WU Qing miao1, LIU Zhen hua2, CHEN Xiao2, LI Ren qing2

(1.Zhejiang Unitemotor Co. Ltd., Jinhua 321300, China, 2.School of Mechanical Engineering, 

Zhejiang University of Technology,Hangzhou 310014,China)

 

 

Abstract: Aiming at the low efficiency and poor reliability of the brush motor in EPS system, the permanent magnet brushless DC motor was used as the power motor. Based on the composition and working principle of the EPS system, the hardware of the EPS controller was designed with MC9S12XS128 as its core, mainly motor drive circuit, signal acquisition circuit and minimum system circuit. In the field of motor control strategy, the EPS system power control object was analyzed, the incremental PID algorithm was used to control the motor torque, and modular program was used to debug the EPS controller main program and each module subroutine, CAN communication module was added to achieve EPS controller and vehicle data transmission. At last tested the EPS controller with bench power experiment, the maximum assist torque error between experimental and design was less than 1%. The results indicated that the brushless DC motor has good power characteristic and achieve the desired goal, the controller is working properly.

Key words: electric power steering(EPS); brushless DC motor; CAN communication; incremental PID