A New Model-Based Dead-Time Compensation Strategy for Cascaded H-Bridge Converters

Abstract

Cascaded H-bridge multilevel converter can generate high-voltage and high-power output with low harmonics. However, the error voltage caused by dead-time effect will distort the output waveform, which depends on the phase current polarity. Since the normal dead-time compensation method based on current sampling is often disturbed by sampling error and transmission delay, a novel current prediction method is proposed for dead-time compensation of cascaded H-bridge converter in this article. This method, based on phase-shift carrier pulsewidth modulation, reconstructs the switch pattern, and combined with the system model, can easily predict the phase currents. Excellent compensation performance can be obtained by dead-time compensation according to the predicted current. Simulation and experiments are built to validate the excellent performance of the proposed method applied to cascaded H-bridge converters.