A practical circuit model of high frequency transformers in power electronic systems

Abstract

This paper presents a practical circuit model of high frequency transformers in power electronic systems. All types of core losses (ie. the hysteresis, classical eddy current and anomalous losses) are included in the model. the thermal effect on magnetic hysteresis, the skin effect of eddy currents in magnetic cores and the effect of stray capacitances are also considered. This model can therefore accurately predict the performance and core losses of transformers used in high frequency switching circuits. The practical methods for determining the circuit parameters are developed and presented in the paper, providing crucial benefit for practical applications. The developed model has been applied to simulate the performance of a 500 W transformer in a full bridge inverter operated with square waveform voltage excitation of 25 kHz. The simulations are validated by the experimental results. © Institution of Engineers, Australia 2007.