Tri-carrier sinusoidal pulse-width modulation without dead time effects for converters

This study presents a tri-carrier sinusoidal pulse-width modulation (SPWM) to eliminate the dead time effects (DTEs) (SPWM without DTE) in principle. Compared with other existing methods, this tri-carrier modulation method directly modified the modulation strategy to remove the DTE. It can reduce current harmonics and suppress the current ripple on the AC side of converters. This method is illustrated by taking the two-level inverter as an example, but it can be directly extended to the case where SPWM can be applied to, such as multi-level inverters and multi-level rectifiers. By analysing the equivalent circuit in the classical SPWM with the dead time (SPWM with DT) submode by submode, a novel SPWM strategy is proposed. It uses triple carriers to modulate the modulating wave. According to the current direction after filtering, driving signals are decided via some simple logic operations. The simulation and experimental results prove the effectiveness of this modulation strategy. It also improves the performance of the induction motor in the illustrated example.