CN103204069B - A kind of range extender of electric vehicle and control method - Google Patents

Abstract

The invention discloses a range extender and a control method for an electric vehicle, comprising an engine, an engine ECU, an electronic throttle controller, a DC starter, an engine speed sensor, an AC permanent magnet synchronous motor, a three-phase full-control rectifier, a filter capacitor, It consists of a voltage sampling resistor, a current sensor, a freewheeling diode and a three-phase fully-controlled rectification, voltage regulation, and phase-shift trigger. After the engine is started by the starter, it drives the AC permanent magnet synchronous motor to generate and output three-phase AC voltage to the thyristor three-phase fully-controlled rectifier. The phase trigger collects the output voltage and current of the range extender to obtain the output power, and adjusts the conduction angle according to the power to realize the power closed-loop control. The electronic throttle controller collects the engine speed, adjusts the throttle opening, and realizes the closed-loop control of the engine speed. The electric vehicle range extender and the control method disclosed by the invention have the advantages of low cost and high control precision.

Description

An electric vehicle range extender and its control method

technical field

The invention mainly relates to an electric vehicle technology, in particular to an electric vehicle range extender and a control method thereof.

Background technique

With the depletion of oil resources and the continuous improvement of people's environmental requirements, electric vehicles do not consume oil. Clean and pollution-free is gradually becoming the development direction of the world automobile market. However, limited by the energy density, charging speed and cost of batteries, the price of electric vehicles is much higher than that of ordinary internal combustion engine vehicles, and the driving range is also very limited. Therefore, the consumer acceptance of electric vehicles is still very low, to a large extent. This restricts the development of electric vehicles.

In order to solve the mileage problem caused by battery technology, the extended-range electric vehicle, as a vehicle that can take into account the electrification of daily driving, zero-emission requirements and long-distance travel, and a low-cost model, is gradually becoming The requirements of major automobile manufacturers and research institutions are hot.

The mechanism of the existing range-extended electric vehicle is shown in Figure 2, which is mainly composed of a range extender, a power battery and an electric drive system. The capacity of the power battery is generally much smaller than that of ordinary electric vehicles, which can meet most of the daily driving mileage requirements; the electric drive system includes the main drive motor and the main drive motor controller, and the main drive motor constitutes the direct power source of the vehicle; when the battery When the capacity drops to a certain value, the range extender starts to provide an additional power source for the vehicle.

Existing range extenders generally include an engine, an ISG (Integrate Starter&Generator) motor, an ISG motor controller, an engine ECU (Electronic Control Unit) and a range extender control unit. The engine is the power source of the range extender, and generally a low-power gasoline engine is used; the ISG motor generally uses a three-phase permanent magnet synchronous motor, which can work in the motor mode, responsible for starting the engine, and can also work in the generator mode, responsible for The power generation of the range extender; the ISG motor controller is mainly responsible for the control of the ISG motor. The ISG motor controller can work in the inverter mode to control the start of the ISG motor to drive the engine, and can also work in the rectification mode for Rectify the three-phase AC voltage sent by the ISG motor; Like the traditional engine ECU, the engine ECU of the range extender is responsible for the collection of various sensor signals inside the engine and the calculation of fuel injection volume, ignition time, etc.; the control unit of the range extender is mainly It is used to receive instructions from the vehicle controller and coordinate the work of the engine ECU and the ISG motor controller.

When the range extender is working, the vehicle controller sends the start signal of the range extender to the control unit of the range extender, and the control unit of the range extender sends a start command to the engine ECU and ISG motor controller, and the engine ECU collects the signals of various sensors in the engine to make the engine At this time, the ISG motor controller works in inverter mode, the ISG motor works in motor mode, and the ISG motor drives the engine to a certain speed to start the engine. After the engine starts, the ISG motor controller works in rectification mode, and the ISG motor Working in generator mode, the engine drives the ISG motor, and the three-phase AC voltage generated by the ISG motor is rectified and filtered by the ISG motor controller to output a DC voltage, which is connected to the DC bus of the vehicle to provide additional power for the vehicle.

The existing electric vehicle range extender has the following disadvantages:

1. Unlike the ISG motor in a hybrid vehicle, which often switches between the motor mode and the generator mode, the range extender generally starts after the capacity of the power battery of the electric vehicle drops to a certain level, and will always work on the generator after starting. Mode, until the end of this driving or the capacity of the power battery reaches the maximum limit, except for the moment of starting, there is only a small amount of time to work in the motor mode. For the starting of the engine, high instantaneous torque and instantaneous power are required, which means that the ISG motor controller must have sufficient VA (volt-ampere) capacity, so the cost of the ISG motor controller is bound to be high. The circuit structure of a common permanent magnet synchronous motor controller is shown in Figure 3. It consists of six fully-controlled power switches (insulated gate bipolar transistor (IGBT) or metal semiconductor oxide field effect transistor (MOSFET)) It consists of an inverter circuit, a power switch tube drive circuit, a microcontroller processing circuit, two or three Hall current sensors, a speed/position detection circuit, a switching power supply, a display, an interface and a communication circuit. The circuit system is relatively complex, and the price of the precise speed/position sensor, high-power full-control power switch tube and Hall current sensor required by high VA capacity is very expensive, which greatly increases the cost of the whole vehicle.

2. The structure of the ISG motor controller control system is shown in Figure 4, that is, the space vector PWM (Pulse Width Modulation) control system according to the rotor flux orientation orientation. The control system usually consists of a speed PI (Proportional Pntegral proportional-integral) regulator, a direct-axis current PI regulator, a quadrature-axis current PI regulator, two-phase rotating coordinate system-three-phase stationary coordinate system transformation (2r/3s transformation), Three-phase stationary coordinate system-two-phase rotating coordinate system transformation (3s/2r transformation), field weakening regulator, space vector pulse width modulation (SVPWM) realization algorithm composition. The algorithm process is complex and involves many floating-point calculations, which requires high real-time performance, complex system debugging, and high development difficulty.

3. The usual range-extender electric vehicle adopts the constant power control algorithm of the range extender or the power following control algorithm. When the electric vehicle is working, due to the different road conditions, driving habits, and factors of braking energy feedback, the power demand of the whole vehicle varies greatly. The fluctuation of power demand will cause the fluctuation of the DC bus voltage, usually the voltage fluctuation range is 0.7 U _N ~1.0 U _N , where U _N is the rated voltage of the DC bus. This poses a great challenge to the constant power output of the range extender. The rectification mechanism inside the ISG motor controller is a diode uncontrollable rectification, and the output power is realized by adjusting the braking torque. It is an indirect control method, and the response speed of the output power is slow and the precision is low.

4. The engine speed adopts open-loop control, and the engine speed fluctuates greatly, causing the engine to not be kept in the high-efficiency working area, which further reduces the fuel economy of the vehicle.

In view of the disadvantages of the existing electric vehicle range extenders such as high cost, difficult development, and poor fuel economy, the market urgently needs an electric vehicle range extender with low cost, simple structure, and excellent control effect.

Contents of the invention

The invention provides an electric vehicle range extender device with low cost, simple structure and excellent control effect and a control method thereof, which are used to solve the problems of high cost, difficult development and poor control effect of the existing electric vehicle range extender.

In order to solve the above problems, the present invention provides a range extender for electric vehicles, the structure of which includes an engine, an engine ECU, an electronic throttle controller, a DC starter, an engine speed sensor, an AC permanent magnet synchronous motor, a three-phase fully-controlled rectifier, filter capacitor, voltage sampling resistor, current sensor, freewheeling diode and three-phase full-control rectification, voltage regulation and phase-shift trigger, characterized in that: the DC starter is connected to the 12V battery via a contactor; the engine and the DC starter, engine EAC, The electronic throttle controller, the engine speed sensor, and the AC permanent magnet synchronous motor are connected, and the electronic throttle controller is connected to the engine speed sensor; the AC permanent magnet synchronous motor is connected to the AC side of the three-phase fully-controlled rectifier; the three-phase fully-controlled rectifier It is composed of six thyristors, and the two ends of the DC side are connected in parallel with the filter capacitor, voltage sampling resistor and freewheeling diode; the filter capacitor is composed of more than two electrolytic capacitors; the voltage sampling resistor is composed of more than two resistors; three-phase full-control rectification The voltage regulation phase-shift trigger is connected with the voltage sampling resistor, and connected with the filter capacitor through the current sensor. The above-mentioned engine is a low-power gasoline engine of 10KW~30KW.

The above-mentioned engine is a low-power gasoline engine of 10KW~30KW.

The above AC permanent magnet synchronous motor is a three-phase motor;

The above-mentioned AC permanent magnet synchronous motor is connected with the engine through a belt, a gear, or is coaxially connected with the engine;

The above-mentioned current sensor is a Hall current sensor.

The above-mentioned freewheeling diode is a high-capacity Schottky diode;

The above-mentioned filter capacitor is composed of two electrolytic capacitors connected in series with the same withstand voltage and the same capacity.

The above-mentioned voltage sampling resistor is composed of two resistors.

The present invention also provides a constant power control method for an electric vehicle range extender, which is characterized in that: the structure of the electric vehicle range extender based on any one of claims 1-8 is adopted, and the three-phase full-control rectification, voltage regulation and phase shifting are adopted. The trigger collects the system output voltage obtained by voltage sampling resistor division and the system output current I _1f obtained by the current sensor, and the system output voltage and output current I _1f are multiplied to obtain the system output power P _f , the output power P _f The difference with the set power P ^* is used as the input of the power PI (proportional-integral) regulator, and the output of the power PI regulator is the target output current of the system , the current PI regulator is based on the system output current I _1f and the target output current output by the power PI regulator Adjust the conduction angle of the phase-shift trigger circuit to form the inner loop of current control to realize the closed-loop control of the system current, and then form the outer loop of power control to realize the closed-loop control of the power of the three-phase fully-controlled rectifier. The constant power of the programmer.

The present invention also provides a constant speed control method for an electric vehicle range extender, which is characterized in that the electric vehicle range extender structure based on any one of claims 1-8 is adopted, and the output of the engine speed sensor is collected by the electronic throttle speed signal , according to the difference between the speed signal and the set speed n ^* determined by the output power of the range extender and the high-efficiency working area of the engine, the speed PI is adjusted, and the throttle opening target value W ^* output by the speed PI regulator and the throttle The difference between the actual valve opening W _f is used as the input of the throttle opening PI regulator to adjust the opening, and the throttle valve driving motor armature target current value output by the throttle opening PI regulator The difference from the actual current value I _2f is used as the input of the current PI regulator, and the PWM (pulse width modulation) duty ratio signal output by the current PI regulator is connected to the throttle drive motor through the drive circuit to realize the adjustment of the throttle opening. And then realize the constant of engine speed.

The specific working method is:

The engine ECU receives the starting signal sent by the vehicle controller, the electronic throttle controller adjusts the opening of the throttle, and the DC starter connected to the 12V battery starts the engine. The engine speed is stable before the set speed, and the three-phase full The conduction angle of the controlled rectification and voltage regulation phase-shift trigger is 90°.

When the range extender starts, the DC starter connected to the 12V battery drives the engine to start the range extender;

After the engine starts, drive the AC permanent magnet synchronous motor to output the three-phase AC voltage to the three-phase fully-controlled rectifier;

The three-phase fully-controlled rectifier includes six semi-controlled thyristors, and the six thyristors are connected to form a three-phase fully-controlled rectifier circuit.

The pulsating DC voltage output by the three-phase fully controlled rectifier is filtered by the filter capacitor;

The three-phase full-control rectification, voltage regulation, and phase-shift trigger collects the system output voltage obtained by dividing the voltage of two resistors and the system output current collected by the Hall current sensor, and obtains the output power of the system from the voltage and current, and according to the output power Adjust the conduction angle of the trigger to realize the constant power output of the range extender;

The electronic throttle controller collects the rotational speed signal output by the rotational speed sensor of the engine to realize the closed-loop control of the rotational speed of the engine.

The electric vehicle range extender with the above structure has a constant engine speed at a constant speed determined by the output power of the range extender and the high-efficiency working area of the engine, and the power output of the range extender is maintained at a set power point.

The present invention has following beneficial effect:

In the electric vehicle range extender device provided by the present invention, the engine is started by a traditional 12V DC starter, which avoids the need for fully controlled power by six insulated gate bipolar transistors (IGBTs) or metal semiconductor oxide field effect transistors (MOSFETs). The expensive ISG motor controller composed of two or three Hall current sensors and precision speed/position sensors can effectively reduce the hardware cost of the system.

The AC voltage signal output by the three-phase AC permanent magnet synchronous motor is filtered and processed by three-phase full-control rectification composed of six thyristors, two electrolytic capacitors with the same capacity and withstand voltage value, and then output DC voltage, three-phase full-control rectification and voltage regulation The phase-shift trigger collects the system current signal output by the Hall current sensor and the voltage signal processed by two resistors to form a current closed-loop PI adjustment and a power PI closed-loop adjustment respectively, which are realized by controlling the conduction angle of six thyristors. With the constant power output of the range extender, its power control accuracy is greatly improved compared with the power control accuracy of the existing ISG motor controller.

Through the closed-loop adjustment of the engine speed by the electronic throttle, the engine speed is kept constant when the range extender is outputting constant power, and the engine is kept in its high-efficiency area, which reduces the fuel efficiency reduction caused by frequent fluctuations in the engine speed and improves the overall vehicle efficiency. fuel economy.

Description of drawings

Fig. 1 is a schematic diagram of an electric vehicle range extender device provided by the present invention;

FIG. 2 is a schematic diagram of the power system of an existing extended-range electric vehicle;

Figure 3 is a schematic diagram of the hardware structure of a common ISG motor controller;

Figure 4 is a schematic diagram of the rotor flux oriented vector control system commonly used by ISG motor controllers;

Fig. 5 is a schematic diagram of the constant power output control system of the range extender provided by the present invention;

Fig. 6 is a schematic diagram of the engine speed control system provided by the present invention;

Fig. 7 is a schematic diagram of the relationship between system voltage and current when the range extender outputs constant power.

Detailed ways

The electric vehicle range extender and its control method provided by the present invention are shown in Fig. 1 , Fig. 5 and Fig. 6 .

As shown in Figure 1, a range extender for electric vehicles, its hardware consists of engine, engine ECU, electronic throttle controller, DC starter, engine speed sensor, AC permanent magnet synchronous motor, three-phase fully-controlled rectifier, filter Capacitors, voltage sampling resistors, current sensors, freewheeling diodes and three-phase full-control rectification and voltage regulation phase-shift triggers.

According to different vehicle configurations, the engine is generally a low-power gasoline engine of 10KW~30KW;

The engine ECU is the same as the ECU of a traditional vehicle. The vehicle controller sends a start command. The engine ECU is responsible for collecting signals such as oil pressure, water temperature, and crankshaft position, and calculating information such as fuel injection volume and ignition time to ensure the normal operation of the internal combustion engine;

The electronic throttle controller is responsible for the adjustment of the throttle opening. It receives the engine target speed sent by the vehicle controller, and adjusts the engine speed PI according to the difference between the actual engine speed and the target speed, so as to realize the closed-loop control of the engine speed;

The DC starter is the same as the ordinary car starter. It is connected to the 12V battery via a contactor. The control terminal of the contactor is controlled by the vehicle controller. To the starting speed, complete the engine start;

The AC permanent magnet synchronous motor is generally a three-phase motor, used as a generator in the electric vehicle range extender provided by the present invention, driven by the engine, generally connected by a belt, a gear and the engine, or coaxially connected with the engine;

The three-phase fully-controlled rectifier is composed of six thyristors, the AC side is connected to the three-phase AC voltage generated by the AC permanent magnet synchronous motor, and the two ends of the DC side are connected to the filter capacitor;

The filter capacitor is responsible for filtering the DC pulsating voltage output by the three-phase fully-controlled rectifier. The filter capacitor is composed of two series-connected electrolytic capacitors with the same withstand voltage value and the same capacity. Adopting a series structure can solve the problem of insufficient withstand voltage of a single capacitor, and can also avoid system short-circuit caused by breakdown and short-circuit of the electrolytic capacitor;

The voltage sampling resistor is composed of two resistors through voltage division, and the voltage value obtained after the voltage division process is generally 0~5V, so the voltage division resistor should be selected reasonably according to the fluctuation range of the system voltage;

The current sensor is a Hall current sensor, which can realize the isolation of the acquisition circuit and the power circuit, and has the advantage of high sampling accuracy;

The freewheeling diode is a large-capacity Schottky diode, which has the advantage of short reverse recovery time and provides a reverse current channel for the resistive load of the system;

The three-phase fully-controlled rectification and voltage-regulating phase-shift trigger provides trigger pulses for the three-phase fully-controlled rectifier circuit. Unlike other phase-shift triggers, it adjusts the conduction of the trigger pulses by collecting the output voltage and current of the system. Angle, realize the power closed-loop control of the rectifier circuit, and then realize the constant power output of the range extender;

The given power of the range extender is sent by the vehicle controller to the three-phase full-control rectification voltage regulation phase-shift trigger according to the vehicle control strategy. Common control strategies include constant power strategy and power following strategy. The constant power strategy means that when the range extender is working, its power remains constant. The power value is generally a certain power value determined by the operating speed of the range extender and the high-efficiency operating area of the engine. At the same time, this value should be slightly less than or equal to the power The rated charging power of the battery, and when the vehicle braking energy is fed back, this value should be appropriately reduced according to the power of the braking energy fed back, so as to avoid damage to the power battery or shorten the life of the power battery caused by excessive charging power; the power following strategy is The output power of the range extender follows the power fluctuation output of the whole vehicle. Using the power following strategy can reduce the damage caused by frequent charging and discharging to the power battery. However, due to the large power fluctuation range in the running range of the whole vehicle, the calculation model of the power demand of the whole vehicle is complicated , it is difficult to achieve a good control effect.

When the vehicle controller requires the range extender to start according to the control strategy of the vehicle, it first sends a start command to the engine ECU, electronic throttle controller, and three-phase full-control rectification, voltage regulation, and phase-shift trigger. At this time, the electronic throttle control The throttle valve is adjusted to the starting opening, and the three-phase full-control rectification voltage regulation phase-shift trigger sets the conduction angle of the three-phase full-control rectification bridge to 90°, and the starter contactor is closed, and the starter turns the engine After dragging to the starting speed, complete the engine start. After the engine speed stabilizes to the set speed, the three-phase full-control rectification, voltage regulation and phase-shifting trigger starts the power closed-loop control.

During the working process of the range extender, due to the continuous change of the required power of the electric vehicle, the DC bus voltage fluctuates. Usually, the voltage fluctuation range is 0.7 U _N ~1.0 U _N , where U _N is the rated voltage of the DC bus. This kind of voltage fluctuation causes the three-phase full-controlled rectification voltage regulation phase-shift trigger to keep the output power of the range extender constant only by continuously adjusting the conduction angle of the three-phase full-control rectifier bridge.

The structure of the power closed-loop control system of the three-phase full-control rectification, voltage regulation, and phase-shifting trigger is shown in Figure 5. The three-phase full-control rectification, voltage regulation, and phase-shifting trigger collects the system output voltage obtained by dividing the voltage by the voltage sampling resistor and the output voltage obtained by the current sensor. The obtained system output current I _1f , the output voltage of the system and the output current I _1f are multiplied to obtain the output power P _f of the system, the difference between the output power P _f and the set power P ^* is used as the input of the power PI regulator, and the power The output of the PI regulator is the target output current of the system , the current PI regulator is based on the system output current I _1f and the target current value output by the power PI regulator The difference between them adjusts the conduction angle of the phase-shift trigger circuit to form an inner current control loop to realize the closed-loop control of the system current, and also forms an outer power control loop to realize the power closed-loop control of the three-phase fully-controlled rectifier.

This power closed loop is essentially to adjust the conduction angle of the three-phase fully-controlled rectifier circuit when the DC bus of the vehicle fluctuates, and then adjust the output voltage U _out of the range extender, and further adjust the output current of the range extender. I _out , so as to achieve the purpose of constant output power. The relationship among the output voltage U _out , the current I _out and the power of the range extender is shown in FIG. 7 .

The operating speed of the engine is sent by the vehicle controller to the electronic throttle controller according to the system configuration. The electronic throttle controller collects the engine speed, adjusts the throttle opening, and realizes the closed-loop control of the engine speed. The operating speed n here is determined by the nominal voltage U _C of the power battery, the counter electromotive force constant E _R of the permanent magnet synchronous motor, and the economical operating speed range of the engine. Generally take , and U _C and E _R should be reasonably designed so that n is located in the economical operating speed region of the engine.

When the engine is working, due to external disturbances such as load fluctuations and vehicle vibration, it is easy to cause speed fluctuations. The fluctuation of rotational speed makes the engine often work in a transient process, resulting in the reduction of engine efficiency. In order to overcome the engine speed fluctuation, the engine speed closed-loop control is adopted, and the structure of the control system is shown in Figure 6. The electronic throttle collects the speed signal output by the engine speed sensor , according to the difference between the speed signal and the set speed n ^* determined by the output power of the range extender and the high-efficiency working area of the engine, the speed PI (proportional-integral) adjustment is performed, and the throttle opening target output by the speed PI regulator The difference between the value W ^* and the actual throttle opening W _f is used as the input of the throttle opening PI regulator for opening adjustment, and the throttle valve driving motor armature target current value output by the throttle opening PI regulator The difference with the actual current value I _2f is used as the input of the current PI regulator, and the PWM duty cycle signal output by the current PI regulator is connected with the throttle drive motor through the drive circuit to realize the adjustment of the throttle opening, and then realize the adjustment of the engine speed. constant.

The above descriptions are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above-mentioned embodiments, and all technical solutions under the idea of the present invention belong to the protection scope of the present invention. It should be pointed out that for those skilled in the art, some improvements and modifications without departing from the principles of the present invention should also be regarded as the protection scope of the present invention.

Claims (10)

1. An electric vehicle range extender, its structure includes engine, engine ECU, electronic throttle controller, DC starter, engine speed sensor, AC permanent magnet synchronous motor, three-phase full-control rectifier, filter capacitor, voltage sampling resistor , a current sensor, a freewheeling diode and a three-phase full-control rectification voltage regulation phase-shift trigger, characterized in that: the DC starter is connected to the 12V battery via a contactor; the engine and the DC starter, engine EAC, electronic throttle controller, The engine speed sensor is connected to the AC permanent magnet synchronous motor, and the electronic throttle controller is connected to the engine speed sensor; the AC permanent magnet synchronous motor is connected to the AC side of the three-phase fully-controlled rectifier; the three-phase fully-controlled rectifier is composed of six thyristors, Both ends of the DC side are connected in parallel with the filter capacitor, voltage sampling resistor and freewheeling diode; the filter capacitor is composed of more than two electrolytic capacitors; the voltage sampling resistor is composed of more than two resistors; It is connected to the voltage sampling resistor and connected to the filter capacitor through the current sensor. 2. A range extender for electric vehicles according to claim 1, characterized in that: the engine is a low-power gasoline engine of 10KW~30KW. 3. The range extender for electric vehicles according to claim 1, wherein the AC permanent magnet synchronous motor is a three-phase motor. 4. A range extender for electric vehicles according to claim 1, characterized in that: the AC permanent magnet synchronous motor is connected to the engine through a belt, a gear, or is coaxially connected to the engine. 5. The range extender for electric vehicles according to claim 1, wherein the current sensor is a Hall current sensor. 6 . The range extender for electric vehicles according to claim 1 , wherein the freewheeling diode is a large-capacity Schottky diode. 7. The range extender for electric vehicles according to claim 1, wherein the filter capacitor is composed of two electrolytic capacitors connected in series with the same withstand voltage and the same capacity. 8. The electric vehicle range extender according to claim 1, wherein the voltage sampling resistor is composed of two resistors. 9. A constant power control method for an electric vehicle range extender, characterized in that: the electric vehicle range extender structure based on any one of claims 1-8, a three-phase full-control rectification voltage regulation phase-shift trigger Collect the system output voltage obtained by dividing the voltage by the voltage sampling resistor and the system output current I _1f obtained by the current sensor, multiply the system output voltage and output current I _1f to obtain the system output power P _f , and the output power P _f is equal to the set The difference of the constant power P ^* is used as the input of the power PI (proportional-integral) regulator, and the output of the power PI regulator is the target output current of the system , the current PI regulator is based on the system output current I _1f and the target output current output by the power PI regulator Adjust the conduction angle of the phase-shift trigger circuit to form the inner loop of current control to realize the closed-loop control of the system current, and then form the outer loop of power control to realize the closed-loop control of the power of the three-phase fully-controlled rectifier. The constant power of the programmer. 10. A method for controlling the constant speed of an electric vehicle range extender, characterized in that, the structure of the electric vehicle range extender based on any one of claims 1-8 is adopted, and the electronic throttle is used to collect the output speed of the engine speed sensor Signal , according to the difference between the speed signal and the set speed n ^* determined by the output power of the range extender and the high-efficiency working area of the engine, the speed PI is adjusted, and the throttle opening target value W ^* output by the speed PI regulator and the throttle The difference between the actual valve opening W _f is used as the input of the throttle opening PI regulator to adjust the opening, and the throttle valve driving motor armature target current value output by the throttle opening PI regulator The difference from the actual current value I _2f is used as the input of the current PI regulator, and the PWM (pulse width modulation) duty ratio signal output by the current PI regulator is connected to the throttle drive motor through the drive circuit to realize the adjustment of the throttle opening. And then realize the constant of engine speed.