High conversion ratio DC-DC converter with isolated transformer and switched-clamp capacitor for Taiwan photon source

Abstract

A new high step-up voltage converter that combines a switch capacitor and isolated transformer, together with a passive clamp circuit, is employed to reduce voltage stress on the main power switch. The voltage stress of the power switch should be clamped to 1/4 Vo, and the proposed converter can achieve high step-up voltage gain with appropriate duty ratio. The energy of the leakage inductor can be recycled by the clamp capacitor because of the passive clamp circuit, and low On-state resistance RDS(on) of the power switch can be adopted to reduce the conduction loss. In this paper, several mathematical derivations are presented, CCM and DCM operating principle are discussed, and experimental results are provided to verify the effectiveness of converter topology. Finally, a 24-V-input voltage to 200-V-output voltage and a 150 W output power prototype converter are fabricated in the laboratory.

Low voltage high current modular DC power supply for solid state RF amplifiers

“…A single phase IGBT based inverter bridge operating in phase shifted pulse width modulation mode is employed in each power module which converts 700 V dc into pulsed ac output. This ac output is applied to high frequency ferrite core step down transformer, rectified and then filtered to obtain 50 V dc output [14]. Infineon made IGBT IKQ75N120CT2 has been used for inverter bridge switches, operating at 25 kHz switching frequency.…”