Input parasitic metal detection

• US 9,524,822 B2
• Filed: 11/26/2013
• Issued: 12/20/2016
• Est. Priority Date: 02/08/2010
• Status: Active Grant

• Current Assignee: Philips IP Ventures B.V. (Koninklijke Philips N.V.)
• Original Assignee: Access Business Group International LLC (Alticor Incorporated)
• Inventors: Baarman, David W., Schwannecke, Joshua K., Kuyvenhoven, Neil W., Umenei, Esai E., Liff, Dale R., Blaha, Mark A., Gruich, Robert D.
• Primary Examiner(s): Deberadinis, Robert
• Application Number:
  US14/090,582
• Publication Number:
  US 20140077616A1
• Time in Patent Office: 1,120 Days
• Field of Search: 307/104
• US Class Current: 1/1
• CPC Class Codes: G01R 21/00 Arrangements for measuring electric power or power factor G01R7/12 takes precedence
• CPC Class Codes: G01V 3/02 operating with propagation of electric current
• CPC Class Codes: H01F 38/14 Inductive couplings for wireless supply or distribution of electric power using inductive coupling H02J50/10
• 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 50/70 involving the reduction of electric, magnetic or electromagnetic leakage fields
• CPC Class Codes: H02J 50/90 involving detection or optimisation of position, e.g. alignment
• CPC Class Codes: H02J 7/0047 with monitoring or indicating devices or circuits

Abstract

A system and method of controlling inductive power transfer in an inductive power transfer system and a method for designing an inductive power transfer system with power accounting. The method of controlling inductive power transfer including measuring a characteristic of input power, a characteristic of power in the tank circuit, and receiving information from a secondary device. Estimating power consumption based on the measured characteristic of tank circuit power and received information and comparing the measured characteristic of input power, the information from the secondary device, and the estimated power consumption to determine there is an unacceptable power loss. The method for designing an inductive power transfer system with power accounting including changing the distance between a primary side and a secondary side and changing a load of the secondary side. For each distance between the primary side and the secondary side and for each load, measuring a circuit parameter on the primary side in the tank circuit and a circuit parameter on the secondary side during the transfer of contactless energy. The method further including selecting a formula to describe power consumption in the system during the transfer of contactless energy based on coefficients and the circuit parameters, and determining the coefficients using the measured circuit parameters.

Claims

1. A method of calibrating a parasitic metal detection system for a secondary device, the method comprising:

providing a primary unit for contactlessly transferring power;

receiving calibration data, the calibration data being a function of at least one of placing the secondary device at a plurality of different locations with respect to the primary unit and operating the secondary device at a plurality of different loads;

calibrating the parasitic metal detection system using the calibration data.

2. The method of claim 1 wherein the calibration data accounts for losses due to poor coupling as the coupling between the primary unit and secondary device changes.

3. The method of claim 1 wherein the calibration data accounts for changes in frequency.

4. The method of claim 1 wherein the calibration data is a function of placing the secondary device at a plurality of different locations with respect to the primary unit and is a function of operating the secondary device at a plurality of different loads.

5. The method of claim 1 wherein the parasitic metal detection system detects metal in proximity to the primary unit by comparing an expected input to a measured input.

6. The method of claim 1 wherein the parasitic metal detection system can distinguish between losses due to coupling and losses due to parasitic metal.

7. The method of claim 1 wherein the calibration data includes adjustments to one or more power loss coefficients.

8. A method of collecting calibration data for a parasitic metal detection system, the method comprising:

providing a primary unit;

placing a secondary device in a plurality of different positions with respect to the primary unit;

collecting calibration data for the secondary device as a function of the plurality of different positions;

storing the calibration data in the secondary device for communication with a parasitic metal detection system during operation or during an initialization calibration routine.

9. The method of claim 8 including operating the secondary device at a plurality of different loads for each of the plurality of different positions and wherein said collecting calibration data includes collecting calibration data for the secondary device as a function of the plurality of different positions and the plurality of different loads.

10. The method of claim 8 wherein the calibration data accounts for changes in frequency.

11. The method of claim 8 wherein the parasitic metal detection system detects metal in proximity to the primary unit by comparing an expected input to a measured input.

12. The method of claim 8 wherein the parasitic metal detection system can distinguish between losses due to coupling and losses due to parasitic metal.

13. The method of claim 8 wherein the calibration data includes adjustments to one or more power loss coefficients.

14. A method of collecting calibration data for a parasitic metal detection system, the method comprising:

providing a primary unit;

operating a secondary device at a plurality of different loads;

collecting calibration data for the secondary device as a function of the plurality of different loads;

storing the calibration data in the secondary device for communication with a parasitic metal detection system during operation or during an initialization calibration routine.

15. The method of claim 14 including placing the secondary device in a plurality of different positions with respect to the primary unit and wherein said collecting calibration data includes collecting calibration data for the secondary device as a function of the plurality of different positions and the plurality of different loads.

16. The method of claim 14 wherein the calibration data accounts for changes in frequency.

17. The method of claim 14 wherein the parasitic metal detection system detects metal in proximity to the primary unit by comparing an expected input to a measured input.

18. The method of claim 14 wherein the parasitic metal detection system can distinguish between losses due to coupling and losses due to parasitic metal.

19. The method of claim 14 wherein the calibration data includes adjustments to one or more power loss coefficients.