Five-Phase LLC Resonant DC/DC Converter Utilizing CLC Filter for Current Sharing

Multiphase
LLC
resonant converters are extensively used in the high-power scenarios. Compared with the common three-phase
LLC
resonant converters, a five-phase
LLC
(FPLLC) resonant converter can operate at higher power density with reduced current ripple, yet the current imbalance issue induced by the passive component tolerance is aggregated. In this article, the FPLLC converter topology is introduced. Via the current phasor diagram and time-domain analysis of resonant current with large component tolerance, an analytical model for unbalanced currents of the worst case is deduced. In addition, a current sharing method utilizing
CLC
output filter is proposed. The high-impedance commutation path introduced by the
LC
parallel resonance tank of
CLC
filter can suppress the unbalanced current. Combining with the derived unbalanced current in the worst case, the design process of the
CLC
filter is presented in details. Both the analytical model of resonant current in the worst case and the current sharing functionality of the proposed
CLC
filter are validated with simulation and experimental study.