Research on Calculation Method of Inlet Capacitance on Converter Transformer Based on FEM

The long-duration induction voltage test of converter transformers often uses the method of resonant connection between parallel inductors and converter inlet capacitors to reduce power supply capacity. To estimate the value of the resonant inductance, accurate calculation of the input capacitance of the converter transformer is necessary. This paper presents a method that combines finite element simulation with formula derivation to quickly calculate the input capacitance of the converter transformer. Firstly, the equivalent dielectric constant of each part of the transformer is calculated. Then, the geometric capacitance of the converter transformer is calculated through finite element simulation, and the capacitance value is corrected by mathematical derivation. Finally, experiments are conducted to validate the accuracy of the model and the feasibility of the calculation method.