Three-phase gun charging circuit

Abstract

The utility model relates to a three-phase gun charging circuit which comprises a three-phase power inlet wire, a three-phase power outlet wire, a three-phase output control module, an AC / DC power supply module, a voltameter power supply module, an MCU module, a voltameter detection module and an isolation communication module. The three-phase output control module controls the on-off of the three-phase power inlet wire and the three-phase power outlet wire; the voltameter detection module is connected with the voltameter power supply module and comprises a voltameter chip, a voltage sampling unit and a current sampling unit, the voltameter chip is provided with a voltage feedback input end, a current feedback input end and a first communication end, and the voltage sampling unit is connected with a three-phase power inlet wire and the voltage feedback input end; the MCU module comprises a second communication end and an output control end, the output control end is connected with the three-phase output control module, and the first communication end is connected with the second communication end of the MCU module through the isolation communication module. According to the utility model, a voltage transformer is omitted, the miniaturization design of the three-phase gun can be facilitated, the cost can be reduced to a certain extent, and the maintenance is facilitated.

Description

Technical Field

[0001] The utility model relates to the technical field of three-phase charging guns, in particular to a three-phase gun charging circuit. Background Art

[0002] Existing three-phase charging guns are typically equipped with a power meter chip, current transformer, and voltage transformer. These sensors collect the current and voltage at the rear end of the main control relay and feed them back to the power meter chip to calculate power consumption. However, the presence of these sensors makes the charging gun head bulky, and three sets of these sensors are generally required, making them relatively expensive. Furthermore, because the current and voltage transformers must be installed on the three-phase lines, if the transformers fail or are damaged, the three-phase lines must be disconnected to remove the transformers, making maintenance relatively cumbersome. Utility Model Content

[0003] The purpose of the utility model is to provide a three-phase gun charging circuit, which omits a voltage transformer, is conducive to the miniaturization design of the three-phase gun, can reduce costs to a certain extent, and is convenient for maintenance.

[0004] To achieve the above-mentioned purpose, the utility model discloses a three-phase gun charging circuit, which includes a three-phase power input line, a three-phase power output line, a three-phase output control module, an AC / DC power supply module, an electricity meter power supply module, an MCU module, an electricity meter detection module and an isolation communication module;

[0005] The AC / DC power supply module is connected to the neutral line and any live line of the three-phase power incoming line to take power and output a first direct current;

[0006] The power meter power supply module is connected to the neutral line and any live line in the three-phase power incoming line to take power and output a second direct current;

[0007] The three-phase output control module is connected to the output end of the AC / DC power supply module to take power, and the three-phase power input line is connected to the three-phase power output line through the three-phase output control module. The three-phase output control module controls the on and off of the three-phase power input line and the three-phase power output line;

[0008] The electricity meter detection module is connected to the output end of the electricity meter power supply module to obtain power, and includes an electricity meter chip, a voltage sampling unit and a current sampling unit. The electricity meter chip has a voltage feedback input end, a current feedback input end and a first communication end. The voltage sampling unit is connected to the three-phase power incoming line and the voltage feedback input end. The current sampling unit has a current transformer, which is sleeved on the three-phase power outgoing line. The current sampling unit is connected to the current sampling feedback input end;

[0009] The MCU module is connected to the output end of the AC / DC power supply module to obtain power. The MCU module includes a second communication end for communicating with the power meter chip and an output control end for controlling the start and stop of the three-phase output control module. The output control end is connected to the three-phase output control module, and the first communication end is connected to the second communication end of the MCU module via the isolation communication module.

[0010] Preferably, the power meter power supply module includes a chip UA, a chip UA1, a diode DA1, a diode DA2, a diode DA3, a diode DA4, an electrolytic capacitor EC3, an electrolytic capacitor ECG1, a capacitor C24, a capacitor C31, a capacitor CA1, a resistor R70, a resistor RS1 and an inductor LA8. Any live wire in the three-phase power incoming line is connected to the anode of the diode DA3, the cathode of the diode DA3 is connected to the anode of the diode DA4, the cathode of the diode DA4 is connected to the DW pin of the chip UA and the positive electrode of the electrolytic capacitor EC3, and the negative electrode of the electrolytic capacitor EC3 is connected to the neutral wire of the three-phase power incoming line, the GND pin of the chip UA1, one end of the resistor R70, and the capacitor C24. One end of the chip UA1 is connected to one end of the capacitor C24, one end of the capacitor C31, the anode of the diode DA1 and the negative electrode of the electrolytic capacitor ECG1. The other end of the resistor R70 is connected to the other end of the capacitor C24, the other end of the capacitor C31 and the VOUT pin of the chip UA1. The VOUT pin of the chip UA1 outputs the second DC power; the VIN pin of the chip UA1 is connected to the positive electrode of the electrolytic capacitor ECG1, one end of the inductor LA8 and the anode of the diode DA2. The cathode of the diode DA2 is connected to one end of the capacitor CA1, which is the VDD pin of the chip UA. The other end of the capacitor CA1 is connected to the other end of the capacitor LA8, one end of the resistor RS1 and the cathode of the diode DA1. The other end of the resistor RS1 is connected to the GND pin of the chip UA.

[0011] Preferably, the voltage sampling unit includes voltage sampling subunits corresponding one-to-one to the three live wires of the three-phase power incoming line, the voltage feedback input end has a voltage feedback input pin group corresponding one-to-one to the voltage sampling subunit, and the voltage feedback input pin group includes a VP pin and a VN pin; the voltage sampling subunit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, and a second capacitor. The live wire of the three-phase power incoming line is connected to one end of the first resistor of the corresponding voltage sampling subunit, the other end of the first resistor is connected to one end of the third resistor, one end of the first capacitor and the VP pin of the corresponding voltage feedback input pin group through the second resistor, the other end of the third resistor is connected to the neutral wire of the three-phase power incoming line, one end of the fourth resistor, one end of the second capacitor and the other end of the first capacitor, and the other end of the fourth resistor is connected to the other end of the second capacitor and the VN pin of the corresponding voltage feedback input pin group.

[0012] Preferably, the first communication end includes an SDO pin and an SDI pin, and the second communication end includes a P61 pin and a P62 pin; the isolated communication module includes an isolation chip U5, a resistor RL2, a resistor RL3, a resistor RE7, a resistor R56, a resistor RV4, a resistor RV5, a resistor RE10, a resistor RE13, and a capacitor C39, the SDO pin is connected to one end of the resistor R56 and the VIB pin of the isolation chip U5 via the resistor RL2, and the other end of the resistor R56 is connected to the output end of the fuel gauge power supply module; the SDI pin is connected to one end of the resistor RE7 and the VOA pin of the isolation chip U5 via the resistor RL3, and the other end of the resistor RE7 is connected to the output end of the fuel gauge power supply module; The VDD1 pin of the isolation chip U5 is connected to one end of the capacitor C39 and the output end of the power meter power supply module, and the other end of the capacitor C39 is connected to the neutral line of the three-phase power incoming line; the VDD2 pin of the isolation chip U5 is connected to the power input end of the MCU module; the VIA pin of the isolation chip U5 is connected to one end of the resistor RE10 and the P62 pin via the resistor RV4, and the other end of the resistor RE10 is connected to the power input end of the MCU module; the VOB pin of the isolation chip U5 is connected to one end of the resistor RE13 and the P61 pin via the resistor RV5, and the other end of the resistor RE13 is connected to the power input end of the MCU module; the GND1 pin of the isolation chip U5 is connected to the neutral line of the three-phase power incoming line, and the GND2 pin of the isolation chip U5 is grounded.

[0013] Preferably, the three-phase output control module includes four relays and at least one relay control unit, the output control end of the MCU module includes output control pins corresponding to the relay control units one by one; each relay control unit corresponds to at least one relay;

[0014] The relay control unit includes a gate drive chip, an N-MOS transistor, a first diode, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor and a third capacitor. The IN pin of the gate drive chip is connected to the corresponding output control pin via the fifth resistor, the VCC pin of the gate drive chip is connected to the output end of the AC / DC power supply module and one end of the third capacitor, and the other end of the third capacitor is grounded; the OUT1 pin of the gate drive chip is connected to one end of the sixth resistor, the OUT2 pin of the gate drive chip is connected to one end of the seventh resistor, the other end of the sixth resistor is connected to the other end of the seventh resistor, the gate of the N-MOS transistor and one end of the eighth resistor, the other end of the eighth resistor and the source of the N-MOS transistor are grounded, the drain of the N-MOS transistor is connected to one end of the corresponding relay coil and the anode of the first diode, and the other end of the corresponding relay coil is connected to the cathode of the first diode and the output end of the AC / DC power supply module.

[0015] Preferably, the relay control unit is provided in two sets, one relay control unit corresponding to two of the relays, and the other relay control unit corresponding to the other two relays. This arrangement is beneficial to the circuit board design of the charging circuit, and the relay control circuit is shorter, the impact is smaller, and the reliability is higher.

[0016] Preferably, it also includes a relay adhesion detection module, which is connected to the three-phase power outgoing line and the MCU module.

[0017] Preferably, it also includes a grounding detection module, which is connected to the three-phase power incoming line and the MCU module.

[0018] Preferably, it further comprises a leakage detection module, wherein the leakage detection module comprises a leakage mutual inductor, and the leakage mutual inductor is arranged on the three-phase power outgoing line.

[0019] Preferably, it further includes a CP module for communicating with the device to be charged, and the CP module is connected to the output end of the MCU module and the AC / DC power supply module.

[0020] The utility model has the following beneficial effects:

[0021] The voltage acquisition unit of this utility model is directly connected to the live wire, eliminating the need for a voltage transformer. This facilitates the miniaturization of the three-phase gun design, reduces costs, and improves maintenance. The fuel gauge detection module communicates with the MCU module via the isolated communication module, reliably ensuring the safety of the MCU module. Furthermore, the fuel gauge detection module detects the three-phase voltage, and the MCU module can determine whether the input is missing a phase and whether the input is single-phase or three-phase. This allows the product to automatically switch between single-phase and three-phase power supply to charge new energy vehicles, broadening the product's compatibility and increasing its competitiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is a schematic diagram of the AC / DC power supply module.

[0023] Figure 2 This is a schematic diagram of the MCU module.

[0024] Figure 3 Schematic diagram of the module that powers the fuel gauge.

[0025] Figure 4 This is a schematic diagram of the three-phase output control module.

[0026] Figure 5 Schematic diagram of the fuel gauge detection module and the isolated communication module.

[0027] Figure 6 Schematic diagram of the relay adhesion detection module.

[0028] Figure 7 Figure 2 is a schematic diagram of the ground detection module.

[0029] Figure 8 This is a schematic diagram of the leakage detection module.

[0030] Figure 9 Figure 2 is a schematic diagram of the CP module.

[0031] Description of main components symbols:

[0032] AC / DC power supply module 10, MCU module 20, power meter power supply module 30, three-phase output control module 40, power meter detection module 50, isolation communication module 60, relay adhesion detection module 70, grounding detection module 80, leakage detection module 90, CP module 100. DETAILED DESCRIPTION

[0033] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0034] like Figure 1-9 As shown, the utility model discloses a three-phase charging gun circuit, which includes a three-phase power input line, a three-phase power output line, a three-phase output control module, an AC / DC power supply module, an energy meter power supply module, an MCU module, an energy meter detection module, an isolation communication module, a relay adhesion detection module, a grounding detection module, a leakage detection module, and a CP module. The three-phase power input line is the neutral line N, the live wires L1, L2, and L3, and the three-phase power output line is the neutral line Nout, the live wire L1out, the live wire L2out, and the live wire L3out corresponding to the three-phase power input line.

[0035] The input end of the AC / DC power supply module is connected to the neutral line N and the live line L1 to take power and output the first DC power (Vcc). Figure 1 As shown. The MCU module mainly includes chip U3 and its peripheral circuits. In this case, the model of chip U3 is BAT32G135-S. The MCU module draws power from Vcc. Figure 2 shown.

[0036] like Figure 3As shown, the power meter power supply module includes chip UA, chip UA1, diode DA1, diode DA2, diode DA3, diode DA4, electrolytic capacitor EC3, electrolytic capacitor ECG1, capacitor C24, capacitor C31, capacitor CA1, resistor R70, resistor RS1 and inductor LA8. Among them, the model of chip UA can be JW1530, and the model of UA1 can be LTP3559A-33XT4. Any live wire in the three-phase power incoming line (L1 in this case) is connected to the anode of diode DA3, the cathode of diode DA3 is connected to the anode of diode DA4, the cathode of diode DA4 is connected to the DW pin of chip UA and the positive electrode of electrolytic capacitor EC3, the negative electrode of electrolytic capacitor EC3 is connected to the neutral line (N) of the three-phase power incoming line, the GND pin of chip UA1, one end of resistor R70, one end of capacitor C24, one end of capacitor C31, the anode of diode DA1 and the negative electrode of electrolytic capacitor ECG1, and the other end of resistor R70 is connected to the GND pin of capacitor C24. The other end of the capacitor C31 is connected to the VOUT pin of chip UA1, which outputs a second DC voltage (Vout). The VIN pin of chip UA1 is connected to the positive electrode of electrolytic capacitor ECG1, one end of inductor LA8, and the anode of diode DA2. The cathode of diode DA2 is connected to one end of capacitor CA1, which is the VDD pin of chip UA. The other end of capacitor CA1 is connected to the other end of capacitor LA8, one end of resistor RS1, and the cathode of diode DA1. The other end of resistor RS1 is connected to the GND pin of chip UA. A half-wave rectifier DA3 and DA4 are connected in series to generate a DC voltage. The voltage is then stepped down by the LDO through the UA Buck circuit to power the three-phase power chip UL1 and the isolated serial port chip U5.

[0037] like Figure 4 As shown, the three-phase incoming power line is connected to the three-phase outgoing power line via a three-phase output control module. The three-phase output control module controls the connection and disconnection of the three-phase incoming power line and the three-phase outgoing power line. The three-phase output control module includes four relays and two relay control units. The four relays are K1, K2, K3, and K4. K1 is used to connect and disconnect N and Nout, K2 is used to connect and disconnect L1 and L1out, K3 is used to connect and disconnect L2 and L2out, and K4 is used to connect and disconnect L3 and L3out. K1 and K2 share one relay control unit, while K3 and K4 share another relay control unit. K1, K2, K3, and K4 are closed or opened simultaneously. The MCU module has an output control terminal for controlling the start and stop of the three-phase output control module. It includes output control pins that correspond one-to-one with the relay control units, namely pins 18 (corresponding to controlling K3 and K4) and 21 (corresponding to controlling K1 and K2) of chip U3.

[0038] Taking the relay control unit corresponding to K1 and K2 as an example, it includes a gate drive chip U8, an N-MOS tube Q1, a first diode D2, a fifth resistor R1, a sixth resistor R3Y, a seventh resistor R1Y, an eighth resistor R2Y and a third capacitor C1, wherein the model of chip U8 can be NSG44273 or SOT23-5. The IN pin of gate driver chip U8 is connected to the corresponding output control pin (pin 21 of chip U3) via the fifth resistor R1. The VCC pin of gate driver chip U8 is connected to the output terminal (Vcc) of the AC / DC power supply module and one end of the third capacitor C1. The other end of the third capacitor C1 is grounded. The OUT1 pin of gate driver chip U8 is connected to one end of the sixth resistor R3Y. The OUT2 pin of gate driver chip U8 is connected to one end of the seventh resistor R1Y. The other end of the sixth resistor R3Y is connected to the other end of the seventh resistor R1Y, the gate of N-MOS transistor Q1, and one end of the eighth resistor R2Y. The other end of the eighth resistor R2Y and the source of N-MOS transistor Q1 are grounded. The drain of N-MOS transistor Q1 is connected to one end of the corresponding relay coil and the anode of the first diode D2. The other end of the corresponding relay coil is connected to the cathode of the first diode D2 and the output terminal (Vcc) of the AC / DC power supply module. Under the control of the MCU, the gate driver chip drives the MOS transistor, thereby controlling the relay.

[0039] like Figure 5 As shown, the fuel gauge detection module is connected to the output of the fuel gauge power supply module to draw power. It includes a fuel gauge chip UL1, a voltage sampling unit, and a current sampling unit. The fuel gauge chip UL1 has a voltage feedback input terminal, a current feedback input terminal, and a first communication terminal. The fuel gauge chip UL1 model can be BL6552. The voltage sampling unit is connected to the three-phase power incoming line and the voltage feedback input terminal. The current sampling unit is a conventional sampling circuit including a current transformer HT1, which is installed on the three-phase power outgoing line. The current sampling unit is connected to the current sampling feedback input terminals (pins IAN, IAP, IBN, IBP, ICN, and ICP of the chip UL1).

[0040] The voltage sampling unit includes voltage sampling sub-units corresponding one-to-one to the three live wires (L1, L2, and L3) of the three-phase power incoming line. The voltage feedback input end has a voltage feedback input pin group corresponding one-to-one to the voltage sampling sub-unit. The voltage feedback input pin group includes the VP pin and the VN pin. Among them, the voltage feedback input pin group corresponding to the voltage sampling sub-unit corresponding to L1 is the VAP pin and the VAN pin, the voltage feedback input pin group corresponding to the voltage sampling sub-unit corresponding to L2 is the VBP pin and the VBN pin, and the voltage feedback input pin group corresponding to the voltage sampling sub-unit corresponding to L3 is the VCP pin and the VCN pin.

[0041] Taking the voltage sampling subunit corresponding to L1 as an example, it includes a first resistor RE1, a second resistor RE2, a third resistor RE9, a fourth resistor RE8, a first capacitor CE2, and a second capacitor CE1. The live line L1 of the three-phase power supply is connected to one end of the first resistor RE1. The other end of the first resistor RE1 is connected to one end of the third resistor RE9, one end of the first capacitor CE2, and the VAP pin via the second resistor RE2. The other end of the third resistor RE9 is connected to the neutral line N of the three-phase power supply, one end of the fourth resistor RE8, one end of the second capacitor CE1, and the other end of the first capacitor CE2. The other end of the fourth resistor RE8 is connected to the other end of the second capacitor CE1 and the VAN pin. By stepping down and sampling the voltage of L1 through the first and second resistors RE1 and RE2, the use of a voltage transformer can be omitted.

[0042] The power meter detection module has a first communication terminal, namely the SDO pin and SDI pin of the power meter chip UL1.

[0043] The MCU module includes a second communication terminal for communicating with the fuel meter chip UL1, namely the P61 pin (pin 8) and the P62 pin (pin 9) of the chip U3. The first communication terminal is connected to the second communication terminal of the MCU module via the isolation communication module.

[0044] like Figure 5 As shown, the isolated communication module includes an isolation chip U5, resistors RL2, RL3, RE7, R56, RV4, RV5, RE10, RE13, and capacitor C39. The model of the isolation chip U5 is BL7121AH. The SDO pin is connected to one end of the resistor R56 and the VIB pin of the isolation chip U5 via resistor RL2. The other end of the resistor R56 is connected to the output end (Vout) of the fuel gauge power supply module. The SDI pin is connected to one end of the resistor RE7 and the VOA pin of the isolation chip U5 via resistor RL3. The other end of the resistor RE7 is connected to the output end (Vout) of the fuel gauge power supply module. The VDD1 pin of the isolation chip U5 is connected to one end of the capacitor C39 and the output end (Vout) of the fuel gauge power supply module. The other end of the capacitor C39 is connected to the neutral line N of the three-phase power supply line. The VDD2 pin of U5 is connected to the power input terminal (VDD) of the MCU module; the VIA pin of the isolation chip U5 is connected to one end of the resistor RE10 and the P62 pin via the resistor RV4, and the other end of the resistor RE10 is connected to the power input terminal (VDD) of the MCU module; the VOB pin of the isolation chip U5 is connected to one end of the resistor RE13 and the P61 pin via the resistor RV5, and the other end of the resistor RE13 is connected to the power input terminal (VDD) of the MCU module; the GND1 pin of the isolation chip U5 is connected to the neutral line N of the three-phase power incoming line, and the GND2 pin of the isolation chip U5 is grounded.

[0045] like Figure 6As shown, the relay adhesion detection module is connected to the three-phase power outgoing line and the MCU module to detect whether the relays K1, K2, K3, and K4 have adhesion faults.

[0046] like Figure 7 As shown, the grounding detection module is connected to the three-phase power incoming line and the MCU module. It detects whether the product is well grounded through resistance and capacitance voltage reduction and MCU sampling.

[0047] like Figure 8 As shown, the leakage detection module includes a leakage transformer LD1, which is installed on the three-phase power outgoing line. LD1 detects whether there is any leakage current of 30mA AC or 6mA DC in the three-phase power. If leakage occurs, TRIP1 outputs a high level, notifying the MCU, which then disconnects the main relays K1, K2, K3, and K4 to ensure personal safety.

[0048] like Figure 9 As shown in the figure, the CP module is connected to the output end (Vcc) of the MCU module and the AC / DC power supply module, and interactively communicates with the device to be charged (such as an electric vehicle) by generating a 1KHz PWM signal, thereby controlling the conduction of relays K1, K2, K3, and K4 to charge the electric vehicle.

[0049] The above is only a preferred specific implementation method of the present invention, but the protection scope of the present invention is not limited to this. Any changes or replacements that can be easily thought of by any technician familiar with this technical field within the technical scope disclosed in the present invention should be covered by the protection scope of the present invention.

Claims

1. A three-phase gun charging circuit, characterized by: It includes three-phase power incoming line, three-phase power outgoing line, three-phase output control module, AC / DC power supply module, power meter power supply module, MCU module, power meter detection module and isolated communication module; The AC / DC power supply module is connected to the neutral line and any live line of the three-phase power incoming line to take power and output a first direct current; The power meter power supply module is connected to the neutral line and any live line in the three-phase power incoming line to take power and output a second direct current; The three-phase output control module is connected to the output end of the AC / DC power supply module to take power, and the three-phase power input line is connected to the three-phase power output line through the three-phase output control module. The three-phase output control module controls the on and off of the three-phase power input line and the three-phase power output line; The electricity meter detection module is connected to the output end of the electricity meter power supply module to obtain power, and includes an electricity meter chip, a voltage sampling unit and a current sampling unit. The electricity meter chip has a voltage feedback input end, a current feedback input end and a first communication end. The voltage sampling unit is connected to the three-phase power incoming line and the voltage feedback input end. The current sampling unit has a current transformer, which is sleeved on the three-phase power outgoing line. The current sampling unit is connected to the current sampling feedback input end; The MCU module is connected to the output end of the AC / DC power supply module to obtain power. The MCU module includes a second communication end for communicating with the power meter chip and an output control end for controlling the start and stop of the three-phase output control module. The output control end is connected to the three-phase output control module, and the first communication end is connected to the second communication end of the MCU module via the isolation communication module.

2. The three-phase gun charging circuit according to claim 1, characterized in that: The electricity meter power supply module includes chip UA, chip UA1, diode DA1, diode DA2, diode DA3, diode DA4, electrolytic capacitor EC3, electrolytic capacitor ECG1, capacitor C24, capacitor C31, capacitor CA1, resistor R70, resistor RS1 and inductor LA8. Any live wire in the three-phase power incoming line is connected to the anode of diode DA3, the cathode of diode DA3 is connected to the anode of diode DA4, the cathode of diode DA4 is connected to the DW pin of chip UA and the positive electrode of electrolytic capacitor EC3, and the negative electrode of electrolytic capacitor EC3 is connected to the neutral wire of the three-phase power incoming line, the GND pin of chip UA1, one end of resistor R70, one end of capacitor C24 and the negative electrode of electrolytic capacitor EC3. End, one end of capacitor C31, the anode of diode DA1 and the negative electrode of electrolytic capacitor ECG1, the other end of resistor R70 is connected to the other end of capacitor C24, the other end of capacitor C31 and the VOUT pin of chip UA1, and the VOUT pin of chip UA1 outputs the second DC power; the VIN pin of chip UA1 is connected to the positive electrode of electrolytic capacitor ECG1, one end of inductor LA8 and the anode of diode DA2, the cathode of diode DA2 is connected to one end of capacitor CA1, which is the VDD pin of chip UA, the other end of capacitor CA1 is connected to the other end of capacitor LA8, one end of resistor RS1 and the cathode of diode DA1, and the other end of resistor RS1 is connected to the GND pin of chip UA.

3. The three-phase gun charging circuit according to claim 1, characterized in that: The voltage sampling unit includes voltage sampling subunits corresponding one-to-one to the three live wires of the three-phase power incoming line. The voltage feedback input end has a voltage feedback input pin group corresponding one-to-one to the voltage sampling subunits, and the voltage feedback input pin group includes a VP pin and a VN pin. The voltage sampling subunit includes a first resistor, a second resistor, a third resistor, a fourth resistor, a first capacitor, and a second capacitor. The live wire of the three-phase power incoming line is connected to one end of the first resistor of the corresponding voltage sampling subunit, and the other end of the first resistor is connected to one end of the third resistor, one end of the first capacitor, and the VP pin of the corresponding voltage feedback input pin group via the second resistor. The other end of the third resistor is connected to the neutral wire of the three-phase power incoming line, one end of the fourth resistor, one end of the second capacitor, and the other end of the first capacitor. The other end of the fourth resistor is connected to the other end of the second capacitor and the VN pin of the corresponding voltage feedback input pin group.

4. The three-phase gun charging circuit according to claim 1, characterized in that: The first communication end includes an SDO pin and an SDI pin, and the second communication end includes a P61 pin and a P62 pin; the isolated communication module includes an isolation chip U5, a resistor RL2, a resistor RL3, a resistor RE7, a resistor R56, a resistor RV4, a resistor RV5, a resistor RE10, a resistor RE13, and a capacitor C39, the SDO pin is connected to one end of the resistor R56 and the VIB pin of the isolation chip U5 via the resistor RL2, and the other end of the resistor R56 is connected to the output end of the power supply module of the fuel gauge; the SDI pin is connected to one end of the resistor RE7 and the VOA pin of the isolation chip U5 via the resistor RL3, and the other end of the resistor RE7 is connected to the output end of the power supply module of the fuel gauge; the isolation The VDD1 pin of chip U5 is connected to one end of capacitor C39 and the output end of the power meter power supply module, and the other end of capacitor C39 is connected to the neutral line of the three-phase power incoming line; the VDD2 pin of the isolation chip U5 is connected to the power input end of the MCU module; the VIA pin of the isolation chip U5 is connected to one end of the resistor RE10 and the P62 pin via the resistor RV4, and the other end of the resistor RE10 is connected to the power input end of the MCU module; the VOB pin of the isolation chip U5 is connected to one end of the resistor RE13 and the P61 pin via the resistor RV5, and the other end of the resistor RE13 is connected to the power input end of the MCU module; the GND1 pin of the isolation chip U5 is connected to the neutral line of the three-phase power incoming line, and the GND2 pin of the isolation chip U5 is grounded.

5. The three-phase gun charging circuit according to claim 1, characterized in that: The three-phase output control module includes four relays and at least one relay control unit. The output control end of the MCU module includes output control pins corresponding to the relay control units one by one. Each relay control unit corresponds to at least one relay. The relay control unit includes a gate drive chip, an N-MOS transistor, a first diode, a fifth resistor, a sixth resistor, a seventh resistor, an eighth resistor and a third capacitor. The IN pin of the gate drive chip is connected to the corresponding output control pin via the fifth resistor, the VCC pin of the gate drive chip is connected to the output end of the AC / DC power supply module and one end of the third capacitor, and the other end of the third capacitor is grounded; the OUT1 pin of the gate drive chip is connected to one end of the sixth resistor, the OUT2 pin of the gate drive chip is connected to one end of the seventh resistor, the other end of the sixth resistor is connected to the other end of the seventh resistor, the gate of the N-MOS transistor and one end of the eighth resistor, the other end of the eighth resistor and the source of the N-MOS transistor are grounded, the drain of the N-MOS transistor is connected to one end of the corresponding relay coil and the anode of the first diode, and the other end of the corresponding relay coil is connected to the cathode of the first diode and the output end of the AC / DC power supply module.

6. The three-phase gun charging circuit according to claim 5, characterized in that: The relay control units are provided in two sets, wherein one relay control unit corresponds to two of the relays, and the other relay control unit corresponds to the other two relays.

7. The three-phase gun charging circuit according to claim 5, characterized in that: It also includes a relay adhesion detection module, which is connected to the three-phase power outgoing line and the MCU module.

8. The three-phase gun charging circuit according to claim 1, characterized in that: It also includes a grounding detection module, which is connected to the three-phase power incoming line and the MCU module.

9. The three-phase gun charging circuit according to claim 1, characterized in that: It also includes a leakage detection module, which includes a leakage transformer. The leakage transformer is arranged on the three-phase power outgoing line.

10. The three-phase gun charging circuit according to claim 1, characterized in that: It also includes a CP module for communicating with the device to be charged, and the CP module is connected to the output end of the MCU module and the AC / DC power supply module.

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