Modified Switching*Table Strategy for Reduction of Current Harmonics in Direct Torque Controlled Dual*three Phase Permanent Magnet Synchronous Machine Drives

K. D. Hoang, Y. Ren, Z.Q.Zhu*, M. Foster Abstract—The switching-table-based direct torque control strategies (ST-DTC) of dual-three phase permanent magnet synchronous machine (PMSM) drives are investigated in this paper. Owing to its inherited advantage of suppression of sixth harmonic torque pulsation, dual-three phase machine has attracted more and more interests among various sorts of multi-phase machines. However, unexpected stator harmonic currents are often observed in the classical ST-DTC strategy for dual-three phase PMSM drives, which cause large losses and decrease the efficiency of the drive system. An optimized ST-DTC strategy which consists a two-step process to determinate the most appropriate inverter voltage vector is proposed to reduce the stator harmonic currents. The merits of the classical direct torque control, i.e. simple structure and good dynamic performance, are still preserved. The experimental results verify that the proposed method can significantly reduce the current harmonics.