A novel quasi-resonant DC-link PWM inverter using minimum number of switching devices

A novel quasi-resonant DC-link (QRDCL) inverter is proposed. The circuit uses only one additional switching device and ensures soft switching of the inverter devices under all loading conditions. The maximum voltage across the inverter devices is clamped at (1.01-1.1) pu. The zero voltage instants in the DC-link are created just prior to the inverter switching. The output voltage of the inverter can be controlled using any PWM technique. In this paper, the principle of operation and the detailed analysis of the proposed QRDCL inverter are presented and design criterion for achieving soft switching of the inverter devices is obtained. Detailed PSPICE simulation studies are carried out to predict the performance of the inverter under various loading conditions and these results are validated with the experimental results.