Research on the Characteristic Change in an Inductive-coupling-type Contactless Power Transformer for a Railway According to the Core Shapes and Misalignment Utilizing a T-type Equivalent Circuit

Abstract

Although an electric railway is an ecological transportation system, there are some obstacles when an electric railway is installed: the high cost for installation and the detrimental effect on the environment. A contactless power transfer system (CPT system) is a solid solution for these obstacles. However, a CPT system for a railway application needs to have a high capacity and a tolerance to the misalignment of the coils. In this paper, inductive power transfer theory, which is able to transfer a greater amount of energy than the electromagnetic resonance method, is chosen, and its tolerance to the misalignment is our focus. The authors measure various core shapes, and their coupling coefficients, leakage inductances, and excitation inductances according to the misalignment are obtained with a finite element method (FEM) analysis. By using these parameters, the transmitted power and efficiency are calculated by two equivalent circuits: the S/S circuit and the S/P circuit. Finally, by comparing the parameters and transmitted power of each core shape and circuit, the authors show that the circular core can transfer 100kW of energy for a misalignment of 300mm.