Direct torque control of three-level inverter-Fed PMSM based on zero voltage vector distribution for torque ripple reduction

Abstract

A direct torque control strategy based on zero voltage vector distribution is proposed for neutral point clamped (NPC) three-level inverter-fed permanent magnet synchronous motor (PMSM) drive system, which is characterized by low torque ripples and fast speed response. In this proposed control scheme, 12 synthesizing voltage vectors with zero voltage vector are selected according to the error switching table of the flux and torque. Subsequently, the action time of zero voltage vector in each sample period is calculated online considering the selected voltage vector and the motor's speed. Simulation results based on MATLAB/Simulink show that the proposed strategy is effective in reducing torque ripples of NPC three-level inverter-fed PMSM drives.