Design Methodology of Free-Positioning Nonoverlapping Wireless Charging for Consumer Electronics Based on Antiparallel Windings

• Published in: IEEE transactions on industrial electronics (1982) 2022-01, Vol.69 (1), p.825-834
• Main Authors: Zhang, Yiming, Chen, Shuxin, Li, Xin, Tang, Yi
• Format: Article
• Language: English
• Subjects: Antiparallel windings (AWs); Coefficient of variation; Coils (windings); Consumer electronics; Converters; coupling coefficient variation; Coupling coefficients; Couplings; Design engineering; Design methodology; Design optimization; Electronics; Equivalent circuits; free positioning; Inductance; Inductive charging; inductive power transfer (IPT); misalignment tolerance; Optimization; User experience; Winding; Windings; wireless power transfer (WPT); Wireless power transmission
• ISSN: 0278-0046; 1557-9948
• DOI: 10.1109/TIE.2020.3048322

Free positioning wireless charging for consumer electronics allows the devices to be charged at arbitrary positions and angles to improve user experience. However, a user-initiated sudden movement of the device during charging can cause hazards due to the abrupt variation of the coupling coefficient. To solve this issue, the coupling coefficient variation at different positions should be mitigated, which is also good for the design and high-efficiency operation of power electronics converters. This article proposes a design methodology to employ antiparallel windings to smooth the coupling coefficient variation over different positions by reducing the coupling coefficient at central positions and enhancing it at boundary positions. Two optimization methods are proposed: turn-by-turn optimization and winding-by-winding optimization. A design flow is offered. The hexagonal coil is compared with the square coil and proved to achieve better performance than the latter. An experimental prototype is implemented to validate the effectiveness of the proposed design methodology.