Improved Transfer Efficiency of Wireless Power Transmission System featuring Coil-Size Disparity

Abstract

Wireless power transmission (WPT) is a hot topic today. However, researches on magnetic coupling resonant WPT system are mostly conducted on the system with equal coil size of the transmitter and receiver. Practically, coil size different condition will certainly exist due to the space constraint on the target receiving device. Researches being done on different coil size system were often reported with degraded performance. This work uses an impedance based quality factor tuning technique to design the WPT system to work with the system with coil size disparity. A prototype has proven to transfer the power wirelessly over a distance up 15cm with a near constant efficiency of 73%. The introduced method shows improved efficiency and it is comparable to those equal coil size systems.