A Novel Direct Torque and Flux Control Method of Matrix Converter-Fed PMSM Drives

Abstract

A novel direct torque and flux control strategy is proposed for matrix converter (MC)-based permanent-magnet synchronous motor (PMSM) drive systems. The proposed method allows the use of all MC switching states including the rotation vectors, and effectively controls input and output variables of the MC. Mapping relationships between MC output voltage vectors and change rates of motor torque and flux, and those between MC input current vectors and change rates of grid reactive charge are derived. Then, four enhanced switching tables are established by means of discretizing and averaging, in which changes of torque, flux and input reactive charge corresponding to all MC switching states can be shown explicitly. Based on the tables, an optimal selection of switching states can be achieved by the proposed method. Numerical simulations and experiments with a prototype are carried out. The results show good performance of the proposed method with small torque and flux ripples, low distortion input currents, and fast dynamic response.