A Single-Stage Universal Input Wireless Inductive Power Transfer System With V2G Capability

This article reports a new single-stage wireless inductive power transfer (IPT) topology, which accepts both ac and dc input for electric vehicle battery charging applications. Also, the proposed system has bidirectional power flow capability; hence, the V2G operation is feasible. On the grid side, an ac-ac matrix converter converts the line frequency ac directly into high-frequency ac, thereby eliminating short-lived bulky dc-link capacitor. Achieving a unity power factor with traditional IPT topology is challenging because the front-end converter always has a buck-derived configuration. In this article, a boost-derived topology with bidirectional power transfer capability is proposed, which can maintain a unity power factor at the grid. The proposed single converter has the following three distinct operating modes: first grid to vehicle, second solar to vehicle, or the dc-dc, and third vehicle to grid mode. The steady-state operation, converter dynamic modeling based on small-signal analysis, and closed-loop control are reported for all the operating modes. The soft-switching performances are analyzed for the ac-ac converter and battery-side converter switches. A 700-W laboratory prototype is built, and the experimental results are presented to verify the analysis and performance of the proposed single-stage universal IPT topology.