Investigation of Radial Force Harmonics Reduction in Consequent-Pole Permanent Magnet Vernier Motors by Current Harmonic Injection

This paper focuses on the reduction of the radial force harmonics of a consequent-pole permanent magnet vernier machine by current harmonic injection. The current harmonic injection has been applied based on dq-axis frame. In the proposed method, a sixth harmonic of d-axis current is injected to reduce a sixth harmonic of the radial force with zero order mode. The effectiveness of the current harmonic injection is verified by finite element analysis. The simulation results show that sixth harmonic of radial force is reduced by 45.7%, resulting in the reduction of a vibration at the respective harmonic by 42%. To demonstrate the controllability of the current regulator for the proposed method, a circuit simulation has been carried out with a proportional, integral, and resonance (PIR) controllers. The simulation results show that the PIR controller can realize superior performance of the current harmonic regulation compared with the conventional PI controller.