Range-extending type electric vehicle control strategy

Abstract

The invention relates to the technical field of electric vehicles, in particular to an extended-range electric vehicle control strategy, the whole vehicle is provided with three driving modes, namely a pure electric driving EV mode, a forced engine starting REV mode and an intelligent mode AUTO, in the EV mode, only a battery discharges to supply power to electric driving and other high-voltage accessories, and in the AUTO mode, only a battery discharges to supply power to other high-voltage accessories; in the REV mode, the engine is controlled to be in a running state all the time, power can be supplied to an electric drive, a battery can be supplemented, power can also be supplied to high-voltage accessories, and meanwhile the requirement for forcibly starting the engine for brand tail gas detection on a new vehicle can be met; and in the Auto mode, when the engine is started can be intelligently decided according to the electric quantity of the whole vehicle and the requirement of a driver. According to the invention, the problems that the fuel consumption is too high and the battery discharge depth is not enough to influence the economical efficiency of the vehicle use of the user due to the premature intervention of the APU are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicles, and in particular to a control strategy for extended-range electric vehicles. Background Art

[0002] For extended-range electric commercial vehicles, power, economy and NVH have always been the three vehicle performances that users are most concerned about. When the pure electric range is not much left, the vehicle control unit VCU will control the start of the engine, so that the range extender APU can run to power the drive and replenish the battery at the same time. At this stage, due to the configuration characteristics of extended-range electric vehicles, the power of the vehicle is the strongest when the range extender and the battery are discharged together. When the battery is low, the power of the APU's independent discharge is generally not enough to fully meet the drive system to achieve constant power operation. When the vehicle is fully loaded, especially in climbing conditions, the power of the vehicle may be insufficient. If the APU intervenes too early, it may lead to excessive fuel consumption and insufficient battery discharge depth, which will affect the economy of the user's use of the vehicle. Summary of the invention

[0003] The present invention provides a control strategy for an extended-range electric vehicle, which scientifically allocates the energy of the entire vehicle, reasonably allocates the oil and electricity usage ratio, prioritizes power, and provides a better NVH experience when users care about NVH performance, thereby solving the problem that premature intervention of the APU may lead to excessive fuel consumption and insufficient battery discharge depth, thereby affecting the economy of the user's use of the vehicle.

[0004] In order to achieve the above-mentioned purpose, the technical solution adopted by the present invention is: a control strategy for extended-range electric vehicles, in which three driving modes are set for the whole vehicle, namely, pure electric drive EV mode, forced engine start REV mode and intelligent mode AUTO. In EV mode, only the battery discharges to power the electric drive and other high-voltage accessories. In REV mode, the engine is always in operation, which can power the electric drive, replenish the battery, and power high-voltage accessories. At the same time, it can also meet the forced engine start requirements of exhaust gas detection for new car registration. In Auto mode, according to the whole vehicle power and driver's needs, intelligent decisions are made as to when to start the engine and how much power the APU needs to run. The VCU receives and transmits the driving mode signal to the mode management module. The mode management module decides whether to allow entry into the driver's target driving mode according to the whole vehicle status. The VCU transmits the driving mode after the decision to the APU control module for further APU control.

[0005] It is further specified that the purchased vehicle model is equipped with a central control large screen, and a soft switch is set on the central control large screen. After the target driving mode is selected on the central control large screen, the central control large screen will forward the target driving mode to the VCU through the central gateway TBOX. After receiving the signal, the VCU will transmit the driving mode signal to the mode management module. The mode management module will decide whether to allow the driver to enter the target driving mode according to the status of the whole vehicle.

[0006] It is further specified that the purchased model is equipped with a large central control screen, and the user can select the driving mode through the hardware switch. Each time the hardware switch is pressed, the target mode calculated inside the VCU jumps once, and then the target driving mode last operated by the user is passed to the mode management module. The mode management module decides whether to allow entry into the driver's target driving mode based on the status of the entire vehicle.

[0007] It is further defined that when the user selects the vehicle driving mode as EV mode, the allowable discharge coefficient of the battery in EV mode is set, and the discharge coefficient is obtained based on the battery SOC table. When the battery SOC is high, the battery discharge system is 1. When the SOC drops to a first threshold, the VCU will begin to limit the discharge power of the battery. When the SOC continues to decrease, the VCU will linearly reduce the battery discharge coefficient according to the SOC. When the SOC is lower than the second threshold, the VCU will reduce the allowable discharge coefficient of the battery to 0. At this time, the VCU does not allow any discharge of the battery. The VCU achieves battery discharge and SOC protection by controlling the available electrical power of other high-voltage components.

[0008] It is further defined that when the user selects the vehicle driving mode as REV mode, the VCU will control the engine to start. The control method for starting the engine is that the VCU will send a target speed requirement to the generator control unit GCU, and the GCU enters the speed control mode. The VCU will send a start command to the EMS. In order to ensure that the engine start process is smooth without speed overshoot and oscillation, when the GCU controls the generator speed to reach the first speed threshold, the VCU will send a fuel injection command to the engine control unit EMS, and the engine will start to inject fuel and ignite. When the GCU controls the generator speed to reach the second speed threshold, the VCU will send a fuel injection command based on the EMS feedback. The VCU uses the engine operating status to determine whether to continue to let the GCU produce positive torque to drag the engine. If the EMS feedback shows that the engine is in the start-up completion state, the VCU will immediately send a new speed command to the GCU. The speed command comes from the calculation of the required power. At this time, the engine runs autonomously and drags the generator. When the vehicle is running on the road, in order to ensure the economy and NVH of the whole vehicle, three power generation control strategies are set to maximize the user's car experience and make the economy and NVH satisfy the user. The three power generation strategies are fixed-point power generation control strategy, power following control strategy and user-selected APU power generation power strategy.

[0009] It is further specified that when the user selects the AUTO mode for the vehicle's driving mode, the VCU will dynamically choose whether to start the engine to generate electricity to adjust the oil-electricity ratio based on the vehicle's working conditions, the vehicle's three-electric system and the APU status. When the user needs to drive medium and long distances and the time requirements are relatively strict, the Auto mode will start to gradually increase the APU's operating ratio after the battery power decreases according to the driver's driving needs.

[0010] It is further defined that the fixed-point power generation control strategy calculates the required APU power generation according to the continuous charging capacity and SOC of the battery. After activation, the VCU controls the engine to start. The VCU will look up the table to obtain the required APU power generation according to the current continuous charging capacity and SOC of the battery, and further control the APU power generation according to the required power generation and the preset power decoupling map, obtain the target torque value of the engine torque control, and the target speed value of the generator speed control, and immediately send the engine target torque and the generator target speed to the EMS and GCU. The EMS and GCU control the engine and generator to operate and generate electricity according to the target torque and target speed sent by the VCU.

[0011] It is further defined that the power following control strategy will be activated when the battery power is low and below a threshold, or the discharge capacity is lower than a threshold or the driver has an urgent acceleration demand. The VCU will calculate the required APU power generation according to the driver's driving power demand, and control the APU power generation to meet the driving demand of the entire vehicle.

[0012] It is further defined that the user's independent selection of APU power generation strategy is to completely hand over the APU power generation control of the entire vehicle to the user. After the entire vehicle enters the REV mode, the VCU will execute the default power generation, and the user can independently select the appropriate APU power generation according to the operating requirements.

[0013] Further limitations include economic driving mode ECO and standard driving mode Normal. Different optional APU power generation upper limits are set for different modes. For the economic mode ECO, the APU power generation upper limit is set to 40kW (Cal). For the standard driving mode Normal, the APU power generation upper limit is set to 50kW. In order to take into account the user's need to start the engine idling for heating in winter, the minimum APU power generation power is set to 2kW.

[0014] The beneficial effects of adopting the above technical solution are:

[0015] 1. The three driving modes and three power generation control strategies fully utilize the configuration characteristics of extended-range electric vehicles, providing core control support for users of extended-range electric commercial vehicles to create products with excellent power, economy and NVH.

[0016] 2. The present invention sets three driving modes and three APU power generation control strategies, allowing users to freely choose the driving mode according to their own needs. Based on different driving modes, the oil-electricity usage ratio and APU power generation strategy are scientifically allocated, giving users more freedom to operate the vehicle, better meeting the user's economy, power and NVH needs, and avoiding problems such as insufficient power during long-distance driving with a full load, excessive APU noise affecting NVH performance, or high fuel consumption leading to unsatisfactory economy performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a control architecture diagram of the present invention;

[0018] Figure 2 is a flow chart of the overall control strategy of the present invention; DETAILED DESCRIPTION

[0019] The specific implementation methods of the present invention are further explained in detail below by describing the embodiments with reference to the accompanying drawings, with the aim of helping those skilled in the art to have a more complete, accurate and in-depth understanding of the concept and technical solution of the present invention and facilitating its implementation.

[0020] The present invention is a control strategy for extended-range electric vehicles, which scientifically allocates the energy of the entire vehicle, reasonably allocates the oil and electricity usage ratio, prioritizes power, and provides a better NVH experience when users care about NVH performance. It solves the problem that premature intervention of the APU may lead to excessive fuel consumption and insufficient battery discharge depth, thereby affecting the economy of the user's use of the vehicle.

[0021] Specifically, Figure 1-Figure 2 As shown in the figure, a control strategy for extended-range electric vehicles is set. The whole vehicle has three driving modes, namely pure electric drive EV mode, forced engine start REV mode and intelligent mode AUTO. In EV mode, only the battery discharges to power the electric drive and other high-voltage accessories. In REV mode, the engine is always in operation, which can power the electric drive, replenish the battery, and power high-voltage accessories. It can also meet the forced engine start requirement of exhaust gas detection for new car registration. In Auto mode, the engine will be started intelligently according to the vehicle power and driver needs, and the APU needs to run at a certain power generation power.

[0022] Some of the purchased models are equipped with a central control large screen, while others are not. In order to meet the different car purchasing needs of users, the drive mode selection can be selected by soft switch on the large screen equipped with a central control large screen, or by hardware switch on a non-central control large screen. For models that match the central control large screen, after selecting the target drive mode on the central control large screen, the central control large screen will forward the target drive mode to the VCU through the central gateway TBOX. After receiving the signal, the VCU will transmit the drive mode signal to the mode management module. The mode management module will decide whether to allow the driver to enter the target drive mode based on the status of the vehicle. For models that do not match the central control large screen, users can The driving mode is selected through the hardware switch. Each time the hardware switch is pressed, the target mode calculated inside the VCU jumps once, and then the target driving mode last operated by the user is passed to the mode management module. The mode management module decides whether to allow entry into the driver's target driving mode based on the vehicle status. The VCU passes the driving mode after the decision to the APU control module for further APU control, including enabling the APU, starting the engine command, and calculating the required APU power generation. The VCU will also send the actual driving mode after the decision to the instrument for driving mode display, so that the user can check the driving mode and understand the driving status of the vehicle.

[0023] If the extended-range electric commercial vehicle is equipped with a large-capacity battery pack that can achieve a longer pure electric range, the entire vehicle will mainly operate on pure electricity, the vehicle operating cost will be lower, and the discharge capacity of the power battery is sufficient to cover the discharge requirements of the drive motor. Therefore, the lower discharge limit of the vehicle battery is set to be further lowered, which can achieve lower vehicle operating costs and improve the economic performance of the vehicle. When the battery SOC is lower than the threshold, the VCU control will control the engine to start, replenish the battery, and supply power to the electric drive and high-voltage accessories. In order to ensure the battery life and ensure that the battery SOC is not lower than the protection limit, there will be no over-discharge when the battery is low. When the vehicle driving mode is EV, the allowable discharge coefficient of the battery in EV mode is set. The discharge coefficient is obtained based on the battery SOC table. When the battery SOC is high, the battery discharge system is 1. When the SOC drops to the first threshold, the VCU will start to limit the battery discharge power. When the SOC continues to drop, the VCU will linearly reduce the battery discharge coefficient according to the SOC. When the SOC is lower than the second threshold, the VCU will reduce the allowable discharge coefficient of the battery to 0. At this time, the VCU does not allow any discharge of the battery. The VCU realizes the discharge of the battery and SOC protection by controlling the available power of other high-voltage components.

[0024] When the vehicle driving mode is REV mode, VCU will control the engine to start. The control method for starting the engine is that VCU will send a target speed demand to the generator control unit GCU, GCU enters the speed control mode, and VCU will send a start command to EMS. In order to ensure that the engine start process is smooth without speed overshoot and oscillation, when GCU controls the generator speed to reach the first speed threshold, VCU will send a fuel injection command to the engine control unit EMS, and the engine starts to inject fuel and ignite. When GCU controls the generator speed to reach the second speed threshold, VCU determines whether to continue to let GCU output positive torque to drag the engine based on the engine running status feedback from EMS. If EMS feedback that the engine is in the start-up completion state, VCU will immediately send a new speed command to GCU. The speed command comes from the calculation of the required power. At this time, the engine runs autonomously and drags the generator. If EMS does not feedback the start completion within the preset time threshold, VCU will report a start failure fault and send a target speed of 0 to GCU. After a short wait, it continues to send a new speed command to GCU. U sends a speed control command to try to start the engine. If the cumulative start failure occurs 3 times, the VCU believes that there is a serious fault that causes the engine to fail to start. The VCU stops sending start commands to the EMS, saves the serious fault of the engine start failure, and sends a signal to the instrument that the power generation system has a serious fault and cannot start. After receiving and parsing, the instrument displays a text prompting the user "APU system failure". The REV mode can meet the user's need for constant engine rotation for exhaust gas detection when purchasing a car and registering a license plate. When the vehicle is running on the road, in order to ensure the economy and NVH of the whole vehicle, three power generation control strategies are set to maximize the user's car experience and make the economy and NVH satisfy the user. The three power generation strategies are fixed-point power generation control strategy, power following control strategy and user-selected APU power generation power strategy.

[0025] The fixed-point power generation control strategy calculates the required APU power generation according to the battery's continuous charging capacity and SOC. When the battery power is higher than the threshold, and the vehicle is not in the parking power generation state and is not in the remote locking control, the fixed-point power generation control strategy is activated. When the battery power is high, the battery discharge capacity is strong, allowing the battery to play the leading role in the dynamic discharge of the vehicle, and the APU is used as a "driving power bank" running at a constant speed, allowing the engine to run at a constant speed as much as possible. The main source of APU noise is the howling caused by the engine speed increase in dynamic conditions and the high engine speed at high power generation. Therefore, the APU is operated at a constant and continuous relatively low power generation, and the NVH performance is better. At the same time, the engine runs in the high-efficiency range of constant speed, and the APU's oil and electricity The conversion ratio and efficiency are higher. If the whole vehicle is in parking power generation control, the user needs to quickly park and generate power to replenish the battery. The user will select the parking power generation speed of the whole vehicle according to the parking power generation speed selection switch set for the whole vehicle. At this time, the VCU is in the parking power generation control function. If the fixed-point power generation strategy is enabled, the APU power generation power will be calculated based on the predefined continuous charging capacity and SOC of the battery, which violates the driver's operating intention. If the whole vehicle is in remote locking control, it means that the user purchased the car for a financial policy and the user has defaulted on the loan. In order to protect the interests of the OEM, it will be prohibited to enter the fixed-point power generation mode with excellent economy and comfort at this time, reducing the user's car experience, forcing the user to repay in time, and protecting the economic interests of the OEM.

[0026] When the fixed-point power generation control strategy is activated and the VCU controls the engine to start successfully, the VCU will look up the table to obtain the required APU power generation according to the current continuous charging capacity of the battery and the SOC, and further control the APU power generation according to the required power generation and the preset power decoupling map, and obtain the target torque value of the engine torque control and the target speed value of the generator speed control, and immediately send the engine target torque and generator target speed to the EMS and GCU. The EMS and GCU control the engine and generator to generate electricity according to the target torque and target speed sent by the VCU.

[0027] The power following control strategy will be activated when the battery power is low and below the threshold, or the discharge capacity is below the threshold or the driver has an urgent acceleration demand. At this time, in order to prioritize the power of the entire vehicle, ensure the power and driving safety of the vehicle under full load and climbing conditions, the VCU will calculate the required APU power generation according to the driver's driving power demand, and control the APU power generation to meet the driving needs of the entire vehicle. Compared with the fixed-point power generation strategy, power following can better guarantee the driver's driving needs. At the same time, for low-temperature cold car operation in winter, it can also better protect the battery from recharging overcurrent and thus protect the battery life.

[0028] The user's independent selection of APU power generation strategy is to completely hand over the APU power generation control of the entire vehicle to the user. After the vehicle enters REV mode, the VCU will execute the default power generation, and the user can independently select the appropriate APU power generation according to the operating requirements. For models that match the central control large screen, users can freely select the APU power generation on the central control large screen. The central control large screen will send the selected APU power generation to the VCU through the central gateway, and the VCU will perform limit processing to control the APU. For models that do not match the central control large screen, users can select the APU power generation through the hardware switch.

[0029] It also includes economic driving mode, ECO and standard driving mode Normal. In order to take into account both power and economy, different optional APU power generation upper limits are set for different modes. For the economic mode ECO, the APU power generation upper limit is set to 40kW (Cal), and for the standard driving mode Normal, the APU power generation upper limit is set to 50kW (Cal). In order to take into account the user's heating needs in winter and need to start the engine idling, the minimum APU power generation power is set to 2kW (Cal, to ensure that the engine is in a power generation state). The reason for setting different APU power generation upper limits is that the greater the APU power generation power, the stronger its power and the higher the actual fuel consumption. Therefore, the APU power generation upper limit set for the ECO mode is lower than that of the Normal mode, giving priority to economy, while the Normal mode has stronger power and secondarily economy, so as to meet the different driving needs of users. The aforementioned consideration of the user's heating needs in winter requires setting the minimum APU power generation to 2kW when the engine is idling to ensure that the engine is in a power generation state. In order to ensure the power generation efficiency of the APU, the conventional control strategy will try to make the APU run at a larger power generation when the APU is running to take into account the high efficiency range of the engine and thus generate electricity efficiently. However, for large-capacity extended-range electric commercial vehicles, the entire vehicle is mainly pure electric. If the user starts the engine for heating, the user may be waiting for charging or simply letting the APU serve as a heating heat source. The entire vehicle is mainly electric, that is, electricity is used whenever possible to optimize economic benefits. Therefore, a relatively larger power generation means relatively more fuel consumption, which will reduce the economic performance of the entire vehicle. If the user subjectively intends to let the APU generate electricity at a higher power generation, then the user can freely choose a higher power generation. This is the significance of this power generation control strategy giving users maximum freedom to manipulate the APU power generation.

[0030] If the user selects the Auto mode, the VCU will dynamically choose whether to start the engine to generate electricity to adjust the oil-electricity ratio according to the working conditions of the vehicle, the vehicle's three-electric system and the APU status. When the user needs to drive medium and long distances, such as long-distance delivery, the pure electric range cannot meet the operating needs, and the time requirements are relatively strict. At this time, if the load mass is high, then the Auto mode can ensure the power sustainability of the entire vehicle. The Auto mode will gradually increase the APU operating ratio according to the driver's driving needs after the battery power decreases. Compared with the EV mode, the APU is forced to start at low power, allowing the APU to intervene earlier to generate electricity, thereby "diluting" the battery discharge and slowing down the battery consumption. In this way, when running medium and long distances, in the second half of the running journey, since the battery still has a certain amount of power, the power sustainability of the entire vehicle is better, which can better meet the driver's power needs and running time requirements, and ensure the user's vehicle benefits and experience. When the Auto mode decides that the APU needs to run to start the engine, the power generation control strategy is mainly based on fixed-point power generation and power following. Unlike the REV mode, in the Auto mode, the VCU will dynamically decide to start and stop the engine based on the vehicle speed, SOC, driving power and other conditions, so as to take into account economy and power, economy and NVH.

[0031] The three driving modes and three power generation control strategies fully utilize the configuration characteristics of extended-range electric vehicles, and provide core control support for users of extended-range electric commercial vehicles to create products with excellent power, economy and NVH. The three driving modes and three APU power generation control strategies allow users to freely choose the driving mode according to their own needs. Based on different driving modes, the oil-electric usage ratio and APU power generation strategy are scientifically allocated, giving users more freedom to operate the vehicle, better meeting their economic, power and NVH needs, and avoiding problems such as insufficient power during long-distance driving with a full load, excessive APU noise affecting NVH performance, or excessive fuel consumption leading to unsatisfactory economic performance.

[0032] The present invention is described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention; or the above-mentioned concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A control strategy for an extended-range electric vehicle, characterized in that: The whole vehicle is equipped with three driving modes, namely pure electric drive EV mode, forced engine start REV mode and intelligent mode AUTO. In EV mode, only the battery discharges to power the electric drive and other high-voltage accessories. In REV mode, the engine is always in operation, which can power the electric drive, replenish the battery, and power high-voltage accessories. It can also meet the forced engine start requirements of exhaust gas detection for new car registration. In Auto mode, according to the vehicle's power and driver's needs, it will intelligently decide when to start the engine and how much power the APU needs to run. The VCU receives and transmits the driving mode signal to the mode management module. The mode management module decides whether to allow entry into the driver's target driving mode based on the vehicle's status. The VCU transmits the driving mode after the decision to the APU control module for further APU control.

2. The control strategy of an extended-range electric vehicle according to claim 1, characterized in that: The purchased model is equipped with a central control screen, on which a soft switch is provided. After the target drive mode is selected on the central control screen, the central control screen will forward the target drive mode to the VCU through the central gateway TBOX. After receiving the signal, the VCU will transmit the drive mode signal to the mode management module. The mode management module will decide whether to allow the driver to enter the target drive mode according to the status of the entire vehicle.

3. The control strategy of an extended-range electric vehicle according to claim 1, characterized in that: The purchased model is equipped with a large central control screen. Users can select the driving mode through the hardware switch. Each time the hardware switch is pressed, the target mode calculated inside the VCU jumps once, and then the target driving mode last operated by the user is passed to the mode management module. The mode management module decides whether to allow entry into the driver's target driving mode based on the status of the entire vehicle.

4. The control strategy of an extended-range electric vehicle according to claim 1, characterized in that: When the user selects the vehicle driving mode as EV mode, the allowable discharge coefficient of the battery in EV mode is set. The discharge coefficient is obtained based on the battery SOC table. When the battery SOC is high, the battery discharge system is 1. When the SOC drops to the first threshold, the VCU will begin to limit the discharge power of the battery. When the SOC continues to decrease, the VCU will linearly reduce the battery discharge coefficient according to the SOC. When the SOC is lower than the second threshold, the VCU will reduce the allowable discharge coefficient of the battery to 0. At this time, the VCU does not allow any discharge of the battery. The VCU achieves battery discharge and SOC protection by controlling the available electrical power of other high-voltage components.

5. The control strategy of an extended-range electric vehicle according to claim 1, characterized in that: When the user selects the vehicle drive mode as REV mode, VCU will control the engine to start. The control method of starting the engine is that VCU will send a target speed demand to the generator control unit GCU, GCU enters the speed control mode, and VCU will send a start command to EMS. In order to ensure that the engine start process is smooth without speed overshoot oscillation, when the GCU controls the generator speed to reach the first speed threshold, VCU will send a fuel injection command to the engine control unit EMS, and the engine starts to inject fuel and ignite. When the GCU controls the generator speed to reach the second speed threshold, VCU determines whether to continue to let GCU output positive torque to drag the engine based on the engine running status feedback from EMS. If EMS feedback that the engine is in the start-up completion state, VCU will immediately send a new speed command to GCU. The speed command comes from the calculation of the required power. At this time, the engine runs autonomously and drags the generator to run. When the vehicle is running on the road, in order to ensure the economy and NVH of the whole vehicle, three power generation control strategies are set to maximize the user's car experience and make the economy and NVH satisfy the user. The three power generation strategies are fixed-point power generation control strategy, power following control strategy and user-selected APU power generation power strategy.

6. The control strategy of an extended-range electric vehicle according to claim 1, characterized in that: When the user selects the AUTO mode for the vehicle's driving mode, the VCU will dynamically choose whether to start the engine to generate electricity to adjust the oil-electricity ratio based on the vehicle's operating conditions, the vehicle's three-electric system and the APU status. When the user needs to drive medium or long distances and the time requirements are relatively strict, the Auto mode will start to gradually increase the APU's operating ratio based on the driver's driving needs after the battery power decreases.

7. The control strategy of an extended-range electric vehicle according to claim 5, characterized in that: The fixed-point power generation control strategy calculates the required APU power generation according to the battery's continuous charging capacity and SOC. After activation, the VCU controls the engine to start. The VCU will look up the table to obtain the required APU power generation according to the battery's current continuous charging capacity and SOC, and further control the APU power generation according to the required power generation and the preset power decoupling map, obtain the target torque value of the engine torque control, and the target speed value of the generator speed control, and immediately send the engine target torque and generator target speed to the EMS and GCU. The EMS and GCU control the engine and generator to operate and generate electricity according to the target torque and target speed sent by the VCU.

8. The control strategy of an extended-range electric vehicle according to claim 5, characterized in that: The power following control strategy described above will be activated when the battery power is low and below a threshold, or when the discharge capacity is below a threshold or when the driver has an urgent acceleration demand. The VCU will calculate the required APU power generation according to the driver's driving power demand and control the APU power generation to meet the driving demand of the entire vehicle.

9. The control strategy of an extended-range electric vehicle according to claim 5, characterized in that: The user's independent selection of APU power generation strategy is to completely hand over the APU power generation control of the entire vehicle to the user. After the vehicle enters the REV mode, the VCU will execute the default power generation, and the user can independently select the appropriate APU power generation according to the operating requirements.

10. The control strategy of an extended-range electric vehicle according to claim 1, characterized in that: It also includes economic driving mode, ECO and standard driving mode Normal. Different optional APU power generation limits are set for different modes. For the economic mode ECO, the APU power generation limit is set to 40kW (Cal). For the standard driving mode Normal, the APU power generation limit is set to 50kW. In order to take into account the user's need to start the engine at idle speed for heating in winter, the minimum APU power generation power is set to 2kW.

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