Current ripple in inverter-fed five-phase drives with space-vector PWM

A number of PWM techniques have been developed in recent times for five-phase voltage source inverters (VSIs), which enable sinusoidal output voltage generation. Relatively little attention has been however paid to the current ripple caused by these PWM methods. This paper investigates stator current ripple (THD), caused by the switching harmonics, for two space vector PWM (SVPWM) techniques that both enable sinusoidal output generation but utilize different sets of active vectors in the modulation process. The first technique uses two large and two medium vectors, while the second method utilizes four large vectors. Detailed simulation studies are performed and corresponding experimental results are included as well. It is shown that, in induction motor drives, PWM method based on four large vectors can yield lower current THD, although it is characterized with higher voltage THD. If however average switching frequency is equalized, then the SVPWM with two large and two medium vectors yields lower current THD.