The Variation of Core Loss in High-Frequency Transformers Under Different Load Conditions

Typically, the core loss of the high-frequency (HF) transformers is considered constant regardless of the load condition on the secondary side. This paper indicates that the various load conditions can affect the core loss in HF transformers due to the variation of winding parasitics elements and subsequently the transformer's excitation voltage and current waveforms, and the field interactions between the primary and secondary windings and between the windings and core. The contribution of this work is demonstrating the core loss variation depending on different load conditions in HF transformers, which is not commonly assessed and considered in previous studies. The captured experimental results are compared with the three-dimensional (3D) finite element analysis (FEA) results conducted in Ansys Maxwell, to provide a better comprehension.