A new energy vehicle charging circuit

Abstract

The utility model discloses a new energy automobile charging circuit, including main control circuit, power supply circuit, electric quantity detection circuit, CP circuit, relay circuit, CP circuit is connected with main control circuit and new energy automobile's car stake, is used for carrying out the communication between main control circuit and car stake, power supply circuit is connected with electric quantity detection circuit, CP circuit, relay circuit, is used for converting commercial power into direct current, and the power supply to each circuit, electric quantity detection circuit is connected with main control circuit, is used for the current detection in the car stake charging process, relay circuit is connected with main control circuit, CP circuit respectively, is used for disconnecting the communication between main control circuit, CP circuit when charging process exception, the utility model overcomes the deficiency of traditional charging pile charging control circuit in current detection precision and CP signal transmission stability, provides a kind of faster more stable more economic, and more simple more flexible charging pile control circuit.

Description

Technical Field

[0001] This utility model relates to the field of electric vehicle charging devices, specifically to a charging circuit for new energy vehicles. Background Technology

[0002] During the charging process, AC charging piles for new energy vehicles require a charging control circuit to ensure the safe transmission and communication control of electrical energy. This circuit primarily consists of two parts: a power detection module and a Control Pilot (CP) module, as well as peripheral circuits such as relays and fault detection circuits. In existing technologies, the power detection module typically uses integrated power metering chips such as RN7302 and BL0910, while the CP module usually uses an optocoupler for communication between the vehicle and the charging pile. The power metering chip, in conjunction with a sampling resistor, detects AC current and provides overcurrent protection. These chips integrate an analog-to-digital converter, RMS calculation logic, and a temperature compensation unit, making them convenient to use, but they lack flexibility, their dynamic range is limited by chip specifications, and they are prone to sampling saturation or delay under high-current transients or surges. The CP circuit works by using the response between the phototransistor and the LED in the optocoupler to achieve communication between the main control chip and the vehicle. Communication speed depends on the optical signal; long-term use can lead to LED attenuation, affecting communication speed and causing lag in communication between the vehicle and the charging pile, posing a certain safety hazard. Therefore, traditional charging pile control circuits have shortcomings in current detection accuracy and CP signal transmission stability, and need to be improved. Utility Model Content

[0003] The purpose of this utility model is to provide a charging circuit for new energy vehicles, which aims to provide a charging pile control circuit with a faster, more stable and more economical CP circuit and a simpler and more flexible metering circuit.

[0004] To achieve the above functions, this utility model designs a new energy vehicle charging circuit, including a main control circuit, a power supply circuit, a power detection circuit, a CP circuit, and a relay circuit.

[0005] The CP circuit is connected to the main control circuit and the charging pile of the new energy vehicle for communication between the main control circuit and the charging pile; the power supply circuit is connected to the power detection circuit, the CP circuit, and the relay circuit for converting AC power to DC power to supply power to each circuit; the power detection circuit is connected to the main control circuit for current detection during the charging process; and the relay circuit is connected to the main control circuit and the CP circuit respectively for disconnecting the communication between the main control circuit and the CP circuit in case of abnormality during the charging process.

[0006] As a preferred technical solution of this utility model: the power supply circuit includes a DC to DC power chip U21, a Schottky diode D18, resistors R83, R84, and R85, a current transformer U20, and capacitors C48, C47, C49, and C50; wherein capacitors C47 and C50 are aluminum electrolytic capacitors.

[0007] The DC-to-DC power supply chip U21 is an MC34063 chip. Pin 1 of the MC34063 chip is connected to pins 7 and 8 of the DC-to-DC power supply chip U21 and one end of resistor R83. Pin 2 of the DC-to-DC power supply chip U21 is connected to one end of current transformer U20 and the negative terminal of Schottky diode D18. Pin 3 of the DC-to-DC power supply chip U21 is connected to one end of capacitor C48. Pin 4 of the DC-to-DC power supply chip U21 is connected to the other end of capacitor C48, one end of capacitor C49, and... One end of resistor R85, the positive terminal of Schottky diode D18, and the negative terminal of capacitor C50 are all connected to -12V. Pin 5 of DC to DC power chip U21 is connected to the other end of capacitor C49, the other end of resistor R85, and one end of resistor R84. Pin 6 of DC to DC power chip U21, the other end of resistor R83, and the positive terminal of capacitor C47 are all connected to +12V. The other end of current transformer U20, the positive terminal of capacitor C50, the other end of resistor R84, and the negative terminal of capacitor C47 are all grounded.

[0008] As a preferred technical solution of this utility model: the CP circuit includes an operational amplifier section, a transistor section, and a terminal block section; wherein, the operational amplifier section includes operational amplifier U25, capacitor C59, capacitor C60, capacitor C61, capacitor C62, resistor R106, resistor R107, resistor R108, resistor R109, resistor R112, switching diode D24, and switching diode D25;

[0009] The transistor section includes transistors Q12, Q13, Q14, and Q15; resistors R88, R91, R95, R98, R101, R102, R103, R104, R105, R110, and R111; capacitors C52, C57, and C58; diode D21; and TVS diode D20. The terminal block section includes terminal block CN1 and resistor R94.

[0010] The operational amplifier U25 is an LM2904 chip. Pins 1, 2, and 3 are left floating. Pin 4, one end of capacitor C61, one end of resistor R112, one end of resistor R106, one end of capacitor C60, one end of capacitor C59, and one end of capacitor C62 are all grounded. Pin 5 is connected to one end of resistor R109 and the other end of resistor R112. Pin 6 is connected to one end of resistor R108. Pin 7 is connected to the positive terminal of switching diode D24. Pin 8 and the other end of capacitor C61 are both connected to +12V. The negative terminal of switching diode D24 is connected to resistor R106. The other end of resistor R8, one end of resistor R107, the other end of resistor R106, the other end of capacitor C60, and the other end of capacitor C59 are connected. The other end of resistor R107 is connected to the other end of capacitor C62. The other end of resistor R109 is connected to the cathode of switching diode D25. The anodes of switching diode D25 and D21, one end of resistor R98, one end of resistor R103, and one end of TVS diode D20 are all connected to pin 1 of terminal CN1. Pin 2 of terminal CN1 is connected to +5V. Pin 3 of terminal CN1 is connected to one end of resistor R94. The other end of resistor R94 is grounded. The base of transistor Q12 is connected to one end of capacitor C52, the other end of capacitor C60, and the other end of capacitor C59. One end of resistor R95 is connected, the emitter of transistor Q12 is grounded, and the emitter of transistor Q12 is connected to one end of resistor R102. The base of transistor Q13 is connected to one end of resistor R101 and the other end of resistor R102. The emitter of transistor Q13 and the other end of resistor R101 are both connected to 12V. The collector of transistor Q13 is connected to the other end of resistor R98 and one end of capacitor C57. The base of transistor Q14 is connected to one end of resistor R104, one end of capacitor C58, and one end of resistor R105. The emitter of transistor Q14, the other end of resistor R104, and one end of resistor R111 are all connected to -12V. The collector of transistor Q14 is connected to the other end of capacitor C57. The other end of resistor R103 is connected to the base of transistor Q15, which is connected to one end of resistor R110 and the other end of resistor R111. The emitter of transistor Q15 is grounded. The collector of transistor Q15 is connected to the other end of resistor R105 and the other end of capacitor C58. The other ends of resistor R95, capacitor C52, and resistor R110 are all connected to pin 4 of relay K4 in the relay circuit. The cathode of switching diode D21 is connected to one end of resistor R91. The other end of resistor R91 is connected to one end of resistor R92 and one end of resistor R88. The other end of resistor R92 and the other end of TVS diode D20 are both grounded. The other end of resistor R88 is connected to the main control chip U22.

[0011] As a preferred technical solution of this utility model: transistors Q12 and Q14 in the CP circuit are NPN transistors, and transistors Q13 and Q15 are PNP transistors.

[0012] As a preferred embodiment of this utility model, the relay circuit includes a relay K4, a diode D26, a resistor R113, a resistor R114, and a field-effect transistor Q16.

[0013] The relay K4 includes four pins. Pin 1 of the relay K4 and the negative terminal of diode D26 are both connected to a +12V voltage. Pin 2 of the relay K4 is connected to the positive terminal of diode D26 and the drain of field-effect transistor Q16. Pin 3 of the relay K4 is connected to the main control chip U22. Pin 4 of the relay K4 is connected to the other end of resistor R95, the other end of capacitor C52, and the other end of resistor R110 in the CP circuit. The gate of field-effect transistor Q16 is connected to one end of resistor R113 and one end of resistor R114. The source of field-effect transistor Q16 and the other end of resistor R113 are both grounded. The other end of resistor R114 is connected to the main control chip U22.

[0014] As a preferred technical solution of this utility model: the power detection circuit includes an operational amplifier U24, a current transformer U23, resistors R87, R89, R90, R93, R96, R97, R99, R100, capacitors C51, C53, C54, C55, and C56, and diodes D19, D22, and D23;

[0015] The operational amplifier U24 is an LM2904 chip. Pin 1 is connected to pin 2 and pin 5 of operational amplifier U24, the cathode of diode D22, the anode of diode D23, and one end of resistor R99. Pin 3 is connected to one end of resistor R96, one end of resistor R100, and one end of capacitor C56. Pin 4, the other end of resistor R100, the other end of capacitor C56, one end of capacitor C55, one end of capacitor C54, and one end of resistor R90 are all grounded. Pin 6 is connected to the anode of diode D22, the cathode of diode D23, one end of resistor R97, one end of resistor R93, and resistor R89. One end of the capacitor C51 is connected to the other end of the operational amplifier U24. Pin 7 of the operational amplifier U24 is connected to the other end of the capacitor C55, one end of the capacitor C53, the positive terminal of the diode D19, the other end of the resistor R89, and the other end of the capacitor C51. Pin 8 of the operational amplifier U24 and the other end of the resistor R96 are both connected to a +12V voltage. Pin 1 of the current transformer U23 is connected to the other end of the resistor R97. Pin 2 of the current transformer U23 is connected to the other end of the resistor R99. The other end of the resistor R93 is connected to the other end of the capacitor C53. The negative terminal of the diode D19 is connected to the other end of the capacitor C54 and one end of the resistor R87. The other ends of the resistor R87 and the other ends of the resistor R90 are both connected to the main control chip U22.

[0016] As a preferred technical solution of this utility model: the main control circuit includes an STM32 microcontroller U22, resistor R82, and resistor R86;

[0017] Among them, pins 1, 19, 32, and 64 of the STM32 microcontroller U22 are connected to input +3.3V voltage, and pins 12, 18, 31, 63, one end of resistor R82, and one end of resistor R86 are all grounded; the other end of resistor R82 is connected to pin 60 of the STM32 microcontroller U22, and the other end of resistor R86 is connected to pin 28 of the STM32 microcontroller U22; pin 13 is connected to the analog power supply ADDA, pin 11 is connected to the other end of resistor R87 and resistor R90 in the power detection circuit, pin 15 is connected to the other end of resistor R88 in the CP circuit, pin 54 is connected to the other end of resistor R114 in the relay circuit, and pin 40 is connected to pin 3 of relay K4 in the relay circuit.

[0018] Beneficial effects: Compared with the prior art, the advantages of this utility model include:

[0019] 1. Compared to traditional charging piles that use optocouplers for communication, the transistor-based communication circuit is more stable and has a faster response time. It is also compatible with more vehicle brands on the market.

[0020] 2. Compared with charging piles that use off-the-shelf metering chips as power detection modules, the combination of operational amplifier and current transformer has a more flexible dynamic range and stronger surge tolerance.

[0021] 3. Compared with optocouplers, transistors are relatively cheaper; compared with power metering chips, the power detection circuit composed of operational amplifiers and current transformers does not require isolation circuits, has a simple structure, low cost, and is easy to maintain. Attached Figure Description

[0022] Figure 1 This is a power supply circuit diagram provided according to an embodiment of the present utility model;

[0023] Figure 2 This is a CP circuit diagram provided according to an embodiment of the present utility model;

[0024] Figure 3 This is a relay circuit diagram provided according to an embodiment of the present utility model;

[0025] Figure 4 This is a power detection circuit diagram provided according to an embodiment of the present utility model;

[0026] Figure 5 This is a main control circuit diagram provided according to an embodiment of the present utility model. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and should not be used to limit the scope of protection of the present invention.

[0028] Traditional optocoupler-based CP circuits rely on an internal LED that emits light upon receiving an electrical signal, which then turns on a phototransistor in the subsequent circuit, pulling the signal low to achieve communication. The accuracy and stability of this circuit are affected by the LED's response speed and luminous efficiency. Over long-term use, the LED is prone to light decay, affecting the overall response speed of the optocoupler. While using readily available power metering chips for power detection is convenient, the data acquisition is affected by the chip's specifications and manufacturing process, and the external circuitry is complex and lacks flexibility.

[0029] This utility model provides a new energy vehicle charging circuit, including a main control circuit, a power supply circuit, a power detection circuit, a CP circuit, and a relay circuit.

[0030] The CP circuit is connected to the main control circuit and the charging pile of the new energy vehicle for communication between the main control circuit and the charging pile; the power supply circuit is connected to the power detection circuit, the CP circuit, and the relay circuit for converting AC power to DC power to supply power to each circuit; the power detection circuit is connected to the main control circuit for current detection during the charging process; and the relay circuit is connected to the main control circuit and the CP circuit respectively for disconnecting the communication between the main control circuit and the CP circuit in case of abnormality during the charging process.

[0031] The power supply circuit described above uses a DC-to-DC power chip as its core, providing the +12V and -12V voltages required for communication with the CP circuit; see reference. Figure 1 Specifically, it includes a DC-to-DC power supply chip U21, a Schottky diode D18, resistors R83, R84, and R85, a current transformer U20, and capacitors C48, C47, C49, and C50; among which, capacitors C47 and C50 are aluminum electrolytic capacitors.

[0032] Reference Figure 1 The typical selection for the DC to DC power supply chip U21 is the MC34063 chip, which has a total of eight pins. Among them, pin 1 is the SC terminal, pin 2 is the SE terminal, pin 3 is the CT terminal, pin 4 is the GND terminal, pin 5 is the FB terminal, pin 6 is the VCC terminal, pin 7 is the IPK terminal, and pin 8 is the DC terminal.

[0033] Specifically, pin 1 of the DC-to-DC power supply chip U21 is connected to pins 7 and 8 of the DC-to-DC power supply chip U21 and one end of resistor R83; pin 2 of the DC-to-DC power supply chip U21 is connected to one end of current transformer U20 and the negative terminal of Schottky diode D18; pin 3 of the DC-to-DC power supply chip U21 is connected to one end of capacitor C48; and pin 4 of the DC-to-DC power supply chip U21, the other end of capacitor C48, one end of capacitor C49, and resistor R85 are connected to... One end of the DC-to-DC power supply chip U21, the positive terminal of Schottky diode D18, and the negative terminal of capacitor C50 are all connected to -12V. Pin 5 of the DC-to-DC power supply chip U21 is connected to the other end of capacitor C49, the other end of resistor R85, and one end of resistor R84. Pin 6 of the DC-to-DC power supply chip U21, the other end of resistor R83, and the positive terminal of capacitor C47 are all connected to +12V. The other end of current transformer U20, the positive terminal of capacitor C50, the other end of resistor R84, and the negative terminal of capacitor C47 are all grounded.

[0034] The function of the power supply circuit is to convert the 220V AC mains power connected to the charging pile into the positive and negative 12V voltage required for CP communication.

[0035] The CP circuit, built using transistors, is responsible for establishing communication between the charging station and the vehicle. Compared to traditional optocoupler circuits, it offers faster response times and better stability. Figure 2 Specifically, it includes an operational amplifier section, a transistor section, and a terminal block section; wherein, the operational amplifier section includes operational amplifier U25, capacitor C59, capacitor C60, capacitor C61, capacitor C62, resistor R106, resistor R107, resistor R108, resistor R109, resistor R112, switching diode D24, and switching diode D25.

[0036] Reference Figure 2 The typical choice for operational amplifier U25 is the LM2904 chip, which has eight pins. Pin 1 is the OUT / A terminal, pin 2 is the -IN / A terminal, pin 3 is the +IN / A terminal, pin 4 is the VEE / GND terminal, pin 5 is the +IN / B terminal, pin 6 is the -IN / B terminal, pin 7 is the OUT / B terminal, and pin 8 is the VCC terminal.

[0037] The transistor section includes transistors Q12, Q13, Q14, and Q15; resistors R88, R91, R95, R98, R101, R102, R103, R104, R105, R110, and R111; capacitors C52, C57, and C58; diode D21; and TVS diode D20. The terminal block section includes terminal block CN1 and resistor R94.

[0038] In the CP circuit, transistors Q12 and Q14 are NPN transistors, while transistors Q13 and Q15 are PNP transistors.

[0039] Pins 1, 2, and 3 of operational amplifier U25 are left floating. Pin 4, one end of capacitor C61, one end of resistor R112, one end of resistor R106, one end of capacitor C60, one end of capacitor C59, and one end of capacitor C62 are all grounded. Pin 5 of operational amplifier U25 is connected to one end of resistor R109 and the other end of resistor R112. Pin 6 of operational amplifier U25 is connected to one end of resistor R108. Pin 7 of operational amplifier U25 is connected to the positive terminal of switching diode D24. Pin 8 of operational amplifier U25 and the other end of capacitor C61 are both connected to a +12V voltage. The negative terminal of switching diode D24 is connected to the other end of resistor R108 and... One end of resistor R107, the other end of resistor R106, the other end of capacitor C60, and the other end of capacitor C59 are connected. The other end of resistor R107 is connected to the other end of capacitor C62. The other end of resistor R109 is connected to the cathode of switching diode D25. The anodes of switching diode D25 and D21, one end of resistor R98, one end of resistor R103, and one end of TVS diode D20 are all connected to pin 1 of terminal CN1. Pin 2 of terminal CN1 is connected to +5V. Pin 3 of terminal CN1 is connected to one end of resistor R94. The other end of resistor R94 is grounded. The base of transistor Q12 is connected to one end of capacitor C52 and resistor R95. One end of the transistor is connected, the emitter of transistor Q12 is grounded, and the emitter of transistor Q12 is connected to one end of resistor R102. The base of transistor Q13 is connected to one end of resistor R101 and the other end of resistor R102. The emitter of transistor Q13 and the other end of resistor R101 are both connected to 12V. The collector of transistor Q13 is connected to the other end of resistor R98 and one end of capacitor C57. The base of transistor Q14 is connected to one end of resistor R104, one end of capacitor C58, and one end of resistor R105. The emitter of transistor Q14, the other end of resistor R104, and one end of resistor R111 are all connected to -12V. The collector of transistor Q14 is connected to the other end of capacitor C57 and resistor R105. The other end of R103 is connected. The base of transistor Q15 is connected to one end of resistor R110 and the other end of resistor R111. The emitter of transistor Q15 is grounded. The collector of transistor Q15 is connected to the other end of resistor R105 and the other end of capacitor C58. The other ends of resistor R95, capacitor C52, and resistor R110 are all connected to pin 4 of relay K4 in the relay circuit. The cathode of switching diode D21 is connected to one end of resistor R91. The other end of resistor R91 is connected to one end of resistor R92 and one end of resistor R88. The other end of resistor R92 and the other end of TVS diode D20 are both grounded. The other end of resistor R88 is connected to the main control chip U22.

[0040] The CP circuit receives instructions from the main control chip and outputs a PWM wave with a specified duty cycle to the vehicle to facilitate communication between the vehicle and the charging pile.

[0041] Reference Figure 3 The relay circuit includes relay K4, diode D26, resistor R113, resistor R114, and field-effect transistor Q16.

[0042] The relay K4 includes four pins: pins 1 and 2 are two control pins (coil pins), and pins 3 and 4 are two controlled pins (contact pins). Pin 1 of the relay K4 and the negative terminal of diode D26 are both connected to +12V. Pin 2 of the relay K4 is connected to the positive terminal of diode D26 and the drain of MOSFET Q16. Pin 3 of the relay K4 is connected to the main control chip U22. Pin 4 of the relay K4 is connected to the other end of resistor R95, the other end of capacitor C52, and the other end of resistor R110 in the CP circuit. The gate of MOSFET Q16 is connected to one end of resistor R113 and one end of resistor R114. The source of MOSFET Q16 and the other end of resistor R113 are both grounded. The other end of resistor R114 is connected to the main control chip U22.

[0043] The relay circuit is responsible for disconnecting the communication between the main controller and the CP circuit when the CP signal is abnormal, thus avoiding potential safety hazards.

[0044] The power detection circuit uses an operational amplifier paired with a current transformer to replace the power metering chip for current acquisition and measurement, offering a more flexible measurement range and better surge withstand capability; (Refer to...) Figure 4 Specifically, it includes operational amplifier U24, current transformer U23, resistors R87, R89, R90, R93, R96, R97, R99, R100, capacitors C51, C53, C54, C55, and C56, diodes D19, D22, and D23;

[0045] Reference Figure 4 The typical choice for the operational amplifier U24 is the LM2904 chip, which includes eight pins: pin 1 is OUTA, pin 2 is -INA, pin 3 is +INA, pin 4 is V-, pin 5 is +INB, pin 6 is -INB, pin 7 is OUTB, and pin 8 is V+.

[0046] Pin 1 of operational amplifier U24 is connected to pin 2 and pin 5 of operational amplifier U24, the cathode of diode D22, the anode of diode D23, and one end of resistor R99. Pin 3 of operational amplifier U24 is connected to one end of resistor R96, one end of resistor R100, and one end of capacitor C56. Pin 4 of operational amplifier U24, the other end of resistor R100, the other end of capacitor C56, one end of capacitor C55, one end of capacitor C54, and one end of resistor R90 are all grounded. Pin 6 of operational amplifier U24 is connected to the anode of diode D22, the cathode of diode D23, one end of resistor R97, one end of resistor R93, one end of resistor R89, and... One end of capacitor C51 is connected to the other end of the operational amplifier U24, one end of capacitor C55, the positive terminal of diode D19, the other end of resistor R89, and the other end of capacitor C51. Pin 8 of operational amplifier U24 and the other end of resistor R96 are both connected to +12V voltage. Pin 1 of current transformer U23 is connected to the other end of resistor R97, pin 2 of current transformer U23 is connected to the other end of resistor R99, the other end of resistor R93 is connected to the other end of capacitor C53, the negative terminal of diode D19 is connected to the other end of capacitor C54 and one end of resistor R87, and the other ends of resistor R87 and resistor R90 are both connected to the main control chip U22.

[0047] The power detection circuit is used to detect the current during the charging process of the charging pile to avoid safety hazards caused by overcurrent faults.

[0048] Reference Figure 5 The main control circuit includes an STM32 microcontroller U22, resistor R82, and resistor R86.

[0049] Among them, pins 1, 19, 32, and 64 of the STM32 microcontroller U22 are connected to input +3.3V voltage, and pins 12, 18, 31, 63, one end of resistor R82, and one end of resistor R86 are all grounded; the other end of resistor R82 is connected to pin 60 of the STM32 microcontroller U22, and the other end of resistor R86 is connected to pin 28 of the STM32 microcontroller U22; pin 13 is connected to the analog power supply ADDA, pin 11 is connected to the other end of resistor R87 and resistor R90 in the power detection circuit, pin 15 is connected to the other end of resistor R88 in the CP circuit, pin 54 is connected to the other end of resistor R114 in the relay circuit, and pin 40 is connected to pin 3 of relay K4 in the relay circuit.

[0050] Reference Figure 5The STM32 microcontroller U22 is model STM32F103RTC6, with a total of 64 pins. Among them, pin 1 is VBAT, pin 11 is PC3, pin 12 is VSSA, pin 13 is VDDA, pin 15 is PA1, pin 18 is VSS_4, pin 19 is VDD_4, pin 28 is PB2, pin 31 is VSS_1, pin 32 is VDD_1, pin 40 is PC9, pin 54 is PD2, pin 60 is BOOT0, pin 63 is VSS_3, and pin 64 is VDD_3.

[0051] The main control circuit uses the STM32 microcontroller U22 as its core, which is responsible for controlling the CP signal and converting and monitoring the current value.

[0052] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present invention.

Claims

1. A charging circuit for new energy vehicles, characterized in that, Includes main control circuit, power supply circuit, power detection circuit, CP circuit, and relay circuit; The CP circuit is connected to the main control circuit and the charging pile of the new energy vehicle for communication between the main control circuit and the charging pile; the power supply circuit is connected to the power detection circuit, the CP circuit, and the relay circuit for converting AC power to DC power to supply power to each circuit; the power detection circuit is connected to the main control circuit for current detection during the charging process; and the relay circuit is connected to the main control circuit and the CP circuit respectively for disconnecting the communication between the main control circuit and the CP circuit in case of abnormality during the charging process.

2. The charging circuit for a new energy vehicle according to claim 1, characterized in that, The power supply circuit includes a DC-to-DC power chip U21, a Schottky diode D18, resistors R83, R84, and R85, a current transformer U20, and capacitors C48, C47, C49, and C50; wherein capacitors C47 and C50 are aluminum electrolytic capacitors. The DC-to-DC power supply chip U21 is an MC34063 chip. Pin 1 of the MC34063 chip is connected to pins 7 and 8 of the DC-to-DC power supply chip U21 and one end of resistor R83. Pin 2 of the DC-to-DC power supply chip U21 is connected to one end of current transformer U20 and the negative terminal of Schottky diode D18. Pin 3 of the DC-to-DC power supply chip U21 is connected to one end of capacitor C48. Pin 4 of the DC-to-DC power supply chip U21 is connected to the other end of capacitor C48, one end of capacitor C49, and... One end of resistor R85, the positive terminal of Schottky diode D18, and the negative terminal of capacitor C50 are all connected to -12V. Pin 5 of DC to DC power chip U21 is connected to the other end of capacitor C49, the other end of resistor R85, and one end of resistor R84. Pin 6 of DC to DC power chip U21, the other end of resistor R83, and the positive terminal of capacitor C47 are all connected to +12V. The other end of current transformer U20, the positive terminal of capacitor C50, the other end of resistor R84, and the negative terminal of capacitor C47 are all grounded.

3. The charging circuit for a new energy vehicle according to claim 1, characterized in that, The CP circuit includes an operational amplifier section, a transistor section, and a terminal block section; wherein, the operational amplifier section includes operational amplifier U25, capacitors C59, C60, C61, and C62, resistors R106, R107, R108, R109, and R112, and switching diodes D24 and D25. The transistor section includes transistors Q12, Q13, Q14, and Q15; resistors R88, R91, R95, R98, R101, R102, R103, R104, R105, R110, and R111; capacitors C52, C57, and C58; diode D21; and TVS diode D20. The terminal block section includes terminal block CN1 and resistor R94. The operational amplifier U25 is an LM2904 chip. Pins 1, 2, and 3 are left floating. Pin 4, one end of capacitor C61, one end of resistor R112, one end of resistor R106, one end of capacitor C60, one end of capacitor C59, and one end of capacitor C62 are all grounded. Pin 5 is connected to one end of resistor R109 and the other end of resistor R112. Pin 6 is connected to one end of resistor R108. Pin 7 is connected to the positive terminal of switching diode D24. Pin 8 and the other end of capacitor C61 are both connected to +12V. The negative terminal of switching diode D24 is connected to resistor R106. The other end of resistor R8, one end of resistor R107, the other end of resistor R106, the other end of capacitor C60, and the other end of capacitor C59 are connected. The other end of resistor R107 is connected to the other end of capacitor C62. The other end of resistor R109 is connected to the cathode of switching diode D25. The anodes of switching diode D25 and D21, one end of resistor R98, one end of resistor R103, and one end of TVS diode D20 are all connected to pin 1 of terminal CN1. Pin 2 of terminal CN1 is connected to +5V. Pin 3 of terminal CN1 is connected to one end of resistor R94. The other end of resistor R94 is grounded. The base of transistor Q12 is connected to one end of capacitor C52, the other end of capacitor C60, and the other end of capacitor C59. One end of resistor R95 is connected, the emitter of transistor Q12 is grounded, and the emitter of transistor Q12 is connected to one end of resistor R102. The base of transistor Q13 is connected to one end of resistor R101 and the other end of resistor R102. The emitter of transistor Q13 and the other end of resistor R101 are both connected to 12V. The collector of transistor Q13 is connected to the other end of resistor R98 and one end of capacitor C57. The base of transistor Q14 is connected to one end of resistor R104, one end of capacitor C58, and one end of resistor R105. The emitter of transistor Q14, the other end of resistor R104, and one end of resistor R111 are all connected to -12V. The collector of transistor Q14 is connected to the other end of capacitor C57. The other end of resistor R103 is connected to the base of transistor Q15, which is connected to one end of resistor R110 and the other end of resistor R111. The emitter of transistor Q15 is grounded. The collector of transistor Q15 is connected to the other end of resistor R105 and the other end of capacitor C58. The other ends of resistor R95, capacitor C52, and resistor R110 are all connected to pin 4 of relay K4 in the relay circuit. The cathode of switching diode D21 is connected to one end of resistor R91. The other end of resistor R91 is connected to one end of resistor R92 and one end of resistor R88. The other end of resistor R92 and the other end of TVS diode D20 are both grounded. The other end of resistor R88 is connected to the main control chip U22.

4. A new energy vehicle charging circuit according to claim 3, characterized in that, In the CP circuit, transistors Q12 and Q14 are NPN transistors, while transistors Q13 and Q15 are PNP transistors.

5. A new energy vehicle charging circuit according to claim 1, characterized in that, The relay circuit includes relay K4, diode D26, resistor R113, resistor R114, and field-effect transistor Q16; The relay K4 includes four pins. Pin 1 of the relay K4 and the negative terminal of diode D26 are both connected to a +12V voltage. Pin 2 of the relay K4 is connected to the positive terminal of diode D26 and the drain of field-effect transistor Q16. Pin 3 of the relay K4 is connected to the main control chip U22. Pin 4 of the relay K4 is connected to the other end of resistor R95, the other end of capacitor C52, and the other end of resistor R110 in the CP circuit. The gate of field-effect transistor Q16 is connected to one end of resistor R113 and one end of resistor R114. The source of field-effect transistor Q16 and the other end of resistor R113 are both grounded. The other end of resistor R114 is connected to the main control chip U22.

6. A new energy vehicle charging circuit according to claim 1, characterized in that, The power detection circuit includes operational amplifier U24, current transformer U23, resistors R87, R89, R90, R93, R96, R97, R99, R100, capacitors C51, C53, C54, C55, and C56, and diodes D19, D22, and D23. The operational amplifier U24 is an LM2904 chip. Pin 1 is connected to pin 2 and pin 5 of operational amplifier U24, the cathode of diode D22, the anode of diode D23, and one end of resistor R99. Pin 3 is connected to one end of resistor R96, one end of resistor R100, and one end of capacitor C56. Pin 4, the other end of resistor R100, the other end of capacitor C56, one end of capacitor C55, one end of capacitor C54, and one end of resistor R90 are all grounded. Pin 6 is connected to the anode of diode D22, the cathode of diode D23, one end of resistor R97, one end of resistor R93, and resistor R89. One end of the capacitor C51 is connected to the other end of the operational amplifier U24. Pin 7 of the operational amplifier U24 is connected to the other end of the capacitor C55, one end of the capacitor C53, the positive terminal of the diode D19, the other end of the resistor R89, and the other end of the capacitor C51. Pin 8 of the operational amplifier U24 and the other end of the resistor R96 are both connected to a +12V voltage. Pin 1 of the current transformer U23 is connected to the other end of the resistor R97. Pin 2 of the current transformer U23 is connected to the other end of the resistor R99. The other end of the resistor R93 is connected to the other end of the capacitor C53. The negative terminal of the diode D19 is connected to the other end of the capacitor C54 and one end of the resistor R87. The other ends of the resistor R87 and the other ends of the resistor R90 are both connected to the main control chip U22.

7. A new energy vehicle charging circuit according to claim 1, characterized in that, The main control circuit includes an STM32 microcontroller U22, resistor R82, and resistor R86; Among them, pins 1, 19, 32, and 64 of the STM32 microcontroller U22 are connected to input +3.3V voltage, and pins 12, 18, 31, 63, one end of resistor R82, and one end of resistor R86 are all grounded; the other end of resistor R82 is connected to pin 60 of the STM32 microcontroller U22, and the other end of resistor R86 is connected to pin 28 of the STM32 microcontroller U22; pin 13 is connected to the analog power supply ADDA, pin 11 is connected to the other end of resistor R87 and resistor R90 in the power detection circuit, pin 15 is connected to the other end of resistor R88 in the CP circuit, pin 54 is connected to the other end of resistor R114 in the relay circuit, and pin 40 is connected to pin 3 of relay K4 in the relay circuit.

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