Winding design of a high power medium frequency transformer

The availability of improved magnetic materials and higher voltage rating semiconductor devices have made the design of high power medium frequency transformers feasible. The paper presents a simple design procedure to determine the core dimensions based on the area product method. A winding design procedure to use foil conductors in the high voltage side to achieve ac-to-dc resistance ratio close to 1 is also shown, providing a possible replacement to the litz wires having low window utilization factor. The paper demonstrates a design example of 13.8kV/690V, 10kHz, 50kVA transformer to validate the design methodology and the winding losses are validated using 2-D FEM.