Design and Implementation of High Switching Frequency LLC Resonant Converter for High Power Density

To improve the power density of switch-mode power supplies, high switching frequency operation is an effective method to make the size of passive components small. The new design methodology of magnetizing inductance for zero voltage switching condition, and the size reduction of passive components should be proposed for 500 kHz high switching frequency operation. To verify the proposed methodology, the simulation and experimental results which include power conversion efficiency, and temperature of each passive and active component will be presented. Using those results, dominant power losses will be investigated according to the comparison of 100 kHz and 500 kHz operations. In addition, the small-sized output capacitor which has small output capacitance, and small effective series resistance induces the unstable operation problem. To analyze these control issue, the frequency response of small signal will be discussed to design the optimal feedback loop compensator for high switching frequency LLC resonant converter.