A Misalignment Tolerant IPT System With Intermediate Coils for Constant-Current Output

Misalignment in an inductive power transfer (IPT) system is inevitable for most of the cases, which leads to system performance degradation due to the variation of system parameters. A novel IPT topology with two intermediate coils, one for primary side and the other for secondary one, is proposed to improve an anti-misalignment characteristic. With the merit of the proposed topology, a constant-current output characteristic is achieved, and the system can operate safely without any secondary side. Then, the parameter design and optimization method of the magnetic coupler with intermediate coils are elaborated to improve misalignment performance. Finally, a 3.4-kW experimental setup is built to verify the feasibility of the proposed method. Experimental results show that the four-coil IPT system can tolerate ±225 mm X-misalignment, -30 to +50 mm Y-misalignment, and -20 to +70 mm Z-misalignment with load varying from 40 to 60 Ω, while the fluctuation of the output current is within ±5%. The system efficiency of the IPT system is from 92.1% up to 96.3% with misalignment and variable load (40-60 Ω).