Analysis and design of a high efficiency high step-up gain DC-DC converter

A high efficiency high voltage step-up gain DC-DC converter is proposed and studied in this paper. The proposed converter consists of a boost converter cell and an isolated single-ended PWM resonant converter cell, with their outputs connected in series to achieve high voltage step-up gain. By using quasi-resonant technology, zero current switching (ZCS) for the diode on the secondary of transformer is achieved, and the turn-off loss of power switch is also reduced. Meanwhile, the boost converter cell in the proposed converter can not only step-up voltage, but also absorbs the leakage inductor energy during the turn-off interval of power switch. Therefore, it is suitable for high step-up high efficiency conversion. The operation principle and characteristics of the proposed converter are presented and verified experimentally with a 20V input, 120V/40W output prototype.