基于能量发射垫的植入式装置磁共振式无束缚无线电能传输机理与关键技术研究

An inductively coupled system with two coils separated by the skin for wireless power transfer (WPT), suffers from relatively low transfer efficiency and typical separations in the range of 10-20mm. Another challenge of transmitting large amounts of power is that the postural change of the patient leads to disalignment between the internal and external coils for poor efficiency associated with heat generation and tissue damage. Moreover, due to dressed transmitter coil, the mobility of the subject is limited. A technology called WiTricity (wireless electricity) enables non-radiative mid-range WPT via strongly coupled magnetic resonance. In order to achieve safe WPT for implantable devices in freely moving subjects, this proposal investigates a novel mat-based WiTricity system by theoretical modeling, finite element simulation and experimental test, whereas a power mat covering the playground is packed with multiple transmitter coils driven by a driver coil array. The addressed issues include (1) theoretical modeling of WiTricity system with multiple transmitter resonators and (2) matched resonance between two tremendously different coils in size. The main innovations involve (1) a theory model established for exploring the energy transfer mechanism of WiTricity system with multiple resonators to fill in a gap in high- dimensional, strongly coupled, and nonlinear WPT system; and (2) a small-size receiver coil with a shallow box assembly, serving as the case, to achieve free-positioning WPT at mid-range distance for implanted devices in an untethered subject. This research provides basic principle and key technology for the development of advanced biomedical devices with social and economic benefits. It is also expected that these findings are of great scientific significance for the exploration of a novel WPT technology.

现有磁耦合经皮无线供能方法存在传输距离短、传输效率低、定向要求高等不足，穿戴发射线圈还限制生物体自由活动。为解决安全、无束缚、经皮无线供能问题，本项目利用驱动线圈阵列对应驱动的发射线圈阵列，构建覆盖生物体活动范围的能量发射垫，采用理论建模分析、有限元数值计算和实验验证相结合，研究用于植入式装置的磁共振耦合无线能量传输（WiTricity）新方法。拟解决的科学问题：① 多发射线圈WiTricity系统的能量传输机理研究；②尺寸1:10的体内外线圈匹配共振。主要创新点：① 建立能量发射垫WiTricity系统的能量传输理论，填补高维、非线性、强耦合、多自谐振发射线圈WiTricity系统研究的空白；②设计三维封闭空心结构的小线圈，突破体内能量接收线圈的性能局限。本项目提供的基础理论和自主关键技术将有助于高端医疗器械的研发，社会与经济效益显著，对于探索无线供能新技术具有重要的科学意义。

具有无线能量和数据传输功能的可植入电子装置是高端医疗设备研发的热点和难点。现有磁耦合经皮无线供能方法存在传输距离短、传输效率低、定向要求高、局部组织发热等不足，穿戴发射线圈还限制生物体自由活动。另一方面，较小的体内能量接收/数据发送端使得体内接收到的能量十分有限，且与体外较大的能量发射/数据接收端严重失配，因此中远距离的上行（体内到体外）数据链路很难建立。为解决安全、无束缚、自由定位的经皮无线供能问题，本项目围绕能量发射垫磁共振耦合经皮无线能量传输（MCR-WPT）系统的理论分析、优化设计和实验验证开展了一系列科学研究工作，取得的主要技术突破如下：① 建立了能量发射垫MCR-WPT系统的等效电路模型，根据频率分裂特性确定了系统的传输特性和最佳工作条件；② 利用耦合模理论（CMT）对能量发射垫MCR-WPT系统进行建模，揭示了系统的多通道能量并行传输机理；③ 设计了能量发射垫的发射线圈样式和阵列驱动方法，降低系统复杂度的同时提高了磁场分布的均匀程度；④ 利用部分元等效电路（PEEC）方法建立平面螺旋线圈的等效分布参数电路，得到低谐振频率、高品质因数的线圈样式，设计了低谐振频率、高品质因数的三维结构体内能量接收小线圈，有效解决了与能量发射大线圈的匹配共振问题；⑤ 建立了面向植入式装置的经皮无线供能实验研究平台，通过离体测试和动物实验，验证了能量发射垫MCR-WPT系统对大鼠体内刺激器实现经皮无线供能的有效性；⑥ 针对深植入智能神经微器件的无线传能和通信需求，提出了GHz微波中场传能和体内主动数据无线传输技术。上述结果不仅为神经康复的医学研究提供了先进的实验手段，而且所提供的基础理论和关键技术有助于无线/无电池可植入智能神经器件的研发与临床转化，促进了工程技术与医学研究的互动。