A novel ZVS quasi-resonant DC-link PWM inverter with minimum voltage stress across the switches

This paper presents a new quasi-resonant DC-link (QRDCL) PWM inverter with zero voltage switching (ZVS) capability. The proposed quasi-resonant circuit creates zero voltage intervals in the DC-link to facilitate ZVS of the inverter switches under all operating conditions. This is achieved with the DC-link voltage being clamped at the source voltage V, using minimum additional components. It requires only two additional switches compared to the conventional PWM converter. Moreover, the control circuit is not called upon to control the inductor current, as it is the case with other circuits of the same family. Hence, it doesn´t require any current sensing device, thereby, making the control circuit simple and cheap. The operating principle of the circuit is explained and detailed analysis of each operating mode is given. A design criterion for achieving ZVS is obtained from the mathematical analysis. The feasibility of the proposed circuit operation has been verified by PSPICE simulation. The simulation results show full ZVS for both the proposed circuit and the PWM inverter