Isolated High Step-up DC-DC Converter with Zero-voltage-switching

摘要

A high step-up DC-DC converter is proposed in this paper.The proposed converter has two transformers.The primary sides of them are paralleled virtually and the secondary sides have series connection to increase the voltage gain.An active clamp circuit is employed to suppress the switch voltage stresses and obtain zero-voltage-switching (ZVS) operation of the switches.Voltage doubler is selected as an output rectifier to increase the voltage gain and confine the voltage across the output diodes to the output voltage.Since the output diode currents are controlled by the total leakage inductance of the transformers,the reverse-recovery problem of the output diodes is significantly alleviated.Due to the ZVS operation and the alleviated reverse-recovery problem,the switching losses of the proposed converter are significantly reduced and the efficiency is improved.Steady-state analysis is performed.Experimental results based on a prototype are also provided to verify the effectiveness and feasibility of the proposed converter.