High-Order Harmonic Currents Analysis for Accurate Coupling Coefficient Extraction in Multi-Transmitter Wireless Power Transfer System

Abstract

This paper proposes an improved coupling coefficient extraction method considering the high-order harmonic component of the input current in a multi-transmitter wireless power transfer(WPT) system. Coupling coefficients between each transmitter coil and receiver coil are necessary to operate the transmitter with high power transfer efficiency according to the characteristics of the receiver in the multi-transmitter WPT system. Some previous studies have analyzed circuits using the first harmonic approximation method and derived coupling coefficient extraction methods. However, in the case of the LCC-S topology, which is widely used in WPT system, the proportion of the high-order harmonic component in the input current is significant, and the proportion increases as the size of the coupling coefficient decreases. Therefore, a method for extracting the coupling coefficient that analyzes the harmonic component of the input current and considers it is required to accurately extract the coupling coefficient.