Full-Range Regulation Method for Half-Bridge Series Resonant Converter

In this article, a fixed on-time modulation (FTM) method for half-bridge series resonate converters (SRCs) is proposed to achieve the full range regulation for all loads. Additionally, the proposed method features low current stresses, zero voltage switching turn-on for transistors and zero current switching turn-off for diodes. A comprehensive analysis of the operation principle, voltage gain curves, component stresses, and comparisons with other methods is given. Besides, the extension of the FTM method to a family of half-bridge SRCs is discussed and the voltage gains of different topologies are provided. A 200 W prototype of the half-bridge SRC was built and tested to verify the theoretical analysis.