Improved DPWM modulation for reducing switching losses in cascaded H-bridge multilevel inverters

Abstract

The switching loss of the traditional DPWM method is large. Therefore, this paper improves the traditional DPWM method by adding a clamping interval to reduce the switching loss. The traditional method is also improved using a modulating waveform spatial reorganization method to improve the modulation signal added to the clamping interval so that the switching frequency of each switch remains consistent, which balances the switching loss of each H-bridge unit of the cascaded H-bridge multilevel inverter and improves the reliability of the inverter. The carrier phase-shifting method is used to realize the power balance of each H-bridge unit. Simulation and experimental results verify the feasibility of the modulation strategy.