Nonlinear system identification for optimization of wireless power transfer

• US 9,726,701 B2
• Filed: 04/18/2014
• Issued: 08/08/2017
• Est. Priority Date: 12/18/2012
• Status: Active Grant

• Current Assignee: Indigo Technologies, Inc.
• Original Assignee: Nucleus Scientific, Incorporated
• Inventors: Hunter, Ian W., Lafontaine, Serge R.
• Primary Examiner(s): Gray, David M
• Assistant Examiner(s): Evans, Geoffrey T
• Application Number:
  US14/256,254
• Publication Number:
  US 20140225451A1
• Time in Patent Office: 1,208 Days
• Field of Search: None
• CPC Class Codes: G01R 19/2509 Details concerning sampling, digitizing or waveform capturing
• CPC Class Codes: G01R 23/02 Arrangements for measuring frequency, e.g. pulse repetition rate; Arrangements for measuring period of current or voltage
• CPC Class Codes: G01R 25/00 Arrangements for measuring phase angle between a voltage and a current or between voltages or currents
• CPC Class Codes: G01R 31/001 Measuring interference from external sources to, or emission from, the device under test, e.g. EMC, EMI, EMP or ESD testing measuring electromagnetic fields G01R29/08; circuits for generating HV pulses in dielectric strength testing G01R31/14
• CPC Class Codes: G06F 30/00 Computer-aided design [CAD]
• CPC Class Codes: H02J 50/10 using inductive coupling
• CPC Class Codes: H02J 50/12 of the resonant type
• CPC Class Codes: H02J 50/60 responsive to the presence of foreign objects, e.g. detection of living beings
• CPC Class Codes: H02J 50/80 involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/007 Regulation of charging or discharging current or voltage
• CPC Class Codes: Y02P 90/02 Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries
• CPC Class Codes: Y02T 10/7072 Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
• CPC Class Codes: Y02T 90/12 Electric charging stations
• CPC Class Codes: Y02T 90/14 Plug-in electric vehicles

Abstract

A method of detecting whether a receiver coil is near a transmit coil in a wireless power transfer system (WPTS), the method involving: applying a pseudo-random signal to the transmit coil; while the pseudo-random signal is being applied to the transmit coil, recording one or more signals produced within the WPTS in response to the applied pseudo-random signal; by using the one or more recorded signals, generating a dynamic system model for some aspect of the WPTS; and using the generated dynamic system model in combination with stored training data to determine whether an object having characteristics distinguishing the object as a receiver coil is near the transmit coil.

Claims

1. A method of finding an operating frequency for a drive signal to a transmit coil in a wireless power transfer system (WPTS), said method comprising:

applying a pseudo-random signal to the transmit coil;

while the pseudo-random signal is being applied to the transmit coil, recording one or more signals produced within the WPTS in response to the applied pseudo-random signal;

by using the one or more recorded signals, generating a dynamic system model for some aspect of the WPTS; and

conducting a search for an optimum frequency for the drive signal, wherein conducting the search comprises repeatedly using the generated dynamic system model to simulate a response to the drive signal while varying the operating frequency of the drive signal until the optimum frequency is found.

2. The method of claim 1, wherein conducting a search further comprises:

computing an output power from the simulated response;

using the computed output power as an objective function; and

conducting the search by using the objective function.

3. The method of claim 1, further comprising setting the operating frequency of the drive signal to the optimum frequency.

4. The method of claim 1, wherein the pseudo-random signal is a pseudo-random voltage signal.

5. The method of claim 4, wherein the one or more signals includes a current signal of the transmit coil.

6. The method of claim 4, wherein the one or more signals includes a current signal and a voltage signal of the transmit coil.

7. The method of claim 1, wherein generating the representation of the transfer function comprises using system identification to fit a model to data derived from the one or more recorded signals.

8. The method of claim 1, wherein generating the dynamic system model comprises using nonlinear system identification to fit a selected model to the data derived from the one or more recorded signals.

9. The method of claim 8, wherein the selected model is a Wiener system.

10. The method of claim 8, wherein the selected model has a dynamic linear part and a static nonlinear part.

11. The method of claim 1, wherein the generated dynamic system model comprises a time domain representation.

12. The method of claim 1, wherein the generated dynamic system model comprises a frequency domain representation.

13. A wireless power transfer system comprising:

a transmit coil;

a power transmitter circuit connected to the transmit coil;

a sensor circuit connected to the transmit coil; and

a controller for controlling the power transmitter circuit and the sensor circuit, wherein said controller includes a memory for storing training data and a processor system programmed to;

cause the power transmitter to apply a pseudo-random signal to the transmit coil;

while the pseudo-random signal is being applied to the transmit coil, cause the sensor circuit to record one or more signals produced within the WPTS in response to the applied pseudo-random signal;

by using the one or more recorded signals, generate a dynamic system model for some aspect of the WPTS; and

conduct a search for an optimum frequency for the drive signal, wherein conducting the search comprises repeatedly using the generated dynamic system model to simulate a response to the drive signal while varying the operating frequency of the drive signal until the optimum frequency is found.