Design and implementation of a multi winding high frequency transformer for MPSST application

Abstract

Development of the new generation of high power and high frequency power electronic switches along with the need for compact controllable converters for utilization of distributed energy resources in the grid, have led to significant developments in the area of solid state transformers in the last years. The design process of a high frequency transformer as the main element in the solid state transformer is illustrated in this article. A multi winding transformer for multiport SST application is designed, studied and built in this research. In a MPSST several windings feed the core. As the result, coupling coefficient between each pair of windings, become an important factor which is studied in this study. Since the transformer is designed for high frequency applications, the power loss in the wire and core of the transformer increases as the result of higher skin effect and eddy current loss in high frequency. Three important factors in the design of HF transformer for MPSST are discussed in the paper. First, four different possible core materials are compared based on their flux density, frequency range, loss and price. Then the cable selection is illustrated and finally, different winding placement and distribution on the same core are suggested and the inductance and coupling coefficient matrices are calculated using ANSYS Maxwell 3D simulation. The transformer is built in the lab and the inductance values matches the expected values from the simulation.