Transmitter configuration to improve resonant coupling efficiency of a wireless power transfer system consisting of misaligned coils

Resonant coupling efficiency (RCE) in an inductively coupled near-field wireless power transfer (WPT) system is proportional to quality factor of the transmitter and receiver resonators, and square of coupling coefficient between them. The coupling between transmitter and receiver is highest when the two coils are perfectly aligned. However, in real-life systems, the transmitter and receiver coils can be angularly or laterally misaligned, thereby reducing the coupling between the coils and hence RCE. In this paper, we propose a transmitter having three orthogonal coils. Depending upon the orientation of the receiver coil, power can be fed only to the transmitter coil which is best coupled to the receiver coil. Alternatively the ratio of power fed to three coils can be adjusted to rotate the magnetic field such that the coupling between transmitter and misaligned receiver is maximized.