Carrier based PWM with harmonics injection for multiphase induction motor drive

摘要

The interest in multi-phase (number of phase higher than three) machines for high performance applications has been growing in recent years due to their potential advantages over three-phase machines. To solve the problems of complex arithmetic in the multiphase Space Vector Pulse Width Modulation (SVPWM) control and low utilization ratio of dc bus voltage and low torque density in the multiphase Sinusoidal Pulse Width Modulation (SPWM) control, a multiphase carrier based PWM control method based on harmonics injection was analyzed. The proposed method improved the output voltage characteristic through injecting several harmonics signals to the standard sine fundamental signal. This paper, firstly, calculated the MMF distribution of a set of multiphase windings. Then, based on it, the magnetic field distribution of multiphase induction motor was discussed, and three kinds of multiphase carrier PWM technologies are compared. Theoretical analysis and experiment results show that the proposed multiphase carrier PWM method based on harmonics injection can enhance the dc bus voltage utilization ratio effectively, improve motor torque density and efficiency, while has the characteristics of low torque ripple and simple realization.