New control strategy for bidirectional LLC resonant converter in energy storage systems

This paper proposes a topology which is based on the traditional LLC resonant converter and has a symmetrical circuit structure to achieve the bidirectional power flow capability. With the advantage of ZVS and ZCS, reverse energy is eliminated, so high efficiency is achieved of the proposed topology, which can be above 97% at full load. In order to be adoptable in bidirectional applications like batteries and super-capacitors, a new control scheme is also proposed in the paper, by which the power flow direction can be regulated automatically. Simulation and experimental results are given to verify the analysis.