Research And Development Of Automotive Electric Oil Pump Controller

The development of intelligent and new energy vehicles,and the increasingly stringent regulations for energy conservation and emission reduction have led to an ever-increasing demand for intelligent engine control and reduced energy consumption,and traditional mechanical oil pumps have failed to meet the requirements of hybrid vehicles.Electric oil pump have become a trend.The electric oil pump works through the motor-driven oil pump and uses electric control technology to improve the performance of the oil pump so that it can output the optimal oil pressure according to different operating conditions of the engine,reduci ng the engine's energy consumption and improving the performance.Therefore,this paper studies the electric oil pump motor control system.The main research contents include:Firstly,the structure and control principle of the electric oil pump were analyzed.According to the requirement that the motor oil pump was immersed in the engine oil and operated in a high temperature environment,the position sensorless brushless DC motor was used as the drive motor,and then the oil pump and brushless DC motor were established.The mathematical model lays the foundation for the subsequent theoretical analysis.According to the brushless DC motor control principle and the demand of the motor oil pump,the control strategy of the brushless DC motor is designed to meet the requirements of its use.A method to detect the back-EMF zero-crossing signal by comparing the voltage of the floating phase terminal and the DC bus voltage is proposed.The three-stage start-up method was improved to meet the control requirements for the motor oil pump to start quickly.Combined with the double closed-loop control of the speed and current,a complete brushless DC motor control strategy is formed and simulated in MATLAB/Simulink to verify its feasibility.Based on NXP's MC9S12 ZVM chip,the hardware circuit of the electric oil pump motor controller was designed,including the minimum system circuit,drive circuit,sampling circuit,and CAN communication circuit.According to the motor control strategy,the software is designed.The software is mainly composed of the bottom driver,motor control program and fault diagnosis program.Among them,the motor control program includes back EMF zero-crossing point detection program,commutation program,three-step startup program and speed-Current double closedloop control program.On the electric oil pump test bench,the actual working condition of the motor oil pump was simulated,and the performance test of the motor oil pump motor controller was performed.The experiment proved that the design of the electric oil pump motor controller is correct and reliable,and the oil pump can be controlled to work normally,meet the lubrication requirements of the engine lubrication system.