Robust double D topology for roadway IPT applications

Roadway Inductive Power Transfer depends on robust and reliable primary magnetic couplers (pads), but existing pads use large quantities of ferrite, a brittle magnetic material. This paper presents two variations on the Double D topology to reduce or remove the ferrite thereby making the system more robust, using an additional coil to help shape the field instead. Simulations and laboratory validations are presented. Results show a ferrite-less Double D could allow a higher power to be transferred for a given leakage at the side of the roadway, at the expense of a higher primary current and system efficiency. In addition, a reduced ferrite pad with an additional coil allows a significant power transfer for a lower leakage profile than a full ferrite pad, enabling a less expensive and more robust system at the expense of end to end efficiency.