Design and Analysis of a High-Efficiency DC–DC Converter With Soft Switching Capability for Renewable Energy Applications Requiring High Voltage Gain

Abstract

Renewable sources like solar photovoltaic (PV) and fuel cell stack are preferred to be operated at low voltages. For applications such as grid-tied systems, this necessitates high voltage boosting resulting in efficiency reduction. To handle this issue, this paper proposes a novel high voltage gain, high-efficiency dc-dc converter based on coupled inductor, intermediate capacitor, and leakage energy recovery scheme. The input energy acquired from the source is first stored in the magnetic field of coupled inductor and intermediate capacitor in a lossless manner. In subsequent stages, it is passed on to the output section for load consumption. A passive clamp network around the primary inductor ensures the recovery of energy trapped in the leakage inductance, leading to drastic improvement in the voltage gain and efficiency of the system. Exorbitant duty cycle values are not required for high voltage gain, which prevents problems such as diode reverse recovery. Presence of a passive clamp network causes reduced voltage stress on the switch. This enables the use of low voltage rating switch (with low “on-state” resistance), improving the overall efficiency of the system. Analytical details of the proposed converter and its hardware results are included.