A new quasi-resonant DC-link PWM inverter using single switch for soft switching

This paper presents a new quasi-resonant DC-link (QRDCL) inverter. The circuit needs only one switching device to create zero voltage instants under all loading conditions. It has minimum voltage stress (1.01-1.10) pu on the switching devices and has the flexibility of selecting switching instants of the resonant link in synchronism with any PWM technique. The control technique does not require the help of the inverter switches to create the zero voltage instants in the DC-link and expensive voltage and current sensors are eliminated from the control circuit. In this paper, the principle of operation and detailed analysis of the proposed QRDCL inverter are presented and design considerations for achieving soft switching are obtained. Detailed PSPICE simulation studies are carried out to study the feasibility of the proposed topology and these results are verified experimentally.