摘要
针对旋转导向设备使用电场耦合式无线电能传输(CWPT)技术为电池负载供电的应用场景,该文提出一种恒流/恒压自切换的CWPT系统。该系统无需任何额外的主动控制即可实现自动、平滑地从恒流输出到恒压输出的切换,同时系统在两种输出模式下均工作于零相角(ZPA)状态。该文首先给出恒流/恒压自切换CWPT系统的拓扑结构,建立耦合结构等效模型,并对耦合结构模型和物理参数进行设计;然后详细分析系统恒流/恒压的输出特性和工作原理;最后搭建实验样机,验证所提方法与系统结构的有效性,实验中实现了1.5 A的恒流输出和60 V的恒压输出,最高效率为90%。
Brushes and slip rings in rotary steerable systems are the main equipment for power transmission under rotational conditions to charge the batteries in steering control and measurement modules.However,this transmission method is prone to generating electrical sparks,potentially triggering safety risks.In addition,the wear and tear caused by long-term operation may lead to poor contact,resulting in unstable power transmission,which reduces the stability of the power supply in a rotary steerable system.Wireless power transfer(WPT)technology can address the issues of poor power supply safety and stability caused by traditional brushes and slip rings.The capacitive power transfer(CPT)system offers advantages such as low eddy current loss and strong resistance to electromagnetic interference.It is well-suited to withstand harsh conditions in the downhole.The battery charging process typically includes two stages:constant current charging and constant voltage charging.Firstly,the charging is carried out in constant current mode,where the charging voltage rises rapidly as the equivalent load of the battery increases.Once the voltage reaches the rated value,it switches to constant voltage mode until the charging process is complete.This paper proposes a CPT system that automatically switches between constant current and voltage modes.The system achieves a smooth,automatic transition from constant current output to constant voltage output without additional active control while maintaining zero phase angle(ZPA)operation in both output modes.The topology of the CPT system with automatic switching between constant current and constant voltage modes was presented.The electric field coupler adopted a single transmitter and dual receiver structure in the system.Therefore,the coupler’s voltage source equivalent model was established.Then,a decoupled secondary-side single-transmitter dual-receiver coupler model was designed based on physical parameter design to avoid mutual interference between the secondary side inputs.The system's output characteristics were theoretically analyzed.The system's output characteristics gradually transition from constant current output to constant voltage output as the load increases.The system maintains the ZPA state throughout the entire charging process.Electromagnetic simulation of the electric field distribution of the coupler was conducted using the finite element method.The simulation results show that the leakage electric field generated by the coupler during system operation does not interfere with the normal operation of the instruments in the rotary steerable system.Then,a prototype was built.The experimental results indicate that the system can achieve a constant current output of 1.5 A and a constant voltage output of 60 V.The current fluctuation is less than 5%in the constant current output mode,the voltage fluctuation is less than 3%in the constant voltage output mode,and the maximum transmission efficiency is approximately 90%during system operation.These results meet the constant current and constant voltage requirements for battery charging.
作者
吉莉
张家琦
张江洪
Ji Li;Zhang Jiaqi;Zhang Jianghong(College of Artificial Intelligence China University of Petroleum,Beijing 102249 China)
出处
《电工技术学报》
北大核心
2025年第24期7879-7890,共12页
Transactions of China Electrotechnical Society
基金
国家自然科学基金资助项目(52377020)。
关键词
电场耦合式无线电能传输
旋转耦合
恒流/恒压
自切换
Capacitive wireless power transfer
rotary coupler
constant current and constant voltage
self-switching
