Non-sinusoidal output voltage for multiphase variable speed drives with space vector PWM

Due to the low DC voltage utilization and small output torque of the multiphase induction motors with sinusoidal output voltage,the non-sinusoidal space vector pulse width modulation (PWM),NSVPWM,is modeled and the inter connection between NSVPWM and harmonic injection PWM is analyzed.The way how to decide the reference voltage vectors on d-q planes is introduced.A nine-phase concentrated winding induction machine is used as a practical example.By maintaining the amplitudes of the tooth flux density and yoke flux density as well as the stator copper loss,the output torques under three control strategies are compared.The experiment results show that the output torque of the ninephase concentrated winding induction machine with NSVPWM is over 6.42% than that with SPWM,and the reasons are given.