Control method of range extender

Abstract

The invention discloses a control method of a range extender. The control method comprises the following steps: starting in different modes according to the value of a battery SOC (State of Charge); the modes comprise a pure electric mode, a fuel oil mode and a charging mode; when SOC is smaller than or equal to 95%, a range extender starting instruction can be manually sent, and a range extender controller conducts condition judgment to judge whether starting can be conducted or not; in the mode selection, the working mode of the range extender is adjusted according to the information input by the user according to the SOC value of the battery, the mileage and the mode input signal, and the defect that the range extender works in a pure electric mode before the battery is used up is avoided; besides, the BMS obtains the output power of the range extender according to the selected driving mode of the strategy, the SOC value of the battery, the actual vehicle speed, the required torque and the actual power, control is achieved according to the output power of the range extender and feedback of the SOC value of the battery, and the defects that an engine is frequently started and cannot stably work in a high-efficiency area are overcome.

Description

[0001] This application is a divisional application of a patent application with the application date of September 30, 2022, application number: 202211205836.6, and the invention name: A starting method and control method for a range extender. Technical Field

[0002] The present invention relates to the technical field of low-speed new energy vehicles, and in particular to a control method for a range extender. Background Art

[0003] The range extender outputs DC power to operate the drive motor while the electric vehicle is in motion, even without stopping. It also stabilizes the generator voltage within a specified range, with any remaining power used to charge the battery. This eliminates the risk of damage to the power battery caused by excessive voltage and current. The range extender controller responds to commands from the vehicle controller, outputting the voltage and current required for electric drive, ensuring stable driving and controlling the engine's most economical operating point.

[0004] Existing range extender control strategies primarily operate in pure electric mode, followed by engine or power-following control. These drive modes are determined solely based on the SOC value, without considering factors such as the vehicle's driving conditions and efficiency. Consequently, efficient system operation cannot be guaranteed, leaving significant room for improvement in drivability and fuel consumption and emissions.

[0005] Therefore, a control method for a range extender is proposed. Summary of the Invention

[0006] An object of the present invention is to provide a control method for a range extender to solve the problems raised in the above background technology.

[0007] To achieve the above object, the present invention provides the following technical solution: a method for starting a range extender, comprising the following steps: S1. Start in different modes according to the battery SOC value; S2, modes include: pure electric mode, fuel mode and charging mode; S3, fuel mode start: When SOC ≤ 95%, you can manually send the range extender start command, and the range extender controller will make a condition judgment to determine whether it can be started; S4, charging mode start: When SOC ≤ 30%, the range extender start command is automatically sent, and the range extender controller makes a condition judgment to determine whether it can be started; S5, charging mode off: After the charging mode is started, when the SOC ≥ 80%, the range extender shutdown command is automatically sent, and the range extender controller makes a condition judgment to determine whether it can be shut down; S6, pure electric mode start: When SOC ≥ 80%, the range extender is turned off and switched to pure electric mode.

[0008] Preferably, in step S3, the conditions are: (1) the start time is ≤ 10 seconds; (2) the number of starts is ≤ 3 times.

[0009] Preferably, in step S4, the conditions are: (1) the start time is ≤ 10 seconds; (2) there is an opening signal of the accelerator pedal; (3) the mileage is ≤ 50% of the maximum cruising range.

[0010] Preferably, in step S5, the conditions are: (1) the ignition delay time is ≤ 15s; (2) the battery voltage is ≥ 80V; and (3) the power generation current is ≤ 5A.

[0011] A control method for a range extender comprises the following steps: Sa. Determine the range extender power, that is, the engine required power, according to the different modes of the range extender; Sb, the driving motor power Pt, the battery charging power Pa, and the high-voltage accessory power consumption Pb are used to determine the engine demand power Pg, that is, Pg = Pt + Pa + Pb; Sc. Perform different controls based on engine power requirements; Sd,control includes: active control, passive control and power following control; Se, power following control: (1) The generator receives the target speed from the vehicle controller, and the PID controller limits the target speed and controls the generator to reach the target speed after the speed limit; (2) The required speed of the range extender should be less than the maximum allowable speed of the engine; (3) The engine receives the target torque from the vehicle controller, the real-time power is used as the feedback value, and the required power is used as the set value to form a feedback system with the PID controller. The output torque of the PID controller reaches the target torque after passing the controller limit; (4) The deviation between the real-time power and the required power is input to the PID controller, and the PID output value is added to the target torque to obtain a new target torque, which is then limited by the range extender controller to reach the target torque; (5) Obtain the real-time power P according to the actual speed n and the target torque T, that is, P = (n*T) / 9550; (6) The vehicle controller sends the target speed and target torque to the range extender controller in real time through the CAN bus, and then sends them to the generator and engine respectively.

[0012] Preferably, in the step Sd, active control is performed by sequentially calculating the engine required power, the target speed and the target torque until the target torque is reached, at which time the engine control ends and a shutdown signal is sent to the engine.

[0013] Preferably: in the step Sd, passive control: through the difference between the current speed of the generator and the target speed, the PID controller uses proportional control and integral control to adjust the load power consumption of the generator in real time, so that the generator speed is stabilized at the target speed, thereby achieving the goal of controllable power generation of the range extender.

[0014] Compared with the prior art, the beneficial effects of the present invention are: the present invention selects the mode according to the battery SOC value, mileage and mode input signal, and realizes the adjustment of the operating mode of the range extender according to user input information, avoiding the disadvantage of operating in pure electric mode until the battery is exhausted.

[0015] In addition, the BMS obtains the range extender output power based on the strategy-selected driving mode, battery SOC value, actual vehicle speed, required torque and actual power, and realizes control based on the feedback of the range extender output power and battery SOC value, avoiding the shortcomings of frequent engine starting and inability to work stably in the high-efficiency area. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of a range extender control method of the present invention; Figure 2 Schematic diagram of the range extender starting method of the present invention; Figure 3 Schematic diagram for determining the power of the range extender of the present invention; Figure 4 Schematic diagram of the energy flow of the range extender of the present invention. DETAILED DESCRIPTION

[0017] The technical solutions in the embodiments of the present invention will be described clearly and completely below with reference to the accompanying drawings in the embodiments of the present invention.

[0018] See also Figure 1-4 , the present invention provides a technical solution: Fuel mode manual start: Under operating temperature conditions, the wake-up signal is valid. When the SOC is ≤ 95%, the range extender start command can be manually sent. The range extender controller determines: (1) the start time is ≤ 10 seconds; (2) the number of starts is ≤ 3 times. If (1) and (2) are met, the start is successful; if any of the conditions are not met, a fault alarm is issued and the fuel and power are cut off.

[0019] Charging mode automatically starts: Under operating temperature conditions, the wake-up signal is valid. When the SOC is ≤ 30%, the range extender start command is automatically sent. The range extender controller determines: (1) the start time is ≤ 10 seconds; (2) the accelerator pedal has an opening signal; (3) the mileage is ≤ 50% of the maximum cruising range. If (1) is met, and either (2) or (3) is met, the charging mode is automatically started successfully. If it is not started when (2) and (3) are met, a fault alarm is issued and the fuel and power are cut off.

[0020] Charging mode automatically shuts off: After the charging mode is automatically started, when the SOC is ≥80%, the range extender shutdown command is automatically sent, and the range extender controller determines: (1) the shutdown delay time is ≤15s; (3) the battery voltage is ≥80V; (4) the power generation current is ≤5A. If (1) is met, and one of (2) and (3) is met, the charging mode is automatically shut down successfully; if it is not shut down when the conditions (2) and (3) are met, a fault alarm is issued and the range extender needs to be manually shut down before the battery SOC value is ≥95%.

[0021] The range extender power is the engine demand power, which is determined according to different modes. When in pure electric mode, the range extender power is zero; When in charging mode, the range extender power is determined based on whether there is driving condition information feedback. If there is driving condition information feedback, the range extender power is determined by the battery SOC value; When there is no driving condition information feedback, the range extender power is determined according to the SOC limit; Active control: Calculate the engine's required power, target speed, and target torque in sequence until the target torque is reached, at which point engine control ends and a shutdown signal is sent to the engine.

[0022] Passive control: Based on the difference between the current speed and the target speed of the generator, the PID controller uses proportional control and integral control to adjust the load power consumption of the generator in real time, so that the generator speed is stabilized at the target speed, achieving the goal of controllable power generation of the range extender.

[0023] Power following control: The drive motor power Pt, battery charging power Pa, and high-voltage accessory power consumption Pb are used to determine the engine demand power Pg. That is, Pg = Pt + Pa + Pb.

[0024] The generator receives the target speed from the vehicle controller, and the PID controller limits the target speed and controls the generator to reach the target speed after the speed limit; The required speed of the range extender should be less than the maximum allowable speed of the engine; The engine receives the target torque from the vehicle controller, uses the real-time power as feedback, and forms a feedback system with the PID controller using the required power as the set value. The engine reaches the target torque after the output torque of the PID controller passes the controller limit. The deviation between the real-time power and the required power is input to the PID controller. The PID output value is added to the target torque to obtain a new target torque, which is then limited by the range extender controller to reach the target torque. According to the actual speed n and the target torque T, the real-time power P is obtained: P=(n*T) / 9550; The vehicle controller sends the target speed and target torque to the range extender controller via the CAN bus in real time, and then sends them to the generator and engine respectively.

[0025] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A control method for a range extender, characterized by: The following steps are involved: Sa. Determine the range extender power, that is, the engine required power, according to the different modes of the range extender; Sb, the driving motor power Pt, the battery charging power Pa, and the high-voltage accessory power consumption Pb are used to determine the engine demand power Pg, that is, Pg = Pt + Pa + Pb; Sc. Perform different controls based on engine power requirements; Sd,control includes: active control, passive control and power following control; Se, power following control: (1) The generator receives the target speed from the vehicle controller, and the PID controller limits the target speed and controls the generator to reach the target speed after the speed limit; (2) The required speed of the range extender should be less than the maximum allowable speed of the engine; (3) The engine receives the target torque from the vehicle controller, the real-time power is used as the feedback value, and the required power is used as the set value to form a feedback system with the PID controller. The output torque of the PID controller reaches the target torque after passing the controller limit; (4) The deviation between the real-time power and the required power is input to the PID controller, and the PID output value is added to the target torque to obtain a new target torque, which is then limited by the range extender controller to reach the target torque; (5) Obtain the real-time power P according to the actual speed n and the target torque T, that is, P = (n*T) / 9550; (6) The vehicle controller sends the target speed and target torque to the range extender controller in real time through the CAN bus, and then sends them to the generator and engine respectively.

2. The control method of a range extender according to claim 1, characterized in that: In the step Sd, active control is performed by sequentially calculating the engine's required power, target speed, and target torque until the target torque is reached, at which point the engine control ends and a shutdown signal is sent to the engine.

3. The control method of a range extender according to claim 1, characterized in that: In step Sd, passive control is performed: based on the difference between the current speed of the generator and the target speed, the PID controller uses proportional control and integral control to adjust the load power consumption of the generator in real time, so that the generator speed is stabilized at the target speed, thereby achieving the goal of controllable power generation of the range extender.

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