Time Domain Coupling Coefficient Estimation Using Transmitter-side Information in Wireless Power Transfer System

Accurate estimation of coupling coefficient between the transmitter and the receiver is a challenge faced in the application of magnetic coupling wireless power transfer (WPT) system. This paper proposes a time domain method to estimate the coupling coefficient only with the requirement of transmitter side instantaneous input voltage and current. The method first provides a systematic way to generate a time domain mathematical model of the WPT system, where the coupling coefficient is introduced as one of the time-varying states of the system. The model is built in such a way that all the physical laws that the WPT system should obey are carefully considered. Afterwards, a standard dynamic state estimation based method is introduced to accurately solve the states of the system including the coupling coefficient. The method does not have further assumptions on the WPT topology as well as system operating conditions. The hardware experiments of an example prototype WPT system demonstrate the feasibility of the proposed coupling coefficient estimation method.