A High-efficiency Resonant DC-DC Converter with Wide Voltage Gain Range

Abstract

A high-efficiency resonant DC-DC converter with wide voltage gain range is presented in this article. It adopts the notch filter to introduce a zero voltage gain point, which contributes to wide voltage gain range. Besides, it employs the sLC (series structure of an inductor and a capacitor) to act as the excitation part of high-frequency transformer, which is beneficial to the fast voltage regulation ability. With the integration of notch filter and sLC excitation structure, a fast and wide voltage gain in a narrow frequency range is achieved. Furthermore, the characteristic analysis and operating principle are conducted in detail. The converter possesses the good soft switching performance, which is conducive to high efficiency operation. Based on the application requirements, the input voltage is 375V, and the output voltage can vary from 0V to 60V theoretically. For the wide voltage gain applications, two-stage converters are used in many occasions. The efficiency comparison is between some two-stage converters and the proposed converter is given, indicating the efficiency advantage of the proposed converter. Finally, a 500W prototype is built. And some experiments are conducted in the laboratory to verify the effectiveness of the theoretical analysis. The highest efficiency is 97.2% which is obtained at 97.4kHz.