A Hybrid Inductive Power Transfer System with High Misalignment Tolerance Using Double-DD Quadrature Pads

Inductive power transfer (IPT) has been widely adopted as an efficient and convenient charging manner for both static and in-motion EVs. In this paper, a new hybrid topology is presented to improve the coupling tolerance under pad misalignment. The double inductor-capacitor-capacitor (LCC-LCC) network and series hybrid network combining the LCC-LCC topology and series-series (SS) topology are connected in parallel to provide better tolerance against self- and mutual inductance changes, particularly with a large Z-axis transmission distance. A double-DD quadrature pad (DD2Q) consists of a Q pad, and double orthogonal DD pads are analyzed in detail, which are employed to decouple the cross-mutual inductance. Moreover, a parametric design method based on the misalignment characteristics of the DD2Q pads is also proposed to maintain relatively constant power output. A 650-W hybrid topology with a fixed operating frequency of 85 kHz was built to verify the system's feasibility. The size of the DD2Q pads was 280 mm x 280 mm, and the air gap was 100 mm. The results clearly show that the proposed hybrid topology can achieve a fluctuation within 5% in the output current with load varying from 100% full load to 25% light load conditions when the Z-axis transmission distance varies from 80 mm to 150 mm, and the maximum efficiency can reach 91% when the Z-axis transmission distance is 80 mm.