A Zero-Voltage Switching Two-Inductor Boost Converter With an Auxiliary Transformer

The two-inductor boost converter with an auxiliary transformer has been previously proposed for the applications where a large difference between the input and the output voltages is required. In the isolated version of the converter implementation, however, the leakage inductance of the high frequency isolation transformer presents an adverse effect and will cause significant voltage ringing on the primary switches. This paper presents a resonant version of this converter which is able to actively utilize the transformer leakage inductance as well as the MOSFET drain source capacitance. The resonant arrangement produces soft-switching conditions for both the primary MOSFETs and the output rectifier diodes. The detailed resonant state analysis is provided in the paper. The simulation waveforms are also produced for one specific operating condition. Finally, the experimental waveforms of a 1-MHz 100-W converter are provided to verify the theoretical analysis.