High power density nanocrystalline core transformer design for resonant converter systems

Design issues of high power density transformers for resonant converter systems are discussed. Under the specified operating condition, the transformer is designed to achieve the minimum volume. Finemet/sup /spl reg// nanocrystalline magnetic material is suitable for the pulse applications, due to its superior low loss density and high operating temperature characteristics. 1000 W/in/sup 3/ power density is achieved for the 30 kW pulse operation converter. Based on an energy-based approach, lumped-component transformer equivalent circuit is developed, with leakage inductances and winding capacitances calculated according to certain transformer geometry. The analysis has been verified by the experimental results.