Half Bridge LLC resonant Converter Design for Wide Input Voltage Range Applications

This manuscript explain the design of half bridge LLC resonant converter for extensive input voltage range applications with high efficiency in normal mode and high voltage gain during hold-up time. Usually, to minimize the primary circulating current and lower conduction losses, large magnetizing inductance is used. Still, when a large magnetizing inductance is designed, it is difficult to adjust output voltage for a wide input voltage range. Therefore, in this paper, an auxiliary inductor and a switch is used in parallel with a magnetizing inductor to change its value according to the input voltage. During normal operation high magnetizing inductance is used for high efficiency and lower conduction losses, when the input voltage is dropped to its minimum value, smaller magnetizing inductance is used to acquire high voltage gain and increase the hold-up time duration. With the auxiliary inductor and a switch, the converter can achieve high efficiency for Normal mode and high voltage conversion ratio during hold-up time. The proposed method is confirmed through MATLAB simulation