Impulse Commutated Current-fed Three-phase Modular DC/DC Converter for Low Voltage High Current Applications

Current-fed converters with their innate boost nature, short circuit protection etc. offer enormous potential for high current and high gain applications. To resolve the issue of turn-off spike severe in current-fed converters, this paper proposes a commutation strategy termed as impulse commutation in a three-phase current-fed full bridge converter. This simple and cost-effective technique employing high frequency (HF) parallel capacitors achieves load adaptive zero current switching (ZCS) of the primary semiconductor devices. Variable frequency modulation ensures output voltage regulation and power transfer with source voltage variations. Modularity and scalability of the full bridge converter improves the converter reliability and a compact light-weight system can be easily realized. Steady-state analysis and converter design has been explained. Simulation and experimental results obtained from a proof-of-concept hardware prototype rated at 1 kW have been included to validate the claims.