Numerical Analysis of the Effect of Converter Transformer Combined Magnetic Shielding on Stray Load Losses Considering DC Bias

In order to accurately analyze the effect of combined magnetic shielding on stray load losses of converter transformer, a three-dimensional (3D) finite-element analysis (FEA) model is established. The total losses can be gotten by summing the simulated losses of each harmonic. The effectiveness of the presented simulation method is verified by comparing the simulated and tested stray load losses of the converter transformer in the case of rated operation without lobe-type magnetic shielding structure. Afterwards, the installation position of lobe-type magnetic shielding is optimized by considering its effect on stray load losses. Finally, the stray load losses under different DC bias currents are simulated and analyzed.