Detection circuit for electric vehicle

Abstract

The utility model discloses a detection circuit for an electric vehicle, and relates to the technical field of detection circuits. The circuit specifically comprises a normally-closed switch S2 circuit which is connected to a line of a vehicle CC1, the line of the vehicle CC1 can be connected with a line of a charger CC1 to form a loop, and in the charging process, when the voltage of the line of the vehicle CC1 is abnormal, the normally-closed switch S2 circuit is disconnected to increase the voltage of the line of the vehicle CC1; and the protective grounding disconnection diagnosis circuit is connected to a line of a vehicle CC2, the line of the vehicle CC2 can be connected with a charger to form a grounding loop, the protective grounding disconnection diagnosis circuit is used for detecting the voltage on the line of the CC2, and when the detected voltage is zero, it is indicated that the line of the CC2 is not disconnected. The utility model aims to accurately identify and report the fault under the condition that the PE protection grounding wire of the vehicle interface of the vehicle is broken.

Description

TECHNICAL FIELD

[0001] The utility model relates to detection circuit technical field, especially relate to a detection circuit for electric vehicle. BACKGROUND

[0002] With the rapid development of new energy vehicles, the technical specifications and standards of charging facilities are constantly improving to ensure the safety and reliability of vehicle charging. As the key connecting component between the charging equipment and the vehicle, the design and performance of the vehicle directly affect the stability and safety of the charging system. In recent years, China has promulgated a new national standard for vehicles, aiming to regulate the design requirements of the structure, performance and related electrical interfaces of vehicles.

[0003] During the charging process, the protective earth (PE) is an important link to ensure charging safety. When the PE is in good conduction, the charging equipment can effectively avoid the harm to personal safety and equipment operation caused by electric leakage and other electrical faults through the grounding protection system. However, in actual application, due to the reasons such as loose connector, aging of connection line or external force damage, the vehicle interface PE may be disconnected. If such faults are not detected and handled in time, the electrical insulation between the vehicle and the charging pile will fail, which may cause potential electric shock risk or equipment damage.

[0004] Therefore, the new national standard emphasizes the importance of safety detection and fault protection in the charging system, and clearly requires that the vehicle can accurately identify and report the fault in the case of disconnection of the vehicle interface PE (protective earth).

[0005] Therefore, how to accurately identify and report the fault in the case of disconnection of the vehicle interface PE (protective earth) of the vehicle has become a technical problem to be solved. INVENTION CONTENTS

[0006] The main purpose of the utility model is to provide a detection circuit for electric vehicle, which aims to accurately identify and report the fault in the case of disconnection of the vehicle interface PE (protective earth) of the vehicle.

[0007] In order to achieve the above purpose, the utility model provides a detection circuit for electric vehicle, which comprises:

[0008] The normally closed switch S2 circuit is connected to the line of vehicle CC1, and the line of vehicle CC1 can be connected with the line of charging machine CC1 to form a loop. During the charging process, when the voltage of CC1 line is abnormal, the normally closed switch S2 circuit is disconnected to pull up the voltage of vehicle CC1 line; and

[0009] The protection ground wire breakage diagnosis circuit is connected to the line of the vehicle CC2, which can be connected with the charger to form a ground loop, and is used to detect the voltage on the line of the vehicle CC2. When the detected voltage is zero, it indicates that the line of the vehicle CC2 is not broken.

[0010] The normally closed switch S2 circuit can timely cut off the signal transmission under abnormal voltage, avoiding damage to the control circuit in the vehicle or electric vehicle caused by abnormal voltage. The protection ground wire breakage diagnosis circuit ensures the continuity of the ground line, avoiding electric shock accidents caused by ground faults. The two circuits have clear division of labor, respectively monitoring and protecting the control signal loop and the ground loop, effectively reducing the risk of single point failure.

[0011] In an embodiment of the present application, the protection ground wire breakage diagnosis circuit comprises:

[0012] The diode D1, the zener diode Z5, the resistor R20, the MOS tube T7, the resistor R19, the capacitor C5, the resistor R21, the resistor R18, the power supply VCC, and the microprocessor unit of the controller.

[0013] The cathode of the diode D1 is connected to the line of the vehicle CC2, the anode of the diode D1 is connected to the source of the MOS tube T7, the drain of the MOS tube T7 is connected to the first end of the resistor R19, and the gate of the MOS tube T7 is connected to the first end of the resistor R21. The second end of the resistor R19 is connected to the microprocessor unit of the controller, and the second end of the resistor R21 is grounded. The anode of the zener diode Z5 is connected to the anode of the diode D1, and the cathode of the zener diode Z5 is connected to the first end of the resistor R21. The first end of the resistor R20 is connected to the anode of the diode D1, and the second end of the resistor R20 is connected to the first end of the resistor R21. The first end of the resistor R18 is connected to the second end of the resistor R19, and the second end of the resistor R18 is connected to the power supply VCC. The first end of the capacitor C5 is connected to the second end of the resistor R19, and the second end of the capacitor is grounded.

[0014] Through the cooperation of the diode D1 and the zener diode Z5, the abnormal voltage or reverse current in the CC2 line of the vehicle can be effectively prevented from damaging the circuit, and the reliability of the system is improved. The MOS tube T7 realizes rapid response to the state of the CC2 line of the vehicle through gate voltage control, can accurately judge whether the PE of the vehicle is disconnected, and improves the real-time performance of detection. The output signal is filtered by the capacitor C5, effectively eliminating interference signals, and ensuring the stability and accuracy of the output signal.

[0015] In an embodiment of the present application, the protection ground wire breakage diagnosis circuit further comprises:

[0016] A bidirectional voltage stabilizing tube ZD1, a first end of the bidirectional voltage stabilizing tube ZD1 is connected to a source of the MOS tube T7, and a second end of the bidirectional voltage stabilizing tube ZD1 is connected to a gate of the MOS tube T7.

[0017] The protection of the MOS tube T7 is effectively enhanced by the bidirectional voltage stabilizing tube ZD1, and the circuit can work stably under high voltage or external interference, and the service life of the element is prolonged.

[0018] In an embodiment of the present application, further comprising:

[0019] A voltage division filter circuit is connected between the controller MCU of the vehicle and the CC2 line of the vehicle, and the voltage division filter circuit comprises resistors R15, R16, R17, and a capacitor C3; wherein a first end of the resistor R15 is connected to the CC2 line of the vehicle, a second end of the resistor R15 is connected to a first end of the resistor R16, a second end of the resistor R16 is connected to the vehicle; a first end of the resistor R17 is connected to the second end of the resistor R15, a second end of the resistor R17 is grounded, a first end of the capacitor C3 is connected to the second end of the resistor R16, and a second end of the capacitor C3 is grounded, and a cathode of the diode D1 is connected to the first end of the resistor R15.

[0020] The voltage division filter circuit effectively filters out high-frequency interference signals through the combination design of the voltage division network and the filter capacitor, avoids electromagnetic interference, adjusts the signal voltage of the CC2 line of the vehicle to the acceptable range of the vehicle, avoids direct damage of abnormal voltage to the controller, and improves the safety of the circuit.

[0021] In an embodiment of the present application, the resistor R15 is further connected with a normally closed controllable switch circuit which is in a normally closed state when the vehicle is not completely connected with the charger.

[0022] On the basis of the protection of the ground wire breakage diagnosis function, the newly added normally closed controllable switch circuit further enhances the judgment ability of the connection state of the vehicle, ensures the accuracy and reliability of signal transmission, prevents signal transmission when the vehicle is not completely connected, and avoids misjudgment; and automatically restores the signal path when the connection is complete, so that the system works more accurately.

[0023] In an embodiment of the present application, the normally closed controllable switch circuit comprises:

[0024] A diode Z2, a resistor R10, a MOS tube T4, a resistor R11, a MOS tube T5, a resistor R13, a voltage stabilizing diode Z3, a MOS tube T6, a resistor R12, and a micro processing unit of the controller.

[0025] The drain of the MOS transistor T4 is connected to the CC2 line of the vehicle, the source of the MOS transistor T4 is connected to the normal power supply, the gate of the MOS transistor T4 is connected to the first end of the resistor R11, the second end of the resistor R11 is connected to the drain of the MOS transistor T5, the source of the MOS transistor T5 is grounded, the gate of the MOS transistor T5 is connected to the collector of the triode T6, the base of the triode T6 is connected to the micro processing unit of the controller, and the emitter of the triode T6 is grounded; the anode of the diode Z2 is connected to the gate of the MOS transistor T4, the cathode of the diode Z2 is connected to the normal power supply; the first end of the resistor R10 is connected to the normal power supply, the second end of the resistor R10 is connected to the gate of the MOS transistor T4, the first end of the resistor R13 is connected to the gate of the MOS transistor T5, and the second end of the resistor R13 is grounded; the anode of the voltage stabilizing diode Z3 is grounded, the cathode of the voltage stabilizing diode Z3 is connected to the gate of the MOS transistor T5, the first end of the resistor R13 is connected to the normal power supply, and the second end of the resistor R13 is connected to the collector of the triode T6.

[0026] The normally closed controllable switch circuit cuts off the signal path in the abnormal connection state, effectively avoids false alarms caused by error signal transmission, and significantly improves the safety of the circuit.

[0027] In an embodiment of the present application, the normally closed controllable switch circuit further comprises:

[0028] The resistor R14 has a first end connected to the drain of the MOS transistor T4 and a second end connected to the CC2 line of the vehicle. The resistor R14 provides effective current limiting protection for the MOS transistor T4, reduces the risk of failure of T4 under high current conditions, and ensures the stability of the switch circuit in complex working environments.

[0029] In an embodiment of the present application, the normally closed controllable switch circuit further comprises:

[0030] The first end of the bidirectional voltage stabilizing tube ZD2 is connected to the gate of the MOS transistor T5, and the second end of the bidirectional voltage stabilizing tube ZD1 is connected to the source of the MOS transistor T5.

[0031] The introduction of the bidirectional voltage stabilizing tube ZD2 provides an additional layer of protection for the MOS transistor T5, significantly reduces the risk of failure of T5 in high voltage or strong interference environments, and improves the reliability of the entire circuit.

[0032] In an embodiment of the present application, the normally closed switch S2 circuit comprises:

[0033] The resistor R3, the resistor R4, the resistor R6, the resistor R7, the MOS transistor T2, the resistor R9, the diode Z1, the resistor R8, the triode T3, and the micro processing unit of the controller.

[0034] The first end of the resistor R4 is connected to the line of the vehicle CC1, the second end of the resistor R4 is connected to the drain of the MOS transistor T2, the source of the MOS transistor T2 is grounded, the gate of the MOS transistor T2 is connected to the collector of the triode T3, the emitter of the triode T3 is grounded, the base of the triode T3 is connected to the micro processing unit of the controller, the first end of the resistor R3 is connected to the first end of the resistor R4, the second end of the resistor R3 is connected to the second end of the resistor R4, the first end of the resistor R6 is connected to the second end of the resistor R4, the second end of the resistor R6 is grounded, the first end of the resistor R7 is connected to the second end of the resistor R4, and the second end of the resistor R7 is grounded, the first end of the resistor R9 is connected to the gate of the MOS transistor T2, and the second end of the resistor R9 is grounded, the cathode of the diode Z1 is connected to the gate of the MOS transistor T2, and the anode of the diode Z1 is grounded, the first end of the resistor R8 is connected to the gate of the MOS transistor T2, and the second end of the resistor R8 is connected to the constant power supply, and the normally closed switch S2 circuit can detect and respond to the voltage abnormality of the CC1 line in time, thereby avoiding damage to the vehicle and the charger.

[0035] By adopting the technical scheme, the normally closed switch S2 circuit can cut off signal transmission under abnormal voltage in time, thereby avoiding damage to the control circuit in the vehicle or the electric vehicle caused by abnormal voltage. The protection ground wire breakage diagnosis circuit ensures continuity of the ground wire, thereby avoiding electric shock or electric leakage accidents caused by ground faults. The two circuits have clear division of labor, and monitor and protect the control signal loop and the ground loop respectively, thereby effectively reducing the risk of single point failure. BRIEF DESCRIPTION OF DRAWINGS

[0036] The utility model will be explained in detail below in combination with specific embodiments and drawings, in which:

[0037] Fig. 1 It is the structure schematic diagram of the normally closed switch S2 circuit of the utility model;

[0038] Fig. 2 It is the structure schematic diagram of the protection ground wire breakage diagnosis circuit and the normally closed controllable switch circuit of the utility model. DETAILED DESCRIPTION

[0039] In order to make the purpose, technical scheme and advantage of the utility model more clear, the utility model will be explained in detail below in combination with drawings and embodiments. It should be understood that the following specific embodiments are only used to explain the utility model, and do not constitute limitation to the utility model.

[0040] As shown in Figs. 1-2 In order to realize the above-mentioned purpose, the utility model provides a detection circuit for electric vehicle, which comprises:

[0041] The normally closed switch S2 circuit is connected to the line of the vehicle CC1, and the line of the vehicle CC1 can be connected with the line of the charger CC1 to form a loop. During the charging process, when the voltage of the line of the vehicle CC1 is abnormal, the normally closed switch S2 circuit is disconnected to pull up the voltage of the line of the vehicle CC1; and

[0042] The protection ground wire breakage diagnosis circuit is connected to the line of the vehicle CC2, and the line of the vehicle CC2 can be connected with the charger to form a ground loop. The protection ground wire breakage diagnosis circuit is used to detect the voltage on the line of the vehicle CC2. When the detected voltage is zero, it indicates that the line of the vehicle CC2 is not broken.

[0043] Specifically, the normally closed switch S2 circuit is connected to the line of the vehicle CC1. The line of the vehicle CC1 can be connected with the line of the charger CC1 to form a complete loop.

[0044] The normally closed switch S2 circuit is used to pull down the voltage on the line of the vehicle CC1. When the voltage of the line of the vehicle CC1 is abnormal, the normally closed switch S2 circuit will switch from the closed state to the open state. In the open state, the voltage on the line of the vehicle CC1 changes, so that the charger detects the voltage change and quickly disconnects the contactor.

[0045] The protection ground wire breakage diagnosis circuit is connected to the line of the vehicle CC2. The line of the vehicle CC2 can be connected with the charger to form a ground loop.

[0046] The protection ground wire breakage diagnosis circuit detects the voltage state on the line of the vehicle CC2 to determine whether the ground line is normal.

[0047] When the detected voltage is zero, it indicates that the line of the vehicle CC2 is not broken, and the ground loop is normally closed. If the voltage is -12V, it indicates that the ground line is abnormal.

[0048] The normally closed switch S2 circuit and the protection ground wire breakage diagnosis circuit are independently connected to the lines of CC1 and CC2, respectively. CC1 represents the charging confirmation, corresponding to the control signal loop of the charger; and CC2 represents that the vehicle after connection is in an un-drivable state, corresponding to the ground signal loop.

[0049] The normally closed switch S2 circuit is mainly used to pull down the voltage state of the CC1 signal loop, and the protection ground wire breakage diagnosis circuit focuses on the state detection of the CC2 ground line. Through the cooperation of the two parts of the circuit, the safety and stability of the electric vehicle are guaranteed.

[0050] The above technical scheme, when the CC1 line is abnormal, the normally closed switch S2 is disconnected, the voltage of the CC1 line is pulled up, so that the charger detects the voltage change on the CC1 line, so that the charger can perform the predetermined protection action, and the damage of the vehicle or the control circuit in the electric vehicle caused by the voltage abnormality is avoided. The protection ground wire breakage diagnosis circuit ensures the continuity of the ground line, avoids the electric shock accident caused by the ground fault. The two circuits have clear division of labor, and monitor and protect the control signal loop and the ground loop respectively, so that the risk of single point failure is effectively reduced.

[0051] In an embodiment of the present application, the protection ground wire breakage diagnosis circuit comprises:

[0052] The diode D1, the zener diode Z5, the resistor R20, the MOS tube T7, the resistor R19, the capacitor C5, the resistor R21, the resistor R18, the power supply VCC, and the microprocessor unit of the controller.

[0053] The cathode of the diode D1 is connected to the CC2 line of the vehicle, the anode of the diode D1 is connected to the source of the MOS tube T7, the drain of the MOS tube T7 is connected to the first end of the resistor R19, and the gate of the MOS tube T7 is connected to the first end of the resistor R21; the second end of the resistor R19 is connected to the microprocessor unit of the controller, and the second end of the resistor R21 is grounded; the anode of the zener diode Z5 is connected to the anode of the diode D1, and the cathode of the zener diode Z5 is connected to the first end of the resistor R21; the first end of the resistor R20 is connected to the anode of the diode D1, and the second end of the resistor R20 is connected to the first end of the resistor R21; the first end of the resistor R18 is connected to the second end of the resistor R19, and the second end of the resistor R18 is connected to the power supply VCC; the first end of the capacitor C5 is connected to the second end of the resistor R19, and the second end of the capacitor is grounded.

[0054] Specifically, the diode D1 provides the one-way conduction ability of the current, prevents the reverse current in the CC2 line of the vehicle from causing damage to the subsequent circuit. The cathode of the diode D1 is connected to the CC2 line of the vehicle, the anode of the diode D1 is connected to the source of the MOS tube T7, and the anode of the zener diode Z5 and the first end of the resistor R20 are connected at the same time.

[0055] The zener diode Z5 stabilizes the input voltage, and protects the gate of the MOS tube T7 from being affected by the excessively high voltage. The anode of the zener diode Z5 is connected to the anode of the diode D1, and the cathode of the zener diode Z5 is connected to the first end of the resistor R21 and the gate of the MOS tube T7.

[0056] The resistor R20 limits the current flowing through the Zener diode Z5, ensuring that it is within the normal operating range. The first end of the resistor R20 is connected to the anode of the diode D1, and the second end is connected to the first end of the resistor R21. The MOS transistor T7 acts as a switching element, controlling its conduction or shutdown through the gate voltage, thereby controlling the state of the microprocessor unit signal of the controller. The source of the MOS transistor T7 is connected to the anode of the diode D1, the drain is connected to the first end of the resistor R19, and the gate is connected to the first end of the resistor R21. When the MOS transistor T7 is turned on, the CC2 line voltage signal of the vehicle is transmitted to the microprocessor unit of the controller; when the MOS transistor is turned off, the signal transmission is blocked.

[0057] The resistor R19 divides the voltage signal of the drain of the MOS transistor T7, while providing a stable current path for the subsequent circuit. The first end of the resistor R19 is connected to the drain of the MOS transistor T7, the second end is connected to the microprocessor unit of the controller, the first end of the resistor R18, and the first end of the capacitor C5. The resistor R21 pulls down the gate voltage of the MOS transistor T7, ensuring that it is stable in the non-conductive state. The first end of the resistor R21 is connected to the cathode of the Zener diode Z5 and the gate of the MOS transistor T7, and the second end is grounded.

[0058] The resistor R18 acts as a pull-up resistor, pulling up the drain voltage, ensuring that the microprocessor unit of the controller can maintain a high level state when the MOS transistor T7 is turned off. The first end of the resistor R18 is connected to the second end of the resistor R19, and the second end is connected to the power supply VCC.

[0059] The capacitor C5 is used for filtering, eliminating transient voltage fluctuations in the circuit, and improving the stability of the output signal. The first end of the capacitor C5 is connected to the second end of the resistor R19, and the second end of the capacitor C5 is grounded. By filtering out high-frequency interference signals, the purity of the microprocessor unit signal of the controller is ensured.

[0060] The power supply VCC provides a stable DC power supply voltage for the circuit. The power supply VCC is connected to the second end of the resistor R18, providing power support for the drain.

[0061] The microprocessor unit of the controller provides an electrical signal output of the CC2 line state of the vehicle for detection by the vehicle or other monitoring units. The microprocessor unit of the controller is connected to the second end of the resistor R19, forming a signal output network with R18 and C5.

[0062] The working principle is as follows:

[0063] When the CC2 line of the vehicle is in a normal state, the diode D1 is turned on, the ground voltage is zero, the gate voltage of the MOS tube T7 is low, and the MOS tube is in a closed state. At this time, the voltage of the microprocessor unit of the controller is pulled up to the power supply voltage VCC through the resistor R18, indicating that the CC2 line of the vehicle is normal. When the PE line is disconnected, the detection point voltage is -12 V, the ground voltage rises, the diode D1 and the voltage stabilizing diode Z5 cooperate, the gate voltage is adjusted through R20 and R21, the MOS tube T7 is turned on, and the voltage of the microprocessor unit of the controller is pulled down to near zero through R19, indicating that the PE contact at the interface of the charger and the vehicle is in a disconnected state

[0064] By using the diode D1 and the voltage stabilizing diode Z5 in cooperation, the abnormal voltage or reverse current in the CC2 line of the vehicle can be effectively prevented from damaging the circuit, and the reliability of the system is improved. The MOS tube T7 realizes rapid response to the state of the CC2 line of the vehicle through gate voltage control, can accurately judge whether the CC2 line of the vehicle is disconnected, and improves the real-time performance of detection. The output signal is filtered through the capacitor C5, interference signals are effectively eliminated, and the stability and accuracy of the output signal are ensured.

[0065] In an embodiment of the present application, the protection ground disconnection diagnosis circuit further comprises:

[0066] The first end of the bidirectional voltage stabilizing tube ZD1 is connected to the source of the MOS tube T7, and the second end of the bidirectional voltage stabilizing tube ZD1 is connected to the gate of the MOS tube T7.

[0067] Specifically, the bidirectional voltage stabilizing tube ZD1 limits the voltage difference between the source and the gate of the MOS tube T7, prevents the MOS tube T7 from being damaged due to excessively high or low transient voltage, and ensures stable operation of the circuit.

[0068] The first end of the bidirectional voltage stabilizing tube ZD1 is connected to the source of the MOS tube T7. The second end of the bidirectional voltage stabilizing tube ZD1 is connected to the gate of the MOS tube T7. The bidirectional voltage stabilizing tube ZD1 forms a voltage clamping between the source and the gate. When the voltage difference exceeds the rated value, the bidirectional voltage stabilizing tube ZD1 is turned on, and the excessively high or low voltage is reduced to a safe range, thereby protecting the normal work of the MOS tube T7.

[0069] When the CC2 line of the vehicle is in a normal state, the diode D1 is turned on, the source voltage is low, and the voltage stabilizing diode Z5 and the resistors R20 and R21 jointly act on the gate voltage of the MOS tube T7 to maintain a low state. The bidirectional voltage stabilizing tube ZD1 only plays a protection role between the source and the gate and does not affect the conduction of the normal voltage. The MOS tube T7 is in a closed state. The voltage of the microprocessor unit of the controller is pulled up to VCC through the resistor R18, indicating that the CC2 line of the vehicle is normal.

[0070] When the PE line between the vehicle and the charger is disconnected, the ground voltage rises, the diode D1 is turned on, and the operating voltage of the voltage stabilizing diode Z5 causes the gate voltage of the MOS tube T7 to rise. When the voltage difference between the gate and the source meets the turn-on condition, the MOS tube T7 is turned on, and the drain voltage is pulled down to near zero through the resistor R19 and the C5. The microprocessor unit voltage of the controller is lowered, and a ground disconnection fault signal is provided to the vehicle or other monitoring devices.

[0071] The above technical scheme effectively enhances the protection of the MOS tube T7 through the bidirectional voltage stabilizing tube ZD1, ensures stable operation of the circuit under high voltage or external interference conditions, and prolongs the service life of the element.

[0072] In an embodiment of the present application, further comprising:

[0073] A voltage division and filtering circuit is connected between the controller MCU of the vehicle and the CC2 line of the vehicle, and comprises a resistor R15, a resistor R16, a resistor R17, and a capacitor C3. The first end of the resistor R15 is connected to the CC2 line of the vehicle, the second end of the resistor R15 is connected to the first end of the resistor R16, the second end of the resistor R16 is connected to the vehicle, the first end of the resistor R17 is connected to the second end of the resistor R15, the second end of the resistor R17 is grounded, the first end of the capacitor C3 is connected to the second end of the resistor R16, and the second end of the capacitor C3 is grounded. The cathode of the diode D1 is connected to the first end of the resistor R15.

[0074] Specifically, the resistor R15 is part of a voltage division network, and R15, R16, and R17 together form a voltage divider for dividing the signal voltage of the CC2 line of the vehicle to a range that can be processed by the vehicle. The first end of the resistor R15 is connected to the CC2 line of the vehicle. The second end of the resistor R15 is connected to the first end of the resistor R16 and the first end of the resistor R17.

[0075] The resistor R16 cooperates with the capacitor C3 to adjust the signal and output a stable signal to the vehicle. The first end of the resistor R16 is connected to the second end of the resistor R15. The second end of the resistor R16 is connected to the vehicle and the first end of the capacitor C3.

[0076] The first end of the resistor R17 is connected to the second end of the resistor R15. The second end of the resistor R17 is grounded. The capacitor C3 filters the signal to remove high-frequency noise and ensures that the signal received by the vehicle is pure and stable. The first end of the capacitor C3 is connected to the second end of the resistor R16. The second end of the capacitor C3 is grounded.

[0077] By adopting the technical scheme, the voltage division filter circuit is designed by combination of a voltage division network and a filter capacitor, high-frequency interference signals are effectively filtered out, and electromagnetic interference is avoided. The voltage division filter circuit adjusts the CC2 line signal voltage of the vehicle to a range acceptable by the vehicle, while avoiding direct damage of abnormal voltage to the controller, and improves the safety of the circuit.

[0078] In an embodiment of the present application, the resistor R15 is further connected with a normally closed controllable switch circuit which is kept in a normally closed state when the vehicle is not completely connected with the charger.

[0079] Specifically, the normally closed controllable switch circuit is used to keep the normally closed controllable switch in a closed state when the vehicle is not completely connected with the charger, and is used to detect the voltage on the CC2 line. After complete connection and voltage detection, the connection state of the vehicle and the charger is confirmed, and the normally closed switch is kept in an open state.

[0080] The normally closed controllable switch circuit is connected to the first end of the resistor R15. When the vehicle is not completely connected with the charger, the normally closed controllable switch circuit is kept in a closed state. When the connection is complete, the switch is automatically opened, and the signal path is restored.

[0081] By adopting the technical scheme, on the basis of protecting the ground wire breakage diagnosis function, the newly added normally closed controllable switch circuit further enhances the judgment ability of the connection state of the vehicle, and ensures the accuracy and reliability of signal transmission.

[0082] In an embodiment of the present application, the normally closed controllable switch circuit comprises:

[0083] a diode Z2, a resistor R10, a MOS tube T4, a resistor R11, a MOS tube T5, a resistor R13, a voltage stabilizing diode Z3, a MOS tube T6, a resistor R12, and a micro processing unit of a controller.

[0084] The drain of the MOS transistor T4 is connected to the CC2 line of the vehicle, the source of the MOS transistor T4 is connected to the constant power supply, the gate of the MOS transistor T4 is connected to the first end of the resistor R11, the second end of the resistor R11 is connected to the drain of the MOS transistor T5, the source of the MOS transistor T5 is grounded, the gate of the MOS transistor T5 is connected to the collector of the triode T6, the base of the triode T6 is connected to the micro processing unit of the controller, and the emitter of the triode T6 is grounded; the anode of the diode Z2 is connected to the gate of the MOS transistor T4, and the cathode of the diode Z2 is connected to the constant power supply; the first end of the resistor R10 is connected to the constant power supply, the second end of the resistor R10 is connected to the gate of the MOS transistor T4, the first end of the resistor R13 is connected to the gate of the MOS transistor T5, and the second end of the resistor R13 is grounded; the anode of the voltage stabilizing diode Z3 is grounded, the cathode of the voltage stabilizing diode Z3 is connected to the gate of the MOS transistor T5, the first end of the resistor R13 is connected to the constant power supply, and the second end of the resistor R13 is connected to the collector of the triode T6.

[0085] Specifically, the drain of the MOS transistor T4 is connected to the CC2 line of the vehicle. The source of the MOS transistor T4 is connected to the constant power supply. The gate of the MOS transistor T4 is connected to the first end of the resistor R11, and the node of the resistor R10 and the diode Z2 is connected.

[0086] The diode Z2 prevents the reverse current of the constant power supply from damaging the gate of the MOS transistor T4, and protects the stable operation of the switching circuit. The anode of the diode Z2 is connected to the gate of the MOS transistor T4. The cathode of the diode Z2 is connected to the constant power supply.

[0087] The resistor R10 provides pull-up voltage for the gate of the MOS transistor T4, ensuring that the MOS transistor T4 remains on in the default state. The first end of the resistor R10 is connected to the constant power supply. The second end of the resistor R10 is connected to the gate of the MOS transistor T4.

[0088] The MOS transistor T5 serves as a control switching element, controls the gate voltage of the MOS transistor T4, and indirectly determines the on and off state of the MOS transistor T4. The drain of the MOS transistor T5 is connected to the second end of the resistor R11. The source of the MOS transistor T5 is grounded. The gate of the MOS transistor T5 is connected to the collector of the triode T6, and the node of the resistor R13 and the voltage stabilizing diode Z3 is connected.

[0089] The resistor R11 limits the gate current of the MOS transistor T4, preventing excessive current from flowing into the gate of T4 and affecting the circuit. The first end of the resistor R11 is connected to the gate of the MOS transistor T4. The second end of the resistor R11 is connected to the drain of the MOS transistor T5.

[0090] Triode T6 is used as a switching control element, and controls the on-off state of MOS tube T5 according to the level signal of the microprocessor unit of the controller, thereby indirectly controlling the on-off of MOS tube T4. The collector of triode T6 is connected to the gate of MOS tube T5. The base of triode T6 is connected to the microprocessor unit of the controller. The emitter of triode T6 is grounded.

[0091] Resistor R13 provides a stable reference voltage for the gate of MOS tube T5, limits the current flowing through the gate of T5, and prevents the circuit from being unstable. The first end of resistor R13 is connected to the constant power supply. The second end of resistor R13 is connected to the gate of MOS tube T5.

[0092] Zener diode Z3 provides voltage stabilization protection for the gate voltage of MOS tube T5, preventing the element from being damaged by excessive voltage. The anode of zener diode Z3 is grounded. The cathode of zener diode Z3 is connected to the gate of MOS tube T5.

[0093] The microprocessor unit of the controller provides external signal input for controlling the on-off of triode T6, thereby realizing the control of the entire switching circuit. The microprocessor unit of the controller is directly connected to the base of triode T6.

[0094] The working principle is as follows:

[0095] Initial state (normally closed):

[0096] When the microprocessor unit of the controller is at low level, triode T6 is in the off state, and the gate voltage of MOS tube T5 is pulled up by resistor R13 and zener diode Z3, and T5 is off.

[0097] At this time, the gate voltage of MOS tube T4 is maintained at high level through R10 and Z2, and T4 is in the on state.

[0098] Control state (off):

[0099] When the microprocessor unit of the controller is at high level, triode T6 is on, and the gate voltage of T5 is pulled down, and MOS tube T5 enters the on state.

[0100] After T5 is on, the gate voltage of MOS tube T4 is pulled down to near ground potential through R11, and T4 is off.

[0101] By adopting the above technical scheme, the normally closed controllable switching circuit cuts off the signal path in the abnormal connection state, effectively avoids false alarm caused by false signal transmission, and significantly improves the safety of the circuit.

[0102] In an embodiment of the present application, the normally closed controllable switching circuit further comprises:

[0103] A resistor R14, a first end of the resistor R14 is connected to the drain of the MOS tube T4, and a second end of the resistor R14 is connected to the CC2 line of the vehicle.

[0104] Specifically, the resistor R14 limits the current and adjusts the voltage of the signal of the CC2 line of the vehicle, ensures the stability of the signal, protects the MOS tube T4 from the impact of excessive current, and avoids damage to the entire circuit caused by abnormal signals or excessive current.

[0105] By using the above technical solution, the resistor R14 provides effective current limiting protection for the MOS tube T4, reduces the risk of failure of T4 under large current conditions, and ensures the stability of the switching circuit under complex working environment.

[0106] In an embodiment of the present application, the normally closed controllable switching circuit further comprises:

[0107] A bidirectional voltage regulator ZD2, a first end of the bidirectional voltage regulator ZD2 is connected to the gate of the MOS tube T5, and a second end of the bidirectional voltage regulator ZD1 is connected to the source of the MOS tube T5.

[0108] Specifically, the bidirectional voltage regulator ZD2 limits the voltage difference between the gate and the source of the MOS tube T5, protects the MOS tube T5 from damage caused by excessive or low voltage, and ensures stable operation. The first end of the bidirectional voltage regulator ZD2 is connected to the gate of the MOS tube T5. The second end of the bidirectional voltage regulator ZD2 is connected to the source of the MOS tube T5.

[0109] By using the above technical solution, the introduction of the bidirectional voltage regulator ZD2 provides an additional layer of protection for the MOS tube T5, significantly reduces the risk of failure of T5 in high-voltage or strong interference environment, and improves the reliability of the entire circuit.

[0110] In an embodiment of the present application, the normally closed switching circuit S2 comprises:

[0111] Resistor R3, resistor R4, resistor R6, resistor R7, MOS tube T2, resistor R9, diode Z1, resistor R8, triode T3, and microprocessor unit of the controller.

[0112] The first end of the resistor R4 is connected to the line of the vehicle CC1, and the second end of the resistor R4 is connected to the drain of the MOS transistor T2. The drain of the MOS transistor T2 is connected to the second end of the resistor R4, the source of the MOS transistor T2 is grounded, and the gate of the MOS transistor T2 is connected to the ground through the resistor R9, and is also connected to the cathode of the diode Z1 and the first end of the resistor R8. The MOS transistor T2 serves as a main switching element. The gate voltage determines the conduction state of the MOS transistor.

[0113] Specifically, the first end of the resistor R4 is connected to the line of the vehicle CC1, and the second end of the resistor R4 is connected to the drain of the MOS transistor T2. The drain of the MOS transistor T2 is connected to the second end of the resistor R4, the source of the MOS transistor T2 is grounded, and the gate of the MOS transistor T2 is connected to the ground through the resistor R9, and is also connected to the cathode of the diode Z1 and the first end of the resistor R8. The MOS transistor T2 serves as a main switching element. The gate voltage determines the conduction state of the MOS transistor.

[0114] The base of the triode T3 is connected to the microprocessor unit of the controller, the collector is connected to the gate of the MOS transistor T2, and the emitter is grounded. The triode T3 is used to amplify the control signal and indirectly control the gate voltage of the MOS transistor, thereby controlling the switching state of the MOS transistor T2.

[0115] The resistors R3, R6 and R7 are all connected to the second end of the resistor R4, and are respectively grounded or connected to other circuit nodes through their second ends. A voltage dividing network is formed to provide appropriate operating voltages for the MOS transistor T2 and other elements.

[0116] The first end of the resistor R9 is connected to the gate of the MOS transistor T2, and the second end is grounded. It is used to stabilize the gate voltage of the MOS transistor and prevent false operation caused by noise interference.

[0117] The cathode of the diode Z1 is connected to the gate of the MOS transistor T2, and the anode is grounded. It protects the gate of the MOS transistor T2 from damage caused by excessive voltage. The first end of the resistor R8 is connected to the gate of the MOS transistor T2, and the second end is connected to a constant voltage power supply. It provides pull-up voltage for the gate to ensure correct conduction of the MOS transistor.

[0118] The micro-processing unit of the controller provides an external control signal for determining whether the triode T3 is turned on or not, thereby controlling the switching state of the MOS tube T2.

[0119] By using the above technical scheme, the normally closed switch S2 circuit can detect and respond to the voltage abnormality of the CC1 line in time, thereby avoiding damage to the vehicle and the charging machine.

[0120] The above only describes the preferred embodiments of the present application, and does not limit the patent range of the present application, and any equivalent structural transformation made by using the content of the present application specification and drawings, or direct / indirect application in other related technical fields is included in the patent protection range of the present application.

Claims

1. A detection circuit for an electric vehicle, characterized by, The application comprises: a normally closed switch S2 circuit connected to the vehicle CC1 line, which can be connected with the charger CC1 line to form a loop, and the normally closed switch S2 circuit is disconnected to pull up the voltage of the vehicle CC1 line when the voltage of the CC1 line is abnormal during charging; and a protection ground wire breakage diagnosis circuit connected to the vehicle CC2 line, which can be connected with the charger to form a ground loop, and the protection ground wire breakage diagnosis circuit is used to detect the voltage on the CC2 line, and when the detected voltage is zero, it indicates that the CC2 line is not broken.

2. The detection circuit for an electric vehicle as claimed in claim 1, wherein, The protection ground wire breakage diagnosis circuit comprises: a diode D1, a zener diode Z5, a resistor R20, a MOS tube T7, a resistor R19, a capacitor C5, a resistor R21, a resistor R18, a power supply VCC, and a microprocessor unit of a controller; wherein the cathode of the diode D1 is connected to the vehicle CC2 line, the anode of the diode D1 is connected to the source of the MOS tube T7, the drain of the MOS tube T7 is connected to the first end of the resistor R19, the gate of the MOS tube T7 is connected to the first end of the resistor R21; the second end of the resistor R19 is connected to the microprocessor unit of the controller, and the second end of the resistor R21 is grounded; the anode of the zener diode Z5 is connected to the anode of the diode D1, and the cathode of the zener diode Z5 is connected to the first end of the resistor R21; the first end of the resistor R20 is connected to the anode of the diode D1, and the second end of the resistor R20 is connected to the first end of the resistor R21; the first end of the resistor R18 is connected to the second end of the resistor R19, and the second end of the resistor R18 is connected to the power supply VCC; the first end of the capacitor C5 is connected to the second end of the resistor R19, and the second end of the capacitor is grounded.

3. The detection circuit for an electric vehicle as claimed in claim 2, wherein The protection ground wire breakage diagnosis circuit further comprises: a bidirectional zener ZD1, the first end of the bidirectional zener ZD1 is connected to the source of the MOS tube T7, and the second end of the bidirectional zener ZD1 is connected to the gate of the MOS tube T7.

4. The detection circuit for an electric vehicle as claimed in claim 3, wherein Further comprising: a voltage division filter circuit connected between the controller MCU of the vehicle and the CC2 line of the vehicle, the voltage division filter circuit comprising: a resistor R15, a resistor R16, a resistor R17, and a capacitor C3; wherein the first end of the resistor R15 is connected to the CC2 line of the vehicle, the second end of the resistor R15 is connected to the first end of the resistor R16, the second end of the resistor R16 is connected to the vehicle; the first end of the resistor R17 is connected to the second end of the resistor R15, the second end of the resistor R17 is grounded, the first end of the capacitor C3 is connected to the second end of the resistor R16, and the second end of the capacitor C3 is grounded, and the cathode of the diode D1 is connected to the first end of the resistor R15.

5. The detection circuit for an electric vehicle as claimed in claim 4, wherein The resistor R15 is further connected with a normally closed controllable switch circuit which remains in a normally closed state when the vehicle is not completely connected with the charger.

6. The detection circuit for an electric vehicle as claimed in claim 5, wherein, The normally closed controllable switch circuit comprises: a diode Z2, a resistor R10, a MOS tube T4, a resistor R11, a MOS tube T5, a resistor R13, a zener diode Z3, a MOS tube T6, a resistor R12, and a microprocessor unit of a controller; The MOS tube T4 is connected to the CC2 line of the vehicle, the source of the MOS tube T4 is connected to the constant power supply, the gate of the MOS tube T4 is connected to the first end of the resistor R11, the second end of the resistor R11 is connected to the drain of the MOS tube T5, the source of the MOS tube T5 is grounded, the gate of the MOS tube T5 is connected to the collector of the triode T6, the base of the triode T6 is connected to the micro processing unit of the controller, the emitter of the triode T6 is grounded; the anode of the diode Z2 is connected to the gate of the MOS tube T4, the cathode of the diode Z2 is connected to the constant power supply; the first end of the resistor R10 is connected to the constant power supply, the second end of the resistor R10 is connected to the gate of the MOS tube T4, the first end of the resistor R13 is connected to the gate of the MOS tube T5, the second end of the resistor R13 is grounded; the anode of the voltage stabilizing diode Z3 is grounded, the cathode of the voltage stabilizing diode Z3 is connected to the gate of the MOS tube T5, the first end of the resistor R13 is connected to the constant power supply, the second end of the resistor R13 is connected to the collector of the triode T6.

7. The detection circuit for an electric vehicle as claimed in claim 6, wherein The normally closed controllable switch circuit further comprises: The first end of the resistor R14 is connected to the drain of the MOS tube T4, and the second end of the resistor R14 is connected to the CC2 line of the vehicle.

8. The detection circuit for an electric vehicle as claimed in claim 6, wherein, The normally closed controllable switch circuit further comprises: The first end of the bidirectional voltage stabilizing tube ZD2 is connected to the gate of the MOS tube T5, and the second end of the bidirectional voltage stabilizing tube ZD1 is connected to the source of the MOS tube T5.

9. The detection circuit for an electric vehicle as recited in claim 1, wherein The normally closed switch S2 circuit comprises: The resistor R3, the resistor R4, the resistor R6, the resistor R7, the MOS tube T2, the diode Z1, the resistor R8, the triode T3, and the micro processing unit of the controller; The first end of the resistor R4 is connected to the line of the vehicle CC1, the second end of the resistor R4 is connected to the drain of the MOS tube T2, the source of the MOS tube T2 is grounded, the gate of the MOS tube T2 is connected to the collector of the triode T3, the emitter of the triode T3 is grounded, and the base of the triode T3 is connected to the micro processing unit of the controller; the first end of the resistor R3 is connected to the first end of the resistor R4, the second end of the resistor R3 is connected to the second end of the resistor R4, the first end of the resistor R6 is connected to the second end of the resistor R4, the second end of the resistor R6 is grounded, the first end of the resistor R7 is connected to the second end of the resistor R4, and the second end of the resistor R7 is grounded; the first end of the resistor R9 is connected to the gate of the MOS tube T2, and the second end of the resistor R9 is grounded; the cathode of the diode Z1 is connected to the gate of the MOS tube T2, and the anode of the diode Z1 is grounded; the first end of the resistor R8 is connected to the gate of the MOS tube T2, and the second end of the resistor R8 is connected to the constant power supply.

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