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 paper. This method, based on phase shift carrier pulse width 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.