Piezoelectric Wireless Power Transfer Using a Halbach Array for the Internet of Implanted Things

• Published in: IEEE internet of things journal 2024-01, Vol.11 (24), p.41049-41060
• Main Authors: Fu, Hailing, Gibson, George, Liu, Zhuowen, Chen, Boli, Lu, Maobin, Chen, Chen, Jiang, Dong, Chrysochoidis, Nikolaos A., Deng, Fang
• Format: Article
• Language: English
• Subjects: Arrays; Cantilever beams; Coils; Halbach array; Human motion; implantable medical devices; Implants; Internet; Internet of Implanted Things (IoIT); Internet of Things; Magnetic devices; Magnetic fields; magnetic plucking; Piezoelectric devices; piezoelectric transducers; Receivers; Rotating bodies; Rotation; self-sustained sensing; Surgical implants; Transplants & implants; Wearable technology; wireless power transfer (WPT); Wireless power transmission
• ISSN: 2327-4662; 2327-4662
• DOI: 10.1109/JIOT.2024.3457810

Implanted devices are increasingly used in chronic disease monitoring, but face challenges in energy autonomy. This article presents a novel wireless power transfer (WPT) method for self-sustained medical implants using Halbach array-based magnetic plucking and piezoelectric transduction. The wearable-implantable coupled system consists of a piezoelectric receiver within the implant to receive power and a near-field magnetic power transmitter as a wearable device. To deliver power over greater distances through the human body, the transmitter features a rotating magnetic Halbach array powered by a miniature motor, or by human motion, to generate an alternating magnetic field. The use of low-frequency rotating magnetic fields periodically excites a cantilevered piezoelectric beam with a tip magnet to realize WPT. A theoretical model that includes magnetic coupling, piezoelectric transduction and receiver beam dynamics has been established to study the electro-magneto-mechanical dynamics of this WPT system. The effectiveness of the Halbach array for extended power transfer is examined through theoretical modeling and numerical simulation, showing a 37.2% enhancement of the magnetic forces. A prototype was also fabricated and tested to examine the WPT performance. The established wireless power link can provide sufficient power ( \sim 32~\mu W) over a large transmission distance (22 mm), providing a potential battery-free solution for the self-sustained Internet of Implanted Things (IoIT) for personalized healthcare.