JP2015128370A - Wireless power transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wireless power transmission system capable of optimizing power transmission efficiency between a power supply coil and a power receiving coil.SOLUTION: A wireless power transmission system 10 includes: a power supply coil 21 generating an AC magnetic field with the supply of an AC current; a power receiving coil 31 receiving power via an AC magnetic field; and a position detecting means 23 detecting the relative positional relationship between the power supply coil 21 and the power receiving coil 31. The position detecting means 23 measures a deviation amount (Xm, Ym) in a plane direction that is a direction orthogonal to a facing direction of the power supply coil 21 and the power receiving coil 31 and a deviation amount (θm) in a rotation direction of a rotation angle with a coil center viewed from the facing direction as a rotation axis, and detects the relative positional relationship between the power supply coil 21 and the power receiving coil 31 on the basis of the measurement result.

Description

  The present invention relates to a wireless power transmission system.

  A technology for transmitting power without using a power cord, so-called wireless power transmission technology, has attracted attention. The wireless power transmission technology can supply power wirelessly from a power feeding device to a power receiving device, and thus is expected to be applied to mobile objects such as electric vehicles and hybrid vehicles.

  In wireless power transmission to a moving body such as an electric vehicle or a hybrid vehicle, power is transmitted via an electromagnetic field between a feeding coil arranged on the ground side and a receiving coil mounted on the moving body side. In such a case, it is necessary to consider the positional deviation between the power feeding coil and the power receiving coil. For example, in Patent Document 1, the primary coil disposed on the floor is horizontally long, and the secondary coil mounted on the vehicle is vertically long. By adopting the shape, studies have been made to stably provide a large amount of power even if the axial positions of the primary coil and the secondary coil are slightly different.

JP 2011-97671 A

  By the way, it is difficult to accurately stop the moving body at a predetermined place, and it is assumed that the moving body is stopped obliquely with respect to the stop space. However, in the technique disclosed in Patent Document 1, only the positional deviation in the direction orthogonal to the traveling direction of the moving body and the traveling direction of the moving body in a plan view is considered. When a vertically long coil is used, there is a possibility that a desired power transmission efficiency may not always be obtained even if the axial center positions of the power feeding coil and the power receiving coil coincide with each other. That is, there is a problem that the power transmission efficiency is reduced when the shift of the stop angle of the moving body with respect to the stop space is increased.

  Therefore, the present invention has been made in view of such circumstances, and an object thereof is to provide a wireless power transmission system capable of optimizing the power transmission efficiency between the feeding coil and the receiving coil.

  A wireless power transmission system according to the present invention is a wireless power transmission system in which power is transmitted wirelessly by opposing a power feeding coil and a power receiving coil, and a power feeding coil that generates an AC magnetic field by being supplied with an AC current; A power receiving coil that receives power via an alternating magnetic field, and a position detecting means that detects a relative positional relationship between the power feeding coil and the power receiving coil, and the position detecting means is orthogonal to the opposing direction of the power feeding coil and the power receiving coil. Measuring the amount of deviation in the plane direction of the direction and the amount of deviation in the rotational direction of the rotation angle with the coil center as seen from the opposite direction as the rotation axis, and detecting the relative positional relationship between the feeding coil and the receiving coil based on the measurement result Features.

  According to the present invention, the position detection unit measures the amount of deviation in the planar direction in the direction orthogonal to the opposing direction of the feeding coil and the receiving coil and the amount of deviation in the rotational direction of the rotation angle with the coil center as viewed from the opposing direction as the rotation axis. Based on the measurement result, the relative positional relationship between the feeding coil and the receiving coil is detected. Therefore, based on the relative positional relationship between the power feeding coil and the power receiving coil detected by the position detecting means, it is possible to guide the moving body so that the amount of deviation in the plane direction and the amount of deviation in the rotational direction are within the allowable range. The power transmission efficiency between the receiving coils can be optimized.

  Preferably, it further includes a living body detecting means for detecting the presence or absence of a living body, and the living body detecting means may define the living body detection area based on the maximum allowable value of the deviation amount in the plane direction and the maximum allowable value of the deviation amount in the rotation direction. By the way, when the wireless power transmission technology is applied to a mobile object, it is necessary to detect the presence of a living body in the vicinity of the mobile object before or during the start of power supply. However, when the moving body is obliquely shifted with respect to the stop space, the positional relationship between the radiation pattern of the magnetic flux generated from the power feeding coil and the moving body on which the power receiving coil is mounted changes. As a result, the area that needs to detect the presence of the living body in the vicinity of the moving body also changes, and there is a concern that detection is not performed even in an area that originally needs to detect the living body. The Even if the moving body is guided so that the amount of deviation in the plane direction and the amount of deviation in the rotational direction are within the allowable range, it is difficult to completely match the relative positional relationship between the feeding coil and the receiving coil. It is also possible that a slight misalignment occurs, and therefore it is necessary to define a living body detection area corresponding to the misalignment of the power feeding coil and the power receiving coil. On the other hand, in the present invention, the feeding coil and the receiving coil define the living body detection area based on the maximum allowable value for both the plane direction deviation amount and the rotation direction deviation amount. Detection can be performed reliably.

  Preferably, it further includes a living body detecting means for detecting the presence or absence of a living body, and the living body detecting means may define a living body detection area based on the amount of deviation in the plane direction and the amount of deviation in the rotation direction measured by the position detecting means. As described above, when the wireless power transmission technology is applied to a moving body, it is necessary to detect the presence of a living body in the vicinity of the moving body before starting feeding or during feeding. However, when the moving body is obliquely shifted with respect to the stop space, the positional relationship between the radiation pattern of the magnetic flux generated from the power feeding coil and the moving body on which the power receiving coil is mounted changes. As a result, the area that needs to detect the presence of the living body in the vicinity of the moving body also changes, and there is a concern that detection is not performed even in an area that originally needs to detect the living body. The Even if the moving body is guided so that the amount of deviation in the plane direction and the amount of deviation in the rotational direction are within the allowable range, it is difficult to completely match the relative positional relationship between the feeding coil and the receiving coil. It is also possible that a slight misalignment occurs, and therefore it is necessary to define a living body detection area corresponding to the misalignment of the power feeding coil and the power receiving coil. In contrast, in the present invention, the living body detection area is defined based on the plane direction deviation amount and the rotation direction deviation amount measured by the position detection means by the living body detection means. Optimization can be achieved and living body detection can be performed efficiently and reliably.

  ADVANTAGE OF THE INVENTION According to this invention, the wireless power transmission system which can optimize the power transmission efficiency between a feeding coil and a receiving coil can be provided.

1 is a schematic diagram showing a wireless power transmission system according to a first embodiment of the present invention. It is a schematic diagram which shows the relationship between an access restriction area and a biometric detection area. It is a flowchart which shows the electric power feeding operation | movement of the wireless power transmission system which concerns on 1st Embodiment of this invention. It is a schematic diagram which shows the positional relationship and rotation angle relationship of a feeding coil and a receiving coil. It is a schematic diagram which shows the state whose rotation direction deviation | shift amount of a feed coil and a receiving coil is 0 degree. It is a schematic diagram which shows the state whose rotation direction deviation | shift amount of a feeding coil and a receiving coil is 90 degrees (degrees) or 270 degrees (degrees). It is a schematic diagram which shows the biological body detection area of the state with which the relative position of a feeding coil and a receiving coil corresponds. It is a schematic diagram which shows the biological body detection area of the state from which the relative position of a feeding coil and a receiving coil has shifted | deviated.

  DESCRIPTION OF EMBODIMENTS Embodiments (embodiments) for carrying out the present invention will be described in detail with reference to the drawings. In the description, the same reference numerals are used for the same elements or elements having the same function, and redundant description is omitted.

(First embodiment)
FIG. 1 is a schematic diagram illustrating a wireless power transmission system according to a first embodiment of the present invention. The wireless power transmission system 10 includes a power supply facility 20 and a moving body 30. Examples of the mobile body 30 include an electric vehicle (Electric Vehicle), a hybrid vehicle (Hybrid Electric Vehicle), and an electric transporter used when moving luggage in a factory.

  As shown in FIG. 1, the power supply facility 20 includes a power supply coil 21, a power supply device 22, a position detection unit 23, a living body detection unit 24, and a power supply side communication device 25. In this example, the moving body 30 is stopped in the stop space 26 of the power supply facility 20.

  The feeding coil 21 is configured by winding a metal wire such as copper or aluminum. The number of windings is appropriately set based on a separation distance between the power feeding coil 21 and a power receiving coil 31 described later and a desired power transmission efficiency. The power supply coil 21 configured as described above is housed and packaged in an insulating casing. The power supply coil 21 is connected to a power supply device 22 described later, and an alternating current is supplied to generate an alternating magnetic field. When a power receiving coil 31, which will be described later, faces the power feeding coil 21, an alternating current based on an AC magnetic field generated by the power feeding coil 21 flows through the power receiving coil 31, which will be described later. That is, the power feeding coil 21 functions as a power feeding unit that wirelessly transmits AC power. In the present embodiment, the power supply coil 21 is installed in the vicinity of the ground of the stop space 26 of the power supply facility 20. The stop space 26 is an area in which the moving body 30 is partitioned so that it can stop, and has a rectangular shape.

  As described above, the power supply device 22 plays a role as a power supply unit that supplies an alternating current to the power supply coil 21. For example, an inverter (not shown) composed of a converter (not shown) that converts commercial frequency AC power input from a commercial power source into DC power and a bridge-connected switching element that converts DC voltage input from the converter into AC voltage. The alternating current based on the alternating voltage output from the inverter flows through the feeding coil 21.

The position detection unit 23 is connected to the power feeding device 22 and has a function of detecting the relative positional relationship between the power feeding coil 21 and a power receiving coil 31 described later. Specifically, the position detection unit 23 recognizes the power supply coil 21 installed in the power supply facility 20, and opposes a power supply coil 21 of the power supply coil 21 and a power receiving coil 31 described later (hereinafter simply referred to as “opposing direction”). And the rotation angle about the coil center as viewed from the opposite direction. Similarly, the position detection unit 23 recognizes a power receiving coil 31 (described later) mounted on the moving body 30 and rotates the position of the coil perpendicular to the facing direction of the power receiving coil 31 (described later) and the coil center viewed from the facing direction as a rotation axis. Measure the rotation angle. Here, there may be a case where the position detection unit 23 cannot directly recognize the power receiving coil 31 to be described later depending on the mounting location. In such a case, the position detection unit 23 recognizes the appearance of the moving body 30 and is orthogonal to the facing direction based on the appearance information and the position information of the power receiving coil 31 attached to the moving body 30 stored in advance. What is necessary is just to calculate the rotation angle about the position of the direction and the coil center seen from the facing direction as the rotation axis. Then, the position detection means 23 calculates the amount of deviation in the plane direction in the direction orthogonal to the opposing direction and the amount of deviation in the rotational direction of the rotation angle about the coil center viewed from the opposite direction from the measurement results. It is possible to detect the relative positional relationship between the coil 21 and a power receiving coil 31 described later. The position detector 23 outputs this relative positional relationship to a power supply side communication device 25 described later. Examples of the position detection means 23 include an optical camera, an infrared camera, an ultrasonic sensor, and a millimeter wave radar. In the case where an optical camera is used as the position detection means 23, in order to improve the visibility of the optical camera, a characteristic pattern is provided on the housing that houses the feeding coil 21 and the housing that houses the receiving coil described later. preferable. In the present embodiment, the position detection unit 23 is connected to the power supply device 22, but may be mounted on the moving body 30. In this case, the relative positional relationship between the detected power feeding coil 21 and a power receiving coil 31 described later may be displayed directly to the user (driver).

  The living body detection unit 24 is connected to the power supply device 22 and has a function of detecting the presence or absence of a living body in the vicinity of the moving body 30. The living body detection unit 24 performs living body detection in the vicinity of the moving body 30 before and during the start of power feeding. When the living body is detected, the living body detecting unit 24 instructs to stop the power feeding operation and does not detect the living body. An instruction is given to start the power feeding operation or to continue the power feeding operation. Specifically, an image of the vicinity of the moving body 30 when the moving body 30 stops in the stop space 26 is acquired, and the image is compared with an image of the vicinity of the moving body 30 when the living body detection is performed. If there is, it is determined that a living body exists. This determination result is configured to be displayed on a monitor (not shown) installed in the power feeding device 22. Examples of the living body detection unit 24 include an optical camera, an infrared camera, an ultrasonic sensor, a millimeter wave radar, and the like. Preferably, the optical camera used for the position detection unit 23 may also be used. In the present embodiment, the living body detection unit 24 is installed in the power supply facility 20, but may be mounted on the moving body 30. The living body detection unit 24 defines a living body detection area for detecting the presence or absence of a living body in advance, and the living body detection is performed based on the living body detection area.

  Here, with reference to FIG. 2, the living body detection area 42 in which the living body detection unit 24 detects the presence or absence of a living body will be described in detail. FIG. 2 is a schematic diagram showing the relationship between the access restriction area and the living body detection area.

  The restricted access area 41 is an area where a living body should not exist during the power feeding operation. The restricted entry area 41 is appropriately defined based on the strength of the electric field and magnetic field generated from the power feeding coil 21 and the power receiving coil 31 described later. In other words, the living body detection means 24 enters the distance calculated from the product of the moving speed at which the living body comes toward the entry restricted area 41 and the time required until the power supply stops after the living body detection means 24 detects the living body. An area enlarged from the outer periphery of the restricted area 41 may be detected. However, since the feeding coil 21 and the receiving coil 31 described later are not necessarily directly facing each other, the living body detection unit 24 sets an appropriate living body detection area in consideration of the amount of positional deviation between the feeding coil 21 and the receiving coil 31 described later. Need to be defined. In the present embodiment, the living body detection unit 24 defines the living body detection area 42 based on the maximum allowable value of the planar direction deviation amount and the maximum allowable value of the rotational direction deviation amount. Therefore, even if a positional deviation occurs between the power feeding coil 21 and a power receiving coil 31 described later, it is possible to detect an area where it is necessary to detect the presence or absence of a living body without omission.

  The power supply side communication device 25 has a function of transmitting information by a wireless signal with a power reception side communication device 34 described later. That is, information is transmitted between the power supply facility 20 and the moving body 30. In the present embodiment, the function of transmitting a signal connected to the power supply device 22 and including information on the relative positional relationship detected by the position detection unit 23 to the power receiving side communication device 34 to be described later, and the moving body 30 and the power supply device 22. It has a function of transmitting and receiving signals for specifying the positional relationship.

  As shown in FIG. 1, the moving body 30 includes a power receiving coil 31, a rectifier 32, a battery 33, and a power receiving side communication device 34.

  The power receiving coil 31 is configured by winding a metal wire such as copper or aluminum. The number of turns is appropriately set based on the separation distance between the power feeding coil 21 and the power receiving coil 31 and the desired power transmission efficiency. The power receiving coil 31 configured as described above is housed and packaged in an insulating housing. The power reception coil 31 is magnetically coupled by facing the power supply coil 21 with a predetermined distance, and an alternating current based on the AC magnetic field generated by the power supply coil 21 flows. That is, the power reception coil 31 functions as a power reception unit that wirelessly receives power from the power supply coil 21. In the present embodiment, the power receiving coil 31 is mounted on the bottom of the moving body 30. The AC power received by the power receiving coil 31 is output to a rectifier 32 described later.

  The rectifier 32 converts the AC power received by the power receiving coil 31 into DC power, and outputs this DC power to the battery 33. As the rectifier 32, a bridge-type circuit in which a plurality of diodes such as a half-wave rectifier circuit and a full-wave rectifier circuit are bridge-connected, and a parallel connection to the bridge-type circuit, smoothing the rectified voltage and generating a DC voltage. Examples thereof include a rectifier circuit composed of a smoothing capacitor to be generated.

  The battery 33 is a rechargeable secondary battery, for example, a lithium ion battery or a nickel metal hydride battery. The battery 33 is supplied with DC power converted by the rectifier 32.

  The power receiving side communication device 34 has a function of transmitting information with the power feeding side communication device 25 by radio signals. That is, information is transmitted between the power supply facility 20 and the moving body 30. In the present embodiment, a function for receiving a signal including information on the relative positional relationship between the power feeding coil 21 and the power receiving coil 31 from the power supply side communication device 25 and a signal for specifying the positional relationship between the moving body 30 and the power feeding device 22. It has a function to send and receive.

  With such a configuration, the power feeding coil 21 installed in the power feeding facility 20 and the power receiving coil 31 mounted on the moving body 30 face each other, so that power is transmitted wirelessly.

  Next, the power feeding operation of the wireless power transmission system 10 according to the first embodiment of the present invention will be described in detail with reference to FIG. FIG. 3 is a flowchart showing a power feeding operation of the wireless power transmission system according to the first embodiment of the present invention.

  First, the power supply side communication device 25 periodically transmits a signal (step S01). When receiving the signal transmitted by the power supply side communication device 25, the power receiving side communication device 34 mounted on the mobile body 30 transmits a signal notifying the power supply side communication device 25 that the signal has been received (step S02). In step S02, when the power supply side communication device 25 receives a signal from the power reception side communication device 34, the power supply side communication device 25 instructs the position detection means 23 to start position detection (step 02Y). Conversely, when the power supply side communication device 25 does not receive the signal from the power reception side communication device 34, the power supply side communication device 25 recognizes that the moving body 30 exists at a position far away from the power supply facility 20, and returns the signal to step S01. Transmission continues periodically (step S02N). Thus, by starting the position detection after the moving body 30 is close to the power supply facility 20 to some extent, it is possible to suppress power consumption.

  Subsequently, when receiving an instruction to start position detection from the power supply side communication device 25, the position detection unit 23 recognizes an image of the position of the power supply coil 21 (step S03). At this time, the position detection unit 23 measures the positions X1 and Y1 [cm] in the direction orthogonal to the facing direction from the preset reference position of the feeding coil 21. At the same time, the position detection means 23 measures a rotation angle θ1 [°] with the coil center as viewed from the facing direction of the feeding coil 21 as the rotation axis. here,

  Subsequently, the position detection unit 23 recognizes the appearance of the moving body 30 (step S04). At this time, the position detection unit 23 opposes the power receiving coil 31 from the preset reference position based on the acquired appearance information of the moving body 30 and the preinstalled position information of the power receiving coil 31 with respect to the moving body 30. A position X2, Y2 [cm] in a direction orthogonal to the direction is measured. At the same time, the position detection unit 23 measures a rotation angle θ2 [°] with the coil center as viewed from the facing direction of the power receiving coil 31 as the rotation axis.

  Subsequently, the position detector 23 measures the measured position X1, Y1 [cm] of the feeding coil 21 and the rotation angle θ1 [°], and the measured position X2, Y2 [cm] of the power receiving coil 31 and the rotation angle θ2 [°]. Based on the above, the amount of displacement Xm, Ym [cm] in the planar direction and the amount of rotational displacement θm [°] between the feeding coil 21 and the receiving coil 31 are calculated, and the relative positional relationship between the feeding coil 21 and the receiving coil 31 is detected. It outputs to the power supply side communication apparatus 25 (step S05).

  Here, referring to FIG. 4, the position X1, Y1 [cm] of the feeding coil 21, the rotation angle θ1 [°], the position X2, Y2 [cm] of the receiving coil 31, the rotation angle θ2, and the feeding coil 21 The amount of deviation Xm, Ym [cm] in the plane direction and the amount of deviation θm [°] in the rotational direction of the power receiving coil 31 will be described in detail. In this example, for convenience of explanation, rectangular coils are used for the feeding coil 21 and the receiving coil 31.

  First, let the long side direction of the stop space 26 be the X direction, and let the short side direction be the Y direction. The center of the position detector 23 is set as a reference position, and the X direction component of the distance from the reference position to the center of the feeding coil 21 is X1 [cm], and the Y direction component is Y1 [cm]. In addition, an angle formed by a short side of the stop space 26 and a virtual line extending in parallel with the long side of the power supply coil 21 and passing through the center of the power supply coil 21 is defined as a rotation angle θ1 [°].

  Similarly, of the distance from the reference position to the center of the power receiving coil 31, the X direction component is X2 [cm] and the Y direction component is Y2 [cm]. Further, an angle formed by a short side of the stop space 26 and a virtual line extending in parallel with the long side of the power receiving coil 31 and passing through the center of the power receiving coil 31 is defined as a rotation angle θ2 [°].

  Using these, the plane direction displacement Xm [cm] between the feeding coil 21 and the receiving coil 31, which is the difference between the position X1 [cm] of the feeding coil 21 and the position X2 [cm] of the receiving coil 31, is calculated. . Similarly, from the position Y1 [cm] of the power feeding coil 21 and the position Y2 [cm] of the power receiving coil 31, a plane direction deviation Ym [cm] between the power feeding coil 21 and the power receiving coil 31 is calculated. Similarly, from the rotation angle θ1 [°] of the power feeding coil 21 and the rotation angle θ2 [°] of the power receiving coil 31, a rotational direction deviation θm [°] between the power feeding coil 21 and the power receiving coil 31 is calculated. To do.

  By the way, the rotational direction deviation θm [°] between the power feeding coil 21 and the power receiving coil 31 is a major factor that determines the power transmission efficiency of the wireless power transmission system 10 depending on the shape, type, and combination of the power feeding coil 21 and the power receiving coil 31. obtain. Here, with reference to FIG. 5, the principle that the power transmission efficiency varies depending on the rotational direction deviation amount θm [°] will be described in detail. FIG. 5A is a schematic diagram showing a state in which the rotational displacement between the feeding coil and the receiving coil is 0 [°]. FIG. 5B is a schematic diagram showing a state in which the amount of shift in the rotation direction of the power feeding coil and the power receiving coil is 90 [°] or 270 [°]. In FIG. 5, the feeding coil 21 and the receiving coil 31 are so-called solenoid coils in which a metal wire is wound around a rod-shaped or plate-shaped magnetic core, and the plane direction deviation amounts Xm and Ym [cm] are both 0. The state is [cm].

  As shown in FIG. 5 a, when the amount of deviation in the rotation direction of the power feeding coil 21 and the power receiving coil 31 is 0 °, the main magnetic flux direction of the magnetic flux generated by the power feeding coil 21 and the magnetic flux generated by the power receiving coil 31. Since most of the magnetic fluxes generated by the feeding coil 21 are linked to the power receiving coil 31, high power transmission efficiency can be realized. On the other hand, as shown in FIG. 5b, when the rotational displacement between the feeding coil 21 and the receiving coil 31 is 90 [°] or 270 [°], the magnetic flux generated by the feeding coil 21 and the receiving coil 31 are Since the main magnetic flux directions of the generated magnetic flux are orthogonal to each other, the magnetic flux generated by the feeding coil 21 is not easily linked to the receiving coil 31 and the power transmission efficiency is lowered.

  As described above, when a solenoid coil is used as the power feeding coil 21 and the power receiving coil 31, the rotational direction shift amount θm greatly affects the power transmission efficiency between the power feeding coil 21 and the power receiving coil 31. Therefore, it is very important for the position detection means 23 to detect the rotational direction deviation amount θm. Table 1 shows examples of coil shapes, types, and combinations in which the rotational direction deviation amount θm greatly affects the power transmission efficiency between the power feeding coil 21 and the power receiving coil 31. In Table 1, “spiral coil” is a coil in which a winding is wound in a flat shape, and “other than a perfect circle” means that the outer shape viewed from the coil axis direction is elliptical, polygonal, etc. That is. The “spiral coil × 2” is a coil in which two spiral coils are juxtaposed and connected so as to generate a magnetic flux interlinking both coils.

  Subsequently, the power supply side communication device 25 transmits a signal including information on the relative positional relationship to the power reception side communication device 34 (step S06).

  Subsequently, based on the relative positional relationship between the power feeding coil 21 and the power receiving coil 31 detected by the position detection unit 23, the user (driver) makes the relative position between the power feeding coil 21 and the power receiving coil 31 fall within an allowable range. The moving body 30 is stopped in the stopping space 26 of the power supply facility 20. At this time, the power feeding device 22 determines whether or not the moving body 30 is stopped so that the relative position between the power feeding coil 21 and the power receiving coil 31 is within the allowable range (step S07). In step S07, when the moving body 30 stops within the allowable range of the relative position between the power feeding coil 21 and the power receiving coil 31, the user is notified that the moving body 30 has stopped at the power feedable position (step S07Y). In step S07, when it is determined that the moving body 30 is not stopped within the allowable range of the relative position between the power feeding coil 21 and the power receiving coil 31, the user (driver) feeds the power feeding coil 21 detected by the position detection unit 23. On the basis of the relative positional relationship between the power receiving coil 31 and the power receiving coil 31, the moving body 30 is stopped in the stopping space 26 of the power feeding facility 20 so that the relative position between the power feeding coil 21 and the power receiving coil 31 is within an allowable range (step S07N). ).

  In step S07Y, the user instructs the living body detection means 24 to detect the presence or absence of the living body in the vicinity of the moving body 30 in response to the fact that the moving body 30 has stopped at the power supply enabled position (step S08).

  Subsequently, upon receiving an instruction to start living body detection, the living body detection unit 24 acquires an image near the moving body 30 and uses this image as a reference image (step S09). The living body detection unit 24 may be in a power-on state before receiving an instruction to start living body detection, but after receiving an instruction to start living body detection, the power source of the living body detection unit 24 is switched from off to on, or The power consumption can be suppressed by switching from the standby mode (the state using the minimum necessary power) to ON.

  Subsequently, the living body detection unit 24 continues to acquire an image near the moving body 30 until the power feeding operation is completed, and compares the acquired image with the reference image (step S10). At this time, the living body detection unit 24 determines that there is a living body if there is a difference between the result of comparing the acquired image and the reference image, and displays the determination result on a monitor (not shown) installed in the power supply apparatus 22. The power supply operation is restricted (the power supply operation is not started) (step S10Y). On the other hand, the living body detection unit 24 determines that there is no living body if there is no difference between the acquired image and the reference image for a certain period of time, and instructs the power supply apparatus 22 to start the power supply operation (step S10N). . If it is determined in step S10Y that a living body is present, the living body detection unit 24 continues to compare the acquired image with the reference image. If there is no difference, the living body detection unit 24 determines that the living body does not exist and supplies power to the power supply device 22. Is instructed to start (step S10N).

  Subsequently, when the power feeding device 22 receives an instruction to start a power feeding operation, the power feeding device 22 supplies an alternating current to the power feeding coil 21. When an alternating current flows, the feeding coil 21 generates an alternating magnetic field, and the alternating current based on the alternating magnetic field flows to the power receiving coil 31 facing the feeding coil 21. That is, transmission of AC power from the feeding coil 21 to the receiving coil 31 is started wirelessly (step S11).

  Here, as described above, even during the power feeding operation by the power feeding device 22, the living body detection unit 24 continues to acquire the image near the moving body 30, and compares the acquired image with the reference image (step S12). If there is a difference in the comparison result between the image acquired during the power feeding operation and the reference image, it is determined that the living body has entered the living body detection area 42, and the power feeding operation of the power feeding device 22 is promptly stopped (step S12Y). On the other hand, if there is no difference between the result obtained by comparing the image acquired during the power feeding operation and the reference image, it is determined that the living body has not entered the living body detection area 42, and the power feeding device 22 continues the power feeding operation until the charging is completed ( Step S12N). In step S12Y, after the power feeding operation of the power feeding device 22 is stopped, the living body detection unit 24 continues to compare the acquired image with the reference image (step S13). In step S <b> 13, the living body detection unit 24 determines that there is no living body in the living body detection area 42 when there is no difference in the result of comparing the acquired image and the reference image during a certain period of time, and performs a power feeding operation to the power feeding device 22. Is instructed to resume (step S13N). In step S <b> 13, the living body detection unit 24 determines that the living body is present in the living body detection area 42 if there is a difference between the result obtained by comparing the image acquired after a certain period of time and the reference image, and uses the determination result as the power supply device 22. The information is displayed on a monitor (not shown) installed in the computer and notified to the user (step S13Y). If it is determined in step S13Y that a living body is present, the living body detection unit 24 continues to compare the acquired image with the reference image (step S14). In step S14, the living body detection unit 24 determines that the living body exists in the living body detection area 42 if there is a difference in the result of comparing the acquired image and the reference image, and continues to compare the acquired image and the reference image (step S14). S14Y). In step S <b> 14, the living body detection unit 24 determines that there is no living body in the living body detection area 42 when there is no difference in the result of comparing the acquired image and the reference image, and instructs the power supply device 22 to restart the power supply operation. (Step S14N).

  Subsequently, in step S12N, when charging is completed, the power feeding device 22 stops the power feeding operation (step S15).

  Subsequently, in step S15, after the power feeding operation of the power feeding device 22 is stopped, the living body detection by the living body detecting unit 24 is also stopped (step S16). The living body detection unit 24 may be in a power-on state even after the living body detection is stopped. However, after the living body detection is stopped, the living body detection unit 24 is switched from on to off, or from off to the standby mode (minimum required). By switching to a state using a limited amount of power, power consumption can be suppressed.

  Subsequently, it is determined whether communication is established between the power supply side communication device 25 and the power reception side communication device 34 (step S17). In step S17, when it is determined that communication between the power supply side communication device 25 and the power reception side communication device is established, the power supply device 22 determines that the relative position of the power supply coil 21 and the power reception coil 31 is within an allowable range. It is determined whether or not the moving body 30 is stopped so as to fit (step S18). Here, when the moving body 30 stops within the allowable range of the relative position between the power feeding coil 21 and the power receiving coil 31 in step S18, the user is notified that the moving body 30 has stopped at the power feedable position (step S18Y). ). If it is determined in step S18 that the moving body 30 has not stopped within the allowable range of the relative position between the power feeding coil 21 and the power receiving coil 31, the process returns to step S17 (step S18N). In step S18Y, when the moving body 30 stops at a position where power can be supplied, the power supply apparatus 22 determines whether or not the user has instructed to start living body detection (step S19). In step S19, when the user instructs to start living body detection, the process returns to step S09 (step S19Y). In step S19, if the user does not instruct the start of biometric detection, the process returns to step S17 (step S19N). On the other hand, when it is determined in step S17 that the power supply side communication device 25 has not established communication with the power reception side communication device 34, the position detection by the position detection unit 23 is stopped (step S20). Thus, the power feeding operation of the wireless power transmission system 10 is completed.

  As described above, in the wireless power transmission system 10 according to the present embodiment, the position detection unit 23 is viewed from the opposing direction and the plane direction deviation amounts Xm and Ym in the direction orthogonal to the opposing direction of the feeding coil 21 and the receiving coil 31. The rotational direction deviation amount θm of the rotation angle with the coil center as the rotation axis is measured, and the relative positional relationship between the feeding coil 21 and the receiving coil 31 is detected based on the measurement result. Therefore, based on the relative positional relationship between the power feeding coil 21 and the power receiving coil 31 detected by the position detecting unit 23, the moving body 30 can be guided so that the amount of deviation in the plane direction and the amount of deviation in the rotational direction are within the allowable range. The power transmission efficiency between the feeding coil 21 and the receiving coil 31 can be optimized.

  In addition, the wireless power transmission system 10 according to the present embodiment includes a living body detection unit 24 that detects the presence or absence of a living body, and the living body detection unit 24 includes the maximum allowable values of the plane direction deviation amounts Xm and Ym and the rotation direction deviation amount. The living body detection area is defined based on the maximum allowable value of θm. By the way, when the wireless power transmission technique is applied to a moving body, it is necessary to detect the presence of a living body in the vicinity of the moving body 30 before or during power feeding. However, when the moving body 30 is stopped obliquely with respect to the stop space 26, the positional relationship between the radiation pattern of the magnetic flux generated from the power feeding coil 21 and the moving body 30 on which the power receiving coil 31 is mounted changes. As a result, the area that needs to detect the presence of the living body in the vicinity of the moving body 30 also changes, so there is a concern that detection is not performed even in an area that normally needs to detect the living body. Is done. Even if the moving body 30 is guided so that the plane direction deviation amounts Xm, Ym [cm] and the rotation direction deviation amount θm [°] are within the allowable range, the relative positional relationship between the feeding coil 21 and the receiving coil 31 is changed. Since it is difficult to make them completely coincide with each other, and it is considered that a slight positional deviation occurs between the feeding coil 21 and the receiving coil 31, it is necessary to define a living body detection area corresponding to the positional deviation between the feeding coil 21 and the receiving coil 31. There is. On the other hand, in the present embodiment, the feeding coil 21 and the receiving coil 31 define the living body detection area 42 based on the maximum allowable values for both the plane direction deviation amounts Xm and Ym and the rotational direction deviation amount θm. Thus, it is possible to reliably detect an area that requires living body detection.

(Second Embodiment)
Next, a wireless power transmission system 10 according to a second embodiment of the present invention will be described with reference to FIG. FIG. 6A is a schematic diagram illustrating a living body detection area in a state in which the relative positions of the power feeding coil and the power receiving coil coincide with each other. FIG. 6B is a schematic diagram illustrating a living body detection area in a state where the relative positions of the power feeding coil and the power receiving coil are shifted. The wireless power transmission system 10 according to the second embodiment is different from the wireless power transmission system 10 according to the first embodiment in terms of a biological detection area 52 defined by the biological detection means 24. Hereinafter, a description will be given focusing on differences from the first embodiment.

  In the present embodiment, the living body detection unit 24 defines the living body detection area 52 based on the plane direction deviation amounts Xm and Ym and the rotation direction deviation amount θm measured by the position detection unit 23. Here, the area in which the presence of the living body needs to be detected changes according to the plane direction deviation amounts Xm and Ym and the rotation direction deviation amount θm. That is, the living body detection unit 24 needs to demarcate the living body detection area 52 in consideration of the plane direction deviation amounts Xm and Ym and the rotation direction deviation amount θm so that the area where the presence of the living body needs to be detected does not leak. is there.

  First, the living body detection area 52a in the case where the relative positions of the power feeding coil 21 and the power receiving coil 31 coincide with each other will be described with reference to FIG. 6a. FIG. 6a shows a state where both the plane direction deviation amounts Xm and Ym are 0 [cm] and the rotational direction deviation amount θm is 0 [°]. In the example shown in FIG. 6A, the area where the presence of a living body needs to be detected is centered on the feeding coil 21 and the vicinity of the side surface of the moving body 30 in the direction orthogonal to the traveling direction of the moving body 30. It becomes an area that spreads out. Accordingly, the living body detection unit 24 may define an area extending from the bottom of the moving body 30 to the vicinity of the side surface of the moving body 30 in a direction orthogonal to the traveling direction of the moving body 30 as the living body detection area 52a.

  Next, the living body detection area 52b in the case where the relative positions of the power feeding coil 21 and the power receiving coil 31 are shifted will be described with reference to FIG. 6b. FIG. 6B shows a state where the plane direction deviation amount Xm is −5 [cm], the plane direction deviation amount Ym is +5 [cm], and the rotational direction deviation amount θm is 10 [°]. In the example shown in FIG. 6b, the area where the presence of the living body needs to be detected is reduced by the amount Xm, Ym of the plane direction displacement with respect to the direction in which the power receiving coil 31 is displaced, and the direction in which the power receiving coil 31 is displaced. With respect to the opposite direction, the plane direction displacement amounts Xm and Ym increase. In addition, the area in which the presence of the living body needs to be detected tends to decrease in the traveling direction of the moving body 30 because the moving body 30 is inclined by the rotational direction deviation amount θm with respect to the feeding coil 21. It tends to increase in the direction orthogonal to the traveling direction of the. The sum of these increases and decreases is an area where the presence of the living body needs to be detected. Here, when the living body detection area 52a in FIG. 6a is employed, there is a concern that the leakage may occur even though it is an area where it is necessary to detect the presence of a living body. On the other hand, in this embodiment, the living body detection unit 24 is based on the plane direction deviation amounts Xm, Ym [cm] and the rotation direction deviation amount θm [°] measured by the position detection unit 23. Since the area 52b is defined, it is possible to optimize an area that requires living body detection, and to perform living body detection efficiently and reliably.

  As described above, the wireless power transmission system 10 according to the present embodiment includes the living body detecting unit 24 that detects the presence or absence of a living body, and the living body detecting unit 24 measures the plane direction deviation amounts Xm and Ym measured by the position detecting unit 23. The living body detection area 52 is defined based on [cm] and the rotational direction deviation amount θm [°]. As described above, when the wireless power transmission technology is applied to a moving body, it is necessary to detect the presence of a living body in the vicinity of the moving body 30 before starting feeding or during feeding. However, when the moving body 30 is stopped obliquely with respect to the stop space 26, the positional relationship between the radiation pattern of the magnetic flux generated from the power feeding coil 21 and the moving body 30 on which the power receiving coil 31 is mounted changes. As a result, the area that needs to detect the presence of the living body in the vicinity of the moving body 30 also changes, so there is a concern that detection is not performed even in an area that normally needs to detect the living body. Is done. Even if the moving body 30 is guided so that the plane direction deviation amounts Xm, Ym [cm] and the rotation direction deviation amount θm [°] are within the allowable range, the relative positional relationship between the feeding coil 21 and the receiving coil 31 is changed. Since it is difficult to make them completely coincide with each other, and it is considered that a slight positional deviation occurs between the feeding coil 21 and the receiving coil 31, it is necessary to define a living body detection area corresponding to the positional deviation between the feeding coil 21 and the receiving coil 31. There is. On the other hand, in this embodiment, the living body detection area 52 is defined based on the plane direction deviation amounts Xm, Ym [cm] and the rotation direction deviation amount θm [°] measured by the position detection means 23. Since the area is defined, it is possible to optimize an area that requires living body detection, and to perform living body detection efficiently and reliably.

  The present invention has been described based on the embodiments. It will be understood by those skilled in the art that the embodiments are illustrative, and that various modifications and changes are possible within the scope of the claims of the present invention, and that such modifications and changes are also within the scope of the claims of the present invention. By the way. Accordingly, the description and drawings herein are to be regarded as illustrative rather than restrictive. For example, in the above-described embodiment, the wireless power transmission system is described using an example in which the wireless power transmission system is applied to a mobile body, but the present invention is not limited to this, and the present invention can also be applied to a communication device such as a mobile phone or a smartphone.

DESCRIPTION OF SYMBOLS 10 ... Wireless power transmission system, 20 ... Feeding equipment, 21 ... Feeding coil, 22 ... Feeding equipment, 23 ... Position detection means, 24 ... Living body detection means, 25 ... Feeding side communication equipment, 26 ... Stop space, 30 ... Mobile , 31 ... power receiving coil, 32 ... rectifier, 33 ... battery, 34 ... power receiving side communication device, 41 ... access restriction area, 42, 52, 52a, 52b ... biological detection area.

Claims (3)

A wireless power transmission system in which power is transmitted wirelessly when a feeding coil and a receiving coil face each other,
The feeding coil that is supplied with an alternating current to generate an alternating magnetic field;
The receiving coil for receiving power via an alternating magnetic field;
A position detecting means for detecting a relative positional relationship between the power feeding coil and the power receiving coil,
The position detecting means measures a planar direction deviation amount in a direction orthogonal to the opposing direction of the feeding coil and the receiving coil and a rotational direction deviation amount of a rotation angle with the coil center as viewed from the opposing direction as a rotation axis, A wireless power transmission system that detects a relative positional relationship between the power feeding coil and the power receiving coil based on the measurement result. It further comprises a living body detecting means for detecting the presence or absence of a living body,
2. The wireless power transmission system according to claim 1, wherein the living body detection unit demarcates a living body detection area based on a maximum allowable value of the displacement amount in the plane direction and a maximum allowable value of the displacement amount in the rotation direction. . It further comprises a living body detecting means for detecting the presence or absence of a living body,
2. The wireless power transmission system according to claim 1, wherein the living body detection unit defines a living body detection area based on the amount of displacement in the planar direction and the amount of shift in the rotation direction measured by the position detection unit. .

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