Cylindrical Misalignment Insensitive Wireless Power Transfer Systems

The widely used wireless power transfer method known as inductive coupling, suffers from dramatic efficiency drops; even over short distances. Strongly coupled magnetic resonance (SCMR) was introduced recently, and can achieve high efficiency at larger distances when compared to inductive coupling. However, standard SCMR systems are highly sensitive to the alignment between the transmitter and receiver, which is an issue that has limited their application in practical wireless powering systems. This paper proposes a new SCMR-based topology that can maintain a constant high efficiency through 360 degrees of misalignment. Specifically, a cylindrical geometry is proposed for the SCMR transmitter instead of using planar loops. Two types of materials are used: copper wire and flexible PCB, and their performances are compared and studied. This new system is able to achieve efficiency above 40% for the entire 360 degrees misalignment without null points, and for the majority of angles the efficiencies stay at 70%. In addition, this new system is wearable and can be used as a portable wireless powering device.