Device for testing charging of electric vehicles

Abstract

The present invention discloses a device for electric vehicle charging test, including a shell for shielding electromagnetic radiation and a load simulation part and a charging pile simulation part contained in the shell, wherein the load simulation part includes a DC load module, an AC load module, a first communication interface and a second communication interface which are independent of each other, the DC load module is connected to the DC charging pile through the first communication interface, and the AC load module is connected to the AC charging pile through the second communication interface; the charging pile simulation part includes a charging guide module, a handshake signal module and a third communication interface, the charging guide module and the handshake signal module are respectively connected to the tested vehicle through the third communication interface, the charging guide module is used to be identified by the tested vehicle, and the handshake signal module is used to output a handshake signal to the tested vehicle. The device can be used to obtain the background noise of the electromagnetic radiation test, and can also be used to test whether the electric vehicle can still normally achieve charging preparation after the anti-interference pulse test.

Description

Technical Field

[0001] The invention relates to the technical field of electric vehicle testing, and in particular to a device for electric vehicle charging testing. Background Art

[0002] In the vehicle electromagnetic compatibility test, when the electric vehicle is in the charging state, it is necessary to detect the impact of the interference signal inside the electric vehicle on the external electromagnetic radiation, and to detect whether the electric vehicle can still prepare for charging normally after the anti-interference pulse test.

[0003] Among them, when an electric vehicle is in a charging state and detects the impact of interference signals inside the electric vehicle on the external electromagnetic radiation, it is necessary to use a charging pile (AC charging pile or DC charging pile), a charger and an on-board charger inside the vehicle. However, the test object is only the on-board charger inside the vehicle. Therefore, the radiation generated by the introduced charging pile and charger may affect the test results. Therefore, a device simulating a vehicle is needed. This device can ensure the normal operation of the charging pile and charger without introducing new electromagnetic radiation noise, and obtain a relatively ideal background test noise. Then, the charging pile is connected to the vehicle to be tested to complete the test of the on-board charger inside the vehicle to obtain the electromagnetic radiation value of the object under test.

[0004] In addition, after the electric vehicle is subjected to an anti-interference pulse test, it is necessary to verify whether the vehicle can prepare for charging normally. At this time, a detection device for charging function inspection is required. This device can replace the charging pile and connect it to the vehicle to verify whether the vehicle can prepare for charging normally. Summary of the invention

[0005] The purpose of the present invention is to provide a device for electric vehicle charging test, which can simulate the connection of an electric vehicle to a charging pile to obtain the background noise of an electromagnetic radiation test, and can also simulate the connection of a charging pile to an electric vehicle to test whether the electric vehicle can still perform charging preparation work normally after an anti-interference pulse test.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] A device for electric vehicle charging test comprises a housing for shielding electromagnetic radiation and a load simulation part and a charging pile simulation part contained in the housing, wherein:

[0008] The load simulation unit includes a DC load module, an AC load module, a first communication interface and a second communication interface which are independent of each other, wherein the DC load module is connected to the DC charging pile through the first communication interface, and the AC load module is connected to the AC charging pile through the second communication interface;

[0009] The charging pile simulation unit includes a charging guidance module, a handshake signal module and a third communication interface. The charging guidance module and the handshake signal module are respectively connected to the vehicle under test through the third communication interface. The charging guidance module is used to be identified by the vehicle under test, and the handshake signal module is used to output a handshake signal to the vehicle under test.

[0010] Preferably, the handshake signal module comprises a handshake signal generating unit, a power boosting unit, a power driving unit and a power switch unit which are connected in sequence, and the power switch unit outputs a handshake signal to the vehicle under test through the third communication interface.

[0011] Specifically, the handshake signal generating unit includes a first power supply and an Arduino board, the first power supply provides a working voltage for the Arduino board, the Arduino board generates two pulse signals with the same frequency and the same duty cycle but not at the same time of high level and outputs them synchronously to the power boosting unit, and the frequency and the duty cycle are set according to different charging states of the charger of the electric vehicle under test.

[0012] Preferably, the power boost unit comprises a bus driver (U2), a first pull-up resistor (R1) and a second pull-up resistor (R2), wherein:

[0013] The bus driver (U2) is provided with two pairs of input terminals and output terminals, the input terminals are respectively connected to the two output pins of the Arduino board for respectively receiving the pulse signals, and the output terminals are respectively connected to the first power supply via the first pull-up resistor (R1) and the second pull-up resistor (R2); the bus driver (U2) synchronously performs same-frequency power amplification on the two pulse signals to obtain two driving signals with the same frequency and the same duty cycle but not at the same high level, and outputs them respectively via the two output terminals.

[0014] Preferably, the power drive unit includes a first IGBT drive board and a second IGBT drive board, which are respectively connected to two output ends of the bus driver (U2); the first IGBT drive board and the second IGBT drive board synchronously amplify the drive signal with the same frequency power and output two drive signals with negative voltage.

[0015] Furthermore, the power switch unit includes a second power supply and an H-bridge circuit, the second power supply provides an operating voltage for the H-bridge circuit, the H-bridge circuit obtains a handshake signal by quickly switching on and off the driving signal with a negative voltage at the same frequency, and outputs the handshake signal to the vehicle under test through the third communication interface.

[0016] Specifically, the H-bridge circuit includes a first IGBT (Q1), a second IGBT (Q2), a third IGBT (Q3), a fourth IGBT (Q4) and a load resistor (R3), wherein:

[0017] The collector of the first IGBT (Q1) is coupled to the positive electrode of the second power supply, the base is coupled to the output end of the first IGBT driving board, and the emitter is coupled to the collector of the third IGBT (Q3);

[0018] The base of the third IGBT (Q3) is coupled to the output terminal of the second IGBT driving board, and the emitter is coupled to the negative electrode of the second power supply;

[0019] The collector of the second IGBT (Q2) is coupled to the positive electrode of the second power supply, the base is coupled to the output end of the second IGBT driving board, and the emitter is coupled to the collector of the fourth IGBT (Q4);

[0020] The base of the fourth IGBT (Q4) is coupled to the output terminal of the first IGBT driving board, and the emitter is coupled to the negative electrode of the second power supply;

[0021] One end of the load resistor (R3) is coupled to the emitter of the first IGBT (Q1), and the other end is coupled to the emitter of the second IGBT (Q2); the two ends of the load resistor (R3) are also respectively connected to the control guide terminal (CP) and the interface protection ground terminal (PE) of the third communication interface.

[0022] Preferably, the device further comprises a filtering unit, the filtering unit comprising a filtering capacitor (C3), a positive electrode of the filtering capacitor (C3) being coupled to a positive electrode of the second power supply, and a negative electrode of the filtering capacitor (C3) being coupled to a negative electrode of the second power supply.

[0023] Preferably, the charging guide module comprises a first identification resistor (R7) and a second identification resistor (R8), wherein:

[0024] One end of the first identification resistor (R7) is coupled to the interface protection ground terminal (PE) of the third communication interface, and the other end is coupled to the AC charging connection confirmation terminal (CC) of the third communication interface; the second identification resistor (R8) is coupled between the load resistor (R3) and the control guide terminal (CP) of the third communication interface.

[0025] Preferably, the DC load module comprises a third identification resistor (R6), and two ends of the third identification resistor (R6) are respectively coupled to an interface protection ground terminal (PE) of the first communication interface and a DC charging connection confirmation terminal (CC1);

[0026] The AC load module comprises a diode (D1) and a fourth identification resistor (R9) connected in series, and two ends of the AC load module are respectively coupled to an interface protection ground terminal (PE) and a control guide terminal (CP) of the second communication interface.

[0027] Compared with the prior art, the device for electric vehicle charging test provided by the present invention has the following beneficial effects:

[0028] In the device for electric vehicle charging test provided by the present invention, all components realizing electrical functions are encapsulated in a shell to avoid introducing new electromagnetic interference into the test; a DC load module is connected to a DC charging pile to obtain the background noise of electromagnetic radiation test during DC charging of the electric vehicle, and an AC load module is connected to an AC charging pile to obtain the background noise of electromagnetic radiation test during AC charging of the electric vehicle, thereby more accurately detecting the influence of interference signals inside the electric vehicle on electromagnetic radiation outside; in addition, after the anti-interference pulse test of the electric vehicle, the charging guidance module and the handshake signal module are respectively connected to the vehicle under test through the third communication interface, and are first identified by the vehicle under test through the charging guidance module, and then the handshake signal module outputs a handshake signal to the vehicle under test, and according to the working state of the vehicle under test after receiving different handshake signals, it can be conveniently and quickly judged whether the vehicle under test can still normally realize charging preparation work. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0030] Figure 1 It is a structural schematic diagram of a device for electric vehicle charging test in an embodiment of the present invention;

[0031] Figure 2 A signal flow diagram of a handshake signal module in an embodiment of the present invention;

[0032] Figure 3 Schematic diagram of the circuit principle of the handshake signal generating unit in an embodiment of the present invention;

[0033] Figure 4 Schematic diagram of the circuit principle of the charging guidance module in an embodiment of the present invention;

[0034] Figure 5a to Figure 5b Two circuit diagrams of the load simulation part in the embodiments of the present invention;

[0035] Figure 6a to Figure 6b They are schematic diagrams of waveforms of the rising edge and falling edge of the handshake signal output pulse in embodiments of the present invention.

[0036] Reference numerals:

[0037] 1-housing, 211-first communication interface;

[0038] 212-second communication interface, 22-third communication interface;

[0039] 3-Handshake signal generating unit. DETAILED DESCRIPTION

[0040] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the technical scheme in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0041] See also Figure 1 , a device for electric vehicle charging test provided in this embodiment includes a shell 1 for shielding electromagnetic radiation and a load simulation part and a charging pile simulation part contained in the shell 1. Among them, the load simulation part includes a DC load module, an AC load module, a first communication interface 211 and a second communication interface 212 which are independent of each other. The DC load module is connected to the DC charging pile through the first communication interface 211, and the AC load module is connected to the AC charging pile through the second communication interface 212. The charging pile simulation part includes a charging guide module, a handshake signal module and a third communication interface 22. The charging guide module and the handshake signal module are respectively connected to the vehicle under test through the third communication interface 22. The charging guide module is used to be identified by the vehicle under test, and the handshake signal module is used to output a handshake signal to the vehicle under test.

[0042] The shell 1 is made of metal, such as aluminum, which can effectively prevent the electrical functional components encapsulated inside it from introducing new electromagnetic interference to the test; on this basis, the DC load module is connected to the DC charging pile to obtain the background noise of the electromagnetic radiation test during DC charging of the electric vehicle, and the AC load module is connected to the AC charging pile to obtain the background noise of the electromagnetic radiation test during AC charging of the electric vehicle, thereby eliminating the influence of the background noise and more accurately detecting the influence of the interference signal of the on-board charger inside the electric vehicle on the external electromagnetic radiation.

[0043] In addition, after the anti-interference pulse test of the electric vehicle, the charging guidance module and the handshake signal module are respectively connected to the vehicle under test through the third communication interface. The function of the charging guidance module is to be identified by the on-board charger of the vehicle under test, and then the handshake signal module outputs a handshake signal to the on-board charger inside the vehicle under test. According to the working status of the on-board charger of the vehicle under test after receiving different handshake signals, it is judged whether the vehicle under test can still achieve charging preparation work normally. For example, by observing the flashing of the indicator light used to identify the working status, it is convenient and quick to judge whether the vehicle under test can still achieve charging preparation work normally.

[0044] In the specific implementation process, please refer to Figure 2 The handshake signal module includes a handshake signal generating unit, a power boosting unit, a power driving unit and a power switch unit connected in sequence, and the power switch unit outputs a handshake signal to the vehicle under test through the third communication interface 22. Then, according to the working state of the on-board charger of the vehicle under test after receiving different handshake signals, it is determined whether the vehicle under test can still perform charging preparation work normally.

[0045] See also Figure 3 In a device for electric vehicle charging test provided in this embodiment, a handshake signal generating unit includes a first power supply and an Arduino board U1. The first power supply provides a working voltage for the Arduino board U1. The Arduino board U1 can use an Arduino ATmega328 to generate two pulse signals with the same frequency and duty cycle but not at the same time at a high level and output them synchronously to the power boosting unit. The frequency and duty cycle are set according to the different charging states of the charger of the tested electric vehicle, and at the same time, the pulse signal is ensured to meet the requirements of GB / T18487.1-2015, so as to use the handshake signal obtained by the final processing to check whether the on-board charger is in normal working condition. The two pulse signals are set to be high levels at different times. In actual settings, a delay time, such as 2μs, can be set between the high levels of the two pulse signals to avoid short circuit of the IGBT in the power switch unit.

[0046] In addition, the first power supply is a +12V DC power supply and is also provided with a voltage stabilizing unit used in conjunction with the first power supply. The voltage stabilizing unit includes a voltage stabilizing chip U5, a capacitor C1 and a capacitor C2, wherein the positive and negative electrodes of the capacitor C1 are respectively connected to the positive and negative electrodes of the first power supply. The voltage stabilizing chip U5 adopts a 7805 chip, whose input end is connected to the positive electrode of the first power supply, and whose output end is connected to the Arduino board U1, so as to provide a stable +5V voltage for the Arduino board U1. The positive electrode of the capacitor C2 is connected to the output end of the voltage stabilizing chip U5, and the negative electrode of the capacitor C2 is connected to the negative electrode of the first power supply. The capacitors C1 and C2 are used to filter out high-frequency clutter and low-frequency fluctuations, and to supply a better +5V DC voltage to the Arduino board U1.

[0047] The power boost unit includes a bus driver U2, a first pull-up resistor R1 and a second pull-up resistor R2, wherein the bus driver U2 is provided with two pairs of input terminals and output terminals, and the input terminals are respectively connected to two output pins of the Arduino board, for example Figure 3 The Pin10 and Pin11 pins in the bus driver are used to receive pulse signals respectively, and the output ends are connected to the first power supply through the first pull-up resistor R1 and the second pull-up resistor R2 respectively; the bus driver U2 synchronously performs the same frequency power amplification on the two pulse signals to obtain two drive signals with the same frequency and the same duty cycle but not at the same high level, and outputs them to the power drive unit through the two output ends. The bus driver U2 can use 74LS245, and the power boost unit still outputs a pulse drive signal of 0~+5V, but the current of the drive signal is increased, and then the power is increased to improve the load carrying capacity of the drive signal.

[0048] Further, see Figure 3 The power drive unit includes a first IGBT drive board U3 and a second IGBT drive board U4, which are respectively connected to the two output terminals of the bus driver U2. The first IGBT drive board and the second IGBT drive board synchronously amplify the drive signal with the same frequency power and output two drive signals with negative voltage. For example, the first IGBT drive board U3 and the second IGBT drive board U4 can use DA962D2 to output a pulse drive signal of -5V to +15V. The drive signal with negative voltage can ensure that the IGBT driven by it is quickly turned off, thereby avoiding short circuit.

[0049] See also Figure 3 and Figure 4In a device for electric vehicle charging test provided in this embodiment, the power switch unit includes a second power supply and an H-bridge circuit. The second power supply is a +12V voltage source, which is used to provide a working voltage for the H-bridge circuit. The H-bridge circuit obtains a handshake signal by quickly switching on and off a driving signal with a negative voltage at the same frequency, and outputs the handshake signal to the vehicle under test through the third communication interface 22.

[0050] Specifically, the H-bridge circuit includes a first IGBT Q1, a second IGBT Q2, a third IGBT Q3, a fourth IGBT Q4 and a load resistor R3, wherein the collector of the first IGBT Q1 is coupled to the positive electrode of the second power supply, the base is coupled to the output end of the first IGBT driving board, and the emitter is coupled to the collector of the third IGBT Q3; the base of the third IGBT Q3 is coupled to the output end of the second IGBT driving board, and the emitter is coupled to the negative electrode of the second power supply; the collector of the second IGBT Q2 is coupled to the positive electrode of the second power supply, the base is coupled to the output end of the second IGBT driving board, and the emitter is coupled to the collector of the fourth IGBT Q4; the base of the fourth IGBT Q4 is coupled to the output end of the first IGBT driving board, and the emitter is coupled to the negative electrode of the second power supply; one end of the load resistor R3 is coupled to the emitter of the first IGBT Q1, and the other end is coupled to the emitter of the second IGBT load resistor R3 can be selected from 50Ω resistors, and both ends of the load resistor R3 are also connected to the control guide terminal CP and the interface protection ground terminal PE of the third communication interface 22 respectively.

[0051] The base of each insulated gate bipolar transistor IGBT receives a driving signal with a negative voltage, and by quickly switching on and off the driving signal with a negative voltage at the same frequency, the external DC power supply, i.e., the second power supply, is chopped to form a handshake signal with positive and negative phase outputs. The handshake signal is a standard handshake signal of 1kHz required by the on-board charger. Although the first power supply and the second power supply are both +12 voltage sources, the first power supply is used to power the handshake signal generating unit, the power boosting unit, and the power driving unit. While providing the working voltage for each chip or integrated circuit board, the current is relatively small; the second power supply is mainly used to power the H-bridge circuit, and the current is relatively large. The first power supply and the second power supply are used to power different working units of the handshake signal module, respectively, which effectively reduces the interference between electrical signals.

[0052] See also Figure 3 The device for electric vehicle charging test provided in this embodiment further includes a filter unit, the filter unit includes a filter capacitor C3, and the filter capacitor C3 can be a 3300uF capacitor. The positive electrode of the filter capacitor C3 is coupled to the positive electrode of the second power supply, and the negative electrode of the filter capacitor C3 is coupled to the negative electrode of the second power supply, which effectively reduces the ripple caused by high-frequency switching.

[0053] See also Figure 4 In a device for electric vehicle charging test provided in this embodiment, the charging guidance module includes a first identification resistor R7 and a second identification resistor R8, wherein one end of the first identification resistor R7 is coupled to the interface protection ground terminal PE of the third communication interface 22, and one end is coupled to the AC charging connection confirmation terminal CC of the third communication interface 22; the second identification resistor R8 is coupled between the load resistor R3 and the control guidance terminal CP of the third communication interface 22. In the specific implementation process, the first identification resistor R7 is selected to be 680Ω, one end is coupled to the charging interface PE terminal, and the other end is coupled to the charging interface CC terminal. The second identification resistor R8 is selected to be 1kΩ, which meets the requirements of GB / T18487.1-2015, so that it can be effectively identified by the on-board charger, and then the handshake signal output by the device is used to check whether the on-board charger is in normal working condition.

[0054] See also Figure 5a or Figure 5b In a device for electric vehicle charging test provided in this embodiment, the DC load module includes a third identification resistor R6. In order to comply with the requirements of GB / T18487.1-2015, the third identification resistor R6 can be a 1kΩ power resistor. The two ends of the third identification resistor R6 are respectively coupled to the interface protection ground terminal PE of the first communication interface 211 and the DC charging connection confirmation terminal CC1. The AC load module includes a diode D1 and a fourth identification resistor R9 connected in series. In order to comply with the requirements of GB / T18487.1-2015, D1 is a fast recovery diode, and the fourth identification resistor R9 can be Figure 5a A resistor can also be Figure 5b The R4 and R5 shown are connected in parallel, wherein the resistance value of R4 is 1300Ω, the resistance value of R5 is 2740Ω, and the two ends of the AC load module are respectively coupled to the interface protection ground terminal PE and the control guide terminal CP of the second communication interface 212. On the basis of meeting the requirements of GB / T18487.1-2015, the DC load module can be effectively connected to the DC charging pile to obtain the background noise of the electromagnetic radiation test during DC charging of the electric vehicle, and the AC load module can be connected to the AC charging pile to obtain the background noise of the electromagnetic radiation test during AC charging of the electric vehicle, thereby eliminating the influence of the background noise and more accurately detecting the influence of the interference signal of the on-board charger inside the electric vehicle on the electromagnetic radiation of the outside world.

[0055] See also Figure 6a or Figure 6b , Figure 6a to Figure 6bThe figure are waveform diagrams of the rising and falling edges of the handshake signal output pulse in the embodiment of the present invention, respectively. It can be seen that the rising edge time is 105.5ns and the falling edge time is 27ns, which meets the requirement of the charging pile output signal that its rising and falling edges are less than 2us. The handshake signal is output to the on-board charger inside the vehicle under test, and the working state of the on-board charger of the vehicle under test after receiving different handshake signals is used to determine whether the vehicle under test can still perform charging preparation work normally.

[0056] In the description of the above embodiments, specific features, structures, materials or characteristics may be combined in a suitable manner in any one or more embodiments or examples.

[0057] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art who is familiar with the technical field can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. A device for electric vehicle charging test, characterized in that: It includes a shell for shielding electromagnetic radiation and a load simulation part and a charging pile simulation part contained in the shell, wherein the load simulation part is used to obtain the background noise of the electromagnetic radiation test when the electric vehicle is charging, wherein: The load simulation unit comprises: A DC load module, an AC load module, a first communication interface, and a second communication interface that are independent of each other, wherein the DC load module is connected to the DC charging pile via the first communication interface, and the AC load module is connected to the AC charging pile via the second communication interface; The charging pile simulation unit comprises: A charging guide module, a handshake signal module and a third communication interface, wherein the charging guide module and the handshake signal module are respectively connected to the vehicle under test through the third communication interface, the charging guide module is used to be identified by the vehicle under test, and the handshake signal module is used to output a handshake signal to the vehicle under test, wherein the handshake signal module includes: A handshake signal generating unit, a power boosting unit, a power driving unit and a power switch unit connected in sequence, wherein the power switch unit outputs a handshake signal to the vehicle under test through the third communication interface, wherein the handshake signal generating unit includes: A first power supply and an Arduino board, wherein the first power supply is The Arduino board provides a working voltage, and the Arduino board generates two pulse signals with the same frequency and the same duty cycle but not at the same high level, and outputs them synchronously to the power boosting unit. The frequency and the duty cycle are set according to different charging states of the charger of the tested electric vehicle.

2. The device for electric vehicle charging test according to claim 1, characterized in that: The power boost unit comprises a bus driver (U2), a first pull-up resistor (R1) and a second pull-up resistor (R2), wherein: The bus driver (U2) is provided with two pairs of input terminals and output terminals, the input terminals are respectively connected to the two output pins of the Arduino board for respectively receiving the pulse signals, and the output terminals are respectively connected to the first power supply via the first pull-up resistor (R1) and the second pull-up resistor (R2); the bus driver (U2) synchronously performs same-frequency power amplification on the two pulse signals to obtain two driving signals with the same frequency and the same duty cycle but not at the same high level, and outputs them respectively via the two output terminals.

3. The device for electric vehicle charging test according to claim 2, characterized in that: The power drive unit comprises a first IGBT drive board and a second IGBT drive board, which are respectively connected to two output ends of the bus driver (U2); the first IGBT drive board and the second IGBT drive board synchronously amplify the drive signal with the same frequency power and output two drive signals with negative voltage.

4. The device for electric vehicle charging test according to claim 3, characterized in that: The power switch unit includes a second power supply and an H-bridge circuit, wherein the second power supply provides an operating voltage for the H-bridge circuit, and the H-bridge circuit obtains a handshake signal by quickly switching on and off the driving signal with a negative voltage at the same frequency, and outputs the handshake signal to the vehicle under test through the third communication interface.

5. The device for electric vehicle charging test according to claim 4, characterized in that: The H-bridge circuit includes a first IGBT (Q1), a second IGBT (Q2), a third IGBT (Q3), a fourth IGBT (Q4) and a load resistor (R3), wherein: The collector of the first IGBT (Q1) is coupled to the positive electrode of the second power supply, the base is coupled to the output end of the first IGBT driving board, and the emitter is coupled to the collector of the third IGBT (Q3); The base of the third IGBT (Q3) is coupled to the output terminal of the second IGBT driving board, and the emitter is coupled to the negative electrode of the second power supply; The collector of the second IGBT (Q2) is coupled to the positive electrode of the second power supply, the base is coupled to the output end of the second IGBT driving board, and the emitter is coupled to the collector of the fourth IGBT (Q4); The base of the fourth IGBT (Q4) is coupled to the output terminal of the first IGBT driving board, and the emitter is coupled to the negative electrode of the second power supply; One end of the load resistor (R3) is coupled to the emitter of the first IGBT (Q1), and the other end is coupled to the emitter of the second IGBT (Q2); the two ends of the load resistor (R3) are also respectively connected to the control guide terminal (CP) and the interface protection ground terminal (PE) of the third communication interface.

6. The device for electric vehicle charging test according to claim 4, characterized in that: The device also includes a filter unit, which includes a filter capacitor (C3), a positive electrode of the filter capacitor (C3) coupled to the positive electrode of the second power supply, and a negative electrode of the filter capacitor (C3) coupled to the negative electrode of the second power supply.

7. The device for electric vehicle charging test according to claim 5, characterized in that: The charging guide module includes a first identification resistor (R7) and a second identification resistor (R8), wherein: One end of the first identification resistor (R7) is coupled to the interface protection ground terminal (PE) of the third communication interface, and the other end is coupled to the AC charging connection confirmation terminal (CC) of the third communication interface; the second identification resistor (R8) is coupled between the load resistor (R3) and the control guide terminal (CP) of the third communication interface.

8. The device for electric vehicle charging test according to claim 1, characterized in that: The DC load module comprises a third identification resistor (R6), and two ends of the third identification resistor (R6) are respectively coupled to an interface protection ground terminal (PE) of the first communication interface and a DC charging connection confirmation terminal (CC1); The AC load module comprises a diode (D1) and a fourth identification resistor (R9) connected in series, and two ends of the AC load module are respectively coupled to an interface protection ground terminal (PE) and a control guide terminal (CP) of the second communication interface.

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