Electromagnetic-Thermal Coupled Simulation of a 10 kW,10kHz High-Frequency Transformer Considering the Dynamic Electromagnetic Parameters of Materials

High-frequency transformer (HFT) plays an important role in power electronics transformer (PET) applications in flexible AC/DC power transmission, data center and rail transport fields. Due to the high dv/dt, non-sinusoidal and multi-harmonic electric stress and high power losses, the electromagnetic-thermal coupled properties of HFT becomes complicated. This paper focuses on the influence of dynamic electromagnetic parameters of materials, such as core material, winding, and insulating material on the electromagnetic and thermal field. The bidirectional coupling fields between electromagnetic field and thermal field of a 10kHz, 10kW is conducted by a FEM simulation. It determined the relationship between the permeability of core, the conductivity of winding and the permittivity of insulating material (epoxy resin) with the temperature and electric field. The results indicated that the maximum electric field is concentrated at the end of the winding, which is 1.17kV/ mm. Severely skin effect and proximity effects occur inside the windings with the distorted current density distribution. Thus, the winding loss can reach to160W. The hotspot temperature occurs at middle of the secondary winding. The temperature rise of the proposed simulation is higher than that of the traditional simulation. This study provide a guideline to the core, winding and insulation design and HFT applications.