Modified Direct Torque Control of Five-Phase Permanent Magnet Synchronous Motor Drives

Conventional direct torque control (DTC) for five-phase permanent magnet synchronous motor drives only controls the flux space vector in the subspace relating to torque production; hence a lot of harmonics exist in the stator current. A DTC strategy for five-phase permanent magnet synchronous motor (PMSM) drives with sinusoidal stator current waveform is introduced. To obtain sinusoidal stator current waveform, flux components in two vector subspaces need to be effectively controlled. Based on the model of PMSM in two subspaces described in this paper, a two-step process is adopted before a switching vector is chosen from a lookup table. The proposed DTC achieves sinusoidal stator current waveform, and preserves the advantages of simplicity and fast response of conventional DTC.