terminal, the first output terminal and the second output terminal being used to output AC power; a first capacitor, the first capacitor being arranged between the first output terminal and the second output terminal; and a third relay and a fourth relay, wherein the third relay is arranged between the first output terminal and a first connection point, the first connection point being between the second relay and the second phase, and wherein the fourth relay is arranged between the second output terminal and the second connection point, the second connection point being between the first relay and the first phase. In this way, it is possible to select from the voltages of the two phases of the AC motor by means of the timing of the relays, thereby forming the required AC power to meet the power needs of the household appliances connected to the output terminal.

[0009] In one embodiment of the present disclosure, the first and second output terminals are configured to output 220V AC power. In this manner, 220V AC power can be output from the first and second output terminals to power various household appliances, such as lights, electric fans, or electric ovens. This provides a variety of lifestyle possibilities for owners who, for example, enjoy outdoor camping, and enhances the user-friendliness of the electric vehicle according to the present disclosure.

[0010] In one embodiment of the present disclosure, an inverter circuit includes an AC motor and an electric drive bridge arm associated with each phase of the AC motor. Each electric drive bridge arm includes two switching transistors, and the connection point of the two switching transistors is connected to a phase of the AC motor. In this way, the DC voltage output by the DC battery of the electric vehicle can be converted into each phase of three-phase AC power, thereby meeting the power requirements of the three-phase AC motor.

[0011] In one embodiment of the present disclosure, the inverter circuit further includes a control circuit configured to control the on / off switching of the switching transistors included in the electric drive bridge arm to control the input voltage level of each phase of the AC motor. In this manner, the control circuit can automatically and programmatically generate AC power that meets requirements (e.g., voltage level and current frequency), thereby providing a stable power supply for household appliances.

[0012] Preferably, in one embodiment according to the present disclosure, the motor is configured as a three-phase AC motor. More preferably, in one embodiment according to the present disclosure, the first phase and the second phase are selected from any two phases of the three-phase AC motor.

[0013] Preferably, in one embodiment of the present disclosure, the inverter circuit further includes a battery configured to provide direct current, the battery being connected across the two switching transistors associated with each phase. More preferably, in one embodiment of the present disclosure, the inverter circuit further includes a second capacitor disposed between the positive and negative electrodes of the battery.

[0014] Furthermore, a second aspect of the present disclosure provides an electric vehicle, comprising the inverter circuit according to the first aspect of the present disclosure. Preferably, in one embodiment of the present disclosure, the electric vehicle further comprises a charging port, wherein the positive and negative terminals of the charging port are electrically connected to the positive and negative terminals of a battery of the electric vehicle via a relay, respectively.

[0015] In summary, in the inverter circuit and the corresponding electric vehicle proposed according to the contents of the present disclosure, it is possible to select from the voltages of the two phases of the AC motor with the help of the timing of the relay to form the required AC power for the power needs of household appliances connected to the output end. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The features, advantages and other aspects of the embodiments of the present disclosure will become more apparent with reference to the following detailed description in conjunction with the accompanying drawings, in which several embodiments of the present disclosure are shown in an illustrative and non-limiting manner. In the accompanying drawings:

[0017] FIG1 shows a schematic structural diagram of a vehicle charger according to the prior art; and

[0018] FIG2 shows a schematic structural diagram of an inverter circuit according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0019] The following describes in detail various exemplary embodiments of the present disclosure with reference to the accompanying drawings. Although the exemplary methods and apparatus described below include software and / or firmware executed on hardware among other components, it should be noted that these examples are merely illustrative and should not be considered restrictive. For example, it is contemplated that any or all hardware, software, and firmware components may be implemented exclusively in hardware, exclusively in software, or in any combination of hardware and software. Therefore, although exemplary methods and apparatus have been described below, it should be readily understood by those skilled in the art that the examples provided are not intended to limit the manner in which these methods and apparatus are implemented.

[0020] In addition, the flowcharts and block diagrams in the accompanying drawings illustrate possible architectures, functions, and operations of the methods and systems according to various embodiments of the present disclosure. It should be noted that the functions marked in the boxes may also occur in an order different from that marked in the accompanying drawings. For example, two boxes represented in succession may actually be executed substantially in parallel, or they may sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each box in the flowchart and / or block diagram, and the combination of boxes in the flowchart and / or block diagram, may be implemented using a dedicated hardware-based system that performs the specified function or operation, or may be implemented using a combination of dedicated hardware and computer instructions.

[0021] As used herein, the terms "including," "comprising," and similar terms are open-ended terms, meaning "including but not limited to," indicating that other contents may also be included. The term "based on" means "based, at least in part, on." The term "one embodiment" means "at least one embodiment," and the term "another embodiment" means "at least one additional embodiment," etc.

[0022] As mentioned above, when electric vehicles in the prior art need to be connected to ordinary civilian household appliances, they require a dedicated on-board charger to use the inverter circuit installed therein to convert direct current into civilian alternating current required by the household appliances. This not only increases the manufacturing cost of the dedicated charger, but also brings additional electromagnetic compatibility issues, which may adversely affect the stability of the vehicle's operation.

[0023] Based on this, in order to solve the above problems, the inventors of the present disclosure innovatively thought of utilizing the components of the electric vehicle itself, that is, the inventors of the present disclosure innovatively thought of achieving the desired alternating current with the help of the timing coordination of two switching tubes and relays associated with each electric drive bridge arm of the electric vehicle and the AC motor. This can not only reuse existing components to reduce costs, but also simplify the structure of the charger to avoid unnecessary electromagnetic compatibility problems, which can be said to kill two birds with one stone.

[0024] In summary, the present disclosure provides an inverter circuit for an electric vehicle, the electric vehicle including an AC motor, the inverter circuit comprising: a first relay connected after a first phase of the AC motor; a second relay connected after a second phase of the AC motor, the first relay having an end remote from the first phase electrically connected to the second relay having an end remote from the second phase; a first output terminal and a second output terminal, the first output terminal and the second output terminal being configured to output AC power; a first capacitor disposed between the first output terminal and the second output terminal; and a third relay and a fourth relay, wherein the third relay is disposed between the first output terminal and a first connection point, the first connection point being between the second relay and the second phase, and the fourth relay is disposed between the second output terminal and a second connection point, the second connection point being between the first relay and the first phase. In this manner, the voltages of the two phases of the AC motor can be selected by timing the relays to generate the desired AC power to meet the power needs of household appliances connected to the output terminals.

[0025] The counting principle and working mode of the inverter circuit disclosed in the present disclosure will be described below with the help of the accompanying drawings. Figure 2 is a schematic diagram of a system for achieving V2L discharge by controlling the on-off of the electric drive bridge arm switch tube according to an embodiment of the present invention.

[0026] First, let's introduce examples of components represented by reference numerals in FIG2 according to the present disclosure. Reference numerals BTA1 and BAT2 in FIG2 represent, for example, 400V battery packs, but may also represent battery packs of other voltage amplitudes. The reference numeral K1 represents the main positive relay, the reference numeral K2 represents the main negative relay, the reference numerals C1 / C2 / C3 represent capacitors, the reference numerals IG1, IG2, IG3, IG4, IG5, and IG6 represent high-voltage switching tubes (IG1 to IG6 form the electric drive bridge arm), the reference numerals D1, D2, D3, D4, D5, and D6 represent diodes, the reference numeral M1 represents a three-phase AC motor, the reference numerals L1 / L2 / L3 represent motor inductors, the reference numeral K5 represents a fast-charge positive relay, the reference numeral K4 represents a fast-charge negative relay, the reference numeral K3 represents an 800V charging relay, the reference numerals K6 / K7 represent a 400V charging relay, the reference numerals K8 / K9 represent motor circuit relays, and the reference numerals K10 / K11 represent discharge relays. In addition, the reference numeral R1 represents an electrical load.

[0027] As shown in Example 1 of the present disclosure, that is, as shown in the system schematic diagram of Figure 2, when relays K1 / K2 / K10 / K11 are turned on and relays K3 / K4 / K5 / K6 / K7 / K8 / K9 are turned on and off, the motor controller controls the on and off status of the switches IG1, IG2, IG3, IG4, IG5 and IG6, and then converts the DC power of the battery pack into AC power through the inductor L1 / L2 of the three-phase AC motor M1. In order to achieve such a conversion, the charge state SOC of the battery pack meets the threshold for starting V2L, that is, the charge state must meet certain requirements and cannot be in a state of low power, for example; secondly, the entire electric vehicle is not in the charging and driving mode, that is, the battery pack needs to be in a discharging rather than charging state at this time, and cannot carry loads such as household appliances as well as the load of the motor required for driving in the vehicle, so as to ensure that the inverter circuit according to the contents of this disclosure can output a stable output voltage; furthermore, the inverter circuit according to the contents of this disclosure or the electric vehicle including the inverter circuit needs to be connected to the discharge load R1, that is, the AC power generated by the inverter circuit needs to be consumed by a load, or there needs to be a load to close the AC circuit.

[0028] During specific operation, the circuit shown in FIG2 can have the following working stages, that is, the specific working logic is as follows:

[0029] During the first phase, the main controller turns on switching transistors IG1 / IG5 and turns off switching transistors IG2 / IG3 / IG4 / IG6. At this point, the current flows from the positive electrode of BAT2 to the main positive relay K1, then to the IG1 switching transistor, then to the L1 motor inductor, then to the K10 relay, then to the R1 electrical load, then to the K11 relay, then to the L2 motor inductor, then to the main negative relay K2, and finally back to the negative electrode of BAT1, forming a complete closed loop.

[0030] During the second phase, the main controller turns on switches IG2 / IG4 and turns off switches IG1 / IG3 / IG5 / IG6. At this point, the current flows from the positive electrode of BAT2 to the main positive relay K1, then to the IG2 switch, then to the L2 motor inductor, then to the K11 relay, then to the R1 electrical load, then to the K10 relay, then to the L1 motor inductor, then to the main negative relay K2, and finally back to the negative electrode of BAT1, forming a complete closed loop.

[0031] The above cycle is repeated repeatedly. By controlling the switching timing and frequency of the electric drive bridge arm, a square wave is formed at the bridge arm end. Then, the LC oscillation circuit formed by the motor inductor L1 / L2 and C3 performs low-pass filtering, converting the square wave into a sinusoidal AC wave and feeding it to the electrical load R1.

[0032] The advantages of this technology, which achieves V2L discharge by controlling the electric drive bridge arm, are as follows: first, system complexity is reduced, and no additional inverter circuit is required. Instead, the existing components of the AC motor are reused, reducing costs; second, system utilization is improved; and finally, the system's electromagnetic compatibility (EMC) risk is also reduced.

[0033] In summary, the technical solution disclosed herein converts the battery pack's DC power into civilian AC power (V2L) through relay switching and the on-off switching of the high-voltage switching tubes in the electric drive bridge arm. This reduces system cost and complexity, increases electric drive system utilization, reduces system EMC risks, and offers users a diverse outdoor camping experience. In other words, the technical solution disclosed herein, which utilizes the on-off control of the electric drive bridge arm switching tubes to convert the battery pack's DC power into civilian 220V power, offers the advantages of system simplicity and low cost.

[0034] In summary, a first aspect of the present disclosure provides an inverter circuit for an electric vehicle, the electric vehicle including an AC motor M1, the inverter circuit including: a first relay K8, the first relay K8 being connected after the first phase of the AC motor M1; a second relay K9, the second relay K9 being connected after the second phase of the AC motor M1, an end of the first relay K8 away from the first phase (e.g., the right end shown in FIG2 ) being electrically connected to an end of the second relay K9 away from the second phase (e.g., the right end shown in FIG2 ); a first output terminal L and a second output terminal N, the first output terminal L and the second output terminal N being used to output AC power, i.e. For example, a load R1 is connected; a first capacitor C3 is provided between the first output terminal L and the second output terminal N; and a third relay K10 and a fourth relay K11 are connected, wherein the third relay K10 is provided between the first output terminal L and a first connection point (the connection point to the left of K9), which is located between the second relay K9 and the second phase, and wherein the fourth relay K11 is provided between the second output terminal N and a second connection point (the connection point to the left of K8), which is located between the first relay K8 and the first phase. In this way, the voltages of the two phases of the AC motor can be selected by timing the relays, thereby generating the required AC power to meet the power needs of the household appliances connected to the output terminals.

[0035] In one embodiment of the present disclosure, the first output terminal L and the second output terminal N are configured to output 220V AC power. In this manner, 220V AC power can be output from the first output terminal L and the second output terminal N, thereby powering various household appliances R1, such as lights, electric fans, or electric ovens. This provides a variety of lifestyle possibilities for owners who, for example, enjoy outdoor camping, and improves the user-friendliness of the electric vehicle according to the present disclosure.

[0036] In one embodiment of the present disclosure, the inverter circuit includes the AC motor M1 and an electric drive bridge arm IG1+IG4, IG2+IG5, or IG3+IG6 associated with each phase of the AC motor M1. Each electric drive bridge arm IG1+IG4, IG2+IG5, or IG3+IG6 includes two switching transistors IG1 and IG4, IG2 and IG5, or IG3 and IG6. The connection point of the two switching transistors IG1+IG4, IG2+IG5, or IG3+IG6 is used to connect one phase of the AC motor M1. In this way, the DC voltage output by the DC battery of the electric vehicle can be converted into each phase of three-phase AC power, thereby meeting the power demand of the three-phase AC motor M1.

[0037] In one embodiment of the present disclosure, the inverter circuit further includes a control circuit (not shown), which is configured to control the on / off switching of the switches IG1 and IG4, IG2 and IG5, or IG3 and IG6 included in the electric drive bridge arms IG1+IG4, IG2+IG5, or IG3+IG6, to control the input potential of each phase of the AC motor M1. In this way, the control circuit can automatically and programmatically generate AC power that meets the requirements (e.g., voltage level, current frequency), thereby providing a stable power supply for the household appliance R1.

[0038] Preferably, in one embodiment according to the present disclosure, the motor M1 is constructed as a three-phase AC motor. More preferably, in one embodiment according to the present disclosure, the first phase and the second phase are selected from any two phases of the three-phase AC motor.

[0039] Preferably, in one embodiment of the present disclosure, the inverter circuit further includes batteries BAT1 and BAT2, configured to provide DC power. The batteries are connected across the two switching transistors IG1 and IG4, IG2 and IG5, or IG3 and IG6 associated with each phase. More preferably, in one embodiment of the present disclosure, the inverter circuit further includes a second capacitor C1, disposed between the positive and negative electrodes of the batteries BAT1 and BAT2.

[0040] In addition, a second aspect of the present disclosure provides an electric vehicle, comprising the inverter circuit according to the first aspect of the present disclosure. Preferably, in one embodiment of the present disclosure, the electric vehicle further comprises interface terminals + / - on the right side of charging interfaces K5 and K4, wherein the positive and negative terminals + / - of the charging interfaces are electrically connected to the positive and negative poles of the battery of the electric vehicle via relays K5 and K4, respectively.

[0041] To sum up, in the inverter circuit and the corresponding electric vehicle proposed according to the contents of the present disclosure, it is possible to select from the voltages of the two phases of the AC motor with the help of the timing of the relay to form the required AC power for the power needs of household appliances connected to the output end.

[0042] Although the embodiments of the present disclosure have been described with reference to several specific embodiments, it should be understood that the embodiments of the present disclosure are not limited to the specific embodiments disclosed. The embodiments of the present disclosure are intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. The scope of the claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

Claims

1. An inverter circuit for an electric vehicle, the electric vehicle comprising an AC motor, characterized in that: The inverter circuit comprises: a first relay (K8), the first relay (K8) being connected after the first phase (L2) of the AC motor; a second relay (K9), the second relay (K9) being connected after the second phase of the AC motor, and an end of the first relay (K8) away from the first phase being electrically connected to an end of the second relay (K9) away from the second phase; A first output end and a second output end, wherein the first output end and the second output end are used to output alternating current; a first capacitor (C3) provided between the first output terminal and the second output terminal; and A third relay (K10) and a fourth relay (K11), wherein the third relay is arranged between the first output terminal and a first connection point, the first connection point is located between the second relay and the second phase, and wherein the fourth relay is arranged between the second output terminal and a second connection point, the second connection point is located between the first relay and the first phase.

2. The inverter circuit according to claim 1, characterized in that: The first output end and the second output end are configured to output 220V AC power.

3. The inverter circuit according to claim 1, characterized in that: The inverter circuit includes the AC motor and an electric drive bridge arm associated with each phase of the AC motor, wherein each electric drive bridge arm includes two switching tubes, and a connection point of the two switching tubes is used to connect one phase of the AC motor.

4. The inverter circuit according to claim 3, characterized in that: The inverter circuit also includes a control circuit, which is configured to control the on and off of the switch tube included in the electric drive bridge arm to control the input potential of each phase of the AC motor.

5. The inverter circuit according to claim 3, characterized in that: The electric machine is designed as a three-phase AC motor.

6. The inverter circuit according to claim 5, characterized in that: The first phase and the second phase are selected from any two phases of the three-phase AC motor.

7. The inverter circuit according to claim 3, characterized in that: The inverter circuit further includes a battery, which is configured to provide direct current and is connected across two switching tubes associated with each phase.

8. The inverter circuit according to claim 7, characterized in that: The inverter circuit further includes a second capacitor, which is arranged between the positive and negative electrodes of the battery.

9. An electric vehicle, characterized in that: The electric vehicle includes the inverter circuit according to any one of claims 1 to 8.

10. The electric vehicle according to claim 9, characterized in that: The electric vehicle further comprises a charging interface, wherein the positive and negative terminals of the charging interface are electrically connected to the positive and negative terminals of the battery of the electric vehicle via a relay, respectively.

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