A Current-Fed Full-Bridge Boost LCL-Type DC/DC Converter With Parallel Capacitors On Switches

This paper investigates a current-fed full-bridge boost DC/AC/DC converter based on series LCL resonance. By paralleling an additional capacitor on every power switch, a wide input voltage range (50-162V) and a narrow switching frequency range (100-125kHz) are achieved. To maintain a constant output voltage, frequency control with a constant turn-off time for switches is employed, enabling Zero Voltage Switching (ZVS) without the need for any auxiliary circuitry. The converter eliminates the DC bus capacitor by utilizing traditional capacitors under a resonant function. Through waveform modulation of the tank voltage, the energy dissipation is minimized. To help the design, A Fourier’s mathematical description is exploited. The operational principle, detailed mathematical analysis are given, and simulation results are presented to validate the feasibility of the proposed converter.