Research On Magnetic Resonant Wireless Energy Transmission System Of Implantable Medical Equipment

Magnetically-coupled Resonant Wireless Power Transfer (MCR-WPT) is a kind of power transmission technology by resonance coupling between coils of system. Applied in implantable medical devices, the important change has brought for the development and technology of energy supply. With implantable medical devices are widely applied, insertion depth and integrated function is becoming more and more demanding. It make the volume smaller and more demanding for power transfer of implantable medical devices.In the process of power transfer, power is dissipate by skin and other tissue, and transmission distance and power transfer efficiency is reduced. The paper design a MCR-WPT applied to implantable medical devices based on wireless power transfer model analysis, to enhance power transfer efficiency and take more flexible power rationing for implantable medical devices. And coil structure and energy receiving circuit are improved.The paper analysis two-coils and four-coils MCR-WPT by the equivalent circuit theory. Pivotal impact factors to efficiency of wireless power transfer is inferred. The pivotal impact factors are coil quality factor decided by resonant coils specification and coupling coefficient decided by the interaction between resonance coils. Through analyzing energy transmission coil structure and comparing experimental results, the results show that four-coils structure can increase coupling coefficient of coil circuit and insulate the influence of launch circuit and receiving circuit. Under the circumstances, the transfer system is operated in resonant frequency by adjust compensation capacitor. In order to reduce the voltage drop and more convenient power management of implant module, voltage-doubling circuit used as rectifier minimize the voltage drop and improve voltage reference.In this paper, the model of the wireless energy transfer in different coil structures and different power transfer structures is established by simulation software. Through simulation and experiments, the magnetic resonance system can improve the efficiency and the transmission distance of the transmission via skin. And low ripple voltage can meet the application of the functional modules in vivo, outputted by double voltage rectifying circuit.