FOREIGN OBJECT DETECTION SYSTEM AND METHOD SUITABLE FOR SOURCE RESONATOR OF WIRELESS ENERGY TRANSFER SYSTEM

• US 20140203629A1
• Filed: 01/18/2013
• Published: 07/24/2014
• Est. Priority Date: 01/18/2013
• Status: Active Grant

• Current Assignee: Aptiv Technologies AG
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: BOYER, RICHARD J., HOFFMAN, PETER F., HENDERSON, RICHARD A.
• Granted Patent: US 9,304,042 B2
• Time in Patent Office: Days
• US Class Current: 307/9.1
• CPC Class Codes: B60L 2240/36 Temperature of vehicle components or parts
• CPC Class Codes: B60L 2250/10 by alarm
• CPC Class Codes: B60L 2270/147 electro magnetic [EMI]
• CPC Class Codes: B60L 53/124 Detection or removal of foreign bodies
• CPC Class Codes: B60L 53/36 by positioning the vehicle
• CPC Class Codes: B60L 53/37 using optical position determination, e.g. using cameras
• CPC Class Codes: G01J 3/463 Colour matching
• CPC Class Codes: G01J 3/50 using electric radiation detectors
• CPC Class Codes: G01J 5/0022 for sensing the radiation of moving bodies
• CPC Class Codes: G01J 5/0025 Living bodies ear thermometers G01J5/0011; detecting, measuring or recording for diagnostic purposes A61B5/00
• CPC Class Codes: G01J 5/0846 having multiple detectors for performing different types of detection, e.g. using radiometry and reflectometry channels
• CPC Class Codes: G01J 5/0859 Sighting arrangements, e.g. cameras
• CPC Class Codes: G01J 5/0896 using a light source, e.g. for illuminating a surface
• CPC Class Codes: G01V 3/12 operating with electromagnetic waves operating with millimetre waves G01V8/005
• 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: 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 system and method to detect a foreign object proximate to a source resonator that is part of a wireless energy transfer system. The wireless energy transfer system may be one used to wirelessly charge the batteries of an electric vehicle. Data from a visible light camera and a multiple zone temperature sensor are combined or fused to determine whether a foreign object, such a metallic object or an animal, is in the vicinity of, or in close proximity to, a source resonator. The system controls an electric current provided to the source resonator based on whether a foreign object is detected to reduce or inhibit energy emitted by the source resonator. The visible light camera may be a monochrome or color camera and the temperature sensor may be an infrared camera or a thermopile array.

Claims

1. A system to detect a foreign object proximate to a source resonator, said system comprising:

a visible light camera mounted so as to have a camera field of view that includes the source resonator, and configured to output image data indicative of visible light intensity detected by pixels in the camera;

a multiple zone temperature sensor mounted so as to have a sensor field of view that includes the source resonator and is similar to the camera field of view, and configured to output thermal data indicative of a zone temperature for each of the multiple zones; and

a controller in communication with the visible light camera and the multiple zone temperature sensor and configured to

receive visible light image data from the camera;

determine an intensity map characterized as an array of intensity data cells;

designate an intensity object on an area of the intensity map;

receive the thermal data from the multiple zone temperature sensor;

determine a thermal map characterized as an array of thermal data cells;

designate a thermal object on an area of the thermal map;

detect the foreign object when the intensity object and the thermal object intersect; and

control an electric current provided to the source resonator when the foreign object is detected.

2. The system in accordance with claim 1, wherein the camera is further configured to output image data indicative of visible light color and wherein the controller is further configured to

determine a hue map characterized as an array of hue data cells;

designate a hue object on an area of the hue map; and

detect the foreign object when the hue object, the intensity object, and the thermal object intersect.

3. The system in accordance with claim 1, wherein the camera is further configured to output image data indicative of visible light color and wherein the controller is further configured to

determine a saturation map characterized as an array of saturation data cells;

designate a saturation object on an area of the saturation map; and

detect the foreign object when the saturation object, the intensity object, and the thermal object intersect.

4. The system in accordance with claim 1, said system further comprising a warning indicator coupled to the controller effective to generate a warning signal when the foreign object is detected.

5. The system in accordance with claim 1, wherein the visible light camera and the multiple zone temperature sensor are mounted on an underside of a vehicle.

6. The system in accordance with claim 5, wherein the visible light camera and the multiple zone temperature sensor are mounted in close proximity to a capture resonator.

7. The system in accordance with claim 1, wherein the camera has more than 100,000 pixels, and the multiple zone temperature sensor has fewer than 1000 zones.

8. A method to detect a foreign object proximate to a source resonator, said detection based on image data from a visible light camera mounted so as to have a camera field of view that includes the source resonator, and a multiple zone temperature sensor mounted so as to have a sensor field of view that includes the source resonator and is similar to the camera field of view, said method comprising the steps of:

receiving visible light image data from the camera, said image data is indicative of visible light intensity detected by pixels in the camera;

determining an intensity map characterized as an array of intensity data cells, wherein each intensity data cell has an intensity value based on an intensity characteristic of the image data detected by of one or more of the pixels;

designating an intensity object on an area of the intensity map where a cluster of intensity data cells are present that have notable intensity values relative to a reference intensity map;

receiving thermal data from the multiple zone temperature sensor, wherein said thermal data includes a zone temperature value for each of the multiple zones;

determining a thermal map characterized as an array of thermal data cells, wherein each thermal data cell has a temperature value based on a temperature characteristic of one or more of the multiple zones;

designating a thermal object on an area of the thermal map where a cluster of thermal data cells are present that have notable temperature values relative to a temperature threshold;

detecting the foreign object when the intensity object and the thermal object intersect; and

controlling an electric current provided to the source resonator when the foreign object is detected.

9. The method in accordance with claim 8, wherein the method further includes the steps of

receiving visible light image data from the camera, said image data is indicative of visible light color detected by the pixels in the camera;

determining a hue map characterized as an array of hue data cells, wherein each hue data cell has a hue value based on a hue characteristic of the image data detected by of one or more of the pixels;

designating a hue object on an area of the hue map where a cluster of hue data cells are present that have notable hue values relative to a reference hue map; and

detecting the foreign object when the hue object, the intensity object, and the thermal object intersect.

10. The method in accordance with claim 9, wherein said method further includes the step of increasing the number of hue data cells designated as the hue object based on one or more of a hue object shape and a hue object size.

11. The method in accordance with claim 8, wherein the method further includes the steps of

receiving visible light image data from the camera, said image data is indicative of visible light color detected by the pixels in the camera;

determining a saturation map characterized as an array of saturation data cells, wherein each saturation data cell has a saturation value based on a saturation characteristic of the image data detected by of one or more of the pixels;

designating a saturation object on an area of the saturation map where a cluster of saturation data cells are present that have notable saturation values relative to a reference saturation map; and

detecting the foreign object when the saturation object, the intensity object, and the thermal object intersect.

12. The method in accordance with claim 11, wherein said method further comprises increasing the number of saturation data cells designated as the saturation object based on one or more of a saturation object shape and a saturation object size.

13. The method in accordance with claim 8, wherein said method further includes the step of increasing the number of intensity data cells designated as the intensity object based on one or more of an intensity object shape and an intensity object size.

14. The method in accordance with claim 8, wherein said method further include the step of increasing the number of thermal data cells designated as the thermal object based on one or more of a thermal object shape and a thermal object size.

15. The method in accordance with claim 8, wherein said method further includes the step of generating a warning signal when the foreign object is detected.

16. The method in accordance with claim 8, wherein the step of detecting the foreign object includes determining that the detection of the foreign object persists for a time longer than a persistence time threshold.

17. The method in accordance with claim 8, wherein the step of determining the thermal map includes

determining a background temperature value based on a zone temperature value of at least one zone;

determining a differential temperature value for each zone based on a difference between the background temperature value and a corresponding zone temperature value; and

generating a thermal binary map based on a comparison of the differential temperature value to a differential temperature threshold value.

18. A controller for a system configured to detect that a foreign object is proximate to a source resonator, said system comprising a visible light camera mounted so as to have a camera field of view that includes the source resonator, and configured to output image data indicative of visible light intensity detected by pixels in the camera, and a multiple zone temperature sensor mounted so as to have a sensor field of view that includes the source resonator and is similar to the camera field of view, and configured to output thermal data indicative of a zone temperature for each of the multiple zones, said controller configured to

receive visible light image data from the camera;

determine an intensity map characterized as an array of intensity data cells;

designate an intensity object on an area of the intensity map;

receive the thermal data from the multiple zone temperature sensor;

determine a thermal map characterized as an array of thermal data cells;

designate a thermal object on an area of the thermal map;

detect the foreign object when the intensity object and the thermal object intersect; and

control an electric current provided to the source resonator when the foreign object is detected.