Multimode LLC Resonant DC?DC Converters for Wide Range Input Voltage

摘要

Conventional resonant DC?DC converters are typically limited to a narrow range of operating input voltage. In this paper, a multimode high-frequency LLC resonant DC?DC converter designed to operate with a wide range of input voltage, is proposed. The converter has three operating modes. It can provide a variable and wide voltage gain conversion via mode switching. Besides, this converter can attain a constant switching frequency operation, as well as ZVS operation for its switches and ZCS operation for its rectifier diodes. A 200 W prototype is constructed. Experiments are conducted to verify its features. Results show that the converter is functional over a wide range of input voltage (25 V-200 V) to provide a fixed output voltage of 200 V, while maintaining the ZVS and ZCS operations and high-efficiency power conversion.