Estimation of Transmitter Inductance on Foreign Object in Wireless Power Transfer

Foreign objects with magnetic or conductive properties between the transmitter and receiver coils alter the resonant frequency, reducing output and efficiency. While circuit parameter-based detection methods offer the simplest approach for detecting foreign objects, considering cost and installation space, most parameters are affected by load characteristics, transmission distance, and coil alignment. Unlike other parameters, self-inductance is independent of the load resistance and coupling coefficient, making it the most suitable parameter for circuit parameter-based detection methods. However, due to the challenges of measuring self-inductance during power transmission, it must be estimated using measurable parameters. In this paper, we propose a method to estimate the transmitter inductance by expressing it solely in terms of measurable parameters based on the circuit model analysis.