Extended-range positioning system based on foreign-object detection

A wireless power receiver apparatus, comprising:

• a wireless power receive coil;
• a passive-beacon circuit comprising a passive-beacon loop and a passive-beacon modulator circuit configured to generate a modulation, based on a modulated impedance state of the passive-beacon modulator circuit, that is detectable by a detection system including one or more sense loops at a wireless power transmitter apparatus for determining first positioning information of the passive-beacon loop relative to the one or more sense loops;
• and
• an active-beacon transmitter circuit comprising a signal generator circuit and a dedicated active-beacon transmit coil that is different from the wireless power receive coil, the signal generator circuit configured to inject an electric current into the active-beacon transmit coil to cause the active-beacon transmit coil to generate an active-beacon magnetic field signal that is detectable by the detection system for determining second positioning information of the wireless power receive coil relative to the one or more sense loops.

A method comprising:

• detecting an induced voltage in two or more sense loops of a detection system in response to a magnetic field generated by an active-beacon transmitter;
• measuring a magnitude of the induced voltage at each of the two or more sense loops;
• estimating a distance between an active-beacon transmit coil of the active-beacon transmitter and a target position defined by the two or more sense loops based on the induced voltage magnitudes measured at the two or more sense loops;
• determining a lateral offset of the active-beacon transmit coil from a centerline defined by the two or more sense loops based on a comparison between the induced voltage magnitudes of the two or more sense loops;
• and
• generating position information based on the estimated distance and the lateral offset, the position information usable to align a wireless power receiver device with a wireless power-transmitter apparatus for transferring power to an electric vehicle connected to the wireless power receiver device.