On digitization of variable structure control for permanent magnet synchronous motors

This chapter describes the sliding-mode control of permanent magnet synchronous motor (PMSM) servo systems. The typical structure of the systems consists of the position, velocity, and current control loops. The design of three controllers, position controller, speed controller, and current controller, and a filter in speed loop has been described respectively, aimed at reaching high-performances of PMSM servo systems, such as fast response, strong robustness, and high precision. The digitization of terminal sliding-mode (TSM) controllers of PMSM servo system has been discussed for the purpose of practical implementation.