A Third Harmonic Current Elimination Strategy for Symmetrical Six-Phase Permanent Magnet Synchronous Motor

This paper mainly focuses on the third harmonic current suppression for symmetrical six-phase fault-tolerant permanent magnet synchronous motor drives. First, a brief motor model is established to analyze the source of the third harmonic current. Resonant controller is always appreciated in terms of harmonic current suppression. However, its performance is highly dependent on the precise motor speed, which makes it not suit for variable-speed applications. Fortunately, adaptive filter can skip this problem. Then a current controller based on the adaptive filter is designed to eliminate the third harmonic current. However, the dynamic response of the controller designed is unsatisfactory. Besides, the steady edge of the controller is rather narrow, which limits the operation range of the motor. Then some improvements are made to the structure of the controller as well as the adaptive algorithm. Finally, several groups of experiments are conducted to compare both steady performance and dynamic performance of the controller based on adaptive filter and the improved controller. The experiments results coincide with the analysis and several conclusions are drawn. Besides, the proposed controller also applies to the elimination of other harmonic currents.