MULTI-COIL SYSTEM AND METHOD WITH TWO-STAGE SELECTION/PING FOR WIRELESS POWER TRANSFER

A wireless power transfer system is disclosed. The wireless power transfer system may comprise a first group of transmitter coils disposed in a first plane, a second group of transmitter coils disposed in a second plane, and a controller unit configured to: supply a first power to the first group, one or more transmitter coils at a time; compare a first coupling strength of the powered first transmitter coil with a first threshold; in response to determining the first coupling strength exceeding the first threshold, determine the transmitter coil as a selected transmitter coil; supply a second power to the second group, one or more transmitter coils at a time; compare a second coupling strength of the powered second transmitter coil with a second threshold; and in response to determining the second coupling strength exceeding the second threshold, determine the transmitter coil as another selected transmitter coil.