Development of a Communication Scheme for Wireless Power Applications With Moving Receivers

Commercial wireless power systems based on inductive coupling are gaining more popularity. These systems rely on a static alignment between a receiver and a transmitter coil for a certain amount of time. To make the technology more responsive when the device has to be charged while moving randomly in a larger area than the size of the transmitter coil, a dedicated communication scheme is required. In the presented solution, the receiver itself is equipped with a supercapacitor on board, in order to provide a constant energy supply to power the receiver functionality. The communication as described in this work is developed in order to meet the requirements of fast detection and quick charging. It has been implemented in the real-life configuration of a commercially available wireless mouse where the battery compartment was replaced with the receiver circuitry. Excellent functionality of the device was observed. It was demonstrated experimentally that the time it takes to force the transmitter in high-power mode equals 450 ms in case the receiver energy storage is completely drained, and on average, 50 ms when the receiver´s microcontroller is still powered. These results contrast significantly with the well-known static receiver Qi-protocol, where these values rise to an average of respectively 2500 and 250 ms. The obtained timing values meet the requirements of rapidly collecting energy and a high degree of autonomy, even when the receiver structure is only a short amount of time above the transmitting structure.