Modelling and Design of a Coils Structure for 100 kW Three-Phase Inductive Power Transfer System

This paper presents the modeling, the design and verification of a three-phase coil structure for high-power Wireless-Power-Transfer (WPT) in automotive applications. The system, a Three- Polar-Pad (TPP), with complex mechanical geometry, is analytically modeled with an equivalent simplified structure. Thanks to this simplification, a numerical design is performed to minimize cross-coupling effects among different phases of the same side (receiver or transmitter) maximizing the linkage flux receiver-to-transmitter and then the power transferred. The analytical model is then verified in a Finite-Element-Analysis (FEA) environment. A final design, comprehensive of the shielding, is proposed matching the preliminary design constraints. Hence, the preliminary model is verified by testing a prototype using a three-phase Silicon Carbide (SiC) inverter at the transmitter side. The capability of the system is demonstrated by transferring 100 kW with more than 94% DC-to-DC efficiency over a 50 mm air gap in perfectly aligned conditions.