Optimization design of transformer used in switching power supply with high power density

A method for designing a transformer used in switching power supply is presented. The transformer designed by this method has advantages of the lowest power loss and higher power density than that designed by traditional method. Furthermore, the mathematical model of power loss which is closer to the reality is built in this study. Both the current density J and the flux density B_m in terms of the lowest power loss can be calculated by this model. The methodology how to select the smallest cores and design the rational coil is also presented. The transformer with the cores and coil can work at the upper limit of temperature rise. Finally, a transformer (2.8 kW / 50 kHz) designed by the method is tested.