TY - GEN
T1 - Electric Field Modelling and Simulation of the High-voltage High-frequency Transformer Insulation Applied for Power Electronics Based on Circuit-field Coupling Analysis
AU - Wang, Zhaoxin
AU - Bak, Claus Leth
AU - Silva, Filipe Miguel Faria da
AU - Sørensen, Henrik
PY - 2022
Y1 - 2022
N2 - This paper established a transient electric field model of a high-voltage high-frequency (HVHF) transformer based on circuit-field coupling analysis. As the key component of power electronic transformers (PETs), the operating conditions of the HVHF transformer are determined by the converter circuit containing it. To find out the electrical stress withstood by the solid insulation, it is essential to model the transient electric field while considering the circuit model of the converter. The circuit model of the converter and the 3-D transient electric field model based on the finite element method (FEM) are built in ANSYS. The voltage and current waveforms on both primary and secondary sides of the HVHF transformer obtained from the converter model are coupled to the transient electric model as the excitations. Based on the established model, a case study of a 60 kHz HVHF transformer used for the dual active bridge (DAB) converter is investigated, and the electric field characteristics of the insulation are analyzed. The electric field distribution inside and on the surfaces of the insulation is present, and magnitude values of the highest electrical stress inside and on the surfaces of the insulation are identified. The theoretical verification is carried out based on the grid convergence index (GCI) method and it verifies the accuracy of the proposed model. This model could be used to calculate the overvoltage capacity of the HVHF transformers in various power electronics applications and it is an essential step in building the digital twin model of the HVHF transformer.
AB - This paper established a transient electric field model of a high-voltage high-frequency (HVHF) transformer based on circuit-field coupling analysis. As the key component of power electronic transformers (PETs), the operating conditions of the HVHF transformer are determined by the converter circuit containing it. To find out the electrical stress withstood by the solid insulation, it is essential to model the transient electric field while considering the circuit model of the converter. The circuit model of the converter and the 3-D transient electric field model based on the finite element method (FEM) are built in ANSYS. The voltage and current waveforms on both primary and secondary sides of the HVHF transformer obtained from the converter model are coupled to the transient electric model as the excitations. Based on the established model, a case study of a 60 kHz HVHF transformer used for the dual active bridge (DAB) converter is investigated, and the electric field characteristics of the insulation are analyzed. The electric field distribution inside and on the surfaces of the insulation is present, and magnitude values of the highest electrical stress inside and on the surfaces of the insulation are identified. The theoretical verification is carried out based on the grid convergence index (GCI) method and it verifies the accuracy of the proposed model. This model could be used to calculate the overvoltage capacity of the HVHF transformers in various power electronics applications and it is an essential step in building the digital twin model of the HVHF transformer.
U2 - 10.5324/nordis.v27i1.4716
DO - 10.5324/nordis.v27i1.4716
M3 - Conference article in Journal
SN - 2535-3969
VL - 27
JO - Proceedings of the Nordic Insulation Symposium
JF - Proceedings of the Nordic Insulation Symposium
IS - 1
ER -