Research on Location Identification and Efficiency Improvement Strategies for Array-Based Wireless Charging Systems With Passive Beacon Coils

Precisely identifying the load position is a critical challenge in array-based wireless power transfer (ABWPT) systems, particularly for applications such as charging unmanned aerial vehicles (UAVs). Accurate localization is essential for selecting the optimal transmitting coils and enhancing overall power transfer efficiency. This study proposes a location identification method for ABWPT systems that utilizes passive beacon coils to improve the system's efficiency. First, a complete circuit model of the system is presented, encompassing both the location identification and power transfer models. Subsequently, the study introduces a detailed location identification method based on bi-directional wireless power transfer technology and a corresponding control strategy for the transmitting coil array to improve system efficiency. To validate the proposed methods, the system was tested under various misalignment conditions, including lateral and longitudinal offsets of the receiving coil. The experimental results show that the load position can be precisely identified. When the receiving coil is not misaligned, the system efficiency is as high as 90.02%, and the charging voltage is 52.85 V. And when a maximum lateral misalignment of 75 mm occurs, the system efficiency increases from 0.4% (ABWPT system without control) to 14.63% (ABWPT system with control), a 14.23% efficiency improvement is achieved. With a maximum longitudinal misalignment of 65 mm, the system efficiency increases by 47.16% from 0.1% (ABWPT system without control) to 47.26% (ABWPT system with control).