Phase and amplitude detection in wireless energy transfer systems

Abstract

Methods, systems, and apparatus, including computer programs encoded on a computer storage medium, for detecting characteristics of an input signal. One aspect includes a first finite input response (FIR) filter, a second FIR filter, and a controller coupled with the first and second FIR filters. The first FIR filter receives an input signal and a first reference signal. The first FIR filter filters the first reference signal to generate a first sinusoidal signal and mixes the first sinusoidal signal and the input signal to generate a first mixed signal. The second FIR filter receives the input signal and a second reference signal. The second FIR filter filters the second reference signal to generate a second sinusoidal signal and mixes the second sinusoidal signal and the input signal to generate a second mixed signal. The controller determines characteristics of the input signal based on the first and second mixed signals.

What is claimed is: 
     
         1 . (canceled) 
     
     
         2 . A device comprising:
 a first input terminal that receives a first input signal;   a second input terminal that receives a second input signal;   a signal generator that generates a sinusoidal reference signal, the sinusoidal reference signal having a phase;   a first mixer coupled with the signal generator and the first input terminal, wherein the first mixer is configured to mix the reference signal and the first input signal to generate a first mixed signal;   a second mixer coupled with the signal generator and the second input terminal, wherein the second mixer is configured to mix the reference signal and the second input signal to generate a second mixed signal;   a controller coupled with the first mixer, the second mixer, and the signal generator, the controller configured to:
 shift the phase of the reference signal, 
 detect a zero crossing of the first mixed signal and, in response to detecting the zero crossing of the first mixed signal, store first data representing the phase of the reference signal, 
 detect a zero crossing of the second mixed signal and, in response to detecting the zero crossing of the second mixed signal, store second data representing the phase of the reference signal, and 
 determine a phase difference between the first input signal and the second input signal based on a difference between the first data and the second data. 
   
     
     
         3 . The device of  claim 2 , further comprising:
 a first filter coupled the first mixer and the controller, wherein the first filter configured to filter the first mixed signal such that the first mixed signal is a direct current (DC) signal; and   a second filter coupled the second mixer and the controller, wherein the second filter configured to filter the second mixed signal such that the second mixed signal is a DC signal.   
     
     
         4 . The device of  claim 2 , further comprising:
 a first comparator coupled with first mixer and the controller; and   a second comparator coupled with the second mixer and the controller,   wherein detecting the zero crossing of the first mixed signal, by the controller, comprises detecting an edge of an output signal of the first comparator, and   wherein detecting the zero crossing of the second mixed signal, by the controller, comprises detecting an edge of an output signal of the second comparator.   
     
     
         5 . The device of  claim 2 , wherein the reference signal is phase-adjustable in a fixed number of steps. 
     
     
         6 . The device of  claim 5 , wherein the first data and the second data represent first and second steps of the sinusoidal reference signal. 
     
     
         7 . The device of  claim 6 , wherein determining the phase difference between the first input signal and the second input signal, by the controller, comprises multiplying the difference between the first data and the second data by a step size associated with steps of the sinusoidal reference signal. 
     
     
         8 . The device of  claim 2 , wherein the controller is further configured to provide data indicating the phase difference between the first input signal and the second input signal to a controller of an impedance matching network. 
     
     
         9 . The device of  claim 2 , further comprising: an impedance matching network coupled with the controller, wherein the impedance matching network is configured to receive data indicating the phase difference between the first input signal and the second input signal from the controller and adjust an impedance value of a component of the impedance matching network in accordance with the received data. 
     
     
         10 . The device of  claim 2 , further comprising:
 an impedance matching network,   wherein the first input terminal is coupled with a first sensor that measures a first voltage or a first current of the impedance matching network, and wherein the second input terminal is coupled with a second sensor that measures a second voltage or a second current of the impedance matching network, and   wherein the first input signal is an output of the first sensor, and the second input signal is an output of the second sensor.   
     
     
         11 . The device of  claim 2 , further comprising:
 a resonator for a wireless power transfer system,   wherein the first input terminal is coupled with a first sensor configured to measure a first voltage or a first current associated with the resonator, and the second input terminal is coupled with a second sensor configured to measure a second voltage or a second current associated with the resonator, and   wherein the first input signal is an output of the first sensor, and the second input signal is an output of the second sensor.   
     
     
         12 . A phase detection method comprising:
 receiving a first input signal and a second input signal;   generating a sinusoidal reference signal, the sinusoidal reference signal having a phase;   mixing the first input signal with the reference signal to provide a first mixed signal;   mixing the second input signal with the reference signal to provide a second mixed signal;   shifting the phase of the reference signal;   detecting a zero crossing of the first mixed signal and, in response to detecting the zero crossing of the first mixed signal, storing first data representing the phase of the reference signal,   detecting a zero crossing of the second mixed signal and, in response to detecting the zero crossing of the second mixed signal, storing second data representing the phase of the reference signal, and   determining a phase difference between the first input signal and the second input signal based on a difference between the first data and the second data.   
     
     
         13 . The method of  claim 12 , further comprising:
 filtering the first mixed signal to remove high-order harmonics and provide the first mixed signal as a direct current (DC) signal; and   filtering the second mixed signal to remove high-order harmonics and provide the second mixed signal as a DC signal.   
     
     
         14 . The method of  claim 12 , wherein shifting the phase of the reference signal comprises adjusting the reference signal in a fixed number of steps. 
     
     
         15 . The method of  claim 14 , wherein the first data and the second data represent first and second steps of the sinusoidal reference signal. 
     
     
         16 . The method of  claim 15 , wherein determining the phase difference between the first input signal and the second input signal comprises multiplying the difference between the first data and the second data by a step size associated with steps of the sinusoidal reference signal. 
     
     
         17 . The method of  claim 12 , further comprising modifying an attribute of an impedance matching network based on the phase difference between the first input signal and the second input signal. 
     
     
         18 . The method of  claim 12 , wherein the first input signal represents a measurement from a first sensor of a first voltage or a first current of an impedance matching network, and
 wherein the second input signal represents a measurement from a second sensor of a second voltage or a second current of the impedance matching network.   
     
     
         19 . The method of  claim 12 , wherein the first input signal represents a measurement from a first sensor of a first voltage or a first current of a wireless power transfer system, and
 wherein the second input signal represents a measurement from a second sensor of a second voltage or a second current of the wireless power transfer system.   
     
     
         20 . The method of  claim 12 , wherein the first input signal is an output signal from a current sensor and the second input signal is an output signal from a voltage sensor. 
     
     
         21 . A non-transitory computer readable storage device storing instructions that, when executed by at least one processor, cause the at least one processor to perform operations comprising:
 receiving a first input signal and a second input signal;   generating a sinusoidal reference signal, the sinusoidal reference signal having a phase;   mixing the first input signal with the reference signal to provide a first mixed signal;   mixing the second input signal with the reference signal to provide a second mixed signal;   shifting the phase of the reference signal;   detecting a zero crossing of the first mixed signal and, in response to detecting the zero crossing of the first mixed signal, storing first data representing the phase of the reference signal,   detecting a zero crossing of the second mixed signal and, in response to detecting the zero crossing of the second mixed signal, storing second data representing the phase of the reference signal, and   determining a phase difference between the first input signal and the second input signal based on a difference between the first data and the second data.   
     
     
         22 . The computer readable storage device of  claim 21 , wherein shifting the phase of the reference signal comprises adjusting the reference signal in a fixed number of steps.