Coupling Coefficient Estimation Method for SP-Type Wireless Power Transfer System

Magnetic resonant coupling has gained attention as a wireless power transfer method for home appliances and electric vehicles. However, its performance can degrade when the coupling coefficient varies. To address this issue, researchers have explored applying parity-time symmetry theory to these systems. The proposed method requires accurate coupling coefficient values for effective frequency control. This paper introduces a method for estimating the coupling coefficient using a recursive least squares algorithm in the proposed wireless power transfer system. Additionally, experiments were conducted with actual equipment to investigate how the parameters of the recursive least squares algorithm-such as the forgetting factor and initial variance matrix-influences the estimation of the coupling coefficients.