Multiload Wireless Power Transfer System With Constant Output Power and Efficiency

• Published in: IEEE transactions on industry applications 2022-01, Vol.58 (1), p.1101-1114
• Main Authors: Luo, Chengxin, Qiu, Dongyuan, Gu, Wenchao, Zhang, Bo, Chen, Yanfeng, Xiao, Wenxun
• Format: Article
• Language: English
• Subjects: Capacitors; Circuits; Coils; Constant output; Controllability; Couplings; Cross coupling; Efficiency; Electric power distribution; Integrated circuit modeling; multiple loads; parity-time symmetry; Power generation; Receivers; Resistance; Resonant frequencies; Resonant frequency; Symmetry; Time sharing; time-sharing control strategy; wireless power transfer (WPT); Wireless power transmission
• ISSN: 0093-9994; 1939-9367
• DOI: 10.1109/TIA.2021.3103493

For a multiload wireless power transfer (WPT) system, it has always been a challenge to maintain constant output power with constant efficiency for each load when the coupling conditions change. Besides, the unbalanced power distribution and cross-coupling among loads are also the key issues. In order to solve these problems, a novel multiload WPT system combining the parity-time (PT) symmetry principle and time-sharing control strategy is proposed. First, the multiload PT-symmetric WPT (PT-WPT) system with single natural resonant frequency is modeled and analyzed based on the circuit model. Then, a multiload PT-WPT system with time-sharing control strategy is constructed by adding a controllable resonant capacitor array at the transmitter. The time-sharing control strategy is realized by periodically turning on / off a controllable resonant capacitor selectively, which enables a single transmitter to supply power to multiple loads with different natural resonant frequencies, and each load realizes PT transmission characteristics. Further, using the time-sharing control strategy, the power distribution among multiple loads is realized by only controlling the duty cycle of each load. Finally, two dual-load PT-WPT experiments are designed and carried out. Experimental results show that each load can maintain constant output power with constant transfer efficiency about 90% in a wide coupling range, and realize power distribution at desired values simultaneously.