Comprehensive Analysis of Electric Field Characteristics for Multi-Winding Medium Frequency Transformer

Abstract

The multi-winding medium frequency transformer (MMFT) has attracted widespread attention, since its application in power electronic transformers can simplify the system structure and reduce the volume and weight. However, the special working conditions of MMFT due to high voltage and high power density increase the difficulty of insulation design for MMFT. For this issue, this paper presents a comprehensive analysis of electric filed characteristics for MMFT. First, the electric field model of MMFT is established using the 2-D finite element method. Based on it, the influences of connection mode, core structure, and hollow winding on the electric field characteristics of MMFT are studied, including the overall electric field distribution, maximum electric field intensity, and the electric field intensity along a fixed path. The results show that there are differences in the maximum electric field intensity for different connection modes and different core structures, which provides references for MMFT insulation design. The proposed modeling method and analysis results in this paper are important for insulation improvement of MMFT.