Research on a New Coupling Technology for Wireless Inductive Links

A wireless inductive link operates both as an energy link to power up an end-use device, as well as a communication link to control and retrieve data of the same device, using the same set of coupled coils. Recent advances in materials science, power semiconductor technologies, and proliferation of micro- and nano-fabrication facilities with inexpensive signal processing systems have led to the widespread use of inductive links in many applications, like biomedical electronics, logistics and transportation. This evolving research area is attracting a vast variety of topics, both in academia and industry, the interest of which ranges from enhancing system power management to augmenting data transmission.The basic wireless inductive link consists of a transmitter, a receiver, and loosely-coupled coils. Energy is transferred between the transmitter coil and the receiver coil through alternating magnetic fields. The system is optimized towards maximum power transfer efficiency and designed to provide high data transmission rate. Although many improved transmitter and receiver designs have emerged, the link efficiency is still determined by a fundamental “bottleneck” – fluctuations in the power transfer and link efficiency due to misaligned positions of the coupled coils. When the coils are coaxially orientated, the magnetic coupling between the coils and thus the link efficiency are maximal. However, if the two coils are misaligned, the magnetic coupling and the overall link efficiency will impair significantly. Although inductive links have been studied extensively during the past few decades, the impact of coil misalignment on link efficiency and the optimization of the coil structure design, excitation, and control have received less attention by researchers. There have been no major advances in the coil coupling method used in today’s inductive links, as compared to the conventional approach.This project aims to make a breakthrough in the coil coupling technology by exploring the use of high-dimensional, including two- and three-dimensional, windings to provide true-omnidirectional control of the magnetic coupling between coils with greater maneuverability and flexibility than the conventional structure. Such concept allows the coils to maintain a high level of coupling, even under misalignment situation, and will also bring a new perspective to the power transfer strategies and the communication schemes. In collaboration with Shanghai Jiao Tong University, the new technology will be implemented and evaluated on several applications, including visual prosthetic device, neuromuscular stimulation device, and battery charger. The research team expects to make significant strides in advancing wireless inductive link technologies.