A High-Voltage DC-DC LLC Resonant Converter by Using a Symmetrical Voltage Multiplier Circuit

This paper introduces a high-voltage output DC-DC LLC resonant converter designed for various applications. Utilizing soft switching techniques, the converter minimizes electromagnetic interference, enhancing efficiency and operational frequency. Notably, it regulates output voltage by modulating switching frequency to accommodate load changes and input voltage fluctuations while ensuring soft switching. The core design employs a six-switch inverter, reducing voltage stresses and enhancing overall performance. Additionally, a symmetrical multiplier in the output stage quadruples the resonant tank voltage, improving power density without significant changes in output impedance or transformer turns ratio. The study includes detailed operational principles, mathematical analysis, and validation through simulation, substantiated by a prototype implementation. The performance of the proposed resonant converter is verified using a prototype that has 40 V input voltage and 320 V output voltage.