Input parasitic metal detection

• US 10,862,335 B2
• Filed: 11/14/2016
• Issued: 12/08/2020
• Est. Priority Date: 02/08/2010
• Status: Active Grant

• Current Assignee: Philips IP Ventures B.V. (Koninklijke Philips N.V.)
• Original Assignee: Philips IP Ventures B.V. (Koninklijke Philips N.V.)
• Inventors: Baarman, David W., Schwannecke, Joshua K., Kuyvenhoven, Neil W., Umenei, Esai E., Liff, Dale R., Zeik, Andrew C., Blaha, Mark A., Amistadi, Jason L., Gruich, Robert D.
• Primary Examiner(s): Barnie, Rexford N
• Assistant Examiner(s): Ortiz, Elim
• Application Number:
  US15/350,191
• Publication Number:
  US 20170063165A1
• Time in Patent Office: 1,485 Days
• 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 with power accounting. Parasitic metal in proximity to the primary unit can be more accurately detected by accounting for changes in known power losses during operation. The amount of power loss during inductive power supply transfer in an inductive power supply system can vary depending on the alignment of the primary unit and the secondary device. The amount of power loss during inductive power supply transfer can also vary as a function of changes in the operating frequency of the switching circuit in the primary unit or as a function of changes in the secondary device load.

Claims

1. A method of detecting an unacceptable amount of parasitic metal in proximity to a primary device, the method comprising:

transferring contactless energy at a first power level from a primary device to a secondary device;

measuring one or more first characteristics of power in the primary device to obtain a first value, wherein the first value is representative of the amount of power transferred from the primary device;

measuring one or more second characteristics of power in the primary device, wherein the one or more second characteristics are indicative of the amount of power transferred from the primary device at the first power level;

receiving information from the secondary device to obtain a second value, wherein the second value is representative of the amount of power received by the secondary device;

receiving information from the secondary device about the amount of power received by the secondary device at the first power level;

transferring contactless energy at a second power level from a primary device to a secondary device;

measuring one or more third characteristics of power in the primary device, wherein one or more third characteristics are indicative of the amount of power transferred from the primary device at the second power level;

receiving information from the secondary device about the amount of power received by the secondary device at the second power level; and

estimating acceptable power loss in at least one of the primary device and the secondary device to obtain a third value,

wherein the third value is representative of estimated acceptable power loss,

wherein the estimated acceptable power loss varies based on at least one of the amount of power transferred from the primary device and the amount of power received by the secondary device;

determining whether there is an unacceptable amount of parasitic metal in proximity to the primary device based on the first value, the second value and the third value;

determining a relationship between a third power level and the acceptable power loss, wherein the relationship is based on the amount of power transferred from the primary device at the first power level, the amount of power received by the secondary device at the first power level, the amount of power transferred from the primary device at the second power level, and the amount of power received by the secondary device at the second power level.

2. The method of claim 1, wherein the determining a relationship between the third power level and the acceptable power loss includes deriving a scalar value.

3. The method of claim 1, wherein the determining a relationship between the third power level and the acceptable power loss includes generating a plurality of coefficients.

4. The method of claim 1, wherein the determining whether there is an unacceptable amount of parasitic metal includes accounting for acceptable power losses due to misalignment of the primary device and secondary device in the third value.

5. The method of claim 1, wherein determining whether there is an unacceptable amount of parasitic metal includes accounting for acceptable power losses due to changes in frequency of the primary device in the third value.

6. The method of claim 1, wherein determining

whether there is an unacceptable amount of parasitic metal includes accounting for acceptable power losses due to friendly parasitics,

wherein the acceptable losses due to friendly parasitics vary based on at least one of the first value and the second value.

7. A primary device for transferring power to a secondary device, the primary device comprising:

a primary coil,

wherein the primary coil is arranged to transfer contactless power at a first power from a primary device to a secondary device,

wherein the primary coil transmits contactless power at a second power level;

one or more sensors measuring one or more first characteristics of power in the primary device,

wherein the one or more first characteristics are representative of information about the amount of power transmitted from the primary device,

wherein the one or more sensors measure one or more second characteristics of power in the primary device,

wherein the one or more second characteristics are representative of information about the amount of power transmitted from the primary device at the first power level

wherein the one or more sensors measure one or more third characteristics of power in the primary device,

wherein the one or more third characteristics are representative of information about the amount of power transmitted from the primary device at the second level;

communication circuitry,

wherein the communication circuitry is arranged to receive information about the amount of power received by a secondary device,

wherein the communication circuitry receives information about the amount of power received by the secondary device at the first power level; and

a controller circuit,

wherein the controller circuit is arranged to determine whether there is an unacceptable amount of parasitic metal in proximity to the primary device based on the one or more first characteristics, the received information about the amount of power received by the secondary device, and a value representative of acceptable power loss, wherein the acceptable power loss varies with at least one of the amount of power transferred from the primary device and the amount of power received by the secondary device,

wherein the communication circuitry receives information about the amount of power received by the secondary device at the second power level,

wherein the controller circuit is configured to determine a relationship between a third power level and acceptable power loss,

wherein the relationship is based on the amount of power transferred from the primary device at the first power level, the amount of power received by the secondary device at the first power level, the amount of power transferred from the primary device at the second power level, and the amount of power received by the secondary device at the second power level.

8. The primary device of claim 7,

wherein the controller circuit is configured to determine the relationship between the third power level and the acceptable power loss includes,

wherein the controller circuit is configured to derive a scalar value for estimating power loss as a function of power transmitted from the primary device, power received by a remote device, or both.

9. The primary device of claim 7,

wherein the controller circuit is being configured to generate a plurality of coefficients,

wherein the coefficients account for acceptable power loss.

10. The method of claim 7, wherein the controller circuit is configured to account for acceptable power loss due to misalignment of the primary device and secondary device by modifying the value representative of acceptable power loss.

11. The method of claim 7, wherein the controller circuit is configured to account for acceptable power loss due to changes in frequency of the primary device by modifying the value representative of acceptable power loss.

12. The method of claim 7,

wherein the controller circuit is configured to account for acceptable power loss due to friendly parasitics,

wherein acceptable power loss due to friendly parasitics vary based on at least one of the amount of power transferred from the primary device and the amount of power received by the secondary device.

13. A method of detecting an unacceptable amount of parasitic metal in proximity to a primary device, the method comprising:

transferring contactless energy at a first power level from a primary device to a secondary device;

transferring contactless energy from a primary device to a secondary device at a second power level;

obtaining information about an amount of power transferred from the primary device at the first power level;

obtaining information about an amount of power received by the secondary device at the first power level;

obtaining information about the amount of power transferred from the primary device at the second power level;

obtaining information about an amount of power received by the secondary device at the second power level;

estimating acceptable power loss, wherein the estimated acceptable power loss varies based on at least one of the amount of power transferred from the primary device and the amount of power received by the secondary device;

determining whether there is an unacceptable amount of parasitic metal in proximity to the primary device based on the amount of power transferred from the primary device, the amount of power received by the secondary device, and the estimated acceptable power loss; and

determining a relationship between a third power level and acceptable power loss for estimating power loss in at least one of the primary device and the secondary device, wherein the relationship is based on the amount of power transferred from the primary device at the first power level, the amount of power received by the secondary device at the first power level, the amount of power transferred from the primary device at the second power level, and the amount of power received by the secondary device at the second power level.

14. The method of claim 13,

wherein determining the relationship between the third power level and the acceptable power loss includes deriving a scalar value,

wherein the scalar value is arranged to estimate power loss due to friendly parasitic metal.

15. The method of claim 13,

wherein determining the relationship between the third power level and the acceptable power loss includes generating a plurality of coefficients,

wherein the plurality of coefficients are arranged to estimate power loss due to friendly parasitic metal.

16. The method of claim 13, wherein estimating acceptable power loss includes estimating losses due to misalignment of the primary device and secondary device.

17. The method of claim 13, wherein estimating acceptable power loss includes estimating acceptable power loss due to changes in frequency of the primary device.

18. The method of claim 13,

wherein estimating acceptable power loss includes estimating acceptable power loss due to friendly parasitics,

wherein the acceptable power loss due to friendly parasitics varies based on at least one of the amount of power transferred from the primary device and the amount of power received by the secondary device.