Direct torque control of matrix converter-fed permanent magnet synchronous motor drives based on master and slave vectors

A novel direct torque control strategy is proposed for matrix converter (MC)-based permanent magnet synchronous motor drive systems, which can achieve smooth control of torque and flux with fixed switching frequency. Analytical expression of torque and flux corresponding to different MC voltage vectors are derived. Evaluation functions for torque and flux are established. A master-vector and a slave-vector are selected from a switching table, whose duty cycles are calculated by the evaluation functions. Experiments with a prototype are carried out. The results show that the proposed method can achieve smooth torque and flux performance and fast dynamic response.