Bidirectional charging and discharging device for electric automobile

Abstract

The utility model discloses a bidirectional charging and discharging device for an electric vehicle. The bidirectional charging and discharging device comprises a charging gun and a power strip, the charging gun comprises a charging and discharging control panel; the charging and discharging control panel comprises an L line, an N line, a CC line, a PE line, an MCU, a first AC-DC conversion module, a second AC-DC conversion module, a relay K1, a relay K2 and a resistor R1. The power strip comprises a power strip control board; the power strip control board comprises an L line, an N line, a CC line, a PE line and a resistor R2 connected between the CC line and the PE line. The R1 is connected in series with the CC line; two switches of the K1 are positioned on an L line and an N line; one end of the switch of the K2 is connected with the CC line, and the other end is connected with the PE line; one end of the first AC-DC conversion module is connected with an L line and an N line, and the other end is connected with the MCU; one end of the second AC-DC conversion module is connected with the L line and the N line, and the other end is connected with the MCU; and the MCU is connected with the K1 and the K2. According to the invention, the occupied space is reduced, and the cost is reduced.

Description

Technical Field

[0001] The present application relates to the field of circuit design technology, and in particular to a bidirectional charging and discharging device for electric vehicles. Background Art

[0002] The market penetration rate of electric vehicles has been increasing year by year, and the number of electric vehicles in use has also increased accordingly. Furthermore, with the continuous development of related technologies, more and more electric vehicles are equipped with external discharge functions, allowing them to not only be charged externally but also serve as mobile power sources to power other devices. This function greatly enhances the practicality and flexibility of electric vehicles. For example, electric vehicles can provide power for electrical devices in scenarios such as camping and outdoor activities.

[0003] However, in traditional technologies, charging and discharging functions are usually achieved by using two different devices, which not only takes up space in the car but also invisibly increases costs. Utility Model Content

[0004] In order to solve the above technical problems, the present application provides a bidirectional charging and discharging device for electric vehicles.

[0005] This application provides a bidirectional charging and discharging device for electric vehicles, which adopts the following technical solutions:

[0006] A bidirectional charging and discharging device for an electric vehicle includes a charging gun and a socket strip; the charging gun includes a charging and discharging control board; the charging and discharging control board includes an L line, an N line, a CC line, a PE line, an MCU, a first AC-DC conversion module, a second AC-DC conversion module, a relay K1, a relay K2, and a resistor R1; the socket strip includes a socket strip control board; the socket strip control board includes an L line, an N line, a CC line, a PE line, and a resistor R2 connected between the CC line and the PE line;

[0007] The resistor R1 is connected in series to the CC line of the charge and discharge control board; the relay K1 includes two switches, and the two switches of the relay K1 are connected in series to the L line and the N line of the charge and discharge control board respectively; the relay K2 includes one switch, and one end of the switch of the relay K2 is connected to the CC line of the charge and discharge control board, and the other end is connected to the PE line of the charge and discharge control board;

[0008] The power input end of the first AC-DC conversion module is connected to the L line and the N line of the charge and discharge control board, and the output end is connected to the power end of the MCU. The first AC-DC conversion module is used to provide the MCU with an operating voltage based on the mains power when the vehicle is charging;

[0009] The power input end of the second AC-DC conversion module is connected to the L line and the N line of the charge and discharge control board, and the output end is connected to the power end of the MCU. The second AC-DC conversion module is used to provide an operating voltage for the MCU based on the electric energy output by the vehicle when the vehicle is discharging;

[0010] The output end of the MCU is connected to the relay K1 and the relay K2, and the MCU is used to control the on and off of the relay K1 and the relay K2.

[0011] By adopting the above technical solution, the charge and discharge control board and the socket control board are designed and connected, and the charging and discharging functions are integrated into one charging device, which not only reduces the space occupied but also reduces the cost.

[0012] In a specific embodiment, the bidirectional charging and discharging device for an electric vehicle further includes a first driving module; the first driving module is connected between the MCU and the relay K1, and the MCU is used to control the switch closure of the relay K1 through the first driving module;

[0013] Among them, the first driving module includes a transistor QK1, a resistor RK1, a resistor RK2, and a capacitor CK1; the MCU is connected to the driving end of the transistor QK1 through the resistor RK2, and the driving end of the transistor QK1 is also connected to the first end of the capacitor CK1 and the first end of the resistor RK1, and the second end of the capacitor CK1, the second end of the resistor RK1, and the first end of the transistor QK1 are all grounded; one end of the coil of the relay K1 is connected to the power supply voltage VCC, and the other end is connected to the second end of the transistor QK1.

[0014] By adopting the above technical solution, when the switch of the relay K1 needs to be closed, the MCU1 can control the coil of the relay K1 to be energized through the first driving module, so that the switch is closed.

[0015] In a specific embodiment, the bidirectional charging and discharging device for an electric vehicle further includes a second driving module; the second driving module is connected between the MCU and the relay K2, and the MCU is used to control the switch closure of the relay K2 through the second driving module;

[0016] Among them, the second driving module includes a transistor QK2, a resistor RK3, a resistor RK4, and a capacitor CK2; the MCU is connected to the driving end of the transistor QK2 through the resistor RK4, and the driving end of the transistor QK2 is also connected to the first end of the capacitor CK2 and the first end of the resistor RK3, and the second end of the capacitor CK2, the second end of the resistor RK3, and the first end of the transistor QK2 are all grounded; one end of the coil of the relay K1 is connected to the power supply voltage VCC, and the other end is connected to the second end of the transistor QK2.

[0017] By adopting the above technical solution, when the switch of the relay K2 needs to be closed, the MCU1 can control the coil of the relay K2 to be energized through the second driving module, so that the switch is closed.

[0018] In a specific implementation scheme, the first driving module further includes a diode DK1; the diode DK1 is connected in parallel at both ends of the coil of the relay K1.

[0019] In a specific embodiment, the bidirectional charging and discharging device for an electric vehicle further includes an AC monitoring module; the AC monitoring module is connected to the L line and the N line on the charging and discharging control board, and is also connected to the MCU;

[0020] The MCU is used to monitor the current, voltage and frequency of the AC power on the charging and discharging circuit through the AC power monitoring module, and perform corresponding protection actions.

[0021] In a specific embodiment, the bidirectional charging and discharging device for an electric vehicle further includes an over-temperature protection module; the over-temperature protection module is connected to the MCU;

[0022] The MCU is used to monitor the temperature of the charging plug end and the vehicle connection end through the over-temperature protection module and perform corresponding over-temperature protection actions; wherein, the charging plug end is the end of the charging gun connected to the mains or socket strip, and the vehicle connection end is the end of the charging gun connected to the vehicle.

[0023] In a specific implementation manner, the transistor QK1 and the transistor QK2 are NN-type transistors.

[0024] In a specific embodiment, the diode DK1 is a Schottky diode.

[0025] One or more technical solutions provided in the embodiments of this application have at least the following technical effects or advantages:

[0026] A first AC-DC conversion module is provided in the charge and discharge control board, so that when the mains is connected to charge the vehicle, the first AC-DC conversion module can provide an operating voltage for the MCU based on the mains, and the MCU controls the operation of the charging device. At the same time, the mains can also charge the vehicle through the charging gun; a second AC-DC conversion module is also provided in the charge and discharge control board, so that when the vehicle needs to output electric energy to charge other loads, the second AC-DC conversion module can provide an operating voltage for the MCU based on the electric energy output by the vehicle, and the MCU controls the operation of the charging device. At the same time, the electric energy output by the vehicle can also charge the load in sequence through the charging gun and the socket strip; the solution of the present application integrates the charging and discharging functions into one charging device by designing and connecting the charge and discharge control board and the socket strip, which not only reduces the space occupied but also reduces the cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a circuit diagram of the charge and discharge control board and the socket control board in the embodiment of the present application;

[0028] Figure 2 This is a schematic diagram of the structure of the power strip in the embodiment of the present application;

[0029] Figure 3 It is a three-dimensional schematic diagram of the charging gun and socket strip in the embodiment of the present application.

[0030] Description of reference numerals:

[0031] 1. MCU; 2. First AC-DC conversion module; 3. Second AC-DC conversion module; 4. First drive module; 5. Second drive module. DETAILED DESCRIPTION

[0032] In order to enable those skilled in the art to better understand the technical solutions in this specification, the technical solutions in the embodiments of this specification will be clearly and completely described below in conjunction with the drawings in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this application, not all of the embodiments.

[0033] The present application provides a bidirectional charging and discharging device for electric vehicles, such as Figure 1 As shown, it includes a charging gun and a socket strip; Figure 1 As shown, the charging gun includes a charge and discharge control board; the charge and discharge control board includes an L line, an N line, a CC line, a PE line, an MCU1, a first AC-DC conversion module 2, a second AC-DC conversion module 3, a relay K1, a relay K2 and a resistor R1;

[0034] like Figure 1 and Figure 2As shown, the socket strip includes a socket strip control board; the socket strip control board includes an L line, an N line, a CC line, a PE line, and a resistor R2 connected between the CC line and the PE line.

[0035] Continue to refer to Figure 1 , the resistor R1 is set in series with the CC line of the charge and discharge control board; the relay K1 includes two switches, and the two switches of the relay K1 are respectively connected in series with the L line and the N line of the charge and discharge control board; the relay K2 includes a switch, and one end of the switch of the relay K2 is connected to the CC line of the charge and discharge control board, and the other end is connected to the PE line of the charge and discharge control board;

[0036] The power input end of the first AC-DC conversion module 2 is connected to the L line and the N line of the charge and discharge control board, and the output end is connected to the power end of the MCU1. The first AC-DC conversion module 2 is used to provide the MCU1 with an operating voltage based on the mains power when the vehicle is charging;

[0037] The power input end of the second AC-DC conversion module 3 is connected to the L line and the N line of the charge and discharge control board, and the output end is connected to the power end of the MCU1. The second AC-DC conversion module 3 is used to provide an operating voltage for the MCU1 based on the electric energy output by the vehicle when the vehicle is discharging;

[0038] The output end of the MCU1 is connected to the relay K1 and the relay K2, and the MCU1 is used to control the on and off of the relay K1 and the relay K2.

[0039] It will be understood by those skilled in the art that Figure 1 As shown, the charging gun includes a charging plug terminal and a vehicle connection terminal. The charging plug terminal is connected to the L line, N line, CC line, and PE line from the charge and discharge control board, and is used to connect to the power strip control board when the vehicle is discharging or to the mains when the vehicle is charging. The vehicle connection terminal is connected to the L line, N line, CC line, and PE line from the charge and discharge control board for connection to the vehicle. The first AC-DC conversion module 2 is connected to the L line and N line of the charging plug terminal, and the second AC-DC conversion module 3 is connected to the L line and N line of the vehicle connection terminal.

[0040] The socket strip includes a discharge input jack and a discharge output jack. The discharge input jack is the L line, N line, CC line, and PE line drawn from the socket strip control board, which are used to connect the charging plug end of the charging gun when the vehicle is discharging. The discharge output jack is the L line, N line, and PE line drawn from the socket strip control board, which are used to connect the load when the vehicle is discharging.

[0041] Therefore, through such a design, a first AC-DC conversion module 2 is set in the charge and discharge control board, so that when the AC power is connected to charge the vehicle, the first AC-DC conversion module 2 can provide an operating voltage to the MCU1 based on the AC power, so that the MCU1 controls the operation of the charging device, and the AC power can also charge the vehicle through the charging gun; a second AC-DC conversion module 3 is also set in the charge and discharge control board, so that when the vehicle needs to output electric energy to charge other loads, the second AC-DC conversion module 3 can provide an operating voltage to the MCU1 based on the electric energy output by the vehicle, so that the MCU1 controls the operation of the charging device, and the electric energy output by the vehicle can also charge the load in turn through the charging gun and the socket strip; in this application, by designing and connecting the charge and discharge control board and the socket strip, the charging and discharging functions are integrated into one charging device, which not only reduces the space occupied but also reduces the cost.

[0042] like Figure 3 The following is a three-dimensional diagram of the charging gun and the socket. Figure 1 and Figure 3 , the working process of the circuit is explained:

[0043] When the charging plug end of the charging gun is connected to the mains and the vehicle connection end is connected to the vehicle, the first AC-DC conversion module 2 is connected to the mains and provides an operating voltage to the MCU1 based on the mains. When the MCU1 detects that the first AC-DC conversion module 2 is working, it controls the switch of the relay K2 to close. When the vehicle detects that the resistance between the CC line and the PE line is R1, it enters the charging preparation state and sends a charging instruction to the MCU1, causing the MCU1 to control the switch of the relay K1 to close. The mains then charges the vehicle through the L line and N line of the charging gun control board.

[0044] When the discharge input socket of the socket strip is connected to the charging plug end of the charging gun and the discharge output socket is connected to the load, the vehicle detects that the resistance between the CC line and the PE line is the sum of R1 and R2, then enters the discharge preparation and outputs electric energy; the second AC-DC conversion module 3 provides the MCU1 with an operating voltage based on the electric energy output by the vehicle. At the same time, the MCU1 detects that the second AC-DC conversion module 3 is working and the system is normal, then controls the switch of the relay K1 to close, so that the electric energy output by the vehicle is sequentially supplied to the load through the L line and N line of the charging gun control board and the L line and N line of the socket strip control board.

[0045] With this setup, when the vehicle is charging, the charging startup process is not affected by the order in which the charging plug and vehicle connection are inserted. Even if the charging gun is not connected to the mains after being inserted into the vehicle, the vehicle will not wake up because it does not recognize the resistance between the CC and PE lines. This effectively prevents the vehicle from being awakened and not entering the charging state for a long time, causing the vehicle's low-voltage auxiliary battery to run low. When the vehicle is discharging, the resistance between CC and PE will only become the sum of R1 and R2 after the charging plug of the charging gun is connected to the discharge input jack of the power strip. Even if the relay sticks, the vehicle's power output will not be mistakenly triggered, avoiding safety accidents. Compared with the method of identifying whether the charging gun is connected to the power strip at the charging gun end, the safety protection effect is better.

[0046] In a possible embodiment, the bidirectional charging and discharging device for electric vehicles further includes a first driving module 4; Figure 1 , the first driving module 4 is connected between the MCU1 and the relay K1, and the MCU1 is used to control the switch of the relay K1 through the first driving module 4;

[0047] Among them, the first driving module 4 includes a transistor QK1, a resistor RK1, a resistor RK2, and a capacitor CK1; the MCU1 is connected to the driving end of the transistor QK1 through the resistor RK2, and the driving end of the transistor QK1 is also connected to the first end of the capacitor CK1 and the first end of the resistor RK1, and the second end of the capacitor CK1, the second end of the resistor RK1, and the first end of the transistor QK1 are all grounded; one end of the coil of the relay K1 is connected to the power supply voltage VCC, and the other end is connected to the second end of the transistor QK1.

[0048] The following is a detailed description of the working process of this part:

[0049] When MCU1 outputs a high level, driving switch QK1 to conduct, the current output by power supply voltage VCC passes through the coil of relay K1 and transistor QK1 before being grounded. Relay K1's coil is energized, closing the switch of relay K1. Those skilled in the art will appreciate that resistor RK2 is used to adjust the current driving switch QK1, and resistor RK1 and capacitor CK1 form a filter circuit.

[0050] Through such a configuration, when the switch of the relay K1 needs to be closed, the MCU1 can control the coil of the relay K1 to be energized through the first driving module 4 to close the switch.

[0051] In one possible implementation, refer to Figure 1 The first driving module 4 further includes a diode DK1; the diode DK1 is connected in parallel at both ends of the coil of the relay K1.

[0052] The unidirectional conduction function of diode DK1 is utilized to avoid current backflow and play a protective role.

[0053] In a possible implementation, the diode DK1 is a Schottky diode.

[0054] In a possible embodiment, the bidirectional charging and discharging device for electric vehicles further includes a second driving module 5; Figure 1 The second driving module 5 is connected between the MCU1 and the relay K2, and the MCU1 is used to control the switch of the relay K2 to be closed through the second driving module 5;

[0055] Among them, the second driving module 5 includes a transistor QK2, a resistor RK3, a resistor RK4, and a capacitor CK2; the MCU1 is connected to the driving end of the transistor QK2 through the resistor RK4, and the driving end of the transistor QK2 is also connected to the first end of the capacitor CK2 and the first end of the resistor RK3, and the second end of the capacitor CK2, the second end of the resistor RK3, and the first end of the transistor QK2 are all grounded; one end of the coil of the relay K1 is connected to the power supply voltage VCC, and the other end is connected to the second end of the transistor QK2.

[0056] The following is a detailed description of the working process of this part:

[0057] When MCU1 outputs a high level, driving switch QK2 to conduct, the current output by power supply voltage VCC passes through the coil of relay K2 and transistor QK2 before being grounded. Relay K2's coil is energized, closing the switch of relay K2. Those skilled in the art will appreciate that resistor RK4 is used to adjust the current driving switch QK4, while resistor RK3 and capacitor CK2 form a filter circuit.

[0058] Through such a configuration, when the switch of the relay K2 needs to be closed, the MCU1 can control the coil of the relay K2 to be energized through the second driving module 5 so that the switch is closed.

[0059] In a possible implementation manner, the transistor QK1 and the transistor QK2 are NN-type transistors.

[0060] In one possible embodiment, the bidirectional charging and discharging device for an electric vehicle further includes an AC monitoring module; the AC monitoring module is connected to the L line and the N line on the charging and discharging control board, and is also connected to the mains and the MCU1;

[0061] The MCU1 is used to monitor the current, voltage and frequency of the AC power on the charging and discharging circuit through the AC power monitoring module, and perform corresponding protection actions.

[0062] The MCU1 monitors the current of the AC power on the charge and discharge circuit through the AC power monitoring module and performs overcurrent protection, specifically: when the current reaches the preset current threshold I c1 And the duration reaches the preset time threshold T c1 When the MCU1 controls the switch of the relay K1 to be disconnected, the charging of the vehicle is stopped in time; further, the MCU1 can also control the switch of the relay K1 to be closed after the switch disconnection time of the relay K1 reaches a preset time, and resume the charging of the vehicle, and continuously monitor the current of the AC power on the charging and discharging circuit through the MCU1. When the current reaches the preset current threshold I c2 When the MCU1 controls the switch of relay K1 to be turned off again, an alarm is sounded, and the charging of the vehicle is no longer resumed;

[0063] Preferably, the preset current threshold I c1 The vehicle rated current value + 2A, the preset current threshold I c2 1.5 times the rated current of the vehicle.

[0064] The MCU1 monitors the voltage of the AC power on the charge and discharge circuit through the AC power monitoring module and performs overvoltage and undervoltage protection. Specifically, when the voltage exceeds the preset voltage threshold V H1 And the duration reaches the time threshold T v1 When the overvoltage protection is activated, the MCU1 controls the switch of the relay K1 to be disconnected, stops the charging of the vehicle in time, and continuously monitors the charging and discharging circuit. When the voltage of the AC power on the monitoring charging and discharging circuit is lower than the voltage threshold V H2 And the duration reaches the time threshold T v2 When , MCU1 controls the switch of relay K1 to close and resume charging.

[0065] In addition, when the voltage of the AC power on the monitoring charge and discharge circuit is lower than the voltage threshold V L1 And the duration reaches the time threshold T v1 When the voltage is higher than the voltage threshold V L2 And the duration reaches the time threshold T v2 , MCU1 controls the switch of relay K1 to close.

[0066] The MCU1 monitors the frequency of the AC power on the charge and discharge circuit through the AC power monitoring module and performs over-frequency and under-frequency protection. Specifically, when the monitored frequency exceeds the preset frequency threshold F H And the duration reaches the preset time threshold T f1When the frequency is lower than the preset frequency threshold F, the MCU1 controls the switch of the relay K1 to be disconnected and continuously monitors. H And the duration reaches the preset time threshold T f2 When the frequency is lower than the preset frequency threshold F, the relay K1 is controlled to close again and charging is resumed. L And the duration reaches the preset frequency threshold T f1 When the frequency is higher than the preset frequency threshold F, the MCU1 controls the switch of relay K1 to be off and continuously monitors. L And the duration reaches the preset time threshold T f2 When , MCU1 controls relay K1 to close again and resume charging.

[0067] In a possible implementation, the bidirectional charging and discharging device for an electric vehicle further includes an over-temperature protection module; the over-temperature protection module is connected to the MCU1;

[0068] The MCU1 is used to monitor the temperature of the charging plug end and the vehicle connection end through the over-temperature protection module and perform corresponding over-temperature protection actions; wherein, the charging plug end is the end of the charging gun connected to the mains or socket strip, and the vehicle connection end is the end of the charging gun connected to the vehicle.

[0069] Specifically, when the MCU1 detects that the temperature of the charging plug end or the vehicle connection end reaches the temperature threshold T p1 And the continuous time reaches the time threshold T t1 MCU1 reduces the charging current of the vehicle by communicating with the vehicle end. When the temperature of the charging plug end or the vehicle connection end reaches the temperature threshold T p2 And the duration reaches the time threshold T t2 When MCU1 controls the switch of relay K1 to be disconnected, and continuously monitors the temperature, when MCU1 detects that the temperature drops back to the temperature threshold T p3 And the duration reaches the time threshold T t3 When , MCU1 controls the switch of relay K1 to close and resume charging.

[0070] In a possible implementation, the MCU1 is also used to detect the grounding status of the charging plug end after the charging plug end is connected to the mains power, and is also used to detect whether the L line and N line between the charging plug end and the mains power are out of phase. If they are not grounded or out of phase, the MCU1 notifies the vehicle to sound an alarm and puts the vehicle in a non-charging state.

[0071] In one possible implementation, the MCU1 is also configured to apply leakage current excitation between the L and N wires of the charging gun after the vehicle enters the charging / discharging preparation phase and detect whether its own leakage protection circuit is functioning properly, thereby implementing a power-on leakage self-test function. Furthermore, the MCU1 can also perform a leakage self-test before the vehicle begins charging or discharging, and monitor the leakage current between the L and N wires of the charging gun in real time during the charging or discharging process. If the leakage current reaches a preset threshold, the relay K1 is controlled to disconnect.

[0072] In a possible implementation, the MCU1 is further configured to perform adhesion detection on the relay K1 before the vehicle is charged or discharged. If the relay K1 is adhered, the MCU1 will not enter the charging or discharging state and will generate an alarm.

[0073] In a possible implementation, the MCU1 is also used to perform short-circuit detection on the charging gun and the socket strip before the vehicle is charged or discharged. If there is a short circuit between the L line and the N line of the charging gun or the L line and the N line of the socket strip, the MCU1 will not enter the charging or discharging state and will alarm.

[0074] The above are all preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the scope of protection of the present application.

Claims

1. A bidirectional charging and discharging device for electric vehicles, characterized in that: The invention comprises a charging gun and a socket strip; the charging gun comprises a charge and discharge control board; the charge and discharge control board comprises an L line, an N line, a CC line, a PE line, an MCU (1), a first AC-DC conversion module (2), a second AC-DC conversion module (3), a relay K1, a relay K2 and a resistor R1; the socket strip comprises a socket strip control board; the socket strip control board comprises an L line, an N line, a CC line, a PE line and a resistor R2 connected between the CC line and the PE line; The resistor R1 is connected in series to the CC line of the charge and discharge control board; the relay K1 includes two switches, and the two switches of the relay K1 are connected in series to the L line and the N line of the charge and discharge control board respectively; the relay K2 includes one switch, and one end of the switch of the relay K2 is connected to the CC line of the charge and discharge control board, and the other end is connected to the PE line of the charge and discharge control board; The power input end of the first AC-DC conversion module (2) is connected to the L line and the N line of the charge and discharge control board, and the output end is connected to the power end of the MCU (1). The first AC-DC conversion module (2) is used to provide an operating voltage for the MCU (1) based on the mains electricity when the vehicle is charging; The power input end of the second AC-DC conversion module (3) is connected to the L line and the N line of the charge and discharge control board, and the output end is connected to the power end of the MCU (1). The second AC-DC conversion module (3) is used to provide an operating voltage for the MCU (1) based on the electric energy output by the vehicle when the vehicle is discharging; The output end of the MCU (1) is connected to the relay K1 and the relay K2, and the MCU (1) is used to control the on and off of the relay K1 switch and the relay K2 switch.

2. The bidirectional charging and discharging device for electric vehicles according to claim 1, characterized in that: It also includes a first driving module (4); the first driving module (4) is connected between the MCU (1) and the relay K1, and the MCU (1) is used to control the switch of the relay K1 to close through the first driving module (4); The first driving module (4) comprises a transistor QK1, a resistor RK1, a resistor RK2, and a capacitor CK1; the MCU (1) is connected to the driving end of the transistor QK1 via the resistor RK2; the driving end of the transistor QK1 is also connected to the first end of the capacitor CK1 and the first end of the resistor RK1; the second end of the capacitor CK1, the second end of the resistor RK1, and the first end of the transistor QK1 are all grounded; one end of the coil of the relay K1 is connected to a power supply voltage VCC, and the other end is connected to the second end of the transistor QK1.

3. The bidirectional charging and discharging device for electric vehicles according to claim 2, characterized in that: The first driving module (4) further comprises a diode DK1; the diode DK1 is connected in parallel to both ends of the coil of the relay K1.

4. The bidirectional charging and discharging device for electric vehicles according to claim 2, characterized in that: It also includes a second driving module (5); the second driving module (5) is connected between the MCU (1) and the relay K2, and the MCU (1) is used to control the switch of the relay K2 to close through the second driving module (5); The second driving module (5) comprises a transistor QK2, a resistor RK3, a resistor RK4, and a capacitor CK2; the MCU (1) is connected to the driving end of the transistor QK2 via the resistor RK4; the driving end of the transistor QK2 is also connected to the first end of the capacitor CK2 and the first end of the resistor RK3; the second end of the capacitor CK2, the second end of the resistor RK3, and the first end of the transistor QK2 are all grounded; one end of the coil of the relay K1 is connected to a power supply voltage VCC, and the other end is connected to the second end of the transistor QK2.

5. The bidirectional charging and discharging device for electric vehicles according to claim 1, characterized in that: It also includes an AC monitoring module; the AC monitoring module is connected to the L line and the N line on the charge and discharge control board, and is also connected to the MCU (1); The MCU (1) is used to monitor the current, voltage and frequency of the AC power on the charging and discharging circuit through the AC power monitoring module, and to perform corresponding protection actions.

6. The bidirectional charging and discharging device for electric vehicles according to claim 1, characterized in that: It also includes an over-temperature protection module; the over-temperature protection module is connected to the MCU (1); The MCU (1) is used to monitor the temperature of the charging plug end and the vehicle connection end through the over-temperature protection module and perform corresponding over-temperature protection actions; wherein the charging plug end is the end of the charging gun connected to the mains or the socket strip, and the vehicle connection end is the end of the charging gun connected to the vehicle.

7. The bidirectional charging and discharging device for electric vehicles according to claim 4, characterized in that: The transistor QK1 and the transistor QK2 are NN-type transistors.

8. The bidirectional charging and discharging device for electric vehicles according to claim 3, characterized in that: The diode DK1 is a Schottky diode.

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