A novel third harmonic current injection method to optimize the air-gap flux for multiphase induction machine

This paper presents a novel harmonic current injection method to optimize air-gap flux density distribution for multiphase induction machine. The control objective is to generate a nearly rectangular air-gap flux for better iron utilization. The proposed method uses air-gap field-oriented control and rotor field-oriented control to realize a real-time adjustment of the third harmonic current under various loads. The control concept is valid for any number of planes with a higher number of phases, and each plane requires two PI controllers. The robustness and effectiveness of the proposed scheme has been validated by experiments.