Sampled-Data Modeling for Wireless Power Transfer Systems

In this paper, a dynamic model based on the sampled-data method is presented for a wireless power transfer (WPT) system. The orders of the derived model are equal to the orders of a system. The modeling is different from the existing dynamic modeling for WPT systems, which almost double the models order. Furthermore, the systematic analysis process is suitable for any WPT topologies and without the higher harmonics neglected and low-frequency approximation. Meanwhile, the state variables are allowed to vary up to twice the switching frequency, since the half-period symmetry property is exploited. In this paper, the series-series (SS) compensated WPT system is chosen as an example and the large-signal model and the steady-state operation point are determined. The small-signal responses perturbed by the phase-shift angle, switching frequency, and input voltage are obtained. The derived model is more adequate with simulation and experimental validation.