PMSM Servo Drive System for Electric Power Steering Based on Two-Degree-of-Freedom Torque Control

Electric power steering (EPS) is a trend for power steering system. In EPS system, torque control of the power-assisted motor is required to have a high performance such as wide bandwidth of torque control, small torque ripple and acoustic noise, high robust performance in different environmental conditions. This paper describes a robust servo torque drive control of permanent magnet synchronous motor (PMSM) for EPS. A two-degree-of-freedom controller is proposed to improve the torque control performance. The effectiveness of the proposed motor drive control is demonstrated by simulation and experiment.