JP2017147853A - Electric power transmission device and vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect a foreign object present in a range that may cause a problem in non-contact electric power transmission, while inhibiting erroneous detection of foreign object caused by a sunshine change or the like, in a vehicle and an electric power transmission device for detecting a foreign object by a fish-eye camera.SOLUTION: An infrared camera 210 is provided in a central portion of an electric power transmission device 200, and configured to photograph its surroundings. A light source 220 is provided in the surroundings of the infrared camera 210, and configured to emit light in the direction of the outer periphery of the transmission device 200. The control device 240 determines that, among foreign objects photographed by the infrared camera 210 during on and off of the light source 220, a foreign object with a higher degree of luminance change synchronized with on and off of the light source 220 is located closer to the electric power transmission device 200.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a power transmission device and a vehicle, and more particularly to a power transmission device and a vehicle that perform non-contact power transmission between the power transmission device and the vehicle.

  A contactless power transmission system that transmits power from a power transmission device to a power reception device in a contactless manner is known (see Patent Documents 1 to 6). In the non-contact power transmission system disclosed in Japanese Unexamined Patent Publication No. 2013-192411 (Patent Document 1), a foreign object existing between the power receiving device and the power transmitting device is detected. This non-contact power transmission system includes a camera capable of photographing a space between a power receiving device and a power transmitting device. In this non-contact power transmission system, a foreign object existing between the power receiving apparatus and the power transmitting apparatus can be detected by using an image taken by a camera (see Patent Document 1).

JP 2013-192411 A JP2013-154815A JP2013-146154A JP2013-146148A JP 2013-110822 A JP 2013-126327 A

  However, in a system that detects a foreign object using a camera, such as the non-contact power transmission system disclosed in Patent Document 1 above, a factor such as a change in sunshine may occur even though there is actually no foreign object near the power transmission device. There is a possibility that a foreign object is erroneously detected due to a change in the captured image. Therefore, it is important to reduce the possibility of foreign objects being erroneously detected due to factors such as changes in sunshine.

  It is also conceivable to use a fish-eye camera to detect foreign objects in a non-contact power transmission system. By using a fisheye camera, foreign substances existing around the power transmission device can be detected over a wide range. However, the fish-eye camera captures not only foreign objects existing near the power transmission apparatus but also foreign objects present at a position far from the power transmission apparatus. When foreign matter exists only at a position far from the power transmission device, no problem occurs even if non-contact power transmission is performed. Therefore, it is important to accurately detect foreign matter existing in a range that causes a problem when non-contact power transmission is performed.

  The present invention has been made to solve these problems, and an object thereof is to suppress erroneous detection of foreign matters due to factors such as changes in sunlight in a power transmission device and a vehicle that detect foreign matters with a fisheye camera. On the other hand, it is to accurately detect foreign matter existing in a range that causes a problem when non-contact power transmission is performed.

  A power transmission device according to an aspect of the present invention transmits power to a power reception device of a vehicle in a contactless manner. The power transmission device includes a fisheye camera, a light source, and a control device. The fisheye camera is provided in the central portion of the power transmission device and is configured to photograph the surroundings. The light source is provided around the fisheye camera and configured to irradiate light in the outer peripheral direction of the power transmission device. The control device determines that, among the foreign objects photographed by the fisheye camera when the light source is blinking, a foreign object having a large degree of luminance change in synchronization with the blinking of the light source is present at a position closer to the power transmission device.

  A vehicle according to another aspect of the present invention includes a power receiving device that receives power from a power transmitting device in a contactless manner. The vehicle includes a fisheye camera, a light source, and a control device. The fish-eye camera is provided in the central portion of the power receiving device and is configured to photograph the surroundings. The light source is provided around the fisheye camera and is configured to emit light in the outer peripheral direction of the power receiving apparatus. The control device determines that, among the foreign objects photographed by the fisheye camera when the light source blinks, a foreign object having a large degree of luminance change in synchronization with the blinking of the light source is present at a position closer to the power receiving apparatus.

  In these inventions, light is emitted from the periphery of the fisheye camera toward the outer periphery of the power transmission device or power reception device. Thereby, illuminance can be ensured at the time of photographing with a fisheye camera. As a result, for example, it is possible to reduce the degree of change in the photographed image due to changes in sunshine, and to suppress erroneous detection of foreign matters due to factors such as changes in sunshine. In addition, when light is emitted from the light source toward the outer periphery of the power transmission device or the power reception device, the light with higher luminance is reflected from the foreign material as the foreign material is located closer to the fisheye camera. In these inventions, it is determined that among foreign objects photographed by the fisheye camera when the light source blinks, a foreign object having a greater degree of luminance change in synchronization with the blinking of the light source is present at a position closer to the power transmission device or the power receiving device. The Therefore, according to these inventions, the presence of a foreign object near the power transmission device or the power reception device can be detected relatively accurately.

  A power transmission device according to another aspect of the present invention transmits power to a power reception device of a vehicle in a contactless manner. The power transmission device includes a fisheye camera, a light source, and a control device. The fisheye camera is provided in the central portion of the power transmission device and is configured to photograph the surroundings. The light source is provided around the fisheye camera and configured to irradiate light in the outer peripheral direction of the power transmission device. The edge portion of the image taken by the fisheye camera is divided into a plurality of regions in the circumferential direction. The control device determines that there is a foreign object when the change in luminance is synchronized with the blinking of the light source in any of the plurality of regions when the light source is blinking.

  A vehicle according to another aspect of the present invention includes a power receiving device that receives power in a non-contact manner from a power transmitting device outside the vehicle. The vehicle includes a fisheye camera, a light source, and a control device. The fish-eye camera is provided in the central portion of the power receiving device and is configured to photograph the surroundings. The light source is provided around the fisheye camera and is configured to emit light in the outer peripheral direction of the power receiving apparatus. The edge portion of the image taken by the fisheye camera is divided into a plurality of regions in the circumferential direction. The control device determines that there is a foreign object when the change in luminance is synchronized with the blinking of the light source in any of the plurality of regions when the light source is blinking.

  In these inventions, light is emitted from the periphery of the fisheye camera toward the outer periphery of the power transmission device or power reception device. Thereby, illuminance can be ensured at the time of photographing with a fisheye camera. As a result, for example, it is possible to reduce the degree of change in the photographed image due to changes in sunshine, and to suppress erroneous detection of foreign matters due to factors such as changes in sunshine. In addition, an area outside the bottom of the vehicle is photographed at the edge portion of the image photographed by the fisheye camera. In these inventions, when the edge portion of the image photographed by the fisheye camera is divided into a plurality of regions in the circumferential direction, and the luminance change of any of the plurality of regions is synchronized with the blinking of the light source when the light source is blinking Is determined that there is a foreign object. Therefore, according to these inventions, non-contact power transmission is performed only by monitoring the luminance change in each region of the edge portion of the image without specifically specifying the foreign matter contained in the edge portion of the captured image. In this case, it is possible to detect a foreign substance existing in a range that causes a problem relatively easily.

  According to the present invention, in a power transmission device and a vehicle that detect a foreign object using a fisheye camera, the erroneous detection of the foreign object due to factors such as a change in sunlight is present in a range that causes a problem when non-contact power transmission is performed. It is possible to accurately detect foreign matter to be detected.

1 is a schematic configuration diagram of a non-contact power transmission system in a first embodiment. It is a perspective view which shows the external appearance structure of a power transmission apparatus. It is a figure which shows the structure relevant to the foreign material detection of a power transmission apparatus. It is a figure which shows the example of the picked-up image image | photographed with an infrared camera in the state which has parked the vehicle on the power transmission apparatus. It is a figure for demonstrating the method to determine whether a foreign material exists near the power transmission apparatus. It is a figure which shows the example of the brightness | luminance change of the foreign material shown by FIG. 5 at the time of the detection of a foreign material intrusion. It is a figure which shows the result of having frequency-analyzed the brightness | luminance change of the foreign material shown by FIG. It is a flowchart which shows the detection processing procedure of a foreign material intrusion. It is a figure which shows the example by which an infrared camera and a light source are provided in a vehicle. FIG. 10 is a diagram for explaining regions A and B in the second embodiment. It is a flowchart which shows the detection processing procedure of a foreign material intrusion.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

(Embodiment 1)
[Configuration of contactless power transmission system]
FIG. 1 is a schematic configuration diagram of a contactless power transmission system to which a power transmission device according to the first embodiment is applied. Referring to FIG. 1, contactless power transmission system 1 includes a vehicle 10 and a power transmission device 200. Non-contact power transmission is performed between the vehicle 10 and the power transmission device 200.

  The power transmission device 200 includes a power transmission coil (not shown). The power transmission coil forms a magnetic field by receiving power from the AC power source 300 such as a system power source, and transmits power to the power receiving coil (not shown) of the power receiving apparatus 100 through the formed magnetic field in a non-contact manner. The number of turns of the power transmission coil is appropriately designed so that the Q value (for example, Q ≧ 100) and the coupling coefficient κ are increased.

  On the other hand, vehicle 10 includes a power receiving device 100 and a power storage device 110, and power receiving device 100 includes a power receiving coil. The power receiving coil receives power from the power transmitting coil of the power transmitting device 200 in a non-contact manner. The power received by the power receiving coil is supplied to the power storage device 110. The number of windings of the power receiving coil is appropriately designed so that the Q value (for example, Q ≧ 100) and the coupling coefficient κ are increased.

  In the non-contact power transmission system 1, the possibility that foreign matter existing around the power transmission device 200 may enter the power transmission device 200 (hereinafter, also simply referred to as “foreign matter intrusion”) is detected. For example, when non-contact power transmission is performed in a state where foreign matter has entered the power transmission device 200, the foreign matter becomes high temperature depending on the type of foreign matter. According to the non-contact power transmission system 1, such a situation can be avoided by detecting the entry of a foreign object before the start of the non-contact power transmission.

[Configuration of power transmission equipment]
FIG. 2 is a perspective view illustrating an external configuration of the power transmission device 200. With reference to FIG. 2, an infrared camera 210 is provided at the center of the upper surface of power transmission device 200. The infrared camera 210 has a fisheye lens, and can take an image of 360 degrees in all directions, for example. What kind of image is captured by the infrared camera 210 will be described in detail later. A light source 220 is provided around the infrared camera 210. The light source 220 irradiates infrared light toward the outer periphery of the power transmission device 200.

  FIG. 3 is a diagram illustrating a configuration related to foreign object detection of the power transmission device 200. Referring to FIG. 3, power transmission device 200 includes a power transmission coil 205, an infrared camera 210, a light source 220, a control IC 230, and a control device 240.

  The infrared camera 210 and the light source 220 are provided in the central portion of the power transmission device 200 in the region on the inner peripheral side of the power transmission coil 205.

  The control IC 230 is a control circuit for switching between turning on and off the light source 220. The control IC 230 switches between turning on and off the light source 220 in accordance with a command from the control device 240.

  The control device 240 includes a CPU (Central Processing Unit) and an internal memory (not shown), and each device (infrared camera 210) of the power transmission device 200 based on information stored in the internal memory and information from each sensor (not shown). , Control IC 230, etc.).

  As a function realized by the control device 240, there is a function of detecting foreign object intrusion (hereinafter also referred to as “intrusion detection function”). Detection of entry of a foreign object is performed based on an image taken by the infrared camera 210. The intrusion detection function will be described in detail later.

[Images taken with an infrared camera]
FIG. 4 is a diagram illustrating an example of a captured image captured by the infrared camera 210 in a state where the vehicle 10 is parked on the power transmission device 200. Referring to FIG. 4, captured image 400 includes region A and region B.

  The detection of the entry of a foreign object is mainly performed in a state where the vehicle 10 is parked on the power transmission device 200. The infrared camera 210 captures 360 degrees of all directions when detecting the entry of a foreign object. Therefore, at the time of detecting the intrusion of the foreign object, the bottom surface of the vehicle 10 is photographed in the central portion (region A) of the photographed image 400, and an object existing outside the bottom surface of the vehicle 10 is photographed in the edge portion (region B) of the photographed image 400. Taken. In this example, the region B includes foreign objects 405 and 410 existing outside the bottom surface of the vehicle 10.

  For example, the control device 240 stores a comparison image in the case where no foreign substance is present in an internal memory (not shown), and compares the comparison image with an image (for example, a captured image 400) captured by the infrared camera 210. Thus, the foreign matter existing in the areas A and B is detected.

  When a foreign object is detected in the area A of the captured image 400, there is a high possibility that a foreign object exists below the bottom surface of the vehicle 10. Therefore, when non-contact power transmission is performed, depending on the type of foreign matter, the foreign matter may become high temperature due to the influence of a magnetic field generated during power transmission. Therefore, in this case, it is preferable that non-contact power transmission is stopped.

  If a foreign object is detected in the region B of the captured image 400 and the foreign object is present near the power transmission device 200, the possibility that the foreign material will enter the power transmission device 200 is high. Therefore, also in this case, it is preferable that non-contact power transmission is stopped. On the other hand, even if a foreign object is detected in the region B of the captured image 400, if the foreign object exists far away from the power transmission device 200 (for example, if the foreign object exists outside the bottom surface of the vehicle), the foreign object is transmitted. Less likely to invade above. Therefore, it is not necessary to stop the non-contact power transmission. Therefore, it is important to determine whether or not a foreign object detected in the region B of the captured image 400 exists near the power transmission device 200.

  In power transmission device 200 according to the first embodiment, it is determined whether or not a foreign object detected in region B of captured image 400 exists near power transmission device 200. Next, a method for determining whether or not a foreign object exists near the power transmission device 200 will be described.

[How to determine whether or not a foreign object exists nearby]
FIG. 5 is a diagram for describing a method for determining whether or not a foreign object exists near the power transmission device 200. Referring to FIG. 5, in power transmission device 200, detection of a foreign object intrusion is performed based on an image taken by infrared camera 210 when light source 220 emits light. Since the light source 220 emits light, a certain level of illuminance can be ensured when photographing with the infrared camera 210. As a result, for example, it is possible to reduce the influence of a change in the captured image due to a change in sunlight, and to suppress erroneous detection of foreign matter.

  When the light source 220 emits light, strong infrared light is reflected from a foreign object (for example, the foreign object 405) existing near the light source 220. On the other hand, when the light source 220 emits light, only weak infrared light is reflected from a foreign object (for example, the foreign object 410) existing at a position far from the light source 220. Therefore, by analyzing the intensity (luminance) of the reflected infrared light with respect to the irradiation of the infrared light from the light source 220, it is determined how far the foreign object exists from the power transmission device 200. can do.

  Therefore, in power transmission device 200 according to the first embodiment, control device 240 synchronizes with the blinking of light source 220 among the foreign matters (for example, foreign matter 405 and 410) photographed by infrared camera 210 when light source 220 blinks. It is determined that a foreign object having a greater degree of luminance change is present at a position closer to the power transmission device 200. By monitoring the degree of luminance change synchronized with the blinking of the light source 220, the possibility of erroneously detecting a foreign object that emits light or a foreign object that reflects light from a light source other than the light source 220 as a foreign object present in the vicinity is reduced. Yes.

  For example, the control device 240 uses the image (moving image) photographed by the infrared camera 210 when the light source 220 blinks, and calculates the frequency component of each foreign object detected in the edge portion of the image (for example, the region B in FIG. 4). To analyze. The control device 240 determines that a foreign object having a stronger intensity at the blinking frequency of the light source 220 exists near the power transmission device 200.

  FIG. 6 is a diagram illustrating an example of a change in luminance of the foreign objects 405 and 410 (FIGS. 4 and 5) when the foreign object intrusion is detected. Referring to FIG. 6, the horizontal axis represents time, and the vertical axis represents the brightness of the foreign matter. In addition, the brightness | luminance of a foreign material is the sum total of the brightness | luminance of each pixel which comprises the foreign material detected in the edge part (for example, area | region B of FIG. 4) of the picked-up image of the infrared camera 210. FIG. A luminance change Y1 indicated by a solid line indicates a luminance change of the foreign object 405. A luminance change Y2 indicated by a one-dot chain line indicates a luminance change of the foreign object 410.

  FIG. 7 is a diagram showing the result of frequency analysis of the luminance change of the foreign objects 405 and 410 shown in FIG. It is assumed that the blinking frequency of the light source 220 (light source blinking frequency) at the time of detecting the entry of a foreign object is f1. Referring to FIG. 7, the horizontal axis indicates the frequency and the vertical axis indicates the intensity. The intensity P1 indicated by the solid line is the result of frequency analysis of the luminance change Y1 (FIG. 6). The intensity P2 indicated by the alternate long and short dash line is a result of frequency analysis of the luminance change Y2 (FIG. 6). The threshold value Pth will be described later.

  Since foreign object 405 is present at a position closer to power transmission device 200 than foreign object 410, the intensity of P1 at frequency f1 (light source blinking frequency) is stronger than the intensity of P2 at frequency f1. In power transmission device 200 according to the first embodiment, the frequency component of the foreign matter included in the edge portion of the image captured by infrared camera 210 is analyzed, and the intensity of the light source blinking frequency of each foreign matter is referred to, whereby each foreign matter is transmitted. It is determined how far away the device 200 is. Hereinafter, the foreign substance intrusion detection processing procedure will be described.

[Intrusion detection procedure]
FIG. 8 is a flowchart showing a foreign matter intrusion detection processing procedure. The processing shown in this flowchart is repeatedly executed by the control device 240 when non-contact power transmission is performed between the power transmission device 200 and the power reception device 100.

  Referring to FIG. 8, control device 240 controls infrared camera 210 to take an image while controlling control IC 230 so that light source 220 is lit (step S100). Thereafter, the control device 240 compares the comparison image stored in the internal memory (the image without foreign matter) with the image taken by the infrared camera 210, so that the foreign matter exists in the area A (FIG. 4). It is determined whether or not to perform (step S102).

  If it is determined that there is a foreign object in area A (YES in step S102), it can be said that there is a foreign object below the bottom surface of vehicle 10, and therefore controller 240 detects the foreign object and stops non-contact power transmission (step S104). ). Thereafter, the process proceeds to return.

  If it is determined that there is no foreign object in area A (NO in step S102), control device 240 compares area B with the comparison image stored in the internal memory and the image captured by infrared camera 210. It is determined whether or not a foreign substance exists in (FIG. 4) (step S110).

  If it is determined that there is no foreign object in area B (NO in step S110), the process proceeds to return because the possibility of a foreign object entering the power transmission device 200 is low. On the other hand, if it is determined that there is a foreign object in region B (YES in step S110), is the foreign object present within a predetermined range from power transmission device 200 (within a range where a problem occurs when non-contact power transmission is performed)? In order to determine whether or not, the control device 240 controls the infrared camera 210 to capture an image (moving image) while controlling the control IC 230 so that the light source 220 blinks (step S120).

  Thereafter, the control device 240 performs frequency analysis of the foreign matter included in the captured moving image (step S130). As a result of the frequency analysis, the control device 240 indicates that a foreign object having a stronger intensity of the blinking frequency of the light source 220 (light source blinking frequency) (a foreign object having a large degree of luminance change in synchronization with the blinking of the light source 220) is closer to the power transmission device 200. It is determined that it exists (step S140).

  Thereafter, control device 240 determines whether or not the intensity at the light source blinking frequency of a foreign object determined to exist closest to power transmission device 200 is equal to or greater than threshold value Pth (step S150). The threshold value Pth is a reference value for determining whether or not to stop the non-contact power transmission, and it is determined that a foreign object having an intensity exceeding the threshold value Pth exists within the predetermined range.

  If it is determined that the intensity at the light source blinking frequency of the foreign object that is determined to be closest to power transmission device 200 is not greater than or equal to threshold value Pth (NO in step S150), the foreign object is within a range that affects non-contact power transmission. Since it can be said that does not exist, the processing shifts to return. When it is determined that the intensity at the light source blinking frequency of a foreign object determined to be present closest to power transmission device 200 is greater than or equal to threshold value Pth (YES in step S150), control device 240 receives a predetermined amount from power transmission device 200. Since it can be said that a foreign object exists within the range, the intrusion of the foreign object is detected and the non-contact power transmission is stopped (step S160). Thereafter, the process proceeds to return.

  As described above, in power transmission device 200 according to the first embodiment, control device 240 has a large degree of brightness change in synchronization with blinking of light source 220 among foreign objects photographed by infrared camera 210 when light source 220 blinks. It is determined that a foreign object is present at a position closer to the power transmission device 200. Therefore, according to this power transmission device, the presence of a foreign object near the power transmission device can be detected relatively accurately.

  In the first embodiment, the infrared camera 210 and the light source 220 are provided in the power transmission device 200. However, the infrared camera and the light source may be provided in the vehicle 10, for example.

  FIG. 9 is a diagram illustrating an example in which the vehicle 10 is provided with an infrared camera and a light source. Referring to FIG. 9, vehicle 10 is provided with a power receiving device 600 instead of power receiving device 100. The power receiving device 600 includes a power receiving coil 605, an infrared camera 610, a light source 620, a control IC 630, and a control device 640 as components related to detection of foreign object intrusion. The infrared camera 610 corresponds to the infrared camera 210, the light source 620 corresponds to the light source 220, and the control IC 630 corresponds to the control IC 230.

  The control device 640 determines that among foreign objects photographed by the infrared camera 610 when the light source 620 blinks, a foreign object having a large degree of luminance change in synchronization with the blinking of the light source 620 is present at a position closer to the vehicle 10. Thereby, according to the vehicle 10 on which the power receiving device 600 is mounted, the presence of a foreign object near the vehicle 10 can be detected relatively accurately.

(Embodiment 2)
In power transmission device 200 according to the first embodiment, the foreign matter included in the edge portion (region B in FIG. 4) of the image photographed by infrared camera 210 is specified, and the specified foreign matter is synchronized with blinking of light source 220. The positional relationship between the foreign object and the power transmission device 200 is determined depending on how much the luminance changes. However, it may be difficult to identify a foreign object, such as when a large number of foreign objects are included in the edge portion of an image captured by the infrared camera 210, or when the change in sunshine is large.

  Therefore, in the second embodiment, foreign object intrusion is detected without specifying the foreign substance contained in the edge portion of the image taken by the infrared camera 210. When the light source 220 blinks when foreign matter exists within a range where problems occur when non-contact power transmission is performed, the region containing the foreign matter in the captured image of the infrared camera 210 is synchronized with the blinking frequency of the light source 220. The brightness should change.

  1 to 3 again, power transmission device 200A according to the second embodiment includes a control device 240A. The control device 240A recognizes the edge portion of the image photographed by the infrared camera 210 by dividing it into a plurality of regions in the circumferential direction, and changes in luminance in any of the plurality of regions when the light source 220 blinks. When synchronized with blinking, it is determined that there is a foreign object. Therefore, according to the power transmission device 200A, it is possible to detect the entry of a foreign object relatively easily only by monitoring the luminance change in each region of the edge portion of the image.

  FIG. 10 is a diagram for explaining regions A and B in the second embodiment. Referring to FIG. 10, captured image 500 includes region A and region B.

  When a foreign object intrusion is detected, the bottom surface of the vehicle 10 is photographed in the center portion (region A) of the photographed image 500, and an object existing outside the bottom surface of the vehicle 10 is photographed in the edge portion (region B) of the photographed image 500. The The control device 240A recognizes the region B of the captured image 500 by dividing it into 36, for example. The control device 240 </ b> A determines whether or not the luminance change of each area divided into 36 when the light source 220 blinks is synchronized with the blinking of the light source 220. 240 A of control apparatuses determine with the foreign material existing, when the area | region to synchronize exists. Hereinafter, the foreign substance intrusion detection processing procedure in the second embodiment will be described.

  FIG. 11 is a flowchart showing a foreign substance intrusion detection processing procedure in the second embodiment. The processing shown in this flowchart is repeatedly executed by the control device 240A when non-contact power transmission is performed between the power transmission device 200A and the power receiving device 100.

  Referring to FIG. 11, control device 240A first executes the processes of steps S200, S202, and S204. Steps S200, S202, and S204 are the same processes as steps S100, S102, and S104 in FIG. 8, respectively.

  If it is determined in step S202 that there is no foreign object in area A (NO in step S202), control device 240A controls the control IC 230 so that the light source 220 blinks and captures an image (moving image). The infrared camera 210 is controlled (step S206). Thereafter, control device 240A performs frequency analysis of each region (each 36-divided region) included in an edge portion (for example, region B in FIG. 10) of the image captured by infrared camera 210 (step S210).

  When the frequency analysis is completed, control device 240A determines whether or not there is a region where the intensity at the light source blinking frequency is equal to or greater than threshold value Pth2 (step S220). The threshold value Pth2 is a reference value for determining whether or not to stop the non-contact power transmission. When there is a region having an intensity equal to or higher than the threshold value Pth2, the non-contact power transmission is stopped. The

  If it is determined that there is no region where the intensity at the light source frequency is equal to or greater than the threshold value Pth2 (NO in step S220), it can be said that there is no foreign matter within a range that affects non-contact power transmission, and the process returns. Migrate to

  If it is determined that there is a region where the intensity at the light source frequency is equal to or higher than threshold value Pth2 (YES in step S220), control device 240A has a foreign object in a range that causes a problem when performing non-contact power transmission. Therefore, foreign object intrusion is detected and non-contact power transmission is stopped (step S230). Thereafter, the process proceeds to return.

  As described above, in power transmission device 200A according to the second embodiment, the edge portion of the image photographed by infrared camera 210 is divided into a plurality of regions in the circumferential direction, and control device 240A provides a plurality of light sources 220 when blinking. When the change in luminance is synchronized with the blinking of the light source 220 in any of the areas, it is determined that there is a foreign object. Therefore, according to the power transmission device 200A, it is possible to detect the entry of a foreign object relatively easily only by monitoring the luminance change in each region of the edge portion of the image.

  In the second embodiment, the infrared camera 210 and the light source 220 are provided in the power transmission device 200A. However, the infrared camera and the light source may be provided in the vehicle 10, for example.

  Referring to FIG. 9 again, vehicle 10 is provided with a power receiving device 600 </ b> A instead of power receiving device 100. The power receiving device 600A includes a power receiving coil 605, an infrared camera 610, a light source 620, a control IC 630, and a control device 640A as a configuration related to detection of foreign object intrusion.

  In this case, the edge portion of the image photographed by the infrared camera 210 is divided into a plurality of regions in the circumferential direction, and the control device 640A changes the luminance in any one of the plurality of regions when the light source 220 blinks. When synchronized with the blinking of the light source 220, it is determined that there is a foreign object. As a result, according to the vehicle 10 equipped with the power receiving device 600A, it is relatively easy to detect the entry of a foreign object only by monitoring the luminance change in each region of the edge portion of the image.

(Other embodiments)
As described above, the first and second embodiments have been described as the embodiments of the present invention. However, the present invention is not necessarily limited to the first and second embodiments. Here, an example of another embodiment will be described.

  In the first and second embodiments, the intensity of the luminance change synchronized with the blinking of the light source 220 is detected by performing frequency analysis on the image (moving image) captured by the infrared camera 210 while the light source 220 is blinking. However, the method for detecting the intensity of the luminance change synchronized with the blinking of the light source 220 is not limited to frequency analysis. For example, the intensity of the luminance change synchronized with the blinking of the light source 220 may be detected by calculating the correlation coefficient between the luminance change of the image captured by the infrared camera 210 and the blinking of the light source 220. In this case, for example, the stronger the correlation between the change in the brightness of the foreign object included in the image captured by the infrared camera 210 and the blinking of the light source 220, the greater the degree of the change in the brightness of the foreign object synchronized with the blinking of the light source 220. I can say that.

  In the first and second embodiments, foreign object intrusion is detected based on an image taken by the infrared camera 210 with the light source 220 blinking. However, the target to be detected based on the image captured by the infrared camera 210 with the light source 220 blinking is not limited to this. For example, even if a foreign object existing on the power transmission device 200 is detected by the same method. Good.

  In the first and second embodiments, the light source 220 that emits infrared light and the infrared camera 210 are used to detect the entry of foreign matter. However, it is not always necessary to use infrared light. For example, the light source 220 may be changed to a light source that emits visible light, and the infrared camera 210 may be a camera that captures visible light.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  1, 1A contactless power transmission system, 10 vehicle, 100, 600, 600A power receiving device, 110 power storage device, 200, 200A power transmission device, 205 power transmission coil, 210, 610 infrared camera, 220, 620 light source, 230, 630 control IC , 240, 240A, 640, 640A control device, 300 AC power supply, 400, 500 photographed image, 405, 410 foreign matter, 605 power receiving coil.

Claims (4)

A power transmission device for non-contact power transmission to a vehicle power receiving device,
A fisheye camera provided in a central portion of the power transmission device and configured to photograph the surroundings;
A light source provided around the fisheye camera and configured to irradiate light in an outer peripheral direction of the power transmission device;
A control device that determines that, among foreign objects photographed by the fish-eye camera when the light source is blinking, a foreign object having a greater degree of brightness change in synchronization with the blinking of the light source is present at a position closer to the power transmission device. , Power transmission equipment. A power transmission device for non-contact power transmission to a vehicle power receiving device,
A fisheye camera provided in a central portion of the power transmission device and configured to photograph the surroundings;
A light source provided around the fisheye camera and configured to irradiate light in an outer peripheral direction of the power transmission device;
The edge portion of the image taken by the fisheye camera is divided into a plurality of regions in the circumferential direction,
A power transmission device further comprising: a control device that determines that a foreign object is present when a change in luminance is synchronized with blinking of the light source in any one of the plurality of regions when the light source is blinking. A vehicle equipped with a power receiving device that receives power from a power transmitting device in a contactless manner,
A fisheye camera provided in a central portion of the power receiving device and configured to photograph the surroundings;
A light source provided around the fisheye camera and configured to irradiate light in an outer peripheral direction of the power receiving device;
A controller that determines that a foreign object that is captured by the fisheye camera when the light source blinks and has a large degree of brightness change in synchronization with the blinking of the light source is present at a position closer to the power receiving device. ,vehicle. A vehicle equipped with a power receiving device that receives power from a power transmitting device in a contactless manner,
A fisheye camera provided in a central portion of the power receiving device and configured to photograph the surroundings;
A light source provided around the fish-eye camera and configured to irradiate light in an outer peripheral direction of the power receiving device;
The edge portion of the image taken by the fisheye camera is divided into a plurality of regions in the circumferential direction,
A vehicle further comprising a control device that determines that a foreign object is present when a change in luminance is synchronized with blinking of the light source in any of the plurality of regions when the light source is blinking.

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