Soft-Switching Power Converter for Energy-Efficient Renewable Power Systems

Abstract

The integration of variable photovoltaic and wind energy into renewable power systems has created a high demand for high-frequency converters that achieve low switching loss, reduced thermal stress, and stable output regulation. In the case of conventional hard-switching converters, turn-on and turn-off losses are significant at higher switching frequencies, resulting in electromagnetic interference (EMI) and device stress. The objective of this work is to devise a soft-switching power converter structure comprising photovoltaic and wind inputs together with resonant energy transfer, transformer isolation, output filtering and aggregation leveraging coordinated Pulse-Width Modulation (PWM) and frequency. Here, Zero Voltage Switching (ZVS) is attained for the primary switch and Zero Current Switching (ZCS) is reached for the auxiliary switch using a resonant inductor–capacitor network. The 5-kW converter operates from a nominal 300 V input, regulates to a 400 V output and switches at 100 kHz with resonant inductance of ${2 0}~{\mu} \mathrm{H}$ and resonant capacitance of 126 nF. Compared to conventional switching ($94.7\%$ and $93.8\%$, respectively), simulation results demonstrate peak efficiency of $97.3\%$ and rated-load efficiency of $97.0\%$. The result yields a switching loss of 126 W down to a final value of 38 W and a total estimated loss reducing from 297 W to a peak of 190 W in balance-of-systems loss metrics conducive for use in photovoltaic–wind hybrid generation systems, distributed renewable plants, battery interfaces, microgrids, and more effective grid-connected power conversion with enhanced thermal- and electromagnetic-response performance under variable renewable conditions across realistic operating ranges.