Modeling method of coil module for wireless power transfer system by two-port S-parameter measurement in frequency domain

Abstract

Wireless power transfer (WPT) has become a very important technology. It is necessary to maximize the transferred power, the transfer distance, and the transfer efficiency for implementation of a practical WPT system. The performance of the WPT system can be efficiently maximized through accurate simulation with more accurate equivalent circuit model of each component in the WPT system in the design stage. This paper proposes and validates a process for modeling a coil module for a WPT system by two-port S-parameter measurement in the frequency domain. The coil parameters such as self-inductance, internal resistance, and magnetic coupling coefficient are calculated using the ABCD parameter, which is transformed from the measured S-parameter of a given coil module. The two-port S-parameter in a frequency range from 30 kHz to 1 MHz was measured using the Vector Network Analyzer. The extracted self-inductances and internal resistances of transmitting and receiving coils were confirmed by a one-port measurement method. The proposed modeling process based on two-port S-parameter measurement for the coil module will be helpful in maximizing the performance of a WPT system.