CN111114531B - Limp-home method and control system of hybrid power system based on P2 structure - Google Patents

Abstract

The invention discloses a junction based on P2A limp home method and control system for a hybrid powertrain system, the limp home method comprising the steps of: firstly, controlling the clutch to be separated, starting the engine by starting the motor when the clutch is in a separated state, enabling the engine to enter an idle state, and acquiring a rotating speed SpeedRef corresponding to the back electromotive force established by the ISG motor; controlling an Engine to execute a speed regulation command so as to regulate the rotating speed to SpeedRef; engine torque down; enabling an ISG motor controller, and regulating the rotation speed of the ISG motor to speedPower; obtaining the torque T of the optimal economic point_outThe engine performs torque regulation to T_out(ii) a Calculating to obtain the required torque T of the whole vehicle_need(ii) a Comparison T_outAnd T_needWhen T is_out≥T_needWhen the power battery is charged by the ISG motor, the ISG motor charges the power battery when the power battery is T_out＜T_needIn time, the output power of the engine is unchanged, and the required power P of the whole vehicle is reduced_needAnd lameness is realized. The problem that the vehicle still needs to run when the battery cannot discharge or the discharge power is not enough to start the engine is solved, and the vehicle can run.

Description

Limp-home method and control system of hybrid power system based on P2 structure

Technical Field

The invention relates to the technical field of new energy automobiles, in particular to a limping method and a control system of a hybrid power system based on a P2 structure.

Background

In recent years, each major ministry of the country has issued a series of policies about the popularization of new energy vehicles, and hybrid vehicles have also been rapidly developed. The P2 hybrid system has become the mainstream of the hybrid system because of its advantages such as cost and fuel saving effect.

At present, the research of the P2 structure hybrid power system is a control method under the condition of a normal mode, and the whole vehicle running mode is controlled according to a basic control method, which is a universal method. However, when an abnormal mode occurs, the general control method cannot meet the driving requirement, and the abnormal mode specifically refers to that when the power battery cannot discharge or the discharge power allowed by the battery is not enough to start the engine, the vehicle needs to drive at the moment.

Disclosure of Invention

The invention aims to provide a limp-home method and a control system of a hybrid power system based on a P2 structure, which solve the problem that a vehicle still needs to drive when a battery of the vehicle cannot be discharged or the discharging power is insufficient to start an engine, and ensure that the vehicle can drive.

In order to solve the technical problem, the invention discloses a limp-home method of a hybrid system based on a P2 structure, the hybrid system based on a P2 structure is characterized in that the abnormal mode is that a power battery cannot discharge or the discharge power of the power battery is lower than the minimum power speedStart E of an engine, and the limp-home method of the hybrid system based on the P2 structure comprises the following steps:

utilizing a starting motor to drive an engine to an idle state, and obtaining a rotating speed SpeedRef corresponding to back electromotive force established by the ISG motor according to the rated voltage VoltageRate of the ISG motor;

controlling an Engine to execute a speed regulating action, regulating the rotating speed to SpeedRef and stabilizing the rotating speed, and regulating the speed of the ISG motor to SpeedRef and stabilizing the rotating speed;

controlling an Engine to execute a torque reduction action until the torque is reduced to 0N m;

controlling an ISG motor to execute speed regulation action, and regulating the rotating speed to a power generation rotating speed SpeedPower, wherein the power generation rotating speed SpeedPower selects a rotating speed corresponding to an economic point according to an engine universal characteristic curve;

obtaining the torque T of the optimal economic point according to the universal characteristic curve of the engine_outThe engine performs torque regulation to T_out；

Calculating to obtain the required torque T of the whole vehicle_needWherein the required torque T_need＝9550*P_need/SpeedPower， P_needThe required power of the whole vehicle is shown, and the SpeedPower is the power generation rotating speed;

comparison T_outAnd T_needWhen T is_out≥T_needWhen the power battery is charged by the ISG motor, the ISG motor charges the power battery when the power battery is T_out＜T_needIn time, the output power of the engine is unchanged, and the required power P of the whole vehicle is reduced_needAnd lameness is realized.

The invention discloses a control method, which comprises the following steps:

judging whether the clutch is separated or not, and if not, executing a separating action;

judging whether the power battery can be discharged or not, if the power battery can be normally discharged, entering a normal mode, and entering a normal mode control method of the P2 structure hybrid power system; if the normal discharge cannot be realized, the abnormal mode is adopted, and the limp home method of the hybrid power system based on the P2 structure is executed.

Preferably, the "normal mode control method for a P2 structure hybrid system" specifically includes:

when the electric vehicle is in pure electric operation, the power battery drives the TM motor to enable the vehicle to run;

when the hybrid power system works in a hybrid mode, the engine drives the ISG motor to generate power for the power battery, and the power battery drives the TM motor to drive the automobile to run; in the parallel mode, the clutch is engaged, and the engine, the ISG motor and the TM motor output power coaxially to drive the automobile to run.

Preferably, the ISG motor is a permanent magnet synchronous motor.

The invention has the beneficial effects that: the invention provides a control method, which solves the problem that a vehicle still needs to run when a battery cannot discharge or the discharge power is insufficient to start an engine, and ensures that the vehicle can run. When the driving power is smaller than the maximum generating power, the power following is realized, and the economy of the whole vehicle is further improved.

Drawings

FIG. 1 is a schematic block diagram of an exemplary environment in which the present invention is implemented;

FIG. 2 is a schematic flow chart according to a first embodiment of the present invention;

fig. 3 is a flowchart illustrating a second embodiment of the present invention.

Detailed Description

The present invention is further described below in conjunction with the following figures and specific examples so that those skilled in the art may better understand the present invention and practice it, but the examples are not intended to limit the present invention.

Referring to fig. 1, a schematic diagram of an implementation environment according to the present invention is shown, where the implementation environment includes an engine 101, astarter motor 102, a torque damping disk 103, an ISG motor (PMSM)104, anMCU2 motor controller 105, a power battery 106, aclutch 107, anMCU1 motor controller 108, a TM motor 109, and a rear axle drive system 110. Wherein theISG motor 104 needs to be a permanent magnet synchronous motor.

Example one

Referring to fig. 2, the invention discloses a limp-home method of a hybrid power system based on a P2 structure, wherein the abnormal mode is that a power battery cannot be discharged or the discharge power of the power battery is lower than the minimum power speedstart e of an engine based on a P2 structure hybrid power system, and the limp-home method of the hybrid power system based on a P2 structure comprises the following steps:

s10, driving the engine to an idle state by using the starting motor, and obtaining a rotating speed speedRef corresponding to the back electromotive force established by the ISG motor according to the rated voltage VoltageRate of the ISG motor;

s20, controlling an Engine to execute a speed regulation action, regulating the rotating speed to speedRef and stabilizing the rotating speed, and regulating the rotating speed to speedRef and stabilizing the rotating speed by the ISG motor;

s30, controlling the Engine to execute a torque reduction action until the torque is reduced to 0N m;

s40, controlling the ISG motor to execute speed regulation action, and regulating the rotating speed to a power generation rotating speed SpeedPower, wherein the power generation rotating speed SpeedPower selects the rotating speed corresponding to the economic point according to the universal characteristic curve of the engine;

s50, obtaining the torque Tout of the optimal economic point according to the universal characteristic curve of the engine, and adjusting the torque to Tout by the engine;

s60, calculating and obtaining a required torque Tneed of the whole vehicle, wherein the required torque Tneed is 9550 multiplied by Pnew/speedPower, Pnew is the required power of the whole vehicle, and speedPower is the power generation rotating speed;

and S70, comparing Tout with Tneed, when Tout is larger than or equal to Tneed, when the output power of the engine is surplus, the surplus part charges the battery, the ISG motor charges the power battery, and when Tout is smaller than Tneed, the output power of the engine is unchanged, the required power Pspeed of the whole vehicle is reduced, and limp is realized.

Example two

Referring to fig. 3, the present invention also discloses a control method, including the following steps:

judging whether the clutch is separated or not, and if not, executing a separating action;

judging whether the power battery can be discharged or not, if the power battery can be normally discharged, entering a normal mode, and entering a normal mode control method of the P2 structure hybrid power system; if the normal discharge cannot be performed, the abnormal mode is set, and the limp home method of the hybrid system based on the P2 structure in embodiment 1 is performed.

The normal mode control method of the P2 structure hybrid power system specifically comprises the following steps:

when the electric vehicle is in pure electric operation, the power battery drives the TM motor to enable the vehicle to run;

when the hybrid power system works in a hybrid mode, the engine drives the ISG motor to generate power for the power battery, and the power battery drives the TM motor to drive the automobile to run; in the parallel mode, the clutch is engaged, and the engine, the ISG motor and the TM motor output power coaxially to drive the automobile to run.

The series mode is that an engine, an ISG motor, a power battery and a TM motor are connected in series; the parallel mode means that the ISG motor, the clutch and the TM motor are sequentially connected in series, and the ISG motor and the TM motor are connected with the power battery in parallel.

The invention provides a control method by utilizing the characteristic that a permanent magnet synchronous motor generates counter electromotive force by rotation, solves the problem that a vehicle still needs to run when a battery cannot discharge or the discharge power is insufficient to start an engine, and ensures that the vehicle can run. When the driving power is smaller than the maximum generating power, the power following is realized, and the economy of the whole vehicle is further improved.

The above-mentioned embodiments are merely preferred embodiments for fully illustrating the present invention, and the scope of the present invention is not limited thereto. The equivalent substitution or change made by the technical personnel in the technical field on the basis of the invention is all within the protection scope of the invention. The protection scope of the invention is subject to the claims.

Claims (7)

1. A limp-home method of a hybrid power system based on a P2 structure is characterized in that an abnormal mode is that a power battery cannot be discharged or the discharge power of the power battery is lower than the minimum power SpeedStartE of an engine, and the limp-home method of the hybrid power system based on the P2 structure comprises the following steps:

utilizing a starting motor to drive an engine to an idle state, and obtaining a rotating speed SpeedRef corresponding to back electromotive force established by the ISG motor according to the rated voltage VoltageRate of the ISG motor;

controlling an Engine to execute a speed regulating action, regulating the rotating speed to SpeedRef and stabilizing the rotating speed, and regulating the speed of the ISG motor to SpeedRef and stabilizing the rotating speed;

controlling an Engine to execute a torque reduction action until the torque is reduced to 0N m;

controlling an ISG motor to execute speed regulation action, and regulating the rotating speed to a power generation rotating speed SpeedPower, wherein the power generation rotating speed SpeedPower selects a rotating speed corresponding to an economic point according to an engine universal characteristic curve;

obtaining the torque T of the optimal economic point according to the universal characteristic curve of the engine_outThe engine performs torque regulation to T_out；

Calculating to obtain the required torque T of the whole vehicle_needWherein the required torque T_need＝9550*P_need/SpeedPower，P_needThe required power of the whole vehicle is shown, and the SpeedPower is the power generation rotating speed;

comparison T_outAnd T_needWhen T is_out≥T_needWhen the power battery is charged by the ISG motor, the ISG motor charges the power battery when the power battery is T_out＜T_needIn time, the output power of the engine is unchanged, and the required power P of the whole vehicle is reduced_needAnd lameness is realized.

2. A control method, characterized by comprising the steps of:

judging whether the clutch is separated or not, and if not, executing a separating action;

judging whether the power battery can be discharged or not, if the power battery can be normally discharged, entering a normal mode, and entering a normal mode control method of the P2 structure hybrid power system; if the normal discharge cannot be realized, the abnormal mode is executed, and the limp home method of the hybrid power system based on the P2 structure, which is disclosed in claim 1, is executed.

3. The control method according to claim 2, wherein the "normal mode control method for a P2 structure hybrid system" specifically includes:

when the electric vehicle is in pure electric operation, the power battery drives the TM motor to enable the vehicle to run;

when the hybrid power system works in a hybrid mode, the engine drives the ISG motor to generate power for the power battery, and the power battery drives the TM motor to drive the automobile to run; in the parallel mode, the clutch is engaged, and the engine, the ISG motor and the TM motor output power coaxially to drive the automobile to run.

4. The control method of claim 2, wherein the ISG motor is a permanent magnet synchronous motor.

5. A computer device comprising a memory, a processor and a computer program stored on the memory and executable on the processor, characterized in that the steps of the method of any of claims 1 to 4 are implemented when the program is executed by the processor.

6. A computer-readable storage medium, on which a computer program is stored which, when being executed by a processor, carries out the steps of the method of any one of claims 1 to 4.

7. A processor, characterized in that the processor is configured to run a program, wherein the program when running performs the method of any of claims 1 to 4.

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