Research on a Three-Coil Hybrid IPT Charger With Improved Tolerance to Coupling Variation and Load-Independent Output

With the purpose of improving the reliability of inductive power transfer (IPT) system, a three-coil hybrid IPT topology with improved tolerance to coupling variation and load-independent output is presented, which can ensure constant output of the system under the condition of load and coupling coefficient changing simultaneously. The topology adds two mode switches and an auxiliary compensation capacitor to the receiver side of the system to switch the series-series (SS) topology with constant current output feature and the series-inductor-capacitor-capacitor (S-LCC) topology with constant voltage output feature. Moreover, the transmitting coil adopts two coils in reverse series to improve the misalignment tolerance. The topology retains the merits of SS and S-LCC topology, such as soft-switching operation, decoupling between output and load, zero phase angle input, and the output features, that do not depend on the coupler parameters. Meanwhile, there is no need to build wireless communication between the receiver and the transmitter, which can simplify the control method. This article systematically describes the operating principle of the presented hybrid IPT charger, and the design ideas of compensation network parameters and coupler are also given. A 460-W experimental prototype is built to test the performance of the presented hybrid IPT charger.