An Ultra-Step-Up Quadratic Boost DC–DC Converter Based on Coupled Inductors and Quasi-Resonance Operation

In this article, an ultra-step-up dc–dc converter is presented which is useful for low-voltage source applications such as fuel cells and solar photovoltaics (PVs). The proposed converter is a quadratic boost converter that yields a high output voltage with a low-duty cycle. In addition, voltage doubler rectifier (VDR) and coupled inductors are used to further increase the voltage gain ratio. Moreover, the voltage stresses on switches are very low, leading to improvements in the efficiency and implementation cost. Due to the resonance operation, the turn-off currents of switches are lower than their maximum values, which reduces turn-off switching losses. In addition, the output diodes of VDR are turned on and off under zero current switching condition, mitigating the diode reverse recovery issues. A 480W lab prototype was built. The maximum efficiency of the converter is 96.28%, and the experimental results confirm the effectiveness of the proposed converter.