Automobile electric power steering system

The invention discloses an automobile electric power steering (EPS) system. The EPS system comprises a motor winding temperature on-line estimation module and a control parameter self-adjusting function module, wherein the motor winding temperature on-line estimation module is used for acquiring the current and the environmental temperature of a motor and estimating the winding temperature and the winding resistance of the motor; and the control parameter self-adjusting function module is used for real-timely adjusting the flux weakening parameter, the d-axis PI control parameter and the q-axis PI control parameter in the motor control algorithm according to the estimated winding temperature and winding resistance of the motor, power assisting moment directive value of the motor, current of the motor, rotational speed of the motor and angle of the motor. The automobile EPS system can achieve on-line estimation of the winding temperature of the motor, realizes self-adjustment of the control parameter, and redu