Ac equivalent circuit analysis for high-frequency isolated dual-bridge series resonant dc/dc converter

Bidirectional dual-bridge DC/DC converter with high-frequency isolation is gaining more attentions due to small size, high power density. In this paper, a dual-bridge series resonant DC/DC converter is analyzed with two simple ac equivalent circuit analysis methods for both voltage source load and resistive load. In both methods, only fundamental components of voltages and currents are considered. All the switches may work in either ZVS or ZCS for a wide changes in load or supply voltage allowing itpsilas use in a wide range of applications, such as renewable energy generation, regular battery charger/discharger, do motor control, etc. It is also shown in the second method that the load side circuit could be represented with an equivalent impedance. The polarity of cosine value of the load angle reveals the power flow direction. The analysis is verified with PSIM simulation results. Experimental results based on a 200 W prototype circuit are also included for validation purpose.