Core Loss Calculation for High-Frequency Transformer with Finite Element Method

Kurzfassung

High-frequency transformers (HFTs) are widely used where weight and space are limited, such as in aircraft applications. It is a key component in DC-DC converters. However, as the frequency increases, core loss also increases in the transformer. Accurate calculation of core losses is essential for designing efficient and reliable transformers. Core loss under sinusoidal excitation is calculated using the Steinmetz equation. However, the core loss under non-sinusoidal excitation, such as square wave cannot be calculated by the Steinmetz equation. Therefore, different improved methods based on the Steinmetz equation, such as modified Steinmetz equation (MSE), improved generalized Steinmetz equation (iGSE) and waveform coefficient Steinmetz equation (WcSE) have been proposed to calculate core loss under non-sinusoidal excitation. A finite element method (FEM) based approach to calculate core loss in high-frequency transformers under square voltage excitation has been developed in this thesis. A single-phase 330 kVA, 100 kHz transformer is designed and simulated using Ansys Maxwell 2D to calculate the core loss. A nanocrystalline material, Vitroperm 500F is used as a core material for high-frequency and high-power applications. The FEM simulation results are verified with PLECS software. Finally, the core losses have been evaluated with improved methods.