Up and down power control system and method of extended-range multi-motor electric vehicle and electric vehicle

Abstract

The application discloses an up and down power control system and method of a range-extender multi-motor electric vehicle, comprising a VCU, a motor controller, a range-extender controller, a DC-DC converter, a PDU, a plurality of motors and an engine, wherein the VCU is installed in a cab and is used for coordinating and controlling the work of each subsystem, and is also used for performing low-voltage self-checking and safety and stability checking, cooperating with a matched up and down power method, perfecting the high-voltage up and down power control strategy of the multi-motor and multi-engine electric vehicle, improving the stability of the up and down power timing, effectively avoiding vehicle diagnosis faults, and improving user experience.

Description

Technical Field

[0001] This invention relates to the field of range-extended electric vehicle control technology, specifically to the power-on / off control system and method for range-extended multi-motor electric vehicles, and the electric vehicle itself. Background Technology

[0002] With the continuous development of new energy vehicles, the requirements for vehicle systems are also increasing. The power-on and power-off processes of new energy vehicles involve numerous technological backgrounds. These technologies are mainly based on pure electric power systems, including core components such as batteries, motors, and electronic controls. Through the synergistic effect of these components, new energy vehicles can achieve efficient utilization and conversion of electrical energy.

[0003] Especially for range-extended multi-motor electric vehicles, the power-on and power-off processes are even more critical due to their larger battery packs and more complex energy management systems. During the power-on and power-off process of range-extended electric vehicles, the coordination and control of the engine and range extender need to be considered to ensure stable engine operation and efficient energy utilization. The electric vehicle's control system is the core of this invention, particularly for electric vehicles with multiple drive systems, where the start-up and control processes are relatively complex due to the integration of the motor, engine, and possibly the range extender in the powertrain.

[0004] To address the aforementioned complex issues and the shortcomings of existing technologies, the applicant provides a power-on / off control system and method for range-extended multi-motor electric vehicles. This system and method offer an efficient, safe, and stable starting and control method that improves the high-voltage power-on / off control strategy for multi-motor, multi-engine electric vehicles, enhances the stability of power-on / off timing, effectively avoids vehicle diagnostic faults, and improves the user experience. Summary of the Invention

[0005] The purpose of this invention is to provide a power-on / off control system and method for a range-extended multi-motor electric vehicle, in order to address the shortcomings of the prior art mentioned in the background section. This invention provides a high-voltage power-on / off control system for a range-extended multi-motor electric vehicle, which aims to improve the high-voltage power-on / off control strategy for multi-motor, multi-engine electric vehicles, enhance the stability of the power-on / off timing, effectively avoid vehicle diagnostic faults, and improve the user experience.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a power-on / off control system for a range-extended multi-motor electric vehicle, comprising: a VCU, a motor controller, a range extender controller, a DC-DC converter, a PDU, and multiple motors and engines. The VCU is installed in the driver's cab and is used to coordinate and control the operation of various subsystems, as well as to perform low-voltage self-tests and safety and stability checks, including checks on battery status, electrical connections of various components, and safety facilities. The motor controller, range extender controller, DC-DC converter, PDU, and multiple motors and engines are all mounted on the vehicle frame. The VCU is pre-loaded with a control algorithm that makes corresponding adjustments and control decisions based on the vehicle's real-time monitoring of the vehicle's status and the driver's operating intentions by the vehicle control system. The above adjustments and control decisions are executed through the motor controller, range extender controller, DC-DC converter, and PDU: When the driver switches the key to the ON position, the VCU immediately enters working mode and performs a series of safety and stability checks to ensure that the vehicle can be started in a safe state. After completing the initial safety check, the VCU will further perform a low-voltage self-check to confirm whether the vehicle's low-voltage system is working properly. When the key is switched from the ON position to the START position, the VCU will enter the battery status detection stage to ensure the safe use of the battery, and then perform the power-on operation. When the VCU detects that the vehicle has the highest level alarm, the battery is being charged externally, or the key is in the OFF position, it will enter the power-off process to ensure that the vehicle can be safely shut down in abnormal conditions or when maintenance is required.

[0007] As a preferred technical solution, it includes three drive motors: a first drive motor, a second drive motor, and a third drive motor, a drive engine, a range extender motor, and a range extender engine.

[0008] As a preferred technical solution, the four motors employ a sequential pre-charging method: the VCU controls the closure of the pre-charging relay of the first motor. After the pre-charging relay closes, the bus voltage of the first drive motor gradually increases. When the bus voltage reaches 95% of the battery bus voltage, the main positive relay closes, and the first drive motor is powered on. After the main positive relay of the first drive motor has been closed for a certain period of time, the second and third drive motors enter the power-on process, which is the same as that of the first drive motor, ensuring the safe power-on of all motors. After the second and third drive motors have been powered on, the range extender motor enters the power-on process.

[0009] A power-on / off control method for a range-extended multi-motor electric vehicle includes a power-on method and a power-off method. The power-on method includes the following steps:

[0010] Step S1: The driver turns the key from the OFF position to the ON position. The VCU enters the low-voltage detection, including the CAN communication alarm status of the motor controller, range extender controller, DC-DC controller, and PDU, as well as the hard-wired signal status of each low-voltage component. If there is a Level 1 fault, high voltage is prohibited.

[0011] Step S2: While the driver presses the brake, he turns the key from the ON position to the START position. The VCU determines whether the battery is being charged externally. If it is not being charged, it controls the DC-DC controller to power on.

[0012] Step S3: If the gear is in neutral (N), the door is closed and the seatbelt is fastened, send a battery power-on command to close the battery main negative relay and the DC-DC high voltage relay.

[0013] Step S4: Power on all the multiple motors;

[0014] Step S5: After the main positive relay of the first drive motor is closed for more than 0.5s, the power-on process of the second drive motor and the third drive motor is initiated. The power-on process of the second drive motor and the third drive motor is the same as that of the first drive motor. If the pre-charging of the second drive motor and the third drive motor fails, the vehicle enters the power-off process.

[0015] Step S6: After the main positive relays of the second drive motor and the third drive motor are closed for more than 0.5 seconds, the power-on process of the range extender motor is entered. The power-on process is the same as that of the first drive motor. If the pre-charging of the range extender motor fails, the range extender motor is powered off, and the whole vehicle continues the power-on process. The display screen will indicate that the pre-charging of the range extender motor has failed, but it will not affect driving.

[0016] Step S7: After the range extender motor is powered on or pre-charge timeout causes the range extender motor to power off, the VCU sends a water pump start command and sends control enable commands for the first drive motor, the second drive motor and the third drive motor to wake up the motor controller.

[0017] Step S8: The VCU sends the high-voltage status to the instrument, and the instrument displays "READY".

[0018] Step S9: After the vehicle is powered on, if the key is in the START position, the VCU sends a CAN message to the TCU to control the second drive motor to start the engine.

[0019] The power-off method includes the following steps:

[0020] Step T1: The VCU detects the highest level alarm in the vehicle, external battery charging, or key OFF position, and initiates the power-down process;

[0021] Step T2: Send stop commands to the drive motor, range extender motor, and engine respectively, and wait for the range extender motor speed to be less than 100 rpm before sending a stop command to the range extender engine.

[0022] Step T3: After the range extender motor torque is less than 10Nm, disconnect the main positive relay of the range extender motor;

[0023] Step T4: After the main positive relay of the range extender motor is disconnected, the torque of each of the three drive motors is judged. If the torque is less than 10 Nm and the speed is less than 50 rpm, the corresponding main positive relay is disconnected.

[0024] Step T5: After the main positive relays of the three drive motors are disconnected, a power-down command is sent to the DC-DC converter to disconnect the DC-DC high-voltage relay, control the battery to disconnect the main negative relay, and turn off the water pump enable.

[0025] Step T6: After the main and negative batteries are disconnected, send a fast discharge command to each of the three drive motors and the range extender motor;

[0026] Step T7: After the motor bus voltage is less than 30V, send a motor stop enable command, and the motor power-off is completed;

[0027] Step T8: Once all motors have been powered down, the power-down process is complete.

[0028] As a preferred technical solution, to avoid excessive circuit impact from simultaneous precharging of four motors, a sequential precharging and power-on method is adopted. The range extender motors are range extenders, ensuring that even if precharging fails, the first, second, and third drive motors can still drive the vehicle normally. After the battery main negative relay closes, the first drive motor precharging relay closes. When the bus voltage of the first drive motor reaches 95% of the battery bus voltage, the first drive motor main positive relay closes. The precharging relay opens after the main positive relay has been closed for more than 2 seconds. If the precharging relay remains closed for more than 2 seconds and the voltage still does not reach the set value, precharging is considered a failure, and the vehicle enters the power-off process. To power on, the driver needs to turn the key to the OFF position and wait for the vehicle to power off before repeating step 1.

[0029] As a preferred technical solution, when the key is not in the ON position, the VCU enters a delayed power-down state to ensure that all components have completely stopped working, avoiding thermal shock or mechanical stress to the electrical system. During the delayed power-down period, the VCU will continue to monitor the vehicle's status parameters and perform corresponding processing. After the delayed power-down ends, the VCU enters a sleep state.

[0030] As a preferred technical solution, when the key is turned to the OFF position, during the VCU power-down process to the delayed power-down stage, turning the key back to the ON position causes the VCU to exit the delayed power-down state and enter the low-voltage self-test mode. The 24V power supply for each controller is provided by the vehicle battery. The motor enable signal is controlled by the VCU via CAN message. The PDU controls the main positive relay, pre-charge relay, and DC-DC high-voltage relay of the four motors. The PDU receives control CAN messages and provides feedback on the status of each relay. The DC-DC converter converts the battery high voltage to low voltage to power the cooling fan.

[0031] As a preferred technical solution, Level 1 faults include brake pedal signal error, accelerator pedal signal error, first drive motor message reception timeout, second drive motor message reception timeout, third drive motor message reception timeout, engine message reception timeout, battery message reception timeout, PDU message reception timeout, highest level fault of the first drive motor, highest level fault of the second drive motor, highest level fault of the third drive motor, highest level fault of the engine, first drive motor drive timeout, second drive motor drive timeout, third drive motor drive timeout, and range extender motor drive timeout.

[0032] Compared with the prior art, the beneficial effects of the present invention are:

[0033] This invention provides a method for starting and controlling an electric vehicle, as well as a corresponding control system. This method achieves safe and stable power-on and operation of the multi-drive system through a series of safety and stability checks and control steps. This control method not only improves vehicle performance and stability but also enhances the user experience and safety. Attached Figure Description

[0034] Figure 1 This is a flowchart of the high-voltage power-on process for the entire vehicle according to the present invention;

[0035] Figure 2 This is a flowchart illustrating the high-voltage power-off process for the entire vehicle according to the present invention.

[0036] Figure 3 This is a structural diagram of the vehicle system of the present invention. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Please see Figure 3This invention provides a technical solution: a power-on / off control system for a range-extended multi-motor electric vehicle, comprising a Vehicle Control Unit (VCU), a motor controller, a range extender controller, a DC-DC converter, a Power Distribution Unit (PDU), and multiple motors and engines. The VCU is installed in the driver's cab and is used to coordinate and control the operation of various subsystems, as well as perform low-voltage self-tests and safety and stability checks, including checks on battery status, electrical connections of various components, and safety facilities. The motor controller, range extender controller, DC-DC converter, PDU, and multiple motors and engines are all mounted on the vehicle frame. The VCU has a pre-installed control algorithm that makes corresponding adjustments and control decisions based on the vehicle's real-time monitoring of the vehicle's status and the driver's operating intentions. These adjustments and control decisions are executed through the motor controller, range extender controller, DC-DC converter, and PDU. These components work together to achieve safe and stable power-on and operation of the multi-drive system. By employing advanced control algorithms and technologies, the control system can monitor the vehicle's status and the driver's operating intentions in real time and make corresponding adjustments and control decisions based on this information. For example, when the driver presses the accelerator pedal, the control system adjusts the output power of the electric motor and the working state of the engine according to the current battery status and driving needs to ensure smooth acceleration and optimal fuel economy.

[0039] When the driver turns the key to the ON position, the VCU immediately enters working mode and performs a series of safety and stability checks to ensure that the vehicle can be started in a safe state. After completing the initial safety check, the VCU will further perform a low-voltage self-check to confirm whether the vehicle's low-voltage system is working properly. When the key is turned from the ON position to the START position, the VCU will enter the battery status detection stage to ensure the safe use of the battery, and then perform the power-on operation. When the VCU detects that the vehicle has the highest level alarm, the battery is being charged externally, or the key is in the OFF position, it will enter the power-off procedure to ensure that the vehicle can be safely shut down in abnormal conditions or when maintenance is required.

[0040] The system includes three drive motors: a first drive motor, a second drive motor, and a third drive motor; one drive engine; one range extender motor; and one range extender engine. The four motors employ a sequential pre-charging method: the VCU controls the closure of the pre-charging relay for the first motor. Once the pre-charging relay is closed, the bus voltage of the first drive motor gradually increases. When the bus voltage reaches 95% of the battery bus voltage, the main positive relay closes, and the first drive motor is powered on. After the main positive relay of the first drive motor has been closed for a certain period, the second and third drive motors enter the power-on process, which is the same as that of the first drive motor, ensuring the safe power-on of all motors. After the second and third drive motors have been powered on, the range extender motor enters the power-on process.

[0041] When the Vehicle Controller Unit (VCU) detects the highest-level alarms in the vehicle (brake pedal signal error, accelerator pedal signal error, first drive motor message reception timeout, second drive motor message reception timeout, third drive motor message reception timeout, engine message reception timeout, battery message reception timeout, PDU message reception timeout, highest-level fault of first drive motor, highest-level fault of second drive motor, highest-level fault of third drive motor, highest-level fault of engine, first drive motor drive timeout, second drive motor drive timeout, third drive motor drive timeout, range extender motor drive timeout), external battery charging, or the key being in the OFF position, it will initiate a power-down procedure. This step is to ensure the vehicle can be safely shut down in abnormal conditions or when maintenance is required.

[0042] After initiating the power-down process, a shutdown command is first sent to the drive motor, range extender motor, and engine. This step is to immediately stop the operation of these components to avoid potential damage or safety issues. Upon receiving the shutdown command, the motor and engine will gradually decelerate and stop running.

[0043] To ensure the range extender motor completely stops operating, the control system continuously monitors its speed. Only when the range extender motor speed drops below 100 rpm will a shutdown command be sent to the engine. This step is to avoid shutting down the engine before it has completely stopped, preventing damage to the engine.

[0044] After the range extender motor stops, the control system will further check the torque of the range extender motor. When the torque of the range extender motor is less than 10 Nm, the control system will disconnect the main positive relay of the range extender motor. This step is to ensure that the range extender motor is completely disconnected from the high-voltage system to avoid potential risks of electric shock or circuit failure.

[0045] After the main positive relay of the range extender motor is disconnected, the control system will assess the torque of the three drive motors. The corresponding main positive relay will only be disconnected when the torque of each drive motor is less than 10 Nm and the speed is less than 50 rpm. This step ensures that the drive motors completely stop operating, avoiding shutdown operations while the motors are still rotating, which could damage the motors and the vehicle.

[0046] After all the main positive relays of the drive motors are disconnected, the control system sends a power-down command to the DC-DC converter. A DC-DC converter is a power supply that converts direct current (DC) energy into DC power to provide a stable DC voltage. By sending a power-down command to the DC-DC converter, the high-voltage relay of the DC-DC converter can be disconnected, thereby cutting off the power supply.

[0047] After the DC-DC high-voltage relay is disconnected, the control system will control the battery to disconnect the main negative relay. The main negative relay is a key component in the battery circuit, used to control the current flow in the battery. By controlling the main negative relay to disconnect, the battery can be safely disconnected from the high-voltage system.

[0048] In addition to disconnecting the main negative relay, the control system will also disable the water pump enable. The water pump is a crucial component in the electric vehicle's cooling system, used to circulate coolant. Disabling the water pump enable stops the cooling system from operating, reducing energy consumption and potential thermal damage.

[0049] In the final stage of the power-off process, the control system will rapidly discharge the battery. This rapid discharge command quickly releases any remaining energy in the battery, ensuring its safe shutdown. During this process, the control system continuously monitors parameters such as battery voltage and temperature to ensure the safe conduct of the discharge.

[0050] After the entire power-down process is completed, the Vehicle Controller Unit (VCU) will enter a delayed power-down state. This delayed power-down is to ensure that all components have completely ceased operation, avoiding thermal shock or mechanical stress to the electrical system. During the delayed power-down period, the VCU will continue to monitor the vehicle's status parameters and process them accordingly.

[0051] After the delayed power-down ends, the VCU will enter sleep mode. In sleep mode, most controllers and sensors will enter low-power mode to extend battery life and reduce energy consumption. By controlling the system's sleep mode, vehicle energy consumption and environmental impact can be further reduced.

[0052] Specifically, the power-on and power-off procedures are as follows:

[0053] Please see Figure 1 The power-on method includes the following steps:

[0054] Step S1: The driver turns the key from the OFF position to the ON position. The VCU enters the low-voltage detection, including the CAN communication alarm status of the motor controller, range extender controller, DC-DC controller, and PDU, as well as the hard-wired signal status of each low-voltage component. If there is a Level 1 fault, high voltage is prohibited.

[0055] Step S2: While the driver presses the brake, he turns the key from the ON position to the START position. The VCU determines whether the battery is being charged externally. If it is not being charged, it controls the DC-DC controller to power on.

[0056] Step S3: If the gear is in neutral (N), the door is closed and the seatbelt is fastened, send a battery power-on command to close the battery main negative relay and the DC-DC high voltage relay.

[0057] Step S4: Power on all the multiple motors;

[0058] Step S5: After the main positive relay of the first drive motor is closed for more than 0.5s, the power-on process of the second drive motor and the third drive motor is initiated. The power-on process of the second drive motor and the third drive motor is the same as that of the first drive motor. If the pre-charging of the second drive motor and the third drive motor fails, the vehicle enters the power-off process.

[0059] Step S6: After the main positive relays of the second drive motor and the third drive motor are closed for more than 0.5 seconds, the power-on process of the range extender motor is entered. The power-on process is the same as that of the first drive motor. If the pre-charging of the range extender motor fails, the range extender motor is powered off, and the whole vehicle continues the power-on process. The display screen will indicate that the pre-charging of the range extender motor has failed, but it will not affect driving.

[0060] Step S7: After the range extender motor is powered on or pre-charge timeout causes the range extender motor to power off, the VCU sends a water pump start command and sends control enable commands for the first drive motor, the second drive motor and the third drive motor to wake up the motor controller.

[0061] Step S8: The VCU sends the high-voltage status to the instrument, and the instrument displays "READY".

[0062] Step S9: After the vehicle is powered on, if the key is in the START position, the VCU sends a CAN message to the TCU to control the second drive motor to start the engine.

[0063] Please see Figure 2 The power-off method includes the following steps:

[0064] Step T1: The VCU detects the highest level alarm in the vehicle, external battery charging, or key OFF position, and initiates the power-down process;

[0065] Step T2: Send stop commands to the drive motor, range extender motor, and engine respectively, and wait for the range extender motor speed to be less than 100 rpm before sending a stop command to the range extender engine.

[0066] Step T3: After the range extender motor torque is less than 10Nm, disconnect the main positive relay of the range extender motor;

[0067] Step T4: After the main positive relay of the range extender motor is disconnected, the torque of each of the three drive motors is judged. If the torque is less than 10 Nm and the speed is less than 50 rpm, the corresponding main positive relay is disconnected.

[0068] Step T5: After the main positive relays of the three drive motors are disconnected, a power-down command is sent to the DC-DC converter to disconnect the DC-DC high-voltage relay, control the battery to disconnect the main negative relay, and turn off the water pump enable.

[0069] Step T6: After the main and negative batteries are disconnected, send a fast discharge command to each of the three drive motors and the range extender motor;

[0070] Step T7: After the motor bus voltage is less than 30V, send a motor stop enable command, and the motor power-off is completed;

[0071] Step T8: Once all motors have been powered down, the power-down process is complete;

[0072] When the key is turned to the OFF position, the VCU power-down process reaches the delayed power-down stage. At this point, turning the key back to the ON position will cause the VCU to exit the delayed power-down state and enter the low-voltage self-test mode.

[0073] Each controller is powered by the vehicle's onboard battery. The motor enable signal is controlled by the VCU via CAN messages.

[0074] The PDU controls the main positive relay, precharge relay, and DC-DC high voltage relay of four motors. The PDU receives control CAN messages and provides feedback on the status of each relay.

[0075] DC-DC converters convert the high voltage of the battery to a low voltage to power the cooling fan.

[0076] In summary, this invention provides a method for starting and controlling an electric vehicle, as well as a corresponding control system. This method achieves safe and stable power-on and operation of the multi-drive system through a series of safety and stability checks and control steps. This control method not only improves vehicle performance and stability but also enhances the user experience and safety.

[0077] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A power-on / off control method for a range-extended multi-motor electric vehicle, applied to the power-on / off control system of a range-extended multi-motor electric vehicle, the system comprising: The system comprises a VCU, a motor controller, a range extender controller, a DC-DC converter, a PDU, and three drive motors: a first drive motor, a second drive motor, and a third drive motor; one drive engine; one range extender motor; and one range extender engine; characterized in that it includes a power-on method and a power-off method, wherein the power-on method includes the following steps: Step S1: The driver turns the key from the OFF position to the ON position. The VCU enters the low-voltage detection, including the CAN communication alarm status of the motor controller, range extender controller, DC-DC controller, and PDU, as well as the hard-wired signal status of each low-voltage component. If there is a Level 1 fault, high voltage is prohibited. Step S2: While the driver presses the brake, he turns the key from the ON position to the START position. The VCU determines whether the battery is being charged externally. If it is not being charged, it controls the DC-DC controller to power on. Step S3: If the gear is in neutral (N), the door is closed and the seatbelt is fastened, send a battery power-on command to close the battery main negative relay and the DC-DC high voltage relay. Step S4: Power on all the multiple motors; Step S5: After the main positive relay of the first drive motor is closed for more than 0.5s, the power-on process of the second drive motor and the third drive motor is initiated. The power-on process of the second drive motor and the third drive motor is the same as that of the first drive motor. If the pre-charging of the second drive motor and the third drive motor fails, the vehicle enters the power-off process. Step S6: After the main positive relays of the second drive motor and the third drive motor are closed for more than 0.5 seconds, the power-on process of the range extender motor is entered. The power-on process is the same as that of the first drive motor. If the pre-charging of the range extender motor fails, the range extender motor is powered off, and the whole vehicle continues the power-on process. The display screen will indicate that the pre-charging of the range extender motor has failed, but it will not affect driving. Step S7: After the range extender motor is powered on or pre-charge timeout causes the range extender motor to power off, the VCU sends a water pump start command and sends control enable commands for the first drive motor, the second drive motor and the third drive motor to wake up the motor controller. Step S8: The VCU sends the high-voltage status to the instrument, and the instrument displays "READY"; Step S9: After the vehicle is powered on, if the key is in the START position, the VCU sends a CAN message to the TCU to control the second drive motor to start the engine. The power-off method includes the following steps: Step T1: The VCU detects the highest level alarm in the vehicle, external battery charging, or key OFF position, and initiates the power-down process; Step T2: Send stop commands to the drive motor, range extender motor, and engine respectively, and wait for the range extender motor speed to be less than 100 rpm before sending a stop command to the range extender engine. Step T3: After the range extender motor torque is less than 10Nm, disconnect the main positive relay of the range extender motor; Step T4: After the main positive relay of the range extender motor is disconnected, the torque of each of the three drive motors is judged. If the torque is less than 10 Nm and the speed is less than 50 rpm, the corresponding main positive relay is disconnected. Step T5: After the main positive relays of the three drive motors are disconnected, a power-down command is sent to the DC-DC converter to disconnect the DC-DC high-voltage relay, control the battery to disconnect the main negative relay, and turn off the water pump enable. Step T6: After the main and negative batteries are disconnected, send a fast discharge command to each of the three drive motors and the range extender motor; Step T7: After the motor bus voltage is less than 30V, send a motor stop enable command, and the motor power-off is completed; Step T8: Once all motors have been powered down, the power-down process is complete.

2. The power-on / off control method for a range-extended multi-motor electric vehicle according to claim 1, characterized in that, To avoid excessive circuit impact from simultaneous precharging of the first drive motor, second drive motor, third drive motor, and range extender motor, a sequential precharging and power-on method is adopted. The range extender motor is a range extender motor, so even if precharging fails, the first drive motor, second drive motor, and third drive motor can still drive the vehicle normally. After the main negative relay of the battery is closed, the pre-charge relay of the first drive motor is closed. When the bus voltage of the first drive motor is 95% of the bus voltage of the battery, the main positive relay of the first drive motor is closed. After the main positive relay is closed for more than s, the pre-charge relay is opened. If the pre-charge relay is closed for more than 2s and the voltage is still not lower than the set value, the pre-charge is judged to have failed and the vehicle enters the power-off process. If power-on is required, the driver needs to turn the key to the OFF position. After the vehicle is powered off, the power-on process of step S1 is repeated.

3. The power-on / off control method for a range-extended multi-motor electric vehicle according to claim 1, characterized in that, If the vehicle battery has a high charge and does not require charging, the range extender engine will not start. If charging is required, after the high voltage is applied to the vehicle, a start control command for the range extender engine is sent to the range extender motor to start the range extender engine.

4. The power-on / off control method for a range-extended multi-motor electric vehicle according to claim 1, characterized in that, When the key is not in the ON position, the VCU enters a delayed power-down state to ensure that all components have completely stopped working, avoiding thermal shock or mechanical stress to the electrical system. During the delayed power-down period, the VCU will continue to monitor the vehicle's status parameters and perform corresponding processing. After the delayed power-down ends, the VCU enters a sleep state.

5. The power-on / off control method for a range-extended multi-motor electric vehicle according to claim 1, characterized in that, When the key is turned to the OFF position, the VCU power-down process reaches the delayed power-down stage. At this point, turning the key back to the ON position will cause the VCU to exit the delayed power-down state and enter the low-voltage self-test mode. The 24V power supply for each controller is provided by the vehicle battery. The motor enable signal is controlled by the VCU via CAN message. The PDU controls the main positive relay, precharge relay, and DC-DC high-voltage relay of the four motors. The PDU receives control CAN messages and provides feedback on the status of each relay. DC-DC converters convert the high voltage of the battery to a low voltage to power the cooling fan.

6. The power-on / off control method for a range-extended multi-motor electric vehicle according to claim 1, characterized in that, The Level 1 faults include brake pedal signal error, accelerator pedal signal error, first drive motor message reception timeout, second drive motor message reception timeout, third drive motor message reception timeout, engine message reception timeout, battery message reception timeout, PDU message reception timeout, highest level fault of the first drive motor, highest level fault of the second drive motor, highest level fault of the third drive motor, highest level fault of the engine, first drive motor drive timeout, second drive motor drive timeout, third drive motor drive timeout, and range extender motor drive timeout.

7. An electric vehicle with a multi-drive system, characterized in that, The invention includes a power-on / off control system for a range-extended multi-motor electric vehicle, and uses a power-on / off control method for a range-extended multi-motor electric vehicle as described in any one of claims 1 to 6 to perform power-on / off operations.

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