Data center power distribution is increasingly transitioning toward high-voltage DC, placing new demands on server rack power supply design to deliver high efficiency and high power density. The Frequency Doubling (FD) LLC resonant converter is a suitable topology for adapting to increased DC voltage while maintaining similar device voltage stress, particularly where high step-down ratios and galvanic isolation are required. To enhance the efficiency and address switching devices thermal imbalance of the FD LLC converter, this paper proposes an optimized solution for selecting primary-stage semiconductor devices and determining tank parameters to achieve Zero Voltage Switching across the full operating range. Using a flexible Resonant Double Pulse Test setup, the performance of different devices is characterized through LTspice simulation and validated experimentally.
