High Frequency Harmonics Dispersion for Dual Three-Phase PMSM Drives With Random Switching Sequence

High frequency harmonics induced by pulse width modulation results in the high frequency vibration in permanent magnet synchronous motor (PMSM) drives. This paper proposes a high frequency harmonics dispersion method for dual three-phase PMSM drives with random switching sequence. Twelve sectors are divided into two parts in space vector pulse width modulation of dual three-phase PMSM drives. Two symmetrical and decentralized switching sequences are devised for each sector. The switching sequences are featured with different switching actions in different phases. The switching sequence for each control period is randomly determined from two alternative switching sequences. The variation of switching action contributes to the dispersion of high frequency harmonics and vibration. In addition, no extra switching action is added within one fundamental period. Moreover, the proposed method maintains the constant sampling frequency. Experimental results are given to verify the proposed method.