Abstract：In large machinery such as ships, electric motors, wind turbines, and tunnel boring machines, rotating power shafts serve as core components, undertaking the critical tasks of transmitting power. To ensure efficient operation and safe maintenance of these systems, multiple sensors and monitoring devices—such as such as strain gauges, accelerometers, data acquisition units, and communication equipment—are typically installed on the shaft. These devices monitor key physical quantities like torque, vibration, stress, and shaft health, such as torque, vibration, stress, and shaft health, in real time. Their stable operation depends on a reliable power supply. However, due to the rotational nature of the shaft, traditional wired power supply faces significant challenges, including wire wear, breakage, and electromagnetic interference. These issues severely impact equipment reliability and maintenance efficiency. Consequently, conventional contact-based power supply methods struggle to meet the demands of mechanical transmission systems. Wireless power transfer (WPT) technology has emerged as an effective practical solution, offering advantages like of no direct electrical connection, continuous operation, safety, and reliability. As an important branch of WPT, capacitive power transfer (CPT) technology utilizes high-frequency electric fields between metal plates or foils for power transmission uses high-frequency electric fields between metal plates or foils to transmit power. Compared to inductive power transfer (IPT) systems, CPT offers significant advantages: lower-cost coupling plates, flexible/portable couplers, lighter weight, and reduced eddy current effects from the coupling electric field, making. These characteristics make CPT highly suitable for powering rotating equipment, particularly for metal shafts and applications within complex metallic environments. To minimize additional power losses and avoid severe electromagnetic radiation caused by long receiver plates around the shaft, segmented receiver plates are introduced into CPT systems for shaft wireless power supply applications. When the receiver plates rotate with the shaft, the transmitter plates are sequentially aligned on different receiver plates. It generates creates two relative positional states: (1) the transmitter plate is directly aligned with a pair of receiver plates, and (2) the transmitter plate is positioned between two pairs of receiver plates. However, this segmented receiver structure introduces a new challenge for rotating CPT systems: how to achieving maximum efficiency point tracking (MEPT) for a one-to-multiple CPT system during rotation and under varying load resistance. This paper addresses the efficiency reduction caused by shaft rotation and dynamic load changes by proposing a cooperative control strategy for a dual-stage DC/DC converter cooperative control strategy. It forms a closed-loop system for MEPT control in one-to-multiple and time-varying coupling scenarios. The main contributions of this work are as follows: (1) Established the equivalent circuit and mathematical model are established for a one-to-multiple capacitive coupler in a rotating segmented CPT system. (2) Developed a power loss model is developed for the system under rotation, and derived the mathematical relationship between system efficiency and the equivalent load is derived. (3) Proposed a dual-stage DC-DC converter cooperative control strategy is proposed, utilizing a front-stage Buck converter to adjust the equivalent load and a rear-stage Boost converter to achieve constant voltage output for the load. Experimental results demonstrate that during shaft rotation (0° to 90°) and load variation (30 Ω to 100 Ω), the system consistently tracks the optimal efficiency point, which experimental results closely aligns with theoretical models. This MEPT control method effectively tracks the maximum efficiency point, improves system efficiency, requires no periodic perturbation of the system, and eliminates the need for complex identification of the coupling coefficient between the transmitter and receiver. It demonstrates strong practical applicability.
周玮, 李志强, 郑靖玮, 张强, 麦瑞坤. 旋转分段式电场耦合无线电能传输系统最大效率跟踪控制方法[J]. 电工技术学报, 2026, 41(8): 2535-2546.
Zhou Wei, Li Zhiqiang, Zheng Jingwei, Zhang Qiang, Mai Ruikun. Maximum Efficiency Tracking Control Method for Rotating Segmented Electric Field-Coupled Wireless Power Transfer Systems. Transactions of China Electrotechnical Society, 2026, 41(8): 2535-2546.
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2026, Vol. 41 
