Partial-Inductance Analysis of Double-D Coupler for IPT Applications

This paper uses simulations to discuss partial-inductance analysis of the double-D (DD) couplers used in inductive power transfer (IPT). Not all coil segments of DD pads are positively coupled to the secondary. Ansys Maxwell is commonly used for IPT magnetics simulation. A comparison between Ansys Maxwell and Q3D is provided to show Ansys Q3D can accurately model coil segments in a DD coupler. The paper identifies and segments the coil in a DD coupler using Ansys Q3D. An analysis is done to understand each coil segment’s coupling and inductance contribution in a DD coupler. It is found that 60%-80% of coupler inductance is due to the centre coil portion, which contributes to the coupling. Although side coil portions contribute up to 22% of pad inductance, it harms the coupling. Methods to improve the magnetic characteristics are suggested.