Voltage source isolation in wireless power transfer systems

Abstract

The disclosure features wireless power transmitters that include a power source, a first coil connected to the power source, a second coil connected in series to the first coil, and a third coil positioned in proximity to the second coil, where during operation of the wireless power transmitters, the power source applies a driving voltage to the first and second coils, the first coil generates a first magnetic field that transfers power to a receiver resonator, the second coil generates a second magnetic field that induces a voltage across the third coil, and the induced voltage across the third coil is applied to a component of the wireless power transmitters.

What is claimed is: 
     
         1 . A wireless power transmitter, comprising:
 a power source;   a first coil connected to the power source; and   a second coil positioned in proximity to the first coil,   wherein during operation of the wireless power transmitter:
 the power source applies a driving voltage to the first coil; 
 the first coil generates a magnetic field that transfers power to a receiver resonator; 
 the magnetic field induces a voltage across the second coil; and 
 the induced voltage across the second coil is applied to a component of the wireless power transmitter. 
   
     
     
         2 . The transmitter of  claim 1 , wherein each of the first and second coils comprises one or more loops of conductive material. 
     
     
         3 . The transmitter of  claim 1 , wherein the component comprises at least one of a resistive element of the wireless power transmitter, a capacitive element of the wireless power transmitter, an inductive element of the wireless power transmitter, a switch of the wireless power transmitter, and a component of an impedance matching network of the wireless power transmitter. 
     
     
         4 . The transmitter of  claim 1 , wherein the component comprises a transceiver configured to generate an information carrying signal. 
     
     
         5 . The transmitter of  claim 1 , wherein the component comprises a third coil configured to generate an information carrying magnetic field that, during operation, is received by a fourth coil connected to the receiver resonator. 
     
     
         6 . The transmitter of  claim 5 , further comprising a modulator configured to modulate the induced voltage to generate the information carrying magnetic field. 
     
     
         7 . The transmitter of  claim 6 , wherein the induced voltage corresponds to an oscillating voltage signal, and wherein the modulator is configured to modulate at least one of an amplitude and a frequency of the oscillating voltage signal to generate the information carrying magnetic field. 
     
     
         8 . The transmitter of  claim 1 , wherein a magnitude of the induced voltage is 1% or less of a magnitude of a voltage induced in the receiver resonator, and wherein the induced voltage is not referenced to a ground voltage of the wireless power transmitter. 
     
     
         9 . The transmitter of  claim 1 , further comprising a third coil positioned in proximity to the first coil, wherein during operation of the wireless power transmitter:
 the magnetic field induces a voltage across the third coil; and   the induced voltage across the third coil is applied to a second component of the wireless power transmitter.   
     
     
         10 . The transmitter of  claim 9 , wherein the second component comprises at least one of a resistive element, a capacitive element, an inductive element, a switch, a component of an impedance matching network, a transceiver configured to generate an information carrying signal, and a fourth coil configured to generate an information carrying magnetic field that, during operation, is received by a fifth coil connected to the receiver resonator.