Two-Stage Optimization Method for Efficient Power Converter Design Including Light Load Operation

Power converter efficiency is always a hot topic for switch mode power supplies. Nowadays, high efficiency is required over a wide load range, e.g., 20%, 50%, and 100% load. Computer-aided design optimization is developed in this research study, to optimize off-line power converter efficiency from light load to full load. A two-stage optimization method to optimize power converter efficiency from light load to full load is proposed. The optimization procedure first breaks the converter design variables into many switching frequency loops. In each fixed switching frequency loop, the optimal designs for 20%, 50%, and 100% load are derived separately in the first stage, and an objective function using the optimization results in the first stage is formed in the second stage to consider optimizing efficiencies at 20%, 50%, and 100% load. Component efficiency models are also established to serve as the objective functions of optimizations. Prototypes 400 V to 12 V/25 A 300 W two-FET forward converters are built to verify the optimization results.