Interleaved Boost-Integrated LC Series Resonant Converter With Frequency-Free Designed Transformer for Wide Voltage Range Applications

In this article, we present a novel interleaved boost-integrated LC series resonant converter with two output rectification modes, which are voltage-doubler rectifier mode and voltage-quadrupler rectifier mode with constant output voltage for wide input voltage range applications. Due to the symmetrical configuration of the rectifier, the voltage stress of switches and diodes on the secondary side is only half of the output voltage. With the proposed pulse frequency modulation, the maximum magnetic flux density B-m of high-frequency transformer is only related to the resonant frequency rather than the switching frequency. Hence, the transformer can be frequency-free designed. The zero-voltage switching of the primary switches and zero-current switching of the secondary switches and diodes are achieved, respectively. Moreover, the design procedure for some key parameters is presented. Finally, a 470 W prototype with a switching-frequency range from 50 to 140 kHz is built to verify the operation principles of the proposed converter and modulation.