Off-line protection method and off-line protection circuit for low-speed electric vehicle battery

Abstract

The invention discloses a low-speed electric vehicle battery off-line protection method and an off-line protection circuit thereof. A system battery is controlled through a normal state mode of the system battery to be connected with a direct-current bus capacitor where a three-phase half-bridge is located through closing of a normally open contact and a conversion contact of a relay for charging; in the battery offline state protection control mode, the reference voltage of a battery offline protection circuit is compared with the direct current bus voltage collected in real time, if the reference voltage exceeds the set reference voltage, braking current is generated in a vehicle motor, the vehicle is subjected to braking deceleration protection, and after the vehicle decelerates to be stable, a driver can conduct manual braking. And safe parking is realized. Braking current is generated in a vehicle motor under the condition that the vehicle is shut down without mechanical braking, the vehicle is braked, and inertial rolling control of the vehicle is restrained. And after the battery is offline, controllable braking torque can be provided, inertial sliding is prevented, and the offline safe parking reliability of the vehicle battery is improved.

Description

Technical Field

[0001] The present invention relates to a low-speed electric vehicle, and in particular to a low-speed electric vehicle battery offline protection method used in low-speed electric vehicles such as electric wheelchairs or scooters. Background Art

[0002] Low-speed electric vehicles (such as electric wheelchairs, electric scooters, golf carts, golf carts, and electric tricycles) are usually used to meet the travel needs of people with convenient mobility for longer distances, or to meet the travel needs of people with mobility difficulties, so as to improve travel efficiency and serve as a means of transportation or auxiliary tools.

[0003] However, existing low-speed electric vehicles usually use manual braking to park, but after the system loses power (the battery is offline), the vehicle is prone to inertial sliding. If the driver cannot quickly perform manual parking, there is a certain safety hazard. Summary of the Invention

[0004] The present invention aims to solve the potential safety hazards that may occur when manual parking is used in existing low-speed electric vehicles, and provides a low-speed electric vehicle battery offline protection method and offline protection circuit for improving the reliability of vehicle battery offline safety parking.

[0005] To achieve the above-mentioned purpose, the present invention adopts a low-speed electric vehicle battery offline protection method, including the following offline protection control method: A1. Normal system battery mode: After the system battery is powered on, the inhibit signal is inactive; the MOSFET is off, and the battery charges the DC bus where the three-phase half-bridge resides through the pre-charge circuit. After the DC bus voltage stabilizes, the MCU relay drive signal activates the relay, and the system battery connects to the DC bus where the three-phase half-bridge resides through the closure of the relay's normally open contact and the changeover contact. The vehicle then drives or brakes normally. A2. Battery Offline Protection Control Mode: If the battery goes offline while the vehicle is in motion, the regenerative braking energy generated by the low-speed electric vehicle's motor cannot be quickly absorbed. The electrolytic capacitors on the DC bus have limited absorption capacity, causing the DC bus voltage to rise rapidly. The PWM signal output by the MCU is filtered by a low-pass filter and output as the reference voltage for the battery offline detection and protection circuit. If the real-time acquired DC bus voltage exceeds the set reference voltage, the inhibit signal output by the battery offline detection and protection circuit is valid, and the MOSFET is switched to the on state. The three-phase half-bridge and relay drivers are both driven off by the inhibit signal, and the relay is deenergized and released, returning to a conductive state between the transfer contact C and the normally closed contact NC. The back electromotive force of the BLDC vehicle's motor is rectified by the three-phase half-bridge and filtered by CAP1. The output voltage is connected to the circuit power supply ground through the relay transfer contact C, the normally closed contact NC, the MOSFET, the current acquisition circuit, and the circuit power supply ground to form a loop. Braking current is generated in the vehicle's motor, and the vehicle is braked and decelerated for protection. After the vehicle slows down to a stable state, the driver can manually brake and park safely. A3. Non-mechanical brake control mode: When the vehicle is powered off and there are no mechanical brakes, the back EMF of the BLDC vehicle motor passes through the rectifier and filter circuits to generate a voltage on the DC bus. This voltage is processed and charges the electrolytic capacitor on the DC bus, which then drives the MOSFET. The MOSFET is turned on and connected to the current acquisition circuit and the circuit power ground to form a loop. A braking current is generated in the vehicle motor, braking the vehicle and suppressing its inertial rolling.

[0006] By implementing this control technology solution in different state modes, including the normal battery state mode, the battery offline state protection control mode, and the non-mechanical brake control mode, it effectively provides a parking method with controllable braking torque after the battery is offline. When the vehicle is powered off and there are no mechanical brakes, it can provide a certain degree of braking to suppress the vehicle's inertial rolling. This effectively provides controllable braking torque after the battery is offline, preventing inertial sliding and improving the reliability of safe parking when the battery is offline.

[0007] Preferably, in step A1, after the system battery is powered on, the inhibit signal is in an inactive state; the MCU outputs a 1 signal to pull down the MOSFET gate, turning off the MOSFET; then the MCU pre-charge control signal drives the pre-charge circuit, and the battery charges the DC bus where the three-phase half-bridge is located through the pre-charge circuit; after the DC bus voltage stabilizes, the MCU relay drive signal drives the relay to operate, and the system battery connects to the DC bus where the three-phase half-bridge is located through the closure of the relay's normally open contact and the transfer contact. This improves the safety, simplicity, reliability, and effectiveness of parking in the system battery normal state mode.

[0008] Preferably, in the above-mentioned step A2, if the battery is offline while the vehicle is driving, the regenerative braking energy generated by the vehicle motor cannot be quickly absorbed, and the absorption capacity of the electrolytic capacitor on the DC bus is limited, resulting in a rapid rise in the DC bus voltage; the PWM signal output by the MCU is filtered by a low-pass filter and output as a reference voltage for the battery offline detection protection circuit, and the voltage acquisition circuit acquires the DC bus voltage in real time. If the DC bus voltage exceeds the set reference voltage, the prohibition signal output by the battery offline detection protection circuit is valid, and the output drive 1 is released from the MOSFET tube state to turn on the MOSFET tube; the three-phase half-bridge is driven and closed by the prohibition signal, the relay drive is driven and closed by the prohibition signal, the relay is deenergized and released, the relay transfer contact C is connected to the normally closed contact NC, and the back electromotive force of the BLDC vehicle motor is connected after the three-phase half-bridge rectification and bus electrolytic capacitor filtering, and then connected to the circuit power ground through the relay transfer contact C, the normally closed contact NC, the MOSFET tube and the current acquisition circuit to form a loop, a braking current is generated in the vehicle motor, and the vehicle is braked and decelerated. After the vehicle decelerates to a stable state, the driver can perform manual braking and park safely. Improve the safety, simplicity, reliability and effectiveness of parking in battery offline protection control mode.

[0009] Preferably, in step A1 and step A3, when the vehicle is turned off and there is no mechanical brake, the back electromotive force of the BLDC vehicle motor passes through a rectifier and filter circuit consisting of a three-phase half-bridge rectifier and an electrolytic capacitor filter on the DC bus to generate a voltage on the DC bus. After voltage processing, the voltage charges the electrolytic capacitor on the DC bus and drives the MOSFET tube. The MOSFET tube is turned on and works. The back electromotive force of the BLDC vehicle motor is connected to the circuit power supply ground through the three-phase half-bridge, the electrolytic capacitor on the DC bus, the relay switching contact, the relay normally closed contact, the MOSFET tube, and the current acquisition circuit to form a loop. A braking current is generated in the vehicle motor, the vehicle is braked, and the vehicle's inertial rolling is suppressed. This improves the safety, simplicity, reliability and effectiveness of parking in the non-mechanical brake control mode.

[0010] Preferably, the larger the energy storage capacity of the electrolytic capacitor on the DC bus, the longer the protection circuit works, and the driver can manually brake after the vehicle slows down to a stable state, which improves the effectiveness of parking safety protection.

[0011] Another invention purpose of the present invention application is to provide a low-speed electric vehicle battery offline protection circuit, including a vehicle motor, a three-phase half-bridge rectifier circuit, and a battery for the system, characterized in that: it is used for the low-speed electric vehicle battery offline protection method described in one of the above technical solutions, wherein the battery offline protection circuit includes a low-pass filter, an offline detection circuit, a voltage acquisition circuit, a current acquisition circuit, a constant current circuit, an output drive module, a voltage processing module and a MOSFET tube, the PWM signal input output by the MCU is electrically connected to the low-pass filter, the voltage acquisition circuit is electrically connected to collect the DC bus voltage in real time, and the voltage acquisition circuit and the low-pass filter are respectively input with electrical The device is connected to an offline detection circuit. The offline detection circuit output is electrically connected to a disable signal. The disable signal is electrically connected to the output driver 1, the three-phase half-bridge, and the relay driver circuit inputs. The MCU outputs a high-level signal electrically connected to the output driver 1 module. Output driver 1 is electrically connected to the gate of the MOSFET tube. The source of the MOSFET tube is connected to the circuit power ground through a current acquisition circuit to form a loop. The gate of the MOSFET tube is electrically connected to the current acquisition circuit through a constant current circuit. The drain of the MOSFET tube is electrically connected to the normally closed contact of the relay. The relay switching contact is electrically connected to the precharge circuit, the voltage acquisition circuit, the three-phase half-bridge, and the positive electrode of the electrolytic capacitor on the DC bus. The circuit structure is simple and effective, effectively achieving controllable braking torque after the battery is offline, preventing coasting and improving the reliability of safe parking when the vehicle battery is offline.

[0012] Preferably, the relay switching contact is electrically connected to the pre-charging circuit, which is electrically connected to the positive electrode of the vehicle power supply voltage and the MCU pre-charging control signal port, respectively, to improve the simplicity and effectiveness of charging the DC bus and stabilizing the DC bus voltage.

[0013] Preferably, the MOSFET gate is connected in series with a resistor and is electrically connected to a voltage processing, a driving voltage and a filter capacitor respectively.

[0014] The beneficial effects of the present invention are as follows: the battery offline protection designed in this solution effectively provides a parking method with controllable braking torque after the battery is offline by applying the above-mentioned control technology scheme in different state modes: normal battery state mode, battery offline protection control mode, and non-mechanical braking control mode. It also provides a certain degree of braking to suppress the vehicle's inertial rolling when the vehicle is shut down and mechanical braking is not available. This invention effectively provides controllable braking torque after the battery is offline, prevents inertial sliding, and improves the reliability of safe parking when the battery is offline. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The present invention is a schematic diagram of the circuit principle structure of the low-speed electric vehicle battery offline protection method and offline protection circuit. DETAILED DESCRIPTION

[0016] Example 1 Figure 1 In the embodiment shown, a low-speed electric vehicle battery offline protection method includes the following offline protection control method: A1. Normal system battery mode: After the system battery is powered on, the inhibit signal is inactive; the MOSFET is off, and the battery charges the DC bus where the three-phase half-bridge resides through the pre-charge circuit. After the DC bus voltage stabilizes, the MCU relay drive signal activates the relay, and the system battery connects to the DC bus where the three-phase half-bridge resides through the closure of the relay's normally open contact and the transfer contact. The vehicle drives or brakes normally. The inhibit signal is output by the offline detection circuit and is a level signal. If a valid inhibit signal is issued, the inhibit signal is level signal 1. A2. Battery Offline Protection Control Mode: If the battery goes offline while the vehicle is in motion, the regenerative braking energy generated by the low-speed electric vehicle motor cannot be quickly absorbed. The electrolytic capacitors on the DC bus have limited absorption capacity, causing the DC bus voltage to rise rapidly. The PWM signal output by the MCU is filtered by a low-pass filter and output as the reference voltage for the battery offline detection and protection circuit. If the real-time acquired DC bus voltage exceeds the set reference voltage, the inhibit signal output by the battery offline detection and protection circuit is valid, and the MOSFET is switched to the on state. The three-phase half-bridge and relay drivers are both driven off by the inhibit signal. The relay is de-energized and returns to the transfer contact C and the normally closed contact NC. The back electromotive force of the BLDC vehicle motor is rectified by the three-phase half-bridge and filtered by CAP1. The output voltage is connected to the circuit power supply ground through the relay transfer contact C, the normally closed contact NC, the MOSFET, the current acquisition circuit, and the circuit power supply ground to form a loop. Braking current is generated in the vehicle motor, and the vehicle is braked and decelerated for protection. After the vehicle slows down to a stable state, the driver can manually brake and park safely. The BLDC vehicle motor is a brushless DC motor. A3. Non-mechanical brake control mode: When the vehicle is powered off and there are no mechanical brakes, the back EMF of the BLDC vehicle motor passes through the rectifier and filter circuits to generate a voltage on the DC bus. This voltage is processed and charges the electrolytic capacitor on the DC bus, which then drives the MOSFET. The MOSFET is turned on and connected to the current acquisition circuit and the circuit power ground to form a loop. A braking current is generated in the vehicle motor, braking the vehicle and suppressing its inertial rolling.

[0017] In the above step A1, after the system battery is powered on, the inhibit signal is in an invalid state; the MCU outputs a high-level signal to pull down the gate of the MOSFET tube to turn off the MOSFET tube, and then the MCU pre-charge control signal drives the pre-charge circuit to operate, and the battery charges the DC bus where the three-phase half bridge is located through the pre-charge circuit; after the DC bus voltage stabilizes, the MCU relay drive signal drives the relay to operate, and the system battery is connected to the DC bus where the three-phase half bridge is located through the closure of the normally open contact and the transfer contact of the relay; the MCU pre-charge control can adopt the existing technical solution; In the above step A2, if the battery is offline while the vehicle is driving, the regenerative braking energy generated by the vehicle motor cannot be quickly absorbed, and the absorption capacity of the electrolytic capacitor on the DC bus is limited, resulting in a rapid increase in the DC bus voltage. The PWM signal output by the MCU is filtered by a low-pass filter and output as a reference voltage for the battery offline detection and protection circuit. The voltage acquisition circuit acquires the DC bus voltage in real time. If the DC bus voltage exceeds the set reference voltage, the prohibition signal output by the battery offline detection and protection circuit is valid, and the output driver 1 is released from the MOSFET tube state to turn on the MOSFET tube. The three-phase half-bridge is driven and closed by the prohibition signal, and the relay drive is driven and closed by the prohibition signal. The relay is deenergized and released, and the relay transfer contact C is connected to the normally closed contact NC to conduct. The back electromotive force of the BLDC vehicle motor is rectified by the three-phase half-bridge and filtered by the bus electrolytic capacitor. It is then connected to the circuit power ground through the relay transfer contact C, the normally closed contact NC, the MOSFET tube and the current acquisition circuit to form a loop. A braking current is generated in the vehicle motor, and the vehicle is braked and decelerated for protection. After the vehicle decelerates to a stable state, the driver can manually brake and park safely.

[0018] In the above step A1 and step A3, when the vehicle is turned off and there is no mechanical brake, the back electromotive force of the BLDC vehicle motor generates a voltage on the DC bus through a rectifier and filter circuit composed of a three-phase half-bridge rectifier and an electrolytic capacitor filter on the DC bus. After voltage processing, the voltage charges the electrolytic capacitor on the DC bus and then drives the MOSFET tube. The MOSFET tube is turned on and works. The back electromotive force of the BLDC vehicle motor is connected to the circuit power ground through the three-phase half-bridge, the electrolytic capacitor on the DC bus, the relay switching contact, the relay normally closed contact, the MOSFET tube and the current acquisition circuit to form a loop. A braking current is generated in the vehicle motor to brake the vehicle and suppress the vehicle's inertial rolling.

[0019] The larger the energy storage capacity of the electrolytic capacitor CAP1 (energy storage filter capacitor) on the DC bus, the longer the protection circuit works. After the vehicle slows down to a stable state, the driver can perform manual braking, and the safe parking protection effect is better.

[0020] Example 2 Figure 1 In the embodiment shown, a low-speed electric vehicle battery offline protection circuit includes a vehicle motor, a three-phase half-bridge rectifier circuit, and a battery for the system, and is used in the low-speed electric vehicle battery offline protection method described in Example 1, wherein the battery offline protection circuit includes a low-pass filter, an offline detection circuit, a voltage acquisition circuit, a current acquisition circuit, a constant current circuit, an output drive module, a voltage processing module, and a MOSFET tube. The PWM signal input output by the MCU is electrically connected to the low-pass filter, the voltage acquisition circuit is electrically connected to collect the DC bus voltage in real time, the voltage acquisition circuit and the low-pass filter are respectively input and electrically connected to the offline detection circuit, the offline detection circuit output is electrically connected to a prohibition signal, and the prohibition signal is respectively electrically connected to the output drive 1, the three-phase half-bridge, and the relay drive circuit input. The MCU output 1 signal is electrically connected to the output drive 1 module, the output drive 1 is electrically connected to the gate of the MOSFET tube, the source of the MOSFET tube is connected to the circuit power ground through the current acquisition circuit to form a loop, the gate of the MOSFET tube is electrically connected to the current acquisition circuit through the constant current circuit, the drain of the MOSFET tube is electrically connected to the normally closed contact of the relay, and the relay switching contact is respectively electrically connected to the pre-charge circuit, the voltage acquisition circuit, the three-phase half-bridge, and the positive electrode of the electrolytic capacitor on the DC bus. The relay's switching contacts are electrically connected to the pre-charge circuit, which is in turn electrically connected to the positive pole of the vehicle's power supply voltage and the MCU's pre-charge control signal port. A resistor is connected in series with the MOSFET's gate, which is then electrically connected to the voltage processing, drive voltage, and filter capacitors.

[0021] The above content and structure describe the basic principles, main features, and advantages of the product of the present invention, which should be understood by those skilled in the art. The above examples and description are merely illustrative of the principles of the present invention. Various changes and modifications may be made to the present invention without departing from the spirit and scope of the present invention, and such changes and modifications are intended to be within the scope of the invention. The scope of protection claimed in the present invention is defined by the appended claims and their equivalents.

Claims

1. A low-speed electric vehicle battery offline protection method, characterized by: Including the following offline protection control methods, A1. Normal system battery mode: After the system battery is powered on, the inhibit signal is inactive; the MOSFET is off, and the battery charges the DC bus where the three-phase half-bridge resides through the pre-charge circuit. After the DC bus voltage stabilizes, the MCU relay drive signal activates the relay, and the system battery connects to the DC bus where the three-phase half-bridge resides through the closure of the relay's normally open contact and the changeover contact. The vehicle then drives or brakes normally. A2. Battery Offline Protection Control Mode: If the battery goes offline while the vehicle is in motion, the regenerative braking energy generated by the low-speed electric vehicle's motor cannot be quickly absorbed. The electrolytic capacitors on the DC bus have limited absorption capacity, causing the DC bus voltage to rise rapidly. The PWM signal output by the MCU is filtered by a low-pass filter and output as the reference voltage for the battery offline detection and protection circuit. If the real-time acquired DC bus voltage exceeds the set reference voltage, the inhibit signal output by the battery offline detection and protection circuit is valid, and the MOSFET is switched to the on state. The three-phase half-bridge and relay drivers are both driven off by the inhibit signal, and the relay is deenergized and released, returning to a conductive state between the transfer contact C and the normally closed contact NC. The back electromotive force of the BLDC vehicle's motor is rectified by the three-phase half-bridge and filtered by CAP1. The output voltage is connected to the circuit power supply ground through the relay transfer contact C, the normally closed contact NC, the MOSFET, the current acquisition circuit, and the circuit power supply ground to form a loop. Braking current is generated in the vehicle's motor, and the vehicle is braked and decelerated for protection. After the vehicle slows down to a stable state, the driver can manually brake and park safely. A3. Non-mechanical brake control mode: When the vehicle is powered off and there are no mechanical brakes, the back EMF of the BLDC vehicle motor passes through the rectifier and filter circuits to generate a voltage on the DC bus. This voltage is processed and charges the electrolytic capacitor on the DC bus, which then drives the MOSFET. The MOSFET is turned on and connected to the current acquisition circuit and the circuit power ground to form a loop. A braking current is generated in the vehicle motor, braking the vehicle and suppressing its inertial rolling.

2. The method for offline protection of a low-speed electric vehicle battery according to claim 1, characterized in that: In the above step A1, after the system battery is powered on, the inhibit signal is in an invalid state; the MCU outputs a high-level signal to pull down the gate of the MOSFET tube to turn off the MOSFET tube, and then the MCU pre-charge control signal drives the pre-charge circuit to work, and the battery charges the DC bus capacitor where the three-phase half bridge is located through the pre-charge circuit; after the DC bus voltage stabilizes, the MCU relay drive signal drives the relay to operate, and the system battery is connected to the DC bus where the three-phase half bridge is located through the closure of the normally open contact and the transfer contact of the relay.

3. The method for offline protection of a low-speed electric vehicle battery according to claim 1, characterized in that: In the above step A2, if the battery is offline while the vehicle is driving, the regenerative braking energy generated by the vehicle motor cannot be quickly absorbed, and the absorption capacity of the electrolytic capacitor on the DC bus is limited, resulting in a rapid increase in the DC bus voltage. The PWM signal output by the MCU is filtered by a low-pass filter and output as a reference voltage for the battery offline detection and protection circuit. The voltage acquisition circuit acquires the DC bus voltage in real time. If the DC bus voltage exceeds the set reference voltage, the prohibition signal output by the battery offline detection and protection circuit is valid, and the output driver 1 is released from the MOSFET tube state to turn on the MOSFET tube. The three-phase half-bridge is driven and closed by the prohibition signal, and the relay drive is driven and closed by the prohibition signal. The relay is deenergized and released, and the relay transfer contact C is connected to the normally closed contact NC to conduct. The back electromotive force of the BLDC vehicle motor is rectified by the three-phase half-bridge and filtered by the bus electrolytic capacitor. It is then connected to the circuit power ground through the relay transfer contact C, the normally closed contact NC, the MOSFET tube and the current acquisition circuit to form a loop. A braking current is generated in the vehicle motor, and the vehicle is braked and decelerated for protection. After the vehicle decelerates to a stable state, the driver can manually brake and park safely.

4. The method for offline protection of a low-speed electric vehicle battery according to claim 1, characterized in that: In the above step A1 and step A3, when the vehicle is turned off and there is no mechanical brake, the back electromotive force of the BLDC vehicle motor generates a voltage on the DC bus through a rectifier and filter circuit composed of a three-phase half-bridge rectifier and an electrolytic capacitor filter on the DC bus. After voltage processing, the voltage charges the electrolytic capacitor on the DC bus and then drives the MOSFET tube. The MOSFET tube is turned on and works. The back electromotive force of the BLDC vehicle motor is connected to the circuit power ground through the three-phase half-bridge, the electrolytic capacitor on the DC bus, the relay switching contact, the relay normally closed contact, the MOSFET tube and the current acquisition circuit to form a loop. A braking current is generated in the vehicle motor to brake the vehicle and suppress the vehicle's inertial rolling.

5. The method for offline protection of a low-speed electric vehicle battery according to claim 1, 3 or 4, characterized in that: The larger the energy storage capacity of the electrolytic capacitor on the DC bus, the longer the protection circuit works. After the vehicle slows down to a stable state, the driver can perform manual braking, and the safe parking protection effect is better.

6. A low-speed electric vehicle battery offline protection circuit, comprising a vehicle motor, a three-phase half-bridge rectifier circuit, and a system battery, characterized in that: A method for offline protection of a low-speed electric vehicle battery according to any one of claims 1 to 5, wherein the battery offline protection circuit includes a low-pass filter, an offline detection circuit, a voltage acquisition circuit, a current acquisition circuit, a constant current circuit, an output drive module, a voltage processing module and a MOSFET tube, the PWM signal input output by the MCU is electrically connected to the low-pass filter, the voltage acquisition circuit is electrically connected to collect the DC bus voltage in real time, the voltage acquisition circuit and the low-pass filter are respectively input and electrically connected to the offline detection circuit, the offline detection circuit output is electrically connected to a prohibition signal, the prohibition signal is respectively electrically connected to the output drive 1, the three-phase half-bridge and the relay drive circuit input, the MCU output 1 signal is electrically connected to the output drive 1 module, the output drive 1 is electrically connected to the gate of the MOSFET tube, the source of the MOSFET tube is connected to the circuit power ground through the current acquisition circuit to form a loop, the gate of the MOSFET tube is electrically connected to the current acquisition circuit through the constant current circuit, the drain of the MOSFET tube is electrically connected to the normally closed contact of the relay, and the relay switching contact is respectively electrically connected to the pre-charging circuit, the voltage acquisition circuit, the three-phase half-bridge and the positive electrode of the electrolytic capacitor on the DC bus.

7. The low-speed electric vehicle battery offline protection circuit according to claim 6, characterized in that: The relay switching contact is electrically connected to the pre-charging circuit, and the pre-charging circuit is electrically connected to the positive electrode of the vehicle power supply voltage and the MCU pre-charging control signal port respectively.

8. The low-speed electric vehicle battery offline protection circuit according to claim 6, characterized in that: The MOSFET gate is connected in series with a resistor and is electrically connected to a voltage processing, a driving voltage and a filter capacitor respectively.

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