Input stage of double-conversion UPS´s using integration concept of ZVT auxiliary commutation circuit

This paper proposes the concept of integrated ZVT (iZVT) auxiliary commutation circuits applied to systems with several power conversion stages. With this concept, it is possible to reduce the number of additional elements, as well as to minimize the circulating reactive energy. A new iZVT is applied to input stage of a double-conversion UPS to demonstrate the functionality of this concept. By using this new circuit, the main switches operate under soft-commutation of ZVT type, and the auxiliary switches are turned on and off under ZCS or ZVS. Experimental results of a 1.2 kW at 100 kHz prototypes are presented to demonstrate the good performance of the new integrated ZVT auxiliary commutation circuit and the feasibility of the proposed concept