Dual-coupled robust wireless power transfer based on parity-time-symmetric model

The characteristics of the wireless power transfer(WPT) system vary under different transfer distances. As distance increases, efficiency drops off sharply, limiting the wider use of WPT technology. In order to mitigate this problem, this paper proposes a novel dual-coupled WPT system, where both electric-coupled mechanism and magnetic-coupled mechanism are utilized to enhance the transfer efficiency. Furthermore, a Parity-Time(PT)-symmetric circuit is utilized to realize robustness of the system. The coupled-mode model of the system is established and the expressions of operating frequency, transfer efficiency and output power are deduced. Analysis results indicate that in the unbroken PT-symmetric state, compared with single-coupled systems, the proposed system can keep constant performance within a longer distance; in broken PT-symmetric state, the proposed system has higher transfer efficiency. Simulated results and comparative results are in accordance with the theoretical analysis. Within 1.4m, this scheme can transfer power with constant efficiency of 77% and constant output power of 70W.