Bidirectional LLC resonant converter is becoming widely applied in energy storage systems because of its high efficiency, high power density, and low EMI characteristics. To increase output power and reduce current ripple, the common approach is to parallel multiple-phase interleaved converter. This paper proposed a three-phase interleaved bidirectional LLC resonant converter with vertically integrated magnetics. Transformers and inductors are vertically integrated to reduce the volume of magnetics and achieve flux cancellation in both forward and backward operation modes, resulting in smaller core loss and improved converter efficiency. The optimal design of magnetics is presented, and a 500kHz 400V/52V 3.5kW prototype will be implemented, with calculated efficiency of 99.08% and power density of 327W/in3 (20kW/L).
