Discrete Library based Automatic Multi-objective Optimal Design Method for LLC Resonant Converter

As one of the most popular isolated DC/DC converters, LLC resonant converter has been widely adopted in different industrial applications. Optimal design for the converter is the most effective and straightforward approach to improve the converter efficiency. In this paper, a discrete library based automatic multi-objective optimal design method is proposed for LLC resonant converter based on the accurate time domain analysis. The key components, including primary switch, secondary rectifier, resonant inductor, transformer, litz wire, and heatsink, are optimized from the library. The resonant frequency, transformer turns ratio, and resonant tank parameters are optimized automatically. The system efficiency and power density are selected as the optimization objectives. The genetic algorithm is used to achieve the automatic optimal design of the converter. In addition, instead of using the fixed operating point's efficiency, a mission profile based averge weighted efficiency (it can also be customized) is selected as one of the optimization objectives. To validate the effectiveness of the proposed discrete library based optimal design method, a design example with 380 V input voltage and 48 V output voltage conversion ratio and 1 kW power rating for data center application is illustrated. The theoretical efficiency over the whole load operation range is above 97% with the optimal design candidate.