A High Efficiency and Wide Voltage Gain sLC_LCC DC–DC Converter With SiC Devices

Abstract

A novel s <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> _ <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LCC</i> resonant dc–dc converter is proposed in this article. With the combination of a notch filter and a new s <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> excitation structure of the transformer, wide and fast gain characteristics are obtained. With the frequency modulation, the notch filter structure helps the converter realize a wide output voltage range adjustable from zero theoretically. Besides, the fast voltage gain regulation capacity is achieved in a narrow frequency range with the s <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">LC</i> excitation structure. In the text, topology structure, operation principle, and characteristics analysis are illustrated in detail. For numerous passive components, an effective design method is necessary to guide parameter determination. And a detailed parameter design process is discussed. With the selected parameters, the soft-switching feature is realized. Finally, a 500 W experimental prototype is fabricated to verify the feasibility and effectiveness of theoretical analysis. The converter achieves 59.3–16.3 V output voltage regulation ability in a narrow frequency range (86 kHz, 189 kHz) under the condition of power 500 W and input voltage 375 V. High efficiency is maintained in the full load range, and the maximal efficiency of the converter reaches 97.7% at 99.5 kHz.