DC Converter with Wide Soft Switching Operation, Wide Input Voltage and Low Current Ripple

A soft switching current-source resonant converter is presented and implemented for wide voltage applications such as fuel cells and solar power. An LLC (inductor–inductor–capacitor) converter is adopted to accomplish zero voltage (current) operation on active switches (diodes). Thus, the circuit efficiency is increased. The interleaved pulse-width modulation (PWM) converter is employed on the input side to accomplish low input ripple current. A hybrid LLC converter is adopted to achieve wide voltage operation from Vin, min to 4Vin, min and to improve the weakness of a conventional LLC converter. Half-bridge diode rectification is employed on the output side to decrease power loss on the rectifier diode. To confirm the theoretical analysis and feasibility, experimental verifications with a 500-W prototype are demonstrated in this paper.