DPDA: Distributed Probability-adaptive Direction Adjustment for Magnetic Wireless Power Transfer

Magnetic resonant coupling (MRC) enabled wireless power transfer (WPT) systems can charge multiple devices concurrently and efficiently via beamforming technology. The existing work proposes various mechanisms for achieving better charging performance, but still lacks the exploration about transmitter (TX) coil direction adjustment, and rarely considers the dynamic deployment of TXs. Thus, in this paper, we propose a Distributed Probability-adaptive Direction Adjustment algorithm for MRC-WPT systems (called DPDA). On the one hand, we design and implement a servo motor-based mechanical device to realize the ability of TX coil direction adjustment. On the other hand, we decompose the charging performance optimization problem, and then devise a distributed direction control algorithm based on random beamforming. We implement the system prototype for DPDA, and conduct extensive experiments on it. The experimental results demonstrate the effectiveness of the proposed algorithm, e.g., in case of large TX-RX horizontal misalignment, DPDA can achieve an average 1.98X improvement of power-delivered-to-load (PDL) as compared with the state-of the-art frequency adjustment-based solution.