Selective Active Zero-State Pulse-Width Modulation for Reduction of Common-Mode Voltage of Three-Phase Inverter Considering Saturation of Filter Inductor

Conventional active zero-state PWM (AZSPWM) techniques are effective in limiting common-mode voltage (CMV) but typically assume linear and balanced three-phase filter inductances. In practice, however, filter inductors are designed for high-power density and inevitably operate near magnetic saturation (e.g., using powder-core materials). This results in periodic unbalanced dynamic inductances among the three phases and thereby degrading the effectiveness of the well-established pulsewidth modulation (PWM) techniques for CMV reduction. This paper reveals the failure of existing PWM techniques on CMV reduction under such conditions and proposes a saturation-aware selective AZSPWM method that adaptively selects the optimal pair of opposite active vectors based on predicted CMV. A common-mode equivalent circuit incorporating unbalanced dynamic inductances is derived, and an online CMV estima…