An Accurate Dead Time Compensation Method for SPWM Voltage Source Inverters

Abstract

Dead time is generally used to avoid the short circuit of the dc source, which causes harmonics in the output voltage and current of the voltage source inverters (VSIs). Based on an accurate harmonics calculation model of digital sinusoidal pulsewidth modulation, harmonics caused by dead time can be analyzed and calculated accurately. The proposed method obtains the compensation waveforms by the derived calculation module and detailed operation steps and then injects these into the sinusoidal reference voltage to eliminate the corresponding frequency harmonics caused by the dead time effect. The phase delay of the fundamental voltage caused by dead time is also considered. Moreover, this method avoids detecting the current polarity, affecting the compensation effect. Simulation and experimental results of the proposed method are presented to validate the effectiveness.