Abstract

This paper presents a high step-up DC-DC converter for fuel cell system. The proposed converter comprises of an input-current doubler, an output-voltage doubler, and an active-clamp circuit. The input-current doubler and the output-voltage doubler both provide much higher voltage conversion ratio by using a low turn ratio transformer. The low turns ratio increases the overall efficiency. A series resonant circuit of the output voltage doubler removes the reverse recovery problem of the rectifying diodes. The active-clamp circuit clamps the surge voltage of switches and recycles the energy stored in the leakage inductance of the transformer. The proposed converter has been simulated in OrCAD software. Simulation results proved that based on the transformer design, better performance of the converter can be achieved for any value of input voltage.

Key words: Series resonant circuit, active clamp circuit, input-current doubler, output-voltage doubler.