Three-Phase Resonant CLLC Current-Source Converter for Low-Voltage High-Current Applications

Aimed at low-voltage high-current applications, such as electrolytic hydrogen production and data center power supply, this paper proposes a three-phase interleaved parallel resonant CLLC current-source converter with selectable Y-Y and Delta-Delta connections. The three-phase circuit topology achieves high-current output capability, while the interleaved switching strategy contributes to small ripples in output current. A loosely coupled three-phase magnetic mechanism is adopted, and bilateral series resonant capacitors fully compensate the dual-sided self-inductances of the magnetic coupler, realizing inherent current-source output features. To validate the proposed design, a 1.8kW/250kHz gallium nitride (GaN) FET-based three-phase CLLC converter prototype is established. Experimental results validate the features of load-independent constant-current (CC) output and low ripples. Furthermore, with an input DC voltage of 175 V, the converter respectively achieves 20.11A and 50.94A in the Y-Y and Delta-Delta connections, and the DC-DC efficiency 93.4% and 92.7% with a synchronous rectifier.