Test and design of controller for pinion-type EPS with brushless DC motor

The electric power steering (EPS) was designed to improve the handling performance of vehicle and the brushless DC motor (BLDCM) had attracted much attentions for its advantages in EPS. In this paper, the mathematical models of BLDCM and pinion-type EPS were established and the co-simulation of P-EPS with BLDCM had been carried out with MATLAB/Simulink. The ARM7LPC2131 chipset was adopted as EPS controller core and the MC33034P120 integrated circuit was selected as driver for commutation decoding. The EPS controller hardware was designed and the control strategy was put forward to achieve steering torque assist, return-to-center, and damping control. In addition, the flowchart of main program was presented. Finally, the control system of EPS with BLDCM was installed in an experimental car. The results showed that the designed controller was well matched with the car based on parking steering test and slalom test. Steering portability and handling stability of the car were greatly improved.