Soft-switching Analysis Of Two Types Of Series Resonant Dual Active Bridge Converters

The dual active bridge dc-dc converter(DAB)can be operated in either the boost mode or the buck mode,which is suitable for bidirectional power transmission.At the same time,it has switches with small voltage and current stress,bidirectional symmetric structure which is easy to modularize,high power density and natural ZVS ability.So it is suitable for high-voltage and high-power situations.Dual bridge series resonant converter(DBSRC)is an organic combination of dual active bridge dc-dc converter and LC series resonant slot.Moreover,the introduction of the resonant tank leads to currents with the quasi-sine wave compared with DAB square/triangle current of the converter.At the same time,the current harmonic will be smaller,and the eddy current loss of high frequency transformer will be reduce,which will lead to the decrement of loss of devices.Therefore,dual bridge series resonant converter has the potential advantages of high efficiency.It has a good application in the field of electric vehicle charger which can complement the energy with micro grid.In order to fully explore the soft switching characteristics of the double-bridge series resonant converter,the traditional two-bridge series resonant converter and the twochannel series resonant converter are taken as the research object in this paper,and three phase-shifting modulation methods are adopted: Extended phase-shift control(EPS),dual phase-shift control(DPS)and triple phase-shift control(TPS).Firstly,the detailed working mode of two dual-bridge resonant circuits under EPS is analyzed,and the steady working relationship of the circuit is deduced.Then,the characteristics of the soft switch behavior of zero voltage switching(ZVS)and zero current switching(ZCS)are analyzed in detail.The theoretical analysis is verified through simulation and experiment results.