Zhuang Haoyu, Wang Wei, Yan Guozheng
IEEE Trans Biomed Circuits Syst. 2023 Feb;17(1):45-53. doi: 10.1109/TBCAS.2023.3241194. Epub 2023 Mar 30.
High permeability material, especially the ferrite, has been widely used in wireless power transfer (WPT) to enhance the power transfer efficiency (PTE). However, for the WPT system of inductively coupled capsule robot, the ferrite core is solely introduced in power receiving coil (PRC) configuration to enhance the coupling. As for the power transmitting coil (PTC), very few studies focus on the ferrite structure design, and only the magnetic concentrating is taken into account without careful design. Therefore, a novel ferrite structure for PTC giving consideration to the magnetic field concentration as well as the mitigation and shielding of the leaked magnetic field is proposed in this paper. The proposed design is realized by combing the ferrite concentrating part and shielding part into a whole and providing a low reluctance closed path for magnetic induction lines, thereby improving the inductive coupling and PTE. Through analyses and simulations, the parameters of the proposed configuration are designed and optimized in terms of average magnetic flux density, uniformity, and shielding effectiveness. Prototypes of PTC with different ferrite configurations are established, tested, and compared to validate the performance enhancement. The experimental results indicate that the proposed design notably improves the average power delivered to the load from 373 mW to 822 mW and the PTE from 7.47% to 16.44%, with a relative percentage difference of 119.9%. Moreover, the power transfer stability is slightly enhanced from 91.7% to 92.8%.
高磁导率材料，尤其是铁氧体，已被广泛应用于无线电能传输（WPT）中以提高功率传输效率（PTE）。然而，对于感应耦合胶囊机器人的WPT系统，铁氧体磁芯仅被引入到功率接收线圈（PRC）结构中以增强耦合。至于功率发射线圈（PTC），很少有研究关注铁氧体结构设计，并且仅考虑了磁集中而没有进行仔细设计。因此，本文提出了一种用于PTC的新型铁氧体结构，该结构既考虑了磁场集中，又考虑了漏磁场的减弱和屏蔽。所提出的设计是通过将铁氧体集中部分和屏蔽部分组合成一个整体，并为磁感应线提供低磁阻闭合路径来实现的，从而提高了电感耦合和PTE。通过分析和仿真，从平均磁通密度、均匀性和屏蔽效能方面对所提出结构的参数进行了设计和优化。建立了具有不同铁氧体结构的PTC原型，进行了测试和比较，以验证性能的提升。实验结果表明，所提出的设计显著提高了输送到负载的平均功率，从373 mW提高到822 mW，PTE从7.47%提高到16.44%，相对百分比差异为119.9%。此外，功率传输稳定性从91.7%略有提高到92.8%。
