Soft-Switching Non-Isolated Current-Fed Inverter for PV/Fuel Cell Applications

A non-isolated impulse commutated current-fed voltage doubler based non-isolated inverter for a solar photovoltaic, battery or fuel cell application is proposed in this paper. Impulse commutation enables device voltage clamping with zero current commutation of the semiconductor devices. It eliminates the traditional problem of turn-off voltage spike across the devices in current-fed converters. Unlike resonant converters, resonance pulse appears for a very short interval leading to zero current turn-off of devices. It therefore, limits peak and circulating currents through the components. Voltage doubler is selected to achieve 2× gain. Variable frequency modulation ensures output voltage regulation with input and load variations. Steady-state operation and analysis of front-end converter is explained. A 500 W prototype has been designed and developed to demonstrate the performance and verify the proposed operation, analysis, and claims.