Design and Analysis of a Novel ZVZCT Boost Converter With Coupling Effect

In this paper, a new zero voltage zero current transition (ZVZCT) boost DC-DC converter using a coupled inductor is proposed. This topology provides the main switch ZVZCT for the turn-on and zero voltage switching (ZVS) for the turn-off. Moreover, the auxiliary switch turns on at zero current switching (ZCS) and turns off at ZVS. The main diode turns on with ZVT and turns off with ZCS, and other diodes also operate under soft-switching conditions. Besides, due to the coupling effect, the proposed converter improves efficiency additionally since resonant energy in the resonance tank could be transferred to the output, and the circulating current can be limited as well. The soft-switching can be realized in almost all the load rang. In this design, there always exist energy releasing circuits to conduct magnetic flux leakage currents, such that the surge currents are eliminated and switch current stress can be accordingly reduced. All the devices resonate in a unique direction within less than half of a resonance period, so power losses with respect to the resonance can be decreased. In this paper, the converter design and operation principles of the converter are given. It also has been verified by a 1-kW experimental prototype with switching frequency of 100 kHz, and the related experimental results are presented.