Research on Optimized Carrier-Based AZSPWM Strategy to Reduce Common-Mode Voltage Frequency and Prevent Overvoltage

Active zero state PWM (AZSPWM) can reduce the amplitude of common-mode voltage (CMV) by two-thirds, but it cannot reduce the frequency of CMV, and will lead to two-level jump of line voltage, resulting in overvoltage. Aiming at the above problems, six optimized AZSPWM vector sequences that can simultaneously reduce the amplitude and frequency of CMV are proposed in this paper firstly. On this basis, by deriving the equivalent modulation wave and carrier of optimized AZSPWM, six optimized carrier-based AZSPWM (OCBAZSPWM) strategies with simpler calculations are further proposed. Then, the cause of the two-level jump of line voltage is analyzed, and the method of OCBAZSPWM to prevent overvoltage is designed. Finally, simulation results verify the validity of the OCBAZSPWM.