Fixed-Frequency Zero Voltage Switching CurrentFed (L) (LC) Resonant DC-DC Converter

Current-fed load resonant converters offer soft-switching against wide variations in load and input fluctuations unlike quasi resonant and impulse resonant converter. However, their modulation characteristics and efficiency are highly influenced by employed load dependent resonant tank. Therefore, parallel LC resonant tank-based converters exhibit compromised part load efficiency due to variable switching frequency operation and load independent circulating currents. On the other hand, series resonant tank-based converters such as current-fed LLCSRC resonant converter operates with constant switching frequency. However, their parallel inductor pulls down part load efficiency due to unnecessary conduction loses. Therefore, this paper proposes simple modification in LLC-SRC resonant tank, leads to proposed current-fed (L)(LC) resonant converter, to eliminate additional conduction loses in converter. Proposed converter inherits all merits of LLC-SRC converter with improved efficiency. This paper presents analysis, design and verify proposed theory with simulations.