Design and modelling of a controlled saturable inductor for an LCC-S compensated WPT system

This paper analyses the design of a controlled variable inductor adopted as the series inductance of an LCC-S compensation network in an Inductive Wireless Power Transfer system. In this compensation topology, the power transfer to the load can be controlled by varying the differential inductance of the component through a DC bias. The analytical design process of a double E ferrite core variable inductor is presented, and the specifications for an experimental prototype are proposed. The design output is verified with FEM simulations to validate the obtained differential inductance profile and with circuit simulations to test the non-linear behaviour of the component under the typical current and voltage waveforms of the LCC-S compensated Wireless Power Transfer system. Finally, a prototype is realized, characterized and tested in an experimental Wireless Power Transfer system.