Design of PI Controller for Space Vector Modulation based Direct Flux and Torque Control of PMSM Drive

Abstract

This paper studies the space vector modulated - direct flux and torque control of permanent magnet synchronous motor, due to occurrence of high torque ripples and variable switching frequency of conventional direct flux and torque control strategy. Using dynamic model, the relation between field fluxes of stator, voltages maintained across stator and electromagnetic torque developed for the permanent magnet synchronous motor are developed. Accordingly, the closed loop feedback control structures of torque and flux is established, where the proportional and integral controllers are used to generate the output voltages by regulating the error signals. Furthermore, controller parameters are designed by analyzing the frequency models of torque and flux control loops. The mathematical expressions for obtaining control parameters with target set and physical significance meaning are obtained with high accuracy. Thereby, designing of PI controller parameters for the control structures of flux and closed loop structure of torque becomes easier in the direct flux and torque control with space vector modulation technology, and accurate control of flux and developed torque can be achieved. Simulation results validate the effectiveness of the proposed technology and the possibility of designing the parameters of closed loop controllers.