Novel Soft-Switching Snubberless Naturally Clamped Current-Fed Full-Bridge Front-End-Converter-Based Bidirectional Inverter for Renewables, Microgrid, and UPS Applications

This paper presents a soft-switching current-fed full-bridge front-end-converter-based bidirectional inverter for residential photovoltaic (PV) applications. The proposed converter is an intrinsic isolated boost converter with a high-step-up voltage conversion ratio. The device voltage is naturally clamped owing to proposed secondary modulation. Zero-current commutation of current-fed devices is novel and makes the converter snubberless and fully soft-switched with natural clamping of the devices´ voltage. Zero-current switching of primary devices and zero-voltage switching of secondary devices are achieved. Soft switching is inherent and is maintained during wide variation of input voltage and load independent. Steady-state operation, analysis, and design have been explained. A 200-W laboratory prototype of the inverter is developed and tested to demonstrate the performance over wide variations in input voltage and output power for PV applications.