A Novel Method for Online Coupling Factor Determination in Inductive Power Transfer Systems

The transient behaviour of serially compensated inductive power transfer systems contains overshoots in the current, which have to be taken into account for the overall system dimensioning. In this contribution, a relation between the coupling factor and the transient response of a system is discovered. The overshoot duration and the envelope of the current show a dependence on design frequency and coupling factor only. With this discovery, the coupling factor can be estimated during operation without any additional communication channel or short-circuit measurements. This novel method for online (i. e., during operation) parameter identification is especially of interest for dynamic energy transfer and for systems in which the coupling factor changes over time.