A starting method and a control method of a range extender

Abstract

The application discloses a starting method of a range extender, and comprises the following steps: starting in different modes according to the value of battery SOC; the modes comprise a pure electric mode, a fuel mode and a charging mode; the fuel mode starting: when SOC is less than or equal to 95%, a range extender starting instruction can be manually sent, and a range extender controller performs condition judgment to determine whether to start; according to the battery SOC value, the driving distance and the mode input signal, the application realizes adjusting the working mode of the range extender according to the user input information, and avoids the shortcoming that the range extender always works in the pure electric mode before the battery is exhausted; in addition, the BMS obtains the range extender output power according to the strategy selection driving mode, the battery SOC value, the actual vehicle speed, the required torque and the actual power, realizes controlling according to the feedback of the range extender output power and the battery SOC value, and avoids the shortcoming that the engine frequently starts and cannot stably work in the high-efficiency area.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of low-speed new energy vehicles, in particular to a starting method and control method of a range extender. BACKGROUND

[0002] The range extender outputs direct current to make the driving motor work without stopping during the driving of the electric vehicle, and controls the voltage of the generator to be stable within a standard range, and the remaining power is charged to the battery, so that damage to the power battery caused by overvoltage and current charging does not have to be worried. Through the range extender controller, the required voltage and current for electric driving are output in response to the command of the electric vehicle controller, so that stable control during driving and engine most economical operating point control are realized.

[0003] The existing range extender control strategy mainly adopts the mode of first working in pure electric mode and then using engine or power following control mode. The driving mode is determined only according to the SOC value, without considering the driving conditions and driving efficiency of the vehicle, so that the efficient operation of the system cannot be guaranteed, and there is a lot of room for improvement in driving performance and fuel consumption emission performance.

[0004] Therefore, a starting method and control method of a range extender are provided. SUMMARY

[0005] The purpose of the present application is to provide a starting method and control method of a range extender to solve the problems raised in the background.

[0006] To achieve the above purpose, the present application provides the following technical scheme: a starting method of a range extender, comprising the following steps:

[0007] S1. Starting in different modes according to the value of the battery SOC;

[0008] S2. The modes include pure electric mode, fuel mode and charging mode;

[0009] S3. Fuel mode starting: when SOC is less than or equal to 95%, the range extender starting instruction can be manually sent, and the range extender controller performs condition judgment to determine whether it can be started;

[0010] S4. Charging mode starting: when SOC is less than or equal to 30%, the range extender starting instruction is automatically sent, and the range extender controller performs condition judgment to determine whether it can be started;

[0011] S5. Charging mode closing: after the charging mode is started, when SOC is greater than or equal to 80%, the range extender shutdown instruction is automatically sent, and the range extender controller performs condition judgment to determine whether it can be closed;

[0012] S6. Pure electric mode starting: when SOC is greater than or equal to 80%, the range extender is closed and switched to pure electric mode.

[0013] Preferred: in the step S3, the condition is: (1) start-up time ≤ 10S; (2) start-up frequency ≤ 3 times.

[0014] Preferred: in the step S4, the condition is: (1) start-up time ≤ 10S; (2) acceleration pedal exists opening degree signal; (3) driving distance ≤ 50% of maximum cruising range.

[0015] Preferred: in the step S5, the condition is: (1) delay time ≤ 15s; (2) battery voltage ≥ 80V; (3) power generation current ≤ 5A.

[0016] A control method of a range extender, comprising the following steps:

[0017] Sa, determining the range extender power according to different modes of the range extender, that is, the engine demand power;

[0018] Sb, determining the engine demand power Pg by the driving motor power Pt, the battery charging power Pa, and the high-voltage accessory consumption power Pb, that is, Pg = Pt + Pa + Pb;

[0019] Sc, performing different controls according to the engine demand power;

[0020] Sd, the control comprises: active control, passive control, and power follow-up control;

[0021] Se, the power follow-up control:

[0022] (1) The generator receives the target speed of the vehicle controller, and a PID controller controls the generator to reach the target speed after the speed limit value;

[0023] (2) The range extender demand speed should be less than the maximum allowable engine speed;

[0024] (3) The engine receives the target torque of the vehicle controller, the real-time power as the feedback value, the demand power as the set value and the PID controller constitute a feedback system, and the output torque of the PID controller reaches the target torque after the controller limit value;

[0025] (4) The deviation value of the real-time power and the demand power is input to the PID controller, the PID output value is added to the target torque to obtain a new target torque, and the target torque is reached after the range extender controller limit;

[0026] (5) According to the actual speed n and the target torque T, the real-time power P is obtained, that is, P = (n*T) / 9550;

[0027] (6) The target speed and target torque are sent to the generator and engine by the vehicle controller through CAN bus.

[0028] Preferably, in the step Sd, active control is performed: engine demand power calculation, target speed calculation and target torque calculation are sequentially performed until the engine control ends when the target torque is reached, and a shutdown signal is sent to the engine.

[0029] Preferably, in the step Sd, passive control is performed: 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, and the goal of controllable power generation of the range extender is achieved.

[0030] Compared with the prior art, the present application has the following advantages: according to the battery SOC value, the driving distance and the mode input signal, the working mode of the range extender is adjusted according to the user input information, and the disadvantage of working in pure electric mode before the battery is exhausted is avoided.

[0031] In addition, the BMS obtains the output power of the range extender according to the selection of the strategy, the driving mode, the battery SOC value, the actual speed, the demand torque and the actual power, and realizes control according to the feedback of the output power of the range extender and the battery SOC value, avoiding the disadvantages of frequent engine starting and inability to work stably in the high efficiency area. BRIEF DESCRIPTION OF DRAWINGS

[0032] Figure 1 The schematic diagram of the range extender control method of the present application is shown in the figure;

[0033] Figure 2 The schematic diagram of the range extender starting method of the present application is shown in the figure;

[0034] Figure 3 The schematic diagram of the determination of the range extender power of the present application is shown in the figure;

[0035] Figure 4 The schematic diagram of the energy flow direction of the range extender of the present application is shown in the figure. DETAILED DESCRIPTION

[0036] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the accompanying drawings in the embodiments of the present application.

[0037] EMBODIMENT

[0038] Please refer to Figures 1-4 The present application provides a technical solution:

[0039] Manual start in fuel mode:

[0040] Under operating temperature conditions, the wake-up signal is valid. When SOC ≤ 95%, the range extender start command can be manually sent, and the range extender controller will make the following judgments: (1) Start time ≤ 10S; (2) Number of starts ≤ 3. If (1) and (2) are met, the start is successful; if any condition is not met, a fault alarm will be triggered and the fuel and power will be cut off.

[0041] Automatic charging mode activation:

[0042] Under operating temperature conditions, the wake-up signal is valid. When SOC ≤ 30%, the range extender start command is automatically sent, and the range extender controller makes the following judgments: (1) Start-up time ≤ 10S; (2) Accelerator pedal has an opening signal; (3) Driving mileage ≤ 50% of the maximum range. If either (2) or (3) is satisfied when (1) is satisfied, the charging mode will start successfully. If the mode does not start when conditions (2) and (3) are satisfied, a fault alarm will be triggered and the fuel and power will be cut off.

[0043] Automatically turns off charging mode:

[0044] After the charging mode is automatically activated, when the SOC is ≥ 80%, the range extender will automatically send a shutdown command. The range extender controller will then determine the following: (1) shutdown delay time ≤ 15s; (2) battery voltage ≥ 80V; (3) generator current ≤ 5A. If either (2) or (3) is satisfied when (1) is satisfied, the charging mode will automatically shut down successfully. If the mode is not shut down when conditions (2) and (3) are satisfied, a fault alarm will be triggered and the range extender will need to be manually shut down before the battery SOC value reaches ≥ 95%.

[0045] The range extender power is the same as the engine power required, and it is determined according to different modes. When in pure electric mode, the range extender power is zero.

[0046] When in charging mode, the power of the range extender is determined based on whether there is driving condition information feedback. When there is driving condition information feedback, the power of the range extender is determined by the battery SOC value.

[0047] When there is no feedback on driving conditions, the range extender power is determined based on the SOC limit.

[0048] Active control: The engine power demand, target speed and target torque are calculated sequentially until the target torque is reached. When the engine control ends, a shutdown signal is sent to the engine.

[0049] Passive control: By using 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, thus achieving the goal of controllable power generation of the range extender.

[0050] Power follower control: The engine's required power Pg is determined by the drive motor power Pt, the battery charging power Pa, and the high-voltage accessory power consumption Pb. That is, Pg = Pt + Pa + Pb.

[0051] The generator receives the target speed from the vehicle controller, and the PID controller sets a speed limit for the target speed and then controls the generator to reach the target speed after the limit is reached.

[0052] The required speed of the range extender should be less than the maximum permissible speed of the engine;

[0053] The engine receives the target torque from the vehicle controller, uses real-time power as a feedback value, and uses the required power as a set value to form a feedback system with the PID controller; after the output torque of the PID controller passes through the controller limit, the engine reaches the target torque.

[0054] 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.

[0055] The real-time power P is obtained based on the actual rotational speed n and the target torque T: P = (n*T) / 9550;

[0056] The vehicle controller sends the target speed and target torque to the range extender controller in real time via the CAN bus, and then sends them to the generator and engine respectively.

[0057] 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 method of starting an upgrader, characterized by, Comprising the following steps: S1, starting different modes according to the value of battery SOC; S2, the modes include: pure electric mode, fuel mode and charging mode; S3, fuel mode start: when SOC≤95%, manual sending range extender start instruction, range extender controller condition judgment, to determine whether to start, the condition is start time≤10S, start times≤3 times; S4, charging mode start: when SOC≤30%, automatically send range extender start instruction, range extender controller condition judgment, to determine whether to start, the condition is start time≤10S, accelerator pedal exists opening signal, driving range≤50% of the maximum driving range; S5, charging mode off: after charging mode start, when SOC≥80%, automatically send range extender stop instruction, range extender controller condition judgment, to determine whether to close, the condition is delay time≤15s, battery voltage≥80V, current≤5A; S6, pure electric mode start: when SOC≥80%, range extender off switch to pure electric mode.

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