US Patent 11515739 FOD and wireless power transfer calibration

In an embodiment, a method includes: wirelessly transmitting power using a transmitter LC tank to a wireless power receiver having a receiver LC tank; receiving a first received power packet from the wireless power receiver, the first received power packet including a received power value field indicative of a power level; determining a first power difference between transmitted power and received power based on the first received power packet; calculating a first received power compensation factor based on the first power difference; interrupting wirelessly transmitting power for a first slot period after receiving the first received power packet; performing a first measurement of a first signal associated with the transmitter LC tank during the first slot period; determining a first Q factor value based on the first measurement; comparing the first Q factor value with a reference Q factor value; and detecting a metallic object based on the comparison.