Inverter circuit for electric vehicle and electric vehicle

Abstract

The present disclosure proposes an inverter circuit for an electric vehicle including an AC motor, including: a first relay connected after a first phase of the AC motor; after the second relay is connected to a second phase of the AC motor, one end, far away from the first phase, of the first relay is electrically connected with one end, far away from the second phase, of the second relay; the first output end and the second output end are used for outputting alternating current; a first capacitor disposed between the first output terminal and the second output terminal; and a third relay and a fourth relay, where the third relay is disposed between the first output and a first connection point, where the first connection point is located between the second relay and the second phase, and where the fourth relay is disposed between the second output and a second connection point, where the second connection point is located between the second relay and the second phase. The second connection point is located between the first relay and the first phase.

Description

Technical Field

[0001] The present disclosure relates to the field of vehicle discharge technology, and more specifically, to a system and vehicle for converting direct current power of a vehicle battery pack into civilian 220V alternating current 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

[0002] With the continuous development of new energy vehicles, their technology is developing more and more rapidly. Vehicle to Load (V2L) discharge technology is designed to meet the needs of car users in various outdoor camping application scenarios.

[0003] The existing technology realizes 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.

[0004] like Figure 1 As shown in the figure, the existing V2L discharge technology converts the battery pack DC power into civilian 220V AC power through the inverter inside the on-board charger OBC (On-Board Charger). Specifically, the existing V2L discharge technology converts the battery pack DC power into civilian 220V AC power through the inverter inside the on-board charger. At this time, the internal components of the electric vehicle itself cannot be reused to achieve this technical purpose, but a separate dedicated inverter circuit (for example, included in Figure 1 The system design is complex, which increases the risk of electromagnetic interference (EMC) and also increases the cost. Summary of the invention

[0005] 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 installed therein to achieve the purpose of converting direct current into civilian alternating current required by household appliances. The inventor of the present disclosure innovatively thought of using the timing coordination of two switching tubes associated with each electric drive bridge arm of the electric vehicle and the AC motor and the relay to achieve the desired alternating current, thereby reusing existing components to reduce costs and simplifying the structure of the charger to avoid unnecessary electromagnetic compatibility problems, which can be said to kill two birds with one stone.

[0006] Based on this, the first aspect of the present disclosure proposes an inverter circuit for an electric vehicle, the electric vehicle includes an AC motor, and the inverter circuit includes: a first relay, the first relay is connected after the first phase of the AC motor; a second relay, the second relay is connected after the second phase of the AC motor, and an end of the first relay away from the first phase is electrically connected to an end of the second relay away from the second phase; a first output end and a second output end, the first output end and the second output end are used to output AC power; a first capacitor, the first capacitor is arranged between the first output end and the second output end; and a third relay and a fourth relay, wherein the third relay is arranged between the first output end 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 end and a second connection point, the second connection point is located 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 relay, so as to form the required AC power for the power demand of the household appliances connected to the output end.

[0007] In one embodiment of the present disclosure, the first output terminal and the second output terminal are configured to output 220V AC power. In this way, 220V AC power can be output from the first output terminal and the second output terminal, so as to power various household appliances such as lighting, electric fans or electric ovens, thereby providing a variety of lifestyle possibilities for owners who have outdoor camping needs, and improving the user-friendliness of the electric vehicle according to the present disclosure.

[0008] In one embodiment of the present disclosure, 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 switch tubes, and the connection point of the two switch tubes is used to connect one 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 the three-phase AC power, thereby meeting the power demand of the three-phase AC motor.

[0009] In one embodiment of the present disclosure, the inverter circuit further 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. In this way, the control circuit can automatically and programmatically generate AC power that meets the requirements (such as voltage level, current frequency), thereby providing a stable power supply for household appliances.

[0010] Preferably, in one embodiment according to the present disclosure, the motor 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.

[0011] Preferably, in one embodiment according to the present disclosure, the inverter circuit further includes a battery, the battery is configured to provide direct current, and the battery is connected across two switching tubes assigned to each phase. More preferably, in one embodiment according to the present disclosure, the inverter circuit further includes a second capacitor, and the second capacitor is arranged between the positive and negative electrodes of the battery.

[0012] In addition, the second aspect of the present disclosure provides an electric vehicle, the 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 interface, the positive and negative terminals of the charging interface are respectively electrically connected to the positive and negative electrodes of the battery of the electric vehicle via a relay.

[0013] 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 coordination of the relay to form the required AC power for the power demand of the household appliances connected to the output end. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] 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 exemplary and non-limiting manner. In the accompanying drawings:

[0015] Figure 1 A schematic diagram of the structure of a vehicle charger according to the prior art is shown; and

[0016] Figure 2 A schematic structural diagram of an inverter circuit according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0017] The various exemplary embodiments of the present disclosure are described in detail below with reference to the accompanying drawings. Although the exemplary methods and devices 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 considered that any or all hardware, software, and firmware components can be implemented exclusively in hardware, exclusively in software, or in any combination of hardware and software. Therefore, although exemplary methods and devices 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 devices are implemented.

[0018] In addition, the flowcharts and block diagrams in the accompanying drawings illustrate the possible architecture, functions and operations of the methods and systems according to the 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 a specified function or operation, or may be implemented using a combination of dedicated hardware and computer instructions.

[0019] The terms "including", "comprising" and similar terms used herein are open terms, i.e., "including / 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"; the term "another embodiment" means "at least one other embodiment", etc.

[0020] 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 an 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 vehicle operation.

[0021] Based on this, in order to solve the above problems, the inventors of the present disclosure innovatively thought of using the components of the electric vehicle itself, that is, the inventors of the present disclosure innovatively thought of using the timing coordination of two switching tubes associated with each electric drive bridge arm of the electric vehicle and the AC motor and the relay to achieve the desired AC power. 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.

[0022] In summary, the present disclosure proposes an inverter circuit for an electric vehicle, the electric vehicle includes an AC motor, the inverter circuit includes: a first relay, the first relay is connected after the first phase of the AC motor; a second relay, the second relay is connected after the second phase of the AC motor, the end of the first relay away from the first phase is 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 are used to output AC power; a first capacitor, the first capacitor is 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 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. 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 for the power demand of the household appliances connected to the output terminal.

[0023] 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 A schematic diagram of a system for realizing V2L discharge by controlling the on-off of the electric drive bridge arm switch tube provided in an embodiment of the present invention.

[0024] First, we will introduce the Figure 2 Examples of components represented by the reference numerals in the figure. Figure 2 The reference numerals BTA1 or BAT2 respectively represent, for example, a 400V battery pack, and of course, can also be a battery pack of other voltage amplitudes. The reference numeral K1 represents the main positive relay, the reference numeral K2 represents the main negative relay, and the reference numerals C1 / C2 / C3 represent capacitors, the reference numerals IG1, IG2, IG3, IG4, IG5 and IG6 represent high-voltage switch tubes (IG1-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 inductance, the reference numeral K5 represents a fast charging positive relay, the reference numeral K4 represents a fast charging 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.

[0025] As shown in Example 1 of the present disclosure, Figure 2 As shown in the system schematic diagram, when relays K1 / K2 / K10 / K11 are turned on and relays K3 / K4 / K5 / K6 / K7 / K8 / K9, the motor controller controls the on and off status of 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 charging state SOC of the battery pack meets the threshold for starting V2L, that is, the charging state must meet certain requirements and cannot be in a state such as a low power state; 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, and cannot carry loads such as household appliances as well as loads of motors required for in-vehicle driving, so as to ensure that the inverter circuit according to the contents of the present disclosure can output a stable output voltage; furthermore, the inverter circuit according to the contents of the present 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 in other words, there needs to be a load to close the AC circuit.

[0026] When doing specific work, Figure 2 The circuit shown can have the following working stages, that is, the specific working logic is as follows:

[0027] In the first stage, the main controller controls the switch tube IG1 / IG5 to be in the on state and controls the open tube IG2 / IG3 / IG4 / IG6 to be in the off state, that is, the disconnected state. At this time, the current path is from the positive electrode of BAT2 to the main positive relay K1, then to the IG1 switch tube, 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, thus forming a complete closed loop.

[0028] In the second stage, the main controller controls the switch tubes IG2 / IG4 to be in the on state and controls the switch tubes IG1 / IG3 / IG5 / IG6 to be in the off state, that is, the disconnected state. At this time, the current path is from the positive electrode of BAT2 to the main positive relay K1, then to the IG2 switch tube, 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, thus forming a complete closed loop.

[0029] The above cycle is repeated repeatedly. By controlling the switching timing and frequency of the electric drive bridge arm, a square wave will be formed at the bridge arm end. Then, low-pass filtering is performed through the LC oscillation circuit formed by the motor inductance L1 / L2 and C3 to convert the square wave into a sinusoidal AC wave for the electrical load R1.

[0030] The advantages of this technology of achieving V2L discharge by controlling the electric drive bridge arm are as follows: first, the system complexity is reduced, and no additional inverter circuit is required. Instead, the existing components of the AC motor are reused to reduce costs; second, the system utilization rate is improved; finally, the system electromagnetic compatibility (EMC) risk is also reduced.

[0031] In general, the technical solution of the present disclosure realizes the V2L discharge technology of converting the DC power of the battery pack into the civilian AC power through relay switching and the on-off of the high-voltage switch tube of the electric drive bridge arm, which reduces the system cost and complexity, has a high utilization rate of the electric drive system, reduces the system EMC risk, and brings users a variety of outdoor camping scene experiences. In other words, the technical solution disclosed in the present disclosure uses the control of the on-off of the electric drive bridge arm switch tube to realize the system of converting the DC power of the battery pack into the civilian 220V, which has the advantages of simple system and low cost.

[0032] In summary, a first aspect of the present disclosure provides an inverter circuit for an electric vehicle, the electric vehicle comprising an AC motor M1, the inverter circuit comprising: a first relay K8, the first relay K8 being connected after a first phase of the AC motor M1; a second relay K9, the second relay K9 being connected after a second phase of the AC motor M1, the first relay K8 being away from an end of the first phase (e.g. Figure 2 The right end shown) and the end of the second relay K9 away from the second phase (for example Figure 2The first output terminal L and the second output terminal N are electrically connected, the first output terminal L and the second output terminal N are used to output AC power, that is, for example, to connect a load R1; a first capacitor C3, the first capacitor C3 is arranged between the first output terminal L and the second output terminal N; and a third relay K10 and a fourth relay K11, wherein the third relay K10 is arranged between the first output terminal L and the first connection point (the connection point on the left side of K9), the first connection point (the connection point on the left side of K9) is located between the second relay K9 and the second phase, and wherein the fourth relay K11 is arranged between the second output terminal N and the second connection point (the connection point on the left side of K8), the second connection point (the connection point on the left side of K8) is located between the first relay K8 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, so as to form the required AC power for the power demand of the household appliance connected to the output terminal.

[0033] 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 way, 220V AC power can be output from the first output terminal L and the second output terminal N, so as to power various household appliances R1 such as lighting, electric fans or electric ovens, so as to provide a variety of lifestyle possibilities for owners who have outdoor camping needs, and improve the user-friendliness of the electric vehicle according to the present disclosure.

[0034] 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, wherein each electric drive bridge arm IG1+IG4, IG2+IG5 or IG3+IG6 includes two switch tubes IG1 and IG4, IG2 and IG5, or IG3 and IG6, and the connection point of the two switch tubes 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 the three-phase AC power, thereby meeting the power demand of the three-phase AC motor M1.

[0035] In one embodiment of the present disclosure, the inverter circuit further includes a control circuit (not shown in the figure), which is configured to control the on and off of the switch tubes IG1 and IG4, IG2 and IG5, or IG3 and IG6 included in the electric drive bridge arm IG1+IG4, IG2+IG5 or IG3+IG6, so as to control the input potential of each phase of the AC motor M1. In this way, the control circuit can be used to automatically and programmatically generate AC power that meets the requirements (such as voltage level, current frequency), thereby providing a stable power supply for the household appliance R1.

[0036] 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.

[0037] Preferably, in one embodiment according to the present disclosure, the inverter circuit further includes batteries BAT1 and BAT2, the batteries BAT1 and BAT2 are configured to provide direct current, and the batteries are connected across two switching tubes IG1 and IG4, IG2 and IG5, or IG3 and IG6 assigned to each phase. More preferably, in one embodiment according to the present disclosure, the inverter circuit further includes a second capacitor C1, which is arranged between the positive and negative electrodes of the batteries BAT1 and BAT2.

[0038] In addition, the second aspect of the present disclosure provides an electric vehicle, the 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 the charging interfaces K5 and K4, and the positive and negative terminals + / - of the charging interface are electrically connected to the positive and negative electrodes of the battery of the electric vehicle via relays K5 and K4, respectively.

[0039] 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 coordination of the relay to form the required AC power for the power demand of the household appliances connected to the output end.

[0040] 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 in the spirit and scope of the appended claims. The scope of the claims is consistent with the broadest interpretation, thereby including 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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