Digital Current Loop for Permanent Magnet Linear Synchronous Motor Based on DSP and FPGA

Abstract

In the high-precision servo control system of permanent magnet linear synchronous motor (PMLSM), the regulation of current loop has a direct effect on the control performances such as accuracy, response speed etc. In order to improve the control performances, a digital current loop control scheme based on DSP and FPGA is presented in this paper. FPGA is used to collect data, while DSP is for completing parallel collection of the input signals read and written from FPGA. P control, P uniting feed-forward compensation control and variable proportional gain control are investigated. Since the method of variable proportional gain can easily meet the requirement of current static error and quick response under different frequencies, PI control can basically eliminate the static error. With rotor initial positioning method, the current closed-loop control is proposed and compared with current open-loop control.