Evaluation of Active Zero Switch PWM for Interleaved Dual Inverter systems

This work investigates the potential of multiple interleaving mechanisms applied on Active Zero Switch PWM (AZPWM) for a dual inverter system. AZPWM, a natural extension of conventional space vector pulse width modulation (SVPWM) to reduce common mode voltage, is marred by increased DC-link current ripples relative to SVPWM. However, for dual inverter systems, the concept of interleaving among individual inverters can be employed to target mutual compensation of DC-link ripples for any given PWM scheme. This idea is validated here on AZPWM by incorporation of numerically optimized interleaving shifts. The numerical results, supported by simulation and experimental results, acclaims significant improvement in DC-link ripples for AZPWM making it a combined package of reduced common mode voltage and DC-link ripples. Furthermore, multiple variants of sequence and time based interleaving methods are compared for their relative impact in reducing DC-link ripple and bringing complexity to the system.