Pole width modulation method of PMSM and its magnetic field analysis

In the paper, an approach of place distributed magnetic pole on the surface of the rotor iron core of permanent magnet motor is proposed. This method uses the center area equivalent principle in the power electronics technology and achieves sine pole width modulation permanent-magnet rotor structure. According to the different modulation scheme, the magnetic field simulation and analysis is researched by 0.8kW PMSM in textile of the magnetic pole distributed using pole width modulation. Then, the experiment results of contrast between prototypes with conventional inblock rotor structure and 5 magnet arrays pole width modulation rotor structure are given in the paper. The results of the theoretic analysis and the experiment show that the magnetic pole which is designed to pole width modulation can weaken the magnetic field harmonics and make the air-gap magnetic field closer to sinusoidal waveform of permanent magnet motor.