Performance of dead time compensation methods in three-phase grid-connection converters

This paper discusses effect of the power factor on voltage error caused by the dead time in voltage-source grid-connection PWM converters. The theoretical analysis derives the voltage error considering output capacitances of the switching devices and brings out that the voltage error depends on the current ripple amplitude through the converter which is changed by the power factor. The analytical result reveals the compensation characteristics of three approximation compensation methods and turn-off transition-based compensation method from the viewpoint of the power factor. The compensation characteristics of four different compensation methods are compared with those with each other in experiments using a 200-V, 5-kW three-phase grid-connection converter. As a result, the approximation compensation methods exhibit a good compensation performances at a specific power factor. In contrast, the turn-off transition-based compensation method has a better compensation performance allover the range of power factor.