JP7331560B2 - Contaminant countermeasure device and power transmission device - Google Patents

Description

The present invention relates to a foreign matter countermeasure device and a power transmission device.

Techniques related to contactless power supply from a power transmission unit of a power transmission device to a power reception unit of a power reception device are known. If a metal foreign object exists on the surface of the power transmission unit of the power transmission device, the power transmission efficiency of the contactless power supply may be lowered. Therefore, for example, Patent Document 1 discloses a second coil that transmits electric power in a non-contact manner with a first coil, and a foreign object detection that detects a foreign object between the first coil and the second coil. and a power control means for controlling transmitted power transmitted from the second coil to the first coil. In the contactless power supply device of Patent Literature 1, when the foreign object detection means detects a foreign object, the power control means lowers the transmitted power and supplies power from the second coil to the first coil.

JP 2012-228121 A

By the way, in the above technique, when a foreign object is detected by the foreign object detection means, the power to be transmitted is lowered and the power to be received by the first coil is lowered. In addition, when the foreign object detection means cannot detect the foreign object that actually exists, the magnetic field of the non-contact power supply interlinks with the metal foreign object, eddy current loss occurs, and the power transmission of the non-contact power supply is interrupted. Since the efficiency decreases, the received power of the first coil decreases even if the transmitted power is constant. In other words, with the above technology, the received power decreases when a foreign object is present. For example, when charging a storage battery with the received power, the time required for the storage battery to be fully charged increases, resulting in reduced convenience. In particular, metallic foreign matter with high magnetic permeability (for example, iron) increases the interlinkage magnetic flux density of the foreign matter.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a foreign matter countermeasure device and a power transmission device capable of reducing the influence of foreign matter.

One aspect of the present invention is a foreign object countermeasure device that reduces the influence of a foreign object on a power transmission unit in contactless power supply from a power transmission unit of a power transmission device to a power reception unit of a power reception device, wherein the power transmission unit is formed on the surface of the power transmission unit. The foreign matter countermeasure device includes a magnetic field applying section that applies a control magnetic field in a direction that intersects the direction of the power supply magnetic field to the surface of the power transmission section.

According to this configuration, in the foreign object countermeasure device that reduces the influence of foreign matter on the power transmission unit in contactless power supply from the power transmission unit of the power transmission device to the power reception unit of the power reception device, the magnetic field application unit causes the power transmission unit to contact the surface of the power transmission unit. A control magnetic field is applied to the surface of the power transmission section in a direction crossing the direction of the feeding magnetic field to be formed. Therefore, when the foreign matter has magnetism, the direction of the foreign matter having magnetism is controlled by the attractive force and the repulsive force of the control magnetic field applied by the magnetic field applying section, and the direction of the feeding magnetic field formed on the surface of the power transmission section and the length of the foreign matter The direction of the power supply magnetic field formed on the surface of the power transmission unit and the longitudinal direction of the foreign object are parallel to each other. and the influence of foreign matter can be reduced.

In this case, the magnetic field applying section may apply to the surface of the power transmitting section a control magnetic field in a direction orthogonal to the direction of the power supply magnetic field that the power transmitting section forms on the surface of the power transmitting section.

According to this configuration, the magnetic field applying section applies to the surface of the power transmitting section a control magnetic field in a direction perpendicular to the direction of the power supply magnetic field that the power transmitting section forms on the surface of the power transmitting section. Therefore, when the foreign matter has magnetism, the direction of the foreign matter having magnetism is controlled by the attractive force and the repulsive force of the control magnetic field applied by the magnetic field applying section, and the direction of the feeding magnetic field formed on the surface of the power transmission section and the length of the foreign matter , the directions are orthogonal to each other, the decrease in the power transmission efficiency of the contactless power supply is minimized, and the influence of foreign matter can be further reduced.

Further, even if the magnetic field applying unit is arranged at a position where the magnetic core is not arranged inside the surface of the power transmitting unit, the magnetic core is arranged inside any position on the surface of the power transmitting unit. good.

According to this configuration, the magnetic field applying section is arranged at a position where the magnetic core is not arranged inside the surface of the power transmission section, with respect to the power transmission section where the magnetic core is arranged inside any position on the surface of the power transmission section. It is Therefore, the influence of the control magnetic field applied by the magnetic field applying section on the magnetic core can be reduced.

In addition, the magnetic field application unit is arranged at a position where no winding is arranged inside the surface of the power transmission unit with respect to the power transmission unit in which the winding is arranged inside any position on the surface of the power transmission unit. may

According to this configuration, with respect to the power transmission unit in which the winding is arranged inside any position on the surface of the power transmission unit, the magnetic field application unit is arranged at a position where the winding is not arranged inside the surface of the power transmission unit. are placed. Therefore, it is possible to reduce the influence of the power supply magnetic field generated from the winding on the magnetic field applying section.

Further, the magnetic field applying section may be capable of changing either the position on the surface of the power transmitting section or the direction of the control magnetic field applied to the surface of the power transmitting section.

According to this configuration, the magnetic field applying section can change either the position or the direction on the surface of the power transmitting section of the control magnetic field applied to the surface of the power transmitting section. Improved handling of foreign objects

Further, the magnetic field applying section applies the control magnetic field to the surface of the power transmission section when the power transmission section forms the power supply magnetic field on the surface of the power transmission section, and applies the control magnetic field to the surface of the power transmission section when the power transmission section does not form the power supply magnetic field on the surface of the power transmission section. It is not necessary to apply a control magnetic field to the surface of the .

According to this configuration, the magnetic field applying section applies the control magnetic field to the surface of the power transmission section when the power transmission section forms the power supply magnetic field on the surface of the power transmission section, and the power transmission section does not form the power supply magnetic field on the surface of the power transmission section. When the control magnetic field is not applied to the surface of the power transmission unit when contactless power supply is not performed and the power transmission unit does not form the power supply magnetic field on the surface of the power transmission unit, the control magnetic field applied by the magnetic field application unit It is possible to reduce the attraction of foreign matter to the surface of the power transmission unit.

On the other hand, another aspect of the present invention is a power transmission device including the foreign matter countermeasure device according to one aspect of the present invention and a power transmission section.

According to the foreign matter countermeasure device of one aspect of the present invention and the power transmission device of the other aspect of the present invention, the influence of foreign matter can be reduced.

1 is a block diagram showing a foreign object countermeasure device and a power transmission device according to a first embodiment; FIG. It is a perspective view which shows the foreign material countermeasure apparatus and power transmission part which concern on 1st Embodiment. (A) is a plan view showing the foreign matter countermeasure device and the power transmission section according to the first embodiment, and (B) is a vertical cross-sectional view taken along line α of (A). FIG. 4 is a plan view showing magnetic flux density interlinking a foreign object; (A) is a graph showing the eddy current loss ratio with respect to the longitudinal direction of the foreign matter when the foreign matter is an iron wire with a length of 13 mm, and (B) is a graph of the foreign matter when it is a clip composed of a bent iron wire. 4 is a graph showing eddy current loss ratios with respect to the longitudinal direction. 4 is a plan view showing a power supply magnetic field formed on the surface of the power transmission section by the power transmission section and a control magnetic field formed on the surface of the power transmission section by the magnetic field application section of the foreign object countermeasure device in the first embodiment. FIG. FIG. 10 is a plan view showing a power supply magnetic field formed on the surface of the power transmission unit by the power transmission unit and a control magnetic field formed on the surface of the power transmission unit by the magnetic field application unit of the foreign object countermeasure device in the second embodiment. FIG. 11 is a plan view showing a power supply magnetic field formed on the surface of the power transmission unit by the power transmission unit and a control magnetic field formed on the surface of the power transmission unit by the magnetic field application unit of the foreign object countermeasure device in the third embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1 , the power transmission device 10 according to the first embodiment includes a foreign object countermeasure device 1A and a power transmission section 15 . The power transmission device 10 supplies power from the power transmission unit 15 of the power transmission device 10 installed on the road surface S to the power reception unit 21 of the power reception device 20 installed on the underside 32 of the vehicle body 30 of the vehicle 30 traveling on the road surface S by contactless power supply. do. The power transmission device 10 is installed, for example, in a parking space P of a parking lot. Before describing the foreign object countermeasure device 1A and the power transmission unit 15 in detail, the outline of the power transmission device 10 and the power reception device 20 will be described below.

Vehicle 30 is, for example, an electric vehicle. The power transmission device 10 utilizes magnetic coupling between coils such as a magnetic resonance method or an electromagnetic induction method to a power reception device 20 mounted on a vehicle 30 such as an electric vehicle that has arrived at a parking space P of a parking lot. configured to supply power. In addition, the vehicle 30 may be various moving bodies such as a plug-in hybrid vehicle, an underwater vehicle, and a drone, instead of the electric vehicle. Also, the vehicle 30 may be various unmanned mobile bodies instead of manned mobile bodies. For example, the vehicle 30 may be an automated guided vehicle (AGV) instead of a manned vehicle.

As shown in FIG. 1, the power transmission device 10 includes a foreign matter countermeasure device 1A, a converter 12, an inverter 13, a power transmission control section 14, and a power transmission section 15. FIG. The power transmission device 10 is supplied with power from an external power source 11 . The power supply 11 supplies electric power required to generate electric power to be transmitted to the vehicle 30, for example, supplies single-phase AC power such as commercial AC power. The power supply 11 is not limited to a single-phase AC power supply, and may be a power supply that supplies three-phase AC power.

The converter 12 is an AC/DC converter that rectifies AC power supplied from the power supply 11 and converts it into DC power. The converter 12 may have a PFC [Power Factor Correction] function and a step-up/step-down function. A DC power source such as a fuel cell or a solar cell may be used as the power source 11, in which case the converter 12 may be omitted. Also, if the power supply 11 is a DC power supply, a DC/DC converter may be provided instead of the converter 12 . Inverter 13 converts the DC power from converter 12 into AC power (high-frequency power) having a higher frequency than the AC power of power supply 11 and supplies the AC power to power transmission unit 15 .

The power transmission control unit 14 is an electronic control unit including, for example, a CPU [Central Processing Unit], a ROM [Read Only Memory], a RAM [Random Access Memory], and the like. The power transmission control unit 14 controls power supply from the power transmission unit 15 of the power transmission device 10 to the power reception unit 21 of the power reception device 20 . The power transmission control unit 14 controls operations of the converter 12 and the inverter 13 so as to change the magnitude of power transmitted from the power transmission unit 15 of the power transmission device 10 to the power reception unit 21 of the power reception device 20 .

The power transmission unit 15 is a coil device installed on a road surface S such as a parking space P of a parking lot. The power receiving unit 21 of the power receiving device 20 is a coil device installed on the vehicle body bottom surface 32 of the vehicle 30 . An electromagnetic coupling circuit is formed by bringing the power transmission unit 15 and the power reception unit 21 close to each other. The electromagnetic coupling circuit means a circuit in which the power transmission unit 15 and the power reception unit 21 are electromagnetically coupled and power is transmitted from the power transmission unit 15 to the power reception unit 21 by contactless power supply. Note that the power transmission unit 15 and the power reception unit 21 may perform contactless power supply using an electromagnetic induction method, or may perform contactless power supply using a magnetic resonance method. Also, the power transmission unit 15 and the power reception unit 21 may be antenna devices. Details of the power transmission unit 15 will be described later.

Note that the power transmission device 10 of the present embodiment may have a configuration for detecting a foreign object in the power transmission section 15 . Further, the power transmission device 10 of the present embodiment may have a configuration for removing foreign matter from the power transmission section 15 .

On the other hand, power receiving device 20 mounted on vehicle 30 includes power receiving unit 21 and rectifier 22 . The power receiving device 20 is a device that receives power from the power transmission unit 15 of the power transmission device 10 and supplies power to a load such as the battery 23 of the vehicle 30 . The power receiving unit 21 is a coil device attached between the four wheels 31 on the vehicle body bottom surface 32 of the vehicle 30 . The magnetic flux generated by the power transmission unit 15 interlinks with the power reception unit 21, thereby causing the power reception unit 21 to generate an induced current. Thereby, the power receiving unit 21 receives power from the power transmitting unit 15 in a contactless manner. The rectifier 22 rectifies the AC power received by the power receiving unit 21 from the power transmitting unit 15 and converts it into DC power. The DC power converted by the rectifier 22 is supplied to loads such as the battery 23 of the vehicle 30 .

The foreign matter countermeasure device 1A and the power transmission unit 15 will be described in detail below. The foreign object countermeasure device 1</b>A of the present embodiment reduces the influence of foreign objects on the power transmission unit 15 in contactless power supply from the power transmission unit 15 of the power transmission device 10 to the power reception unit 21 of the power reception device 20 . A foreign object is a magnetic metal that can cause loss of power supplied between power transmission unit 15 and power reception unit 21 . The foreign matter is, for example, a small piece of metal such as an iron sewing needle, a stapler hook, and a clip made of bent iron wire.

As shown in FIGS. 2, 3A, and 3B, each configuration of the foreign matter countermeasure device 1A is stored in the sheet-like storage section 2 laid on the surface 16 of the power transmission section 15. As shown in FIG. Further, power transmission section 15 has magnetic core 17 , winding 18</b>A and aluminum plate 19 inside surface 16 . 2, 3A, and 3B, for convenience of explanation, the surface 16 of the sheet-shaped storage section 2 and the power transmission section 15 of the foreign matter countermeasure device 1A is shown in a transparent state. .

A surface 16 of the power transmission unit 15 is a smooth plane that is continuous with the road surface S. The winding 18A is a concentric coil having a plurality of concentric circles in plan view. The magnetic core 17 is made of a soft magnetic material, such as a ferrite core. The magnetic core 17 is arranged on the inner side of the surface 16 with respect to the winding 18A. The magnetic core 17 has a radial shape extending outward in eight directions from the center in plan view. In plan view, the centers of the magnetic core 17 and the winding 18A are substantially aligned. The aluminum plate 19 is arranged on the inner side of the surface 16 with respect to the magnetic core 17 .

The foreign matter countermeasure device 1A includes a plurality of magnetic field application units 3A inside the sheet-like storage unit 2. As shown in FIG. The sheet-like storage part 2 is a flexible plate-like body having a thickness of, for example, about 5 mm to 30 mm, made of synthetic resin, synthetic rubber, or the like. The front and back surfaces of the sheet-like storage portion 2 are smooth planes. The sheet-shaped storage section 2 has strength to such an extent that the magnetic field applying section 3A is not damaged when the wheel 31 of the vehicle 30 passes over the sheet-shaped storage section 2 . The foreign matter countermeasure device 1A can be easily installed by laying the sheet-shaped storage section 2 on the surface 16 of the power transmission section 15 while aligning the positions thereof. Further, the foreign matter countermeasure device 1A can be easily removed from the surface 16 of the power transmission section 15 .

The magnetic field applying unit 3A applies a static magnetic field in a direction crossing the direction of the power supply magnetic field formed on the surface 16 of the power transmission unit 15 by the power transmission unit 15 as a control magnetic field for controlling the direction of the magnetic foreign object. applied to More specifically, the plurality of magnetic field applying units 3A apply, as a control magnetic field, a static magnetic field in a direction orthogonal to the direction of the power supply magnetic field formed on the surface 16 of the power transmission unit 15 by the power transmission unit 15 to the surface of the power transmission unit 15. 16. Permanent magnets such as ferrite magnets, neodymium magnets, heat-resistant neodymium magnets, samarium-cobalt magnets, and alnico magnets can be applied to the magnetic field applying unit 3A. A heat-resistant neodymium magnet with Further, for example, when the magnetic field applying section 3A is a magnet, it may have a sufficiently large coercive force (coercive force) with respect to the supplied magnetic field in order to reduce the possibility of demagnetization due to the supplied magnetic field.

The strength of the static magnetic field of the magnetic field applying unit 3A is such that the magnetic field applying unit 3A determines the direction of a magnetic metal foreign object such as an iron sewing needle, a stapler hook, or a clip made of a bent iron wire. It can be made strong enough to be aligned with the direction of the static magnetic field of a 3A neodymium magnet. Further, the strength of the static magnetic field of the magnetic field applying section 3A can be made, for example, greater than the strength of the power supply magnetic field formed on the surface 16 of the power transmission section 15 by the power transmission section 15, or greater than the holding power of the foreign matter. That is, when the magnetic field application section 3A is a magnet, the magnet may have a sufficiently large residual magnetic flux density with respect to the power supply magnetic field formed on the surface of the power transmission section 15, for example.

The magnetic field application unit 3A is arranged at a position where the power supply magnetic field formed on the surface 16 of the power transmission unit 15 by the power transmission unit 15 has little influence. A magnetic field is applied to a position where the winding 18A is not arranged inside the surface 16 of the power transmission unit 15 with respect to the power transmission unit 15 in which the winding 18A is arranged inside any position on the surface 16 of the power transmission unit 15. Part 3A is arranged. In the present embodiment, the winding 18A has a plurality of concentric circular shapes in plan view, and the plurality of magnetic field applying units 3A surrounds the outer periphery of the winding 18A in plan view, and is closer to the winding 18A in plan view than the winding 18A. They are arranged in concentric circles with a large diameter.

With respect to power transmission unit 15 in which magnetic core 17 is arranged inside any position on surface 16 of power transmission unit 15, magnetic field applying unit 3A is placed at a position where magnetic core 17 is not arranged inside surface 16 of power transmission unit 15. are placed. In this embodiment, the magnetic core 17 has a radial shape extending outward in eight directions from the center in plan view, and the plurality of magnetic field applying units 3A are arranged between adjacent radial lines of the magnetic core 17. It is

A plurality of magnetic field applying units 3A arranged to form a circle in a plan view are arranged such that the north and south poles of the neodymium magnets are oriented in the tangential direction of the circle. In addition, in the plurality of magnetic field applying units 3A arranged to form a circle in plan view, the N poles and S poles of the neodymium magnets of the magnetic field applying units 3A adjacent to each other on the circumference of the circle are opposed to each other. are arranged to

The operation of the foreign matter countermeasure device 1A of this embodiment will be described below. The power loss due to foreign matter depends on the magnitude of the interlinking magnetic flux density to the foreign matter, as shown in the following equations (1) and (2). In equations (1) and (2), We is eddy current loss, Wh is hysteresis loss, Ke and Kh are proportional coefficients, f is frequency, and Bm is flux linkage density.
We=Ke×f ² ×Bm ² (1)
Wh=Kh×f×Bm ^1.6 (2)

To simplify the explanation, only the eddy current loss will be described below. It depends on the alternating magnetic flux density Bm.

The relationship between the magnetic resistance Rm, the magnetic circuit length lm, the magnetic flux linkage area A, the magnetic permeability _μ0 of vacuum, and the relative magnetic permeability _μr is given by the following equation (3). Also, the relationship between the magnetic flux Φ, the magnetomotive force Fm, and the magnetic resistance Rm is expressed by the following equation (4).
Rm ₌ lm/ _μ0μrA (3)
Φ=Fm/Rm (4)

As shown in FIG. 4, we consider in two dimensions for simplicity. The relationship between the magnetic resistance Rm of the foreign matter F, the magnetic circuit length lm, the magnetic flux linkage area A, the magnetic permeability _μ0 of the vacuum, and the relative magnetic permeability _μr is calculated by the above equation (3). With respect to the external magnetic field H, the interlinking magnetic flux density Bm depends on the angle θ between the direction of the external magnetic field H and the longitudinal direction of the foreign object F. That is, the interlinkage magnetic flux density Bm depends on the longitudinal direction of the foreign matter F. It is assumed that the longitudinal length of the foreign matter F is sufficiently longer than the lateral length, and the relative magnetic permeability _μr is sufficiently greater than one. The interlinkage magnetic flux density Bm is shown by the following formula (5).
Bm≈μ ₀ ×μ _r ×H×cos θ=B×cos θ (5)

Based on Equations (1) and (5), the eddy current loss We due to the foreign matter F is expressed by Equation (6) below. FIG. 5A shows the case where the foreign matter F is an iron wire with a length of 13 mm, and FIG. 5B shows the case where the foreign matter F is a clip made of a bent iron wire. It can be seen that the loss ratios of the calculated value represented by Equation (6), that is, the value of cos ² θ, and the analytical value obtained by the finite element method in consideration of the shape and physical properties of the actual metal foreign matter match each other. That is, when the angle θ formed by the direction of the external magnetic field H and the longitudinal direction of the metal foreign matter F is 0°, the interlinking magnetic flux density to the foreign matter is maximized, and the eddy current loss We due to the foreign matter F is maximized. Become. Further, when the angle θ between the direction of the external magnetic field H and the longitudinal direction of the metallic foreign matter F is 90°, the interlinking magnetic flux density to the foreign matter is minimized, so the eddy current loss We due to the foreign matter F is minimized. Become.
We=Ke×f ² ×B ² ×cos ² θ (6)

As shown in FIG. 6, in the present embodiment, when a current flows in a direction indicated by a dashed arrow in a winding 18A having a plurality of concentric circles in a plan view, the surface 16 of the power transmission section 15 has the shape of the concentric circles. A feeding magnetic field M is formed in a direction from the outer periphery to the center. On the other hand, in the plurality of magnetic field applying units 3A arranged to form a circle surrounding the outer circumference of the winding 18A in plan view, the north and south poles of the neodymium magnets are oriented in the tangential direction of the circle. , the N and S poles of the neodymium magnets of the magnetic field applying section 3A adjacent to each other on the circumference of the circle are arranged so as to face each other. Therefore, the magnetic field applying units 3</b>A apply to the surface 16 of the power transmitting unit 15 a control magnetic field m in a direction perpendicular to the direction of the power supply magnetic field M that the power transmitting unit 15 generates on the surface 16 of the power transmitting unit 15 .

For example, for a magnetic foreign object F placed on a flat surface, if the cross-sectional area of linkage S _a with respect to the control magnetic field m, the mass of the foreign object m _a , the acceleration of gravity g, and the coefficient of friction η, then the cross-sectional area of linkage S _a Assuming that the magnetic flux density B _a is uniform, the magnetic attraction force (magnetic attraction force) exceeds the frictional force when equation (7) holds, so the foreign object can be moved in the direction of the magnetic attraction force. That is, the control magnetic field m applied by the magnetic field applying unit 3A exerts a force on the magnetic metal foreign matter F to direct it in the direction in which the direction of the control magnetic field m and the longitudinal direction of the foreign matter F match. The longitudinal direction thereof is oriented perpendicular to the direction of the feeding magnetic field M generated by the power transmission section 15 .
S _a ×B _a ² /(2×μ ₀ )>ma×g×η (7)

The angle θ between the direction of the power supply magnetic field M formed by the power transmission unit 15 and the longitudinal direction of the foreign object F is 90°, and the interlinking magnetic flux density is minimized, so the eddy current loss We due to the foreign object F is minimized. Therefore, even if the foreign matter F existing on the surface 16 of the power transmission unit 15 is not detected and the foreign matter F is not removed from the surface 16, the influence of the foreign matter F can be minimized.

When the foreign object countermeasure device 1A of the present embodiment is used, for example, the sheet-like storage section 2 is laid on the surface 16 of the power transmission section 15 while aligning its position before the power transmission device 10 performs contactless power supply. As a result, the foreign matter countermeasure device 1A is installed. As described above, the foreign object countermeasure device 1A reduces the influence of the foreign object F during non-contact power supply. While the non-contact power supply is interrupted, the foreign matter countermeasure device 1A is appropriately removed from the surface 16 of the power transmission section 15, and the foreign matter F in the sheet-shaped storage section 2 is removed by cleaning or the like. As a result, the foreign matter countermeasure device 1A can be used repeatedly.

According to the present embodiment, in the foreign object countermeasure device 1A that reduces the influence of a foreign object F in the power transmission unit 15 in contactless power supply from the power transmission unit 15 of the power transmission device 10 to the power reception unit 21 of the power reception device 20, the magnetic field application unit 3A , a control magnetic field m is applied to the surface 16 of the power transmission unit 15 in a direction crossing the direction of the power supply magnetic field M formed by the power transmission unit 15 on the surface 16 of the power transmission unit 15 . Therefore, when the foreign matter F has magnetism, the direction of the foreign matter F having magnetism is controlled by the attractive force and the repulsive force of the control magnetic field m applied by the magnetic field applying unit 3A, and the power supply magnetic field is formed on the surface 16 of the power transmission unit 15. The direction of M and the longitudinal direction of the foreign object F intersect each other, and the direction of the power supply magnetic field M formed on the surface 16 of the power transmission unit 15 and the longitudinal direction of the foreign object F become parallel, thereby preventing contactless power supply. The maximum decrease in power transmission efficiency is suppressed, and the influence of the foreign matter F can be reduced.

That is, according to the present embodiment, regardless of whether the foreign matter F can be detected and removed, the influence of the foreign matter F can be reduced. In addition, since the influence of the foreign matter F can be reduced, the effort required to stop the non-contact power supply and remove the foreign matter F is reduced, and the convenience is improved.

Further, according to the present embodiment, the control magnetic field m in the direction orthogonal to the direction of the feeding magnetic field M that the power transmission unit 15 forms on the surface 16 of the power transmission unit 15 is applied to the surface 16 of the power transmission unit 15 by the magnetic field application unit 3A. be done. Therefore, when the foreign matter F has magnetism, the direction of the foreign matter F having magnetism is controlled by the attractive force and the repulsive force of the control magnetic field m applied by the magnetic field applying unit 3A, and the power supply magnetic field is formed on the surface 16 of the power transmission unit 15. The direction of M and the longitudinal direction of the foreign matter F are orthogonal to each other, minimizing the decrease in the power transmission efficiency of contactless power supply, and the influence of the foreign matter F can be further reduced.

Further, according to the present embodiment, the magnetic core 17 is arranged inside the surface 16 of the power transmission unit 15 , in contrast to the power transmission unit 15 in which the magnetic core 17 is arranged inside any position on the surface 16 of the power transmission unit 15 . The magnetic field applying section 3A is arranged at a position where it is not. Therefore, the influence of the control magnetic field m applied by the magnetic field applying section 3A on the magnetic core 17 can be reduced.

Further, according to the present embodiment, the winding 18A is arranged inside the surface 16 of the power transmission unit 15, whereas the winding 18A is arranged inside the surface 16 of the power transmission unit 15 at some position. The magnetic field applying unit 3A is arranged at a position where is not arranged. Therefore, the influence of the feeding magnetic field M generated from the winding 18A on the magnetic field applying section 3A can be reduced.

Further, according to the present embodiment, the front surface 16 of the power transmission unit 15 is a smooth plane continuous with the road surface S, and the front and back surfaces of the sheet storage unit 2 are smooth planes. Therefore, the foreign matter countermeasure device 1A and the power transmission device 10 according to the present embodiment are superior in load resistance to the case where the front surface 16 of the power transmission unit 15 and the front and back surfaces of the sheet storage unit 2 have inclined surfaces or unevenness, and the foreign matter F It is also easy to remove.

A second embodiment of the present embodiment will be described below. As shown in FIG. 7, in the foreign object countermeasure device 1B of the present embodiment, the winding 18B of the power transmission section 15 is a rectangular coil having a plurality of rectangular shapes having a common center in plan view. A plurality of magnetic field applying units 3B surround the outer periphery of the winding 18B in plan view, and are centered on the winding 18B in plan view. Arranged to form a matching rectangular shape. Note that the winding 18B and the magnetic field applying section 3B may have an elliptical shape. Alternatively, the winding 18B may be a solenoid type coil. Except for the above matters, the second embodiment is the same as the first embodiment.

In the foreign matter countermeasure device 1B of the present embodiment, the influence of the foreign matter F can be reduced even if the winding 18B of the power transmission section 15 is a rectangular coil, an elliptical coil, or a solenoidal coil.

A third embodiment of the present embodiment will be described below. As shown in FIG. 8, the foreign matter countermeasure device 1C of the present embodiment includes a single magnetic field applying section 3C that is movable inside the sheet-like storage section 2. As shown in FIG. The sheet storage section 2 has an internal space, and the magnetic field applying section 3C is movable in the internal space of the sheet storage section 2 and can change its direction. Therefore, the magnetic field applying unit 3</b>C can change the position and direction of the control magnetic field m applied to the surface 16 of the power transmitting unit 15 on the surface 16 of the power transmitting unit 15 .

Further, the magnetic field application unit 3C applies the control magnetic field m to the surface 16 of the power transmission unit 15 using an electromagnet. The magnetic field applying unit 3C applies a control magnetic field m to the surface 16 of the power transmission unit 15 when the power transmission unit 15 forms the power supply magnetic field M on the surface 16 of the power transmission unit 15, The control magnetic field m is not applied to the surface 16 of the power transmission section 15 when the power supply magnetic field M is not formed.

The magnetic field applying unit 3C can be configured as a small unmanned mobile body that is equipped with an electromagnet and moves in the internal space of the sheet-like storage unit 2, for example. The magnetic field applying unit 3C, for example, moves regularly to each position in the internal space of the sheet storage unit 2. As shown in FIG. Before applying the control magnetic field m, the magnetic field applying unit 3C applies to the surface 16 of the power transmission unit 15 a control magnetic field m in a direction that intersects the direction of the power supply magnetic field M that the power transmission unit 15 forms on the surface 16 of the power transmission unit 15. change direction to

In the example of FIG. 8, the magnetic field applying section 3C located at the outer peripheral portion of the winding 18A of the power transmission section 15 moves to the vicinity of the center of the winding 18A of the power transmission section 15. FIG. Magnetic field applying unit 3</b>C changes its direction so as to apply control magnetic field m in a direction crossing the direction of power supply magnetic field M formed on surface 16 of power transmitting unit 15 by power transmitting unit 15 to surface 16 of power transmitting unit 15 . As a result, the direction of the power supply magnetic field M of the power transmission unit 15 and the longitudinal direction of the foreign matter F present near the center of the winding 18A of the power transmission unit 15 become orthogonal to each other, and the influence of the foreign matter F can be reduced. . Except for the above matters, the second embodiment is the same as the first embodiment.

According to the present embodiment, the magnetic field applying unit 3C can change the position and direction of the control magnetic field m applied to the surface 16 of the power transmitting unit 15 on the surface 16 of the power transmitting unit 15. The ability to cope with the foreign matter F existing at various positions of the is improved. Further, according to the present embodiment, foreign matter F present at various positions on the surface 16 of the power transmission section 15 can be dealt with by a small number of the magnetic field application sections 3C.

Further, according to the present embodiment, the magnetic field applying unit 3C applies the control magnetic field m to the surface 16 of the power transmitting unit 15 when the power transmitting unit 15 forms the power supply magnetic field M on the surface 16 of the power transmitting unit 15, Since the control magnetic field m is not applied to the surface 16 of the power transmission unit 15 when the power transmission unit 15 does not form the power supply magnetic field M on the surface 16 of the power transmission unit 15, contactless power supply is not performed, and the power transmission unit 15 When the power supply magnetic field M is not formed on the surface 16, it is possible to reduce the attraction of the foreign matter F to the surface 16 of the power transmission unit 15 by the control magnetic field m applied by the magnetic field application unit 3C.

Although the embodiments and modifications of the present invention have been described above, the present invention is not limited to the above embodiments. For example, in the above-described embodiment, the magnetic field applying units 3A, 3B, and 3C cause the control magnetic field m in the direction perpendicular to the direction of the power supply magnetic field M formed on the surface 16 of the power transmission unit 15 by the power transmission unit 15 to be applied to the surface 16 of the power transmission unit 15. Although the application mode has been mainly described, for example, the power transmission section 15 forms an angle of 45° or more with respect to the direction of the power supply magnetic field M formed on the surface 16 of the power transmission section 15 by the magnetic field application sections 3A, 3B, and 3C. If the directional control magnetic field m is applied to the surface 16 of the power transmission section 15, the effect of greatly reducing the influence of the foreign matter F can be obtained.

Further, in the above embodiment, the magnetic field applying units 3A, 3B, and 3C apply the control magnetic field m in the direction parallel to the surface 16 of the power transmitting unit 15. By applying the control magnetic field m in the direction crossing the power transmission unit 16 , the control magnetic field m in the direction crossing the direction of the feeding magnetic field M formed on the surface 16 of the power transmission unit 15 by the power transmission unit 15 is applied to the surface 16 of the power transmission unit 15 . It may be prevented that the direction of the power supply magnetic field M applied to the power transmission unit 15 and the longitudinal direction of the foreign object F become parallel.

Further, in the above embodiment, the magnetic field application units 3A and 3B are fixed to the power transmission unit 15. It may consist of a single fixed electromagnet. Also, the dimensions and shapes of the magnetic field application units 3A, 3B, and 3C can be changed as appropriate.

In the above-described embodiments, the foreign matter countermeasure devices 1A, 1B, and C are installed by laying the sheet-shaped storage portion 2 on the surface 16 of the power transmission portion 15 while aligning the positions thereof. , the power transmission unit 15 and the sheet storage unit 2 may be of an integral structure, or may be of a separable structure.

1A, 1B, 1C foreign object countermeasure device 2 sheet-shaped storage units 3A, 3B, 3C magnetic field application unit 10 power transmission device 11 power source 12 converter 13 inverter 14 power transmission control unit 15 power transmission unit 16 surface 17 magnetic cores 18A, 18B winding 19 aluminum plate 20 Power receiving device 21 Power receiving unit 22 Rectifier 23 Battery 30 Vehicle 31 Wheel 32 Underside of vehicle body P Parking space S Road surface F Foreign matter H External magnetic field Bm Interlinking magnetic flux density M Power supply magnetic field m Control magnetic field

Claims (6)

A foreign object countermeasure device for reducing the influence of a foreign object on a power transmission unit in contactless power supply from a power transmission unit of a power transmission device to a power reception unit of a power reception device,
a magnetic field applying unit that applies to the surface of the power transmission unit a control magnetic field in a direction that intersects the direction of the power supply magnetic field that the power transmission unit forms on the surface of the power transmission unit ;
The foreign matter countermeasure device, wherein the magnetic field applying section can change either a position or a direction on the surface of the power transmitting section of the control magnetic field applied to the surface of the power transmitting section. The foreign object according to claim 1, wherein the magnetic field applying section applies the control magnetic field in a direction orthogonal to a direction of the power supply magnetic field formed on the surface of the power transmitting section by the power transmitting section to the surface of the power transmitting section. countermeasure device. The magnetic field application section is arranged at a position where no magnetic core is arranged inside the surface of the power transmission section with respect to the power transmission section where the magnetic core is arranged inside any position on the surface of the power transmission section. 3. The foreign matter countermeasure device according to claim 1 or 2, wherein: With respect to the power transmission unit in which a winding is arranged inside any position on the surface of the power transmission unit, the magnetic field application unit is located at a position where no winding is arranged inside the surface of the power transmission unit. 4. The foreign matter countermeasure device according to any one of claims 1 to 3, wherein: The magnetic field applying section applies the control magnetic field to the surface of the power transmission section when the power transmission section forms the power supply magnetic field on the surface of the power transmission section, and the power transmission section applies the control magnetic field to the surface of the power transmission section. The foreign matter countermeasure device according to any one of claims 1 to 4 , wherein the control magnetic field is not applied to the surface of the power transmission section when the power supply magnetic field is not generated. A power transmission device comprising the foreign object countermeasure device according to any one of claims 1 to 5 and the power transmission section.

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