Soft switched capacitively coupled DC-AC converter for high power

A capacitively coupled DC-AC power converter which is capable of zero current soft switching is presented. A form of amplitude modulation is introduced to provide a sinusoidal output waveform. Due to its favorable current stresses on the switches, this converter is suitable for high current high power inductive load applications. With this technique, switching losses can be reduced. The soft switching method is accomplished by the alternating voltage of the capacitor. The series inductive snubbers assure the zero current turn-on of the switches. Reduction of the switching losses implies that the switching frequency and the overall system efficiency can be increased for high-power gate-turn-off devices. Since this converter can operate at higher switching frequencies, the reactive component sizes can be decreased and the power density can be raised in high-power applications. The zero current soft switching method makes the capacitively coupled converter suitable for high-current, high-power inductive load applications, such as motor drives, without significantly increasing the conduction losses.<>