Novel PMSM Control for Anti-Lock Braking Considering Transmission Properties of the Electric Vehicle

Abstract

The driving motor of the electric vehicle (EV) can recover the kinetic energy during normal braking maneuvers by a regenerative function. At the same time, its dynamic torque response proves to be accurate and fast for an emergency braking, namely an anti-lock braking, with the coordinated control of the frictional braking system. However, vehicle transmission properties will deteriorate the control performance of the motor, especially in the anti-lock braking process. A novel permanent magnet synchronous motor (PMSM) control method is proposed considering the transmission influence on this high-dynamic braking process of the pure EV. First, the EV's dynamic model, which includes the PMSM field-oriented control model, the transmission dynamic model, and the hydraulic braking system, is built, and the influences of transmission elasticity and backlash non-linearity on the motor-braking torque are analyzed. Then, based on the wheel slip ratio target of the anti-lock braking, the novel mode-switching method for the motor-torque control between the backlash sliding-mode compensation and the elasticity double-closed-loop PID compensation is put forward. Two state-of-the-art anti-lock braking algorithms, which simplify the transmission properties, the slip ratio phase-plane theory, and the sliding-mode control, are compared with the proposed method. Simulation and test-bench experiment results show that, on different test-road surfaces, the mode-switching PMSM control can effectively compensate for transmission effects and significantly improve the EV's anti-lock braking comfort, stability, and maneuverability with fast and accurate motor-torque regulating.