A Detection Method of Misalignment for a WPT System using Three-Power Transfer Circuits

This paper presents a method for detecting the direction of misalignment of the receiver coil for wireless power transfer (WPT) systems. Three-power transfer circuits are applied in the presented WPT system, and then, phase difference of the currents in the transfer coils are compared to detect misalignment. The current in the transfer coil which is closer to the receiver coil shows a leading phase with respecting to the voltage, while the current in the coil which is farther away shows a lagging phase. Experimental results demonstrate the phase difference of the currents in the transfer coils according to misalignment, and thus, the direction of misalignment of the receiver coil can be detected from their phase differences.