Current ripple analysis for an asymmetric dual two-level inverter drive with reduced Common mode voltage PWM technique

Induction motor fed from an asymmetric voltage source dual two-level inverter would witness a four level voltage profile compared to that of a symmetric voltage source dual two-level inverter that would only see a three level voltage profile. The principle drawback with this asymmetric configuration is the presence of a non-zero common mode voltage (CMV). A new space vector based PWM is proposed for the asymmetric dual two-level inverter in this paper that reduces the CMV compared to the use of conventional space vector PWM. The effect of reduced CMV gets reflected in terms of increased ripple content in the load current. This effect is also analyzed in this paper and both, CMV and the current ripple are theoretically predicted directly from the switching state information of the asymmetric dual two-level inverter. Finally, the proposed PWM is simulated and experimentally verified by conducting suitable experiments. The current ripple predicted theoretically and obtained using simulations exactly match with the experimental results that demonstrate the efficacy of the analytical approach.