WO2016121055A1 - Power transmission coil structure in contactless power transmission device - Google Patents

Abstract

A cutout portion (p1) is formed in a part of a ferrite (72) provided in a disc-type coil (71). Formation of the cutout portion (p1) causes a change in the density of magnetic flux produced by a main coil (74), resulting in the formation of a general portion with a predetermined magnetic flux density and a magnetic flux changed portion with a magnetic flux density different from that of the general portion. If a frame-shaped foreign body is present on the upper surface side of the disc-type coil (71), the ratio between the magnetic flux density detected in the general portion and the magnetic flux density detected in the magnetic flux changed portion will change compared with a situation in which the foreign body is not placed thereon. Accordingly, the presence of a frame-shaped foreign body can be detected on the basis of the change.

Description

Coil structure for power transmission of non-contact power transmission equipment

This invention relates to the structure of the coil for electric power transmission used for a non-contact electric power transmission apparatus.

Conventionally, a non-contact power transmission device that transmits power in a non-contact manner and charges the battery provided in the power receiving side device has been proposed. In a non-contact power transmission device, when a foreign metal object exists in the vicinity of a power transmission coil for transmitting power or a power reception coil for receiving power, the foreign object may generate heat. Therefore, if there is a foreign object, it must be detected and removed. As a conventional example of foreign object detection, for example, one described in Patent Document 1 is known. In Patent Document 1, a plurality of signal primary coils smaller than the power transmission primary coil are provided in order to detect whether or not there is a foreign object in the vicinity of the power transmission primary coil, and are generated in each signal primary coil. It is shown that a foreign object existing in the vicinity of a primary coil for power transmission is detected by measuring a voltage.

JP 2010-259172 A

However, in the conventional technique disclosed in Patent Document 1 described above, when a foreign object having a shape similar to the power transmission coil, such as a metal frame-shaped foreign object, is placed on the power transmission coil, for example, a metal frame-like foreign material. Thus, it is difficult to distinguish a change in the magnetic flux distribution caused by the foreign matter from a change in the magnetic flux distribution caused by a gap change between the power transmission coil and the power reception coil or a positional deviation between the power transmission coil and the power reception coil. For this reason, the problem that the presence of a foreign object cannot be detected occurs.

The present invention has been made to solve such a conventional problem. The object of the present invention is to place a foreign object having a shape similar to the main coil of the power transmission coil in the vicinity of the power transmission coil. It is an object of the present invention to provide a coil structure for power transmission that can detect the presence of a foreign substance with high accuracy even when it is used.

The coil structure for power transmission of the non-contact power transmission apparatus according to one aspect of the present invention is configured such that the power transmission coil has a flat plate-shaped magnetic body and a surface on the power transmission side or reception side with respect to the magnetic body. It includes a main coil that is provided and spirally wound. Furthermore, a general part that generates a predetermined magnetic flux density and a magnetic flux changing part that generates a magnetic flux density different from the general part are provided.

It is a block diagram which shows the structure of the non-contact charge system by which the coil for electric power transmission which concerns on embodiment of this invention was employ | adopted. It is explanatory drawing which shows the search coil used for the non-contact charge system which concerns on embodiment of this invention. It is explanatory drawing which shows the state by which the ground coil and vehicle coil which are used for the non-contact charging system which concerns on embodiment of this invention are opposingly arranged. It is a block diagram which shows the structure of the voltage detection control part used for the non-contact charge system which concerns on embodiment of this invention. It is explanatory drawing which shows the structure of the disk type coil used for the non-contact charge system which concerns on embodiment of this invention. It is explanatory drawing which shows the magnetic flux produced when an electric current is sent through a disk type coil. It is explanatory drawing which shows the structure of the disk type coil which concerns on 1st Example of this invention. It is a characteristic view which shows the reference voltage distribution table used with the non-contact charge system which concerns on embodiment of this invention. It is a characteristic view which shows the contrast of the reference voltage distribution table used with the non-contact charge system which concerns on embodiment of this invention, and the actually measured voltage. It is explanatory drawing which shows the change of voltage distribution when iron is placed on the search coil of the non-contact charging system which concerns on embodiment of this invention. It is explanatory drawing which shows the change of the voltage distribution in case aluminum is placed on the search coil of the non-contact charging system which concerns on embodiment of this invention. It is explanatory drawing which shows the state by which the frame-shaped foreign material was placed on the disk type coil. It is a graph which shows the magnetic flux density which arises in a general part and a magnetic flux change part. It is a flowchart which shows the measurement processing procedure of the reference voltage table of the non-contact charge system which concerns on embodiment of this invention. It is a flowchart which shows the process sequence of a foreign material detection of the non-contact charge system which concerns on embodiment of this invention. It is explanatory drawing which shows the structure of the disk type coil which concerns on 2nd Example of this invention. It is explanatory drawing which shows the structure of the disk type coil which concerns on 3rd Example of this invention. It is explanatory drawing which shows the structure of the disk type coil which concerns on 4th Example of this invention. It is explanatory drawing which shows the structure of the disk type coil which concerns on 5th Example of this invention. It is explanatory drawing which shows the structure of the disk type coil which concerns on 6th Example of this invention. It is explanatory drawing which shows the structure of the disk type coil which concerns on 7th Example of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing a configuration of a non-contact charging system that employs a power transmission coil structure of a non-contact power transmission apparatus according to an embodiment of the present invention. As shown in FIG. 1, this non-contact charging system 100 includes a vehicle-side device 101 mounted on an electric vehicle (hereinafter referred to as “vehicle”) and a power supply device 102 that is installed on the ground side and supplies power to the vehicle. It is configured. And electric power is transmitted from the electric power feeder 102, this electric power is received non-contact in the vehicle side apparatus 101, and the received electric power is charged to the battery mounted in an electric vehicle.

Here, the “non-contact power transmission device” according to the present invention indicates both the vehicle side device 101 and the power feeding device 102. That is, the power feeding device 102 is a non-contact power transmission device that transmits power in a non-contact manner via a power transmission coil (a ground coil 14 described later), and the vehicle-side device 101 includes a power transmission coil (a vehicle described later). This is a non-contact power transmission device that receives power in a non-contact manner via a coil 35). Hereinafter, the configuration of the non-contact charging system 100 will be described.

A power supply apparatus 102 shown in FIG. 1 desires a DC power source 11 that rectifies AC power output from a commercial power source 10 (for example, 100 V, 50 Hz) to obtain DC power, and DC power output from the DC power source 11. The inverter 12 which converts into the alternating current power of frequency, the ground coil 14 for electric power feeding provided in the road surface of the parking space of a vehicle, and the resonance capacitor 13 which resonates electric power between this ground coil 14 are provided. In addition, the voltage / current / temperature sensor 16 that detects the voltage, current, and temperature of the DC power supply 11 and the inverter 12, the ground side control unit 15, and operations for acquiring reference voltage data (described later) used for foreign object determination are performed. Display of calibration switch 18 to be performed, reference voltage storage unit 21 that stores a reference voltage table, wireless LAN 17 that performs short-range communication with vehicle-side device 101, and various types of information (particularly, information regarding the presence of foreign matter) And a display unit 22 for displaying.

Furthermore, a planar search coil 19 provided on the upper surface side (power transmission side) of the ground coil 14 and provided substantially parallel to the ground coil 14, and a voltage detection control unit for measuring a voltage generated in the search coil 19. 20.

A disk-type coil is used as the ground coil 14. Details of the disk type coil will be described later. As shown in the plan view of FIG. 2, the search coil 19 is configured by a plurality of sensor coils 19 </ b> L (in the figure, 54 of 9 × 6 are shown as an example) arranged in a plane. A voltage resulting from the magnetic flux output from the ground coil 14 is generated in each sensor coil 19L.

The voltage detection control unit 20 shown in FIG. More specifically, the voltage generated in each sensor coil 19 </ b> L provided in the search coil 19 is individually detected, and each detected voltage data is transmitted to the ground side control unit 15. Details will be described later.

The ground side control unit 15 comprehensively controls the power supply apparatus 102. In particular, various controls including operations of the inverter 12 and the DC power supply 11 are performed. Specifically, when transmitting power to the vehicle-side device 101, the ground-side control unit 15 supplies AC power output from the inverter 12 to the ground coil 14 so that the ground coil 14 is used. Performs excitation control. Further, when it is confirmed by the operator that no foreign matter (nails, bolts, empty cans, etc.) exists around the search coil 19 and the calibration switch 18 is operated, the ground coil 14 is excited. And the voltage which generate | occur | produces in each sensor coil 19L at this time is measured as a reference voltage, and the process which memorize | stores this reference voltage in the reference voltage memory | storage part 21 as a reference voltage table is performed. Furthermore, the voltage data detected by the voltage detection control unit 20 is compared with the reference voltage table to determine whether or not there is a foreign object in the vicinity of the ground coil 14. In addition, when there is a foreign object, the position where the foreign object exists and the material of the foreign object are determined to notify the operator of the power supply apparatus 102 or the driver of the vehicle, output an alarm, Controls to cut off power.

On the other hand, the vehicle-side device 101 includes a vehicle coil 35 provided on the bottom surface of the vehicle, a resonance capacitor 34 that resonates power between the vehicle coil 35, and AC power received via the vehicle coil 35. Are rectified and converted to DC power, a battery 31 that charges DC power, and a relay box 32 that switches between charging and discharging of the battery 31.

In addition, the voltage / current / temperature sensor 38 for detecting the input / output voltage and current of the battery 31 and the temperature of the relay box 32, the vehicle side control unit 39, and the operation for acquiring the reference voltage table used for foreign object determination are performed. A calibration switch 44 to be performed, a reference voltage storage unit 43 that stores a reference voltage table, a wireless LAN 41 that performs near field communication with the power supply apparatus 102, and various types of information (particularly, information related to the presence of foreign matter) are displayed. Display unit 42.

Further, the vehicle-side control unit 39 is connected to the vehicle network 40, and can transmit and receive data to and from in-vehicle devices such as an ECU in the vehicle.

Further, a planar search coil 36 provided so as to cover the lower surface side (electric power reception side) of the vehicle coil 35 and provided substantially parallel to the vehicle coil 35, and a voltage generated in the search coil 36 are measured. And a voltage detection control unit 37.

The disk coil 35 is used for the vehicle coil 35 as in the case of the ground coil 14 described above. The search coil 36 has a configuration in which a plurality of sensor coils are arranged in a plane, similarly to the search coil 19 (see FIG. 2) on the power supply apparatus 102 side described above.

The voltage detection control unit 37 measures the voltage generated in the search coil 36. More specifically, the voltage generated in each sensor coil provided in the search coil 36 is individually detected, and each detected voltage data is transmitted to the vehicle side control unit 39.

The vehicle-side control unit 39 controls the vehicle-side device 101 as a whole. In particular, after confirming that no foreign matter is present around the search coil 36, the vehicle coil 35 is excited, the voltage generated at each sensor coil is measured, and this voltage is used as a reference voltage table. Store in the voltage storage unit 43. Further, based on the detection signal from the voltage detection control unit 37, it is determined whether or not there is a foreign object in the vicinity of the search coil 36. Further, when it is determined that a foreign object is present, the position where the foreign object is present and the material of the foreign object are determined to notify the operator of the power supply apparatus 102 or the driver of the vehicle, or to output an alarm. Then, control for forcibly cutting off charging of the battery 31 is performed.

Here, the vehicle-side control unit 39 and the above-described ground-side control unit 15 can be configured as, for example, an integrated computer including a central processing unit (CPU) and storage means such as a RAM, a ROM, and a hard disk. .

Next, the positional relationship between the ground coil 14 and the vehicle coil 35 when non-contact charging is performed between the vehicle-side device 101 and the power feeding device 102 will be described with reference to FIG. FIG. 3 is a side view schematically showing a state when the ground coil 14 and the vehicle coil 35 face each other.

As shown in FIG. 3, the search coil 19 is provided so as to cover the upper surface side of the ground coil 14 provided on the road surface of the parking space, and the lower surface side of the vehicle coil 35 provided on the vehicle bottom surface is covered. A search coil 36 is provided. When the vehicle stops at a predetermined position in the parking space, the ground coil 14 and the vehicle coil 35 face each other. And if electric power is supplied to the ground coil 14, this electric power will be transmitted to the coil 35 for vehicles without contact, and the battery 31 shown in FIG. 1 can be charged.

FIG. 4 is a block diagram showing a detailed configuration of the voltage detection control unit 20. As shown in FIG. 4, the voltage detection control unit 20 is connected to each sensor coil 19L (in FIG. 4, each sensor coil 19L is represented as channel 1, channel 2,... Channel n), and each sensor coil A multiplexer 51 that sequentially switches and outputs a voltage signal detected by 19L, a differential amplifier 52 that amplifies the voltage signal output from the multiplexer 51, and a rectifier for the voltage signal output from the differential amplifier 52 A rectifier 53 for removing the AC component, and a CPU 55 for A / D converting the voltage signal.

The CPU 55 has a function of transmitting a channel designation signal to the multiplexer 51. Accordingly, the voltage signal detected by each sensor coil 19L is input to the CPU 55 as a serial signal, digitized by the CPU 55, and transmitted to the ground side control unit 15 shown in FIG. Note that the voltage detection control unit 37 provided in the vehicle-side device 101 also has the same configuration as in FIG.

Next, the disk type coil 71 used as the ground coil 14 and the vehicle coil 35 will be described with reference to FIGS. 5A and 5B are explanatory views showing the configuration of the disk-type coil 71, where FIG. 5A is a plan view and FIG. 5B is a cross-sectional view taken along line A-A 'in FIG. As shown in FIG. 5, the disk-shaped coil 71 is provided with an insulating material 73 so as to cover the upper surface of a ferrite 72 (magnetic material) having a flat plate shape. Further, the electric wire is rectangular on the upper surface of the insulating material 73. A main coil 74 wound in a spiral shape is provided. Further, terminals 75a and 75b are provided at the outer peripheral end and the inner peripheral end of the main coil 74, respectively.

The terminals 75a and 75b are connected to the inverter 12 via the resonance capacitor 13 shown in FIG. 1, and an alternating current is passed through the main coil 74, whereby a magnetic flux can be generated around the disk-type coil 71. Since this magnetic flux is transmitted to the vehicle coil 35 side, electric power can be transmitted to the vehicle coil 35.

FIG. 6 is an explanatory diagram schematically showing magnetic flux generated in the disk-type coil 71 when an alternating current is passed through the main coil 74. FIG. 6 shows a cross section of the disk-type coil 71, and a magnetic flux is generated around the main coil 74 in which an electric wire is wound in a spiral shape as indicated by an arrow in the figure. That is, the magnetic flux density increases on the inner side (center side) and the outer side (outer peripheral side) of the main coil 74, and the magnetic flux density decreases in the region therebetween.

In the present embodiment, a voltage generated in each sensor coil 19L when no foreign matter is present around the disk type coil 71 is detected in advance, and this voltage is stored as a reference voltage in the reference voltage storage unit 21 (see FIG. 1). . When detecting the presence or absence of a foreign object, the voltage detected by each sensor coil 19L is compared with the reference voltage. When foreign objects such as empty cans and bolts exist around the disk type coil 71, the voltage detected by each sensor coil 19L changes with respect to the reference voltage. Therefore, the presence of foreign objects is detected based on this change. can do.

Further, when there is a frame-like foreign material such as a window frame around the disk-shaped coil 71 (see reference numeral 83 in FIG. 12 described later), the voltage detected by each sensor coil 19L, the reference voltage, There may be no significant difference between the two. That is, if there is a frame-like foreign matter, the voltage detected by each sensor coil 19L is uniformly reduced or raised, so the presence of the foreign matter may not be detected. This is because when the voltage generated in each sensor coil 19L is uniformly reduced or increased, the change in voltage is due to the difference in gap between the ground coil 14 and the vehicle coil 35, or there is a frame-like foreign matter. This is because it is impossible to tell whether it is due to a problem.

In the first embodiment, the magnetic flux density is changed by forming a notch in a part of the ferrite 72 (magnetic material) constituting the disk-type coil 71, and a frame-like foreign material is formed on the upper surface side of the disk-type coil 71. Even if exists, this is reliably detected. Hereinafter, specific examples of the first embodiment will be described in the first example and the second example.

(First embodiment)
FIG. 7 is an explanatory diagram schematically showing the configuration of the disk-type coil 71 (power transmission coil) and its peripheral devices according to the first embodiment. 7A is a plan view, FIG. 7B is an explanatory diagram showing magnetic flux density generated when a current is passed through the main coil 74, FIG. 7C is an AA ′ cross-sectional view shown in FIG. FIG. 4 shows a cross-sectional view along the line BB ′ shown in FIG. The disk type coil 71 is shown by taking the ground coil 14 shown in FIG. 1 as an example.

As shown in FIG. 5 described above, the disk-type coil 71 includes a rectangular ferrite 72, an insulating material 73 provided on the upper surface side of the ferrite 72, and an electric wire on the upper surface side of the insulating material 73. The main coil 74 wound in the shape is provided. Further, as shown in FIGS. 7A and 7D, a notch p1 is formed from the center of the ferrite 72 downward. Then, the end portion of the electric wire on the inner peripheral side of the main coil 74 is drawn out to the outside and connected to the terminal 75b via the space formed by the cutout portion p1. That is, by inserting the electric wire at the end of the main coil 74 into the notch p1 formed in the ferrite 72 (magnetic material), the electric wire at the end of the main coil 74 is drawn out of the main coil 74. .

Further, as shown in FIGS. 7C and 7D, the ferrite 72, the insulating material 73, and the main coil 74 constituting the disk-type coil 71 are housed in a metal case 82, and the metal case The search coil 19 shown in FIGS. 1 and 2 is provided at the top end of 82, and the upper surface thereof is closed by a resin lid 81.

As shown in FIG. 7B, the magnetic flux density B1 of the region R1 around which the main coil 74 is wound, the magnetic flux density B2 of the region R2 inside the region R1, and the region R1 As described with reference to FIG. 6, the relationship (B2, B3)> B1 is established between the magnetic flux density B3 in the outer region R3. That is, the magnetic flux densities B2 and B3 in the regions R2 and R3 are larger than the magnetic flux density B1 in the region R1.

Further, since the notch p1 is formed in the ferrite 72, the magnetic flux densities B4 and B5 in the inner and outer regions of the main coil 74 corresponding to this, that is, the regions R4 and R5 shown in FIG. , The magnetic flux densities B2 and B3 in the regions R2 and R3 are small. That is, the relationship (B2, B3)> (B4, B5)> B1 is established. The regions R2 and R3 are general portions that are regions that generate a predetermined magnetic flux density, and the regions R4 and R5 are magnetic flux changing portions that are regions that generate a magnetic flux density different from the general portion.

In the region where the notch p1 is formed (magnetic flux changing portion), the magnetic flux density generated when a current is passed through the disk-type coil 71 is smaller than the other regions (general portion). With such a configuration, as will be described later, when a metal frame-like foreign material such as a window frame is placed on the upper surface side of the disk-type coil 71, the regions R2, R3 and the region are caused by the presence of the foreign material. The magnitude of the magnetic flux density and the ratio of the magnetic flux density of R4 and R5 change. Therefore, it is possible to detect whether or not a frame-like foreign substance exists by detecting the change in the magnitude and ratio of the magnetic flux density.

Next, a foreign object detection method executed using the power transmission coil structure of the non-contact power transmission apparatus according to the first embodiment described above will be described. In the present invention, as described above, as an initial operation, when there is no foreign object in the vicinity of the search coil 19, power is supplied to the ground coil 14 to excite the ground coil 14. A voltage generated in the sensor coil 19L is detected. The detected voltage data is stored in the reference voltage storage unit 21 as a reference voltage table.

FIG. 8 is a characteristic diagram showing an example of a reference voltage table set for each output power. In FIG. 8, a curve s1 indicates the reference voltage detected by each sensor coil 19L when the output power of the ground coil 14 is 1 KW. The horizontal axis in FIG. 8 indicates “channels” (numbers of the sensor coils 19L) in the order of decreasing generated voltage toward the right. That is, the left end of the curve s1 indicates the channel with the lowest generated voltage, and the right end indicates the channel with the highest generated voltage. Similarly, the curve s2 indicates the reference voltage when the output power is 2 KW, and the curve s3 indicates the reference voltage when the output power is 3 KW.

Then, when detecting foreign matter existing in the vicinity of the search coil 19 during actual power transmission, the difference between the voltage generated in each sensor coil 19L detected by the voltage detection control unit 20 and the reference voltage table is calculated. . As a result, for example, as shown in FIG. 9, the difference between the measured voltage data (curve s12) and the reference voltage (curve s11) stored in the reference voltage table is obtained. Detect presence.

That is, the ground side control unit 15 compares the voltage detected by each sensor coil 19L with the above reference voltage, and if there is a large difference, the vicinity of the search coil 19 and thus the ground coil 14 It is determined that a metal foreign object exists in the vicinity.

Here, the presence of a foreign object can be detected by the same method as described above for the search coil 36 provided on the lower surface side of the vehicle coil 35 shown in FIG. Detailed description is omitted. By using the search coil 36, it is possible to detect a foreign object in the vicinity of the vehicle coil 35 due to a metal foreign object entangled with the vehicle coil 35 or the like.

Next, a description will be given of the disturbance of the magnetic flux when a foreign object is present in the vicinity of the ground coil 14. First, a case where a foreign matter having a high magnetic permeability such as iron is placed in the vicinity of the search coil 19 will be described with reference to FIG. FIG. 10A shows a case in which a rod-like foreign matter (for example, iron) having a high magnetic permeability is placed at substantially the center of the search coil 19, and FIG. 10B is slightly shifted from the center of the search coil 19. It is a top view which shows a voltage change when the foreign material (for example, iron) with the block shape and the high magnetic permeability is put in the position.

As shown in FIG. 10 (a), when the rod-like foreign material x1 is placed, the voltage generated in the central region r1 of the foreign material x1 is lower than the reference voltage, and both end regions r2, The voltage generated at r3 increases. On the other hand, as shown in FIG. 10 (b), when a lump-like foreign material x2 is placed, the voltage generated in the nearby region r4 rises with respect to the reference voltage and is generated in the regions r5 and r6 at both ends. The voltage drops. Therefore, based on such a voltage change pattern, it is possible to recognize the position and material where the foreign matter exists.

Next, a case where a foreign matter having a low magnetic permeability such as aluminum or copper is placed in the vicinity of the search coil 19 will be described. FIG. 11A shows a case where a rod-like foreign material (for example, aluminum) having a low magnetic permeability is placed at the substantially central portion of the search coil 19, and FIG. 11B is slightly shifted from the center of the search coil 19. It is a top view which shows a voltage change when the block-shaped foreign material with low magnetic permeability is put in the position.

As shown in FIG. 11A, when a rod-like foreign material x3 is placed in the direction of the magnetic flux on the search coil 19, the foreign material x3 hardly affects the change of the magnetic flux. Accordingly, the voltage detected by the search coil 19 does not change. Further, as shown in FIG. 11B, when a lump-like foreign matter x4 is placed, the voltage generated in the region r7 where the foreign matter x4 is present decreases. Therefore, based on such a voltage change pattern, it is possible to recognize the position and material where the foreign matter exists.

Next, a change in magnetic flux density when a frame-like foreign matter such as a window frame is placed on the search coil 19 will be described with reference to an explanatory diagram shown in FIG. 12 and a characteristic diagram shown in FIG. . 12A and 12B are explanatory views showing a state in which a frame-like foreign material 83 is placed on the upper surface side of the disk-type coil 71. FIG. 12A is a plan view, and FIG. 12B is a cross-sectional view taken along line AA ′ in FIG. (C) is a BB ′ cross-sectional view in (a).

For example, since the metal window frame has a rectangular shape, the foreign matter 83 overlaps with the main coil 74 as shown in FIG. In such a case, the magnetic flux density generated by the disk type coil 71 is uniformly reduced, and does not appear as a local voltage change as shown in the characteristic diagram of FIG. In the first embodiment, the presence of a frame-like foreign object is detected based on a change in the magnetic flux density ratio.

Hereinafter, the change in the ratio of the magnetic flux density when a frame-like foreign matter is placed on the search coil 19 will be described with reference to the graph shown in FIG. The inter-coil gap, which is the distance between the ground coil 14 and the vehicle coil 35 shown in FIG. 1, differs depending on the vehicle. Therefore, the current flowing through the ground coil 14 is changed according to the gap between the coils.

As shown in FIG. 13, when the inter-coil gap is N1 (for example, 100 mm), for example, the current flowing through the main coil 74 is defined as current I. At this time, the magnetic flux densities B2 and B3 in the regions R2 and R3 are “b * I” as indicated by the symbol q2. Further, the magnetic flux densities B4 and B5 of the regions R4 and R5 are “a * I” as indicated by the symbol q1. Note that a and b are proportional constants (where a <b), and in this embodiment, “b = 2a” is taken as an example.

Further, when the inter-coil gap is N2 (for example, 120 mm), for example, the current flowing through the main coil 74 is defined as current 2I. As a result, the magnetic flux density in the regions R2 and R3 is “a * 2I” as indicated by the symbol q4, and the magnetic flux density in the regions R4 and R5 is “b * 2I” as indicated by the symbol q3. That is, when there is no foreign matter on the upper surface side of the disk-type coil 71, when the gap between the coils changes, the ratio of the magnetic flux density between the regions R2, R3 and the regions R4, R5 is “2: 1. This ratio does not change greatly even if the gap between the coils changes.

On the other hand, when the gap between the coils is N2 and there is a frame-like foreign matter on the upper surface side of the disk-type coil 71, the magnetic flux density is reduced due to the presence of the foreign matter. As a specific example, the magnetic flux density of the regions R2 and R3 is “b * 2Ic” as indicated by the symbol q6, and the magnetic flux density of the regions R4 and R5 is “a * 2Ic” as indicated by the symbol q5. . Therefore, the ratio of magnetic flux density is “3: 1”, and the ratio changes. That is, by measuring changes in the magnetic flux density and ratio of the regions R2 and R3 (general portion) and the regions R4 and R5 (magnetic flux changing portions), a frame-like foreign matter is formed on the upper surface side of the disk-type coil 71. It is possible to determine whether or not it exists.

Thus, in the first embodiment, the notch p1 for inserting the electric wire of the main coil 74 is formed in the central portion of the ferrite 72 included in the disk type coil 71, and the regions R4 and R5 (magnetic flux changing portions) are formed. ) Is a region having a smaller magnetic flux density than the other regions R2 and R4 (general part). Therefore, even when a frame-shaped foreign object is placed on the upper surface side of the disk-type coil 71 (power transmission coil), the presence of the foreign object can be detected with high accuracy.

Next, the operation when detecting the presence of a foreign object in the non-contact charging system 100 employing the power transmission coil structure according to the first embodiment will be described with reference to the flowcharts shown in FIGS. In the non-contact charging system 100 according to the present embodiment, voltage data detected by each sensor coil 19L when no foreign object is present in the vicinity of the search coil 19 is acquired in advance, and this is stored as a reference voltage table. The data is stored in the unit 21 (see FIG. 1). Further, the ratio of the magnetic flux density generated in the regions R2 and R3 and the magnetic flux density generated in the regions R4 and R5 is calculated, and this ratio is stored and stored in the reference voltage storage unit 21.

Hereinafter, a processing procedure for creating a reference voltage table stored in the reference voltage storage unit 21 and calculating a magnetic flux density ratio will be described with reference to a flowchart shown in FIG.

First, in step S31, the ground-side control unit 15 shown in FIG. 1 supplies power to the ground coil 14 so that the output becomes 1 KW. In step S32, the voltage distribution in each sensor coil 19L of the search coil 19 at this time is acquired and stored in the reference voltage storage unit 21 as a reference voltage table at 1 kW.

In step S33, the ground-side control unit 15 supplies power to the ground coil 14 so that the output becomes 2 KW. In step S34, the voltage distribution in each sensor coil 19L of the search coil 19 at this time is acquired and stored in the reference voltage storage unit 21 as a reference voltage table at 2 kW.

Furthermore, in step S35, the ground side control part 15 supplies electric power to the ground coil 14 so that an output may be 3KW. In step S36, the voltage distribution in each sensor coil 19L of the search coil 19 at this time is acquired and stored in the reference voltage storage unit 21 as a reference voltage table at 3 kW.

Next, in step S37, the magnetic flux densities of the regions R2, R3 (general part) and the regions R4, R5 (magnetic flux changing part) are calculated from the current I during operation at each output.

In step S37, the magnetic flux density ratio in each region is calculated, and the calculation result is stored and saved in the reference voltage storage unit 21.

By doing this, it is possible to obtain a reference voltage table indicating the voltage distribution of the search coil 19 at each output. And the ratio of the magnetic flux density of a general part and the magnetic flux density of a magnetic flux change part is computable. In the flowchart of FIG. 14, the ground coil 14 is excited and the reference voltage table for the search coil 19 provided on the upper surface side of the ground coil 14 and the magnetic flux density ratio are obtained. For the search coil 36 provided in the apparatus 101, a reference voltage table for each output power can be created by similar processing.

Next, with reference to a flowchart shown in FIG. 15, a specific processing procedure for detecting a foreign object existing in the vicinity of the search coil 19 will be described. This process is executed under the control of the ground side control unit 15 shown in FIG.

First, when an initial diagnosis, that is, a foreign object detection process is started in step S51, the ground side control unit 15 determines whether or not to perform a reference voltage table calibration process in step S52. This process can be determined by whether or not the operator has pressed the calibration switch 18. When the calibration switch 18 is pressed (ON in step S52), in step S53, the ground side control unit 15 executes the process shown in FIG. 14 and creates a new reference voltage table. .

On the other hand, when the calibration switch 18 is not pressed (OFF in step S52), voltage data detected by each sensor coil 19L included in the search coil 19 is acquired in step S54. That is, voltage data for each sensor coil 19L detected by the voltage detection control unit 20 shown in FIG. 1 is acquired.

In step S55, the ground side control unit 15 reads the reference voltage table stored and saved in advance in the reference voltage storage unit 21. At this time, a reference voltage table corresponding to the output power of the ground coil 14 is used. For example, when the output power of the ground coil 14 is 2 KW, the reference voltage table corresponding to 2 KW is read.

In step S56, the ground side control unit 15 compares the reference voltage table read in step S55 with the voltage data acquired in step S54 to obtain a differential voltage.

In step S57, the ground-side control unit 15 determines a voltage change pattern in an area where the differential voltage is equal to or higher than a preset threshold voltage (an installation position of the sensor coil 19L). Based on the voltage change pattern, the position on the search coil 19 where the foreign substance exists is specified. Further, it is determined whether the foreign material is a foreign matter having a high magnetic permeability such as iron or a foreign matter having a low magnetic permeability such as copper or aluminum. Specifically, the position and material of the foreign matter are specified based on the method shown in FIGS.

In step S58, the ratio of the magnetic flux density B2 in the region R2 (or the magnetic flux density B3 in the region R3) and the magnetic flux density B4 in the region R4 (or the magnetic flux density B5 in the region R5) shown in FIG. 7 is calculated.

In step S59, the ratio calculated in step S58 is compared with the magnetic flux density ratio calculated in step S38 of FIG. If there is a large difference in the ratio, it is detected that there is a frame-like foreign object in the vicinity of the disk type coil 71.

Specifically, as shown in the graph of FIG. 13 described above, when there is a metal frame-like foreign material, the ratio of the magnetic flux density changes in the regions R2 and R3 and the regions R4 and R5. Therefore, based on this change, it can be determined whether or not a frame-like foreign substance exists.

Then, by displaying these pieces of information on the display unit 22 shown in FIG. 1, it is possible to notify the operator of the power feeding apparatus 102 that there is a foreign object in the vicinity of the search coil 19. Further, since the foreign object detection information can be notified to the vehicle side device 101 by communication between the wireless LAN 17 of the power supply device 102 and the wireless LAN 41 of the vehicle side device 101, the detection information of the vehicle side device 101 can be notified. It can be displayed on the display unit 42 and can inform the driver of the vehicle that a foreign object exists. As a result, if a foreign object exists in the vicinity of the search coil 19, an operator or the like who recognizes the foreign object can remove it in advance, so that a metal foreign object placed in the vicinity of the search coil 19 can be removed. The occurrence of problems such as heat generation can be avoided.

In the flowchart shown in FIG. 15, the foreign object detection procedure by the search coil 19 installed on the upper surface side of the ground coil 14 has been described. However, the search coil 36 installed on the lower surface side of the vehicle coil 35 is similar in procedure. Foreign matter can be detected.

In this way, in the non-contact power transmission apparatus employing the power transmission coil structure according to the first embodiment, the search coil 19 including the plurality of sensor coils 19L is provided on the upper surface side of the ground coil 14, and each sensor coil 19L is provided. Detects the voltage generated in Further, the detected voltage data is compared with the reference voltage set in the reference voltage table acquired in advance, and the presence position of the foreign matter and the foreign material are detected based on the voltage increase / decrease pattern. Therefore, it is possible to reliably detect the position and material of the metallic foreign object existing in the vicinity of the search coil 19 and notify the operator of the power supply apparatus 102 and the driver of the vehicle.

That is, when the vehicle is parked in the parking space for charging, it is difficult to visually recognize the situation on the search coil 19 provided on the road surface from the surroundings. Therefore, it is possible to confirm the presence, position and material of the foreign material with certainty, and it is possible to immediately remove the foreign material.

In addition, when the ratio between the magnetic flux density generated in the regions R2 and R3 (general part) and the magnetic flux density generated in the regions R4 and R5 (magnetic flux changing part) is calculated in advance, and the ratio changes, a frame-shaped foreign matter exists. I can recognize that. Accordingly, even when a foreign object having a shape similar to that of the main coil (for example, a frame-shaped foreign object such as a window frame) exists around the disk-type coil 71, the presence of the foreign object is reliably detected and the operator or the driver Can be notified.

Further, by forming the notch portion p1 in the ferrite 72, a general portion that is a region that generates a predetermined magnetic flux density and a magnetic flux change portion that is a region that generates a magnetic flux density different from the general portion are formed. The general part and the magnetic flux change part can be formed with a simple operation. Moreover, since the electric wire inside the main coil 74 can be pulled out using this notch part p1, the main coil 74 can be easily connected.

The search coil 36 provided on the lower surface side of the vehicle coil 35 can detect the presence of foreign matter existing in the vicinity of the vehicle coil 35.
In the first embodiment described above, an example in which the disk-type coil 71 in which the electric wire is wound in a rectangular spiral shape has been described. However, the present invention is not limited to this, for example, in a circular shape. It is also possible to use a disk-type coil having a wound electric wire.

(Second embodiment)
Next, a second embodiment will be described. FIG. 16 is an explanatory diagram schematically showing the configuration of the disk-type coil 71 (coil for power transmission) and its peripheral devices according to the second embodiment. 16A is a plan view, FIG. 16B is an explanatory diagram showing magnetic flux density generated when a current is passed through the electric wire, FIG. 16C is a cross-sectional view along AA ′ shown in FIG. 16A, and FIG. A cross-sectional view taken along line BB ′ shown in a) is shown. The disk type coil 71 is the ground coil 14 or the vehicle coil 35 shown in FIG.

In the second embodiment, as shown in FIGS. 16A and 16C, the ferrite 72 at one corner of the disk-type coil 71 is notched, forming a notch p2. And by forming this notch part p2, as shown in FIG.16 (b), magnetic flux density B6, B7 of area | region R6, R7 in which the notch part p2 is formed becomes magnetic flux density B2 of area | region R2, R3. , Smaller than B3. That is, when the magnetic flux density in the region R1 is B1, there is a relationship of (B2, B3)> (B6, B7)> B1.

Therefore, as in the first embodiment described above, it is possible to detect foreign matter existing around the disk-type coil 71. Further, when there is a frame-like foreign matter on the upper surface side of the disk-type coil 71, the ratio of the magnetic flux densities B2, B3 and the magnetic flux densities B6, B7 changes, so that the frame-like foreign matter is placed. Can be detected. In the second embodiment, since the notch p2 is formed at the corner of the rectangular ferrite 72, the ferrite 72 can be easily arranged.

In the first and second embodiments described above, the ground coil 14 shown in FIG. 1 has been described. Similarly, for the vehicle coil 35, a frame-like foreign matter is formed by forming a notch in the ferrite. The presence can be detected.

[Description of Second Embodiment]
Next, a second embodiment of the present invention will be described based on the third to sixth examples. In the second embodiment, the magnetic flux density generated on the upper surface side of the disk type coil 71 is changed by providing a step in the ferrite 72 constituting the disk type coil 71 and the main coil 74 provided on the upper surface side of the ferrite 72. . That is, a region without a step is a general portion, and a region that is lowered or raised by a step is a magnetic flux change portion.

(Third embodiment)
FIG. 17 is an explanatory diagram schematically showing the configuration of a disk-type coil 71 (coil for power transmission) and its peripheral devices according to the third embodiment. 17A is a plan view, FIG. 17B is an explanatory diagram showing magnetic flux density generated when a current is passed through the electric wire, FIG. 17C is a cross-sectional view taken along the line AA ′ shown in FIG. A cross-sectional view taken along line BB ′ shown in a) is shown. The disk type coil 71 is the ground coil 14 or the vehicle coil 35 shown in FIG.

Then, as shown in FIGS. 17A to 17D, a part on the right side in the drawing in the region around which the main coil 74 is wound is a recessed portion p3 that is recessed downward. The recess p3 has a longer distance from the main coil 74 to the lid 81 than the other regions. That is, a step that faces the normal direction of the ferrite 72 is provided in a part of the main coil 74. Further, a part of the ferrite 72 is provided with a step that faces the normal direction of the ferrite 72. The hollow portion p3 is a magnetic flux changing portion, and the other region is a general portion. As a result, as shown in FIG. 17B, the magnetic flux densities B8 and B9 in the regions R8 and R9 where the recess p3 is formed are smaller than the magnetic flux densities B2 and B3 in the regions R2 and R3. Become. That is, when the magnetic flux density in the region R1 is B1, the relationship is (B2, B3)> (B8, B9)> B1.

Therefore, as in the first embodiment described above, it is possible to detect foreign matter existing around the disk-type coil 71. Further, when there is a frame-like foreign matter on the upper surface side of the disk-type coil 71, the ratio of the magnetic flux densities B2, B3 and the magnetic flux densities B8, B9 changes, so that the frame-like foreign matter is placed. Can be detected. In the third embodiment, the ferrite 72, the insulating material 73, and the main coil 74 are arranged at a low position in the region of the recess p3.

That is, since a step facing the normal direction of the ferrite 72 is formed in a part of the main coil 74, the configuration of the disk-type coil 71 can be simplified. Further, since a step is formed in a part of the ferrite 72 so as to face the normal direction of the ferrite 72, the configuration of the disk-type coil 71 can be simplified.

(Fourth embodiment)
Next, a fourth embodiment will be described. FIG. 18 is an explanatory view schematically showing the configuration of the disk-type coil 71 (coil for power transmission) and its peripheral devices according to the fourth embodiment. 18A is a plan view, FIG. 18B is an explanatory diagram showing the magnetic flux density generated when a current is passed through the electric wire, FIG. 18C is a cross-sectional view along AA ′ shown in FIG. 18A, and FIG. A cross-sectional view taken along line BB ′ shown in a) is shown. The disk type coil 71 is the ground coil 14 or the vehicle coil 35 shown in FIG.

Then, as shown in FIGS. 18A to 18D, the right half of the region around which the main coil 74 is wound is a recessed portion p4 that is recessed downward. That is, the recess p4 has a longer distance from the main coil 74 to the lid 81 as compared with other regions. The hollow portion p4 is a magnetic flux changing portion, and the other region is a general portion. By doing so, as shown in FIG. 18B, the magnetic flux densities B10 and B11 of the regions R10 and R11 where the recess p4 is formed are smaller than the magnetic flux densities B2 and B3 of the regions R2 and R3. Become. That is, when the magnetic flux density in the region R1 is B1, there is a relationship of (B2, B3)> (B10, B11)> B1.

Therefore, as in the first embodiment described above, it is possible to detect foreign matter existing around the disk-type coil 71. Furthermore, when there is a frame-like foreign matter on the upper surface side of the disk-type coil 71, the ratio of the magnetic flux densities B2, B3 and the magnetic flux densities B10, B11 changes, so that the frame-like foreign matter is placed. Can be detected. In the fourth embodiment, since the ferrite 72, the insulating material 73, and the main coil 74 are arranged at a low position in the region of the recess p4, the configuration can be simplified.

(5th Example)
Next, a fifth embodiment will be described. FIG. 19 is an explanatory diagram schematically showing the configuration of the disk-type coil 71 (coil for power transmission) and its peripheral devices according to the fifth embodiment. 19A is a plan view, FIG. 19B is an explanatory diagram showing magnetic flux density generated when a current is passed through the main coil 74, FIG. 19C is a sectional view taken along line AA ′ shown in FIG. FIG. 4 shows a cross-sectional view along the line BB ′ shown in FIG. The disk type coil 71 is the ground coil 14 or the vehicle coil 35 shown in FIG.

Then, as shown in FIGS. 19A to 19D, the lower right corner in the figure of the region around which the main coil 74 is wound is a recess p5 that is recessed downward. That is, the distance from the main coil 74 to the lid 81 is longer in the recess p5 than in other regions. The hollow portion p5 is a magnetic flux changing portion, and the other region is a general portion. By doing so, as shown in FIG. 19B, the magnetic flux densities B12 and B13 in the regions R12 and R13 where the recess p5 is formed are smaller than the magnetic flux densities B2 and B3 in the regions R2 and R3. Become. That is, when the magnetic flux density in the region R1 is B1, there is a relationship of (B2, B3)> (B12, B13)> B1.

Therefore, as in the first embodiment described above, it is possible to detect foreign matter existing around the disk-type coil 71. Furthermore, when there is a frame-like foreign matter on the upper surface side of the disk-type coil 71, the ratio of the magnetic flux densities B2, B3 and the magnetic flux densities B12, B13 changes, so that the frame-like foreign matter is placed. Can be detected. Further, in the fifth embodiment, the depression p5 is formed in the corner, and the ferrite 72, the insulating material 73, and the main coil 74 are arranged in a low position in this region, so that the configuration is simplified. Is possible.

In the third to fifth embodiments described above, the height of the ferrite 72, the insulating material 73, and the main coil 74 is reduced. However, the height of the main coil 74 is not changed, and the ferrite 72 and the insulation are changed. A configuration in which only the height of the material 73 is reduced is also possible.

(Sixth embodiment)
Next, a sixth embodiment will be described. FIG. 20 is an explanatory diagram schematically showing the configuration of the disk-type coil 71 (coil for power transmission) and its peripheral devices according to the sixth embodiment. 20A is a plan view, FIG. 20B is an explanatory diagram showing magnetic flux density generated when a current is passed through the main coil 74, FIG. 20C is a cross-sectional view taken along line AA ′ shown in FIG. FIG. 4 shows a cross-sectional view along the line BB ′ shown in FIG. The disk type coil 71 is the ground coil 14 or the vehicle coil 35 shown in FIG.

Then, as shown in FIGS. 20A to 20D, the lower right corner in the drawing of the region around which the main coil 74 is wound is a protruding portion p6 protruding upward. That is, the distance from the main coil 74 to the lid 81 is shorter in the protrusion p6 than in other regions. The protrusion p6 is a magnetic flux change part, and the other region is a general part. As a result, as shown in FIG. 20B, the magnetic flux densities B14 and B15 of the regions R14 and R15 where the protrusions p6 are formed are larger than the magnetic flux densities B2 and B3 of the regions R2 and R3. Become. That is, when the magnetic flux density in the region R1 is B1, there is a relationship of (B14, B15)> (B2, B3)> B1.

Therefore, as in the first embodiment described above, it is possible to detect foreign matter existing around the disk-type coil 71. Further, when there is a frame-like foreign matter on the upper surface side of the disk-type coil 71, the ratio of the magnetic flux densities B2, B3 and the magnetic flux densities B14, B15 changes, so that the frame-like foreign matter is placed. Can be detected. Further, in the sixth embodiment, the projecting portion p6 is formed at the corner, and the ferrite 72, the insulating material 73, and the main coil 74 are arranged at a high position in this region, so that the configuration is simplified. Is possible.

In the above-described sixth embodiment, the height of the ferrite 72, the insulating material 73, and the main coil 74 is increased. However, the height of the ferrite 72 and the insulating material 73 is not changed, and the main coil 74 is changed. It is also possible to adopt a configuration that raises only the height of the.

Further, in the third to sixth embodiments described above, the ground coil 14 shown in FIG. 1 has been described. Similarly, the vehicle coil 35 is also formed with a hollow portion or a protruding portion so that a frame-like foreign object is formed. Can be detected.

[Description of Third Embodiment]
Next, 3rd Embodiment of this invention is described based on 7th Example. In the third embodiment, the ferrite 72, the insulating material 73, and the main coil 74 are not changed, and the end portion of the electric wire is wound only once or a plurality of times to form a subcoil, so that the general portion and the magnetic flux changing portion are changed. Form.

(Seventh embodiment)
FIG. 21 is an explanatory view schematically showing the configuration of the disk-type coil 71 (coil for power transmission) and its peripheral devices according to the seventh embodiment. FIG. 21A is a plan view, and FIG. 21B is an explanatory diagram showing the magnetic flux density generated when a current is passed through the main coil 74. The disk type coil 71 is the ground coil 14 or the vehicle coil 35 shown in FIG.

In the seventh embodiment, as shown in FIG. 21, a sub-coil 91 having a rectangular loop shape is formed on the upper surface of the insulating material 73 using an electric wire inside the main coil 74. That is, the main coil 74 in which the electric wire is wound in a spiral shape has an opening Q1 at the center, and a subcoil 91 is formed in the opening. By passing a current through the main coil 74, a current flows through the spiral loop, and at the same time, a current flows through the subcoil 91. When the current flows through the subcoil 91, the magnetic flux density of the disk type coil 71 changes.

Specifically, as shown in FIG. 21B, the magnetic flux density B16 in the region R16 is larger than the magnetic flux density B2 in the surrounding region R2, and the magnetic flux density B17 in the region R17 is smaller than the magnetic flux density B2. Become. That is, when the magnetic flux density in the region R1 is B1, the relationship is B16> (B2, B3)> B17> B1. Regions R16 and R17 are magnetic flux changing portions, and the other regions are general portions.

Therefore, as in the first embodiment described above, it is possible to detect foreign matter existing around the disk-type coil 71. Further, when there is a frame-like foreign matter on the upper surface side of the disk-type coil 71, the ratio of the magnetic flux density B2, B3 and the magnetic flux density B16, B17 changes, so that the frame-like foreign matter is placed. Can be detected. In the seventh embodiment, since the subcoil 91 is formed by using the electric wire at the end of the main coil 74, the magnetic flux changing portion and the general portion can be formed with a simple configuration. Furthermore, since the subcoil 91 is formed in the central opening Q1 of the main coil 74, the electric wires can be easily arranged. In FIG. 21, the example in which the main coil 74 is wound only once to form the subcoil 91 has been described. However, the subcoil 91 can be formed by winding a plurality of turns.

In the seventh embodiment, the ground coil 14 shown in FIG. 1 has been described. Similarly, it is possible to detect the presence of a frame-like foreign matter by forming a sub-coil for the vehicle coil 35 as well. it can.

As mentioned above, although the coil structure for electric power transmission of the non-contact electric power transmission apparatus of this invention was demonstrated based on embodiment of illustration, this invention is not limited to this, The structure of each part has the same function. It can be replaced with any configuration.

For example, in the above-described embodiment, the example in which the search coil 36 is provided on the lower surface side of the vehicle coil 35 and the search coil 19 is provided on the upper surface side of the ground coil 14 has been described, but the present invention is not limited to this. Alternatively, at least one of the search coils may be provided. For example, if the search coil 19 is provided only on the upper surface side of the ground coil 14, it is possible to detect foreign matter existing in the vicinity of the ground coil 14. Further, if the search coil 36 is provided only on the lower surface of the vehicle coil 35, foreign matter existing in the vicinity of the vehicle coil 35 can be detected.

DESCRIPTION OF SYMBOLS 10 Commercial power supply 11 DC power supply 12 Inverter 13 Resonance capacitor 14 Ground coil 15 Ground side control part 16 Voltage / current / temperature sensor 17 Wireless LAN
18 Calibration Switch 19 Search Coil 19L Sensor Coil 20 Voltage Detection Control Unit 21 Reference Voltage Storage Unit 22 Display Unit 31 Battery 32 Relay Box 33 Rectifier Circuit 34 Resonance Capacitor 35 Coil for Vehicle 36 Search Coil 37 Voltage Detection Control Unit 38 Voltage / Current / Temperature sensor 39 Vehicle side control unit 40 Vehicle network 41 Wireless LAN
42 Display Unit 43 Reference Voltage Storage Unit 44 Calibration Switch 51 Multiplexer 52 Differential Amplifier 53 Rectifier 54 Filter 55 CPU
71 Disc type coil 72 Ferrite (magnetic material)
73 Insulating material 74 Main coil 75a, 75b Terminal 81 Lid 82 Metal case 83 Foreign object 91 Subcoil 100 Non-contact charging system 101 Vehicle side device 102 Power feeding device

Claims (7)

1. In the structure of the coil for power transmission used in the non-contact power transmission device,
   The power transmission coil is:
   A magnetic body having a flat plate shape, and a main coil that is provided on a surface on the power transmission side or reception side of the magnetic body and wound in a spiral shape,
   Further, the power of the non-contact power transmission apparatus is provided with a general part that generates a predetermined magnetic flux density and a magnetic flux changing part that generates a magnetic flux density different from the general part. Coil structure for transmission.
2. The coil structure for electric power transmission of the non-contact electric power transmission device according to claim 1, wherein the magnetic flux changing part is formed by forming a notch part in a part of the magnetic body.
3. The non-wire according to claim 2, wherein the wire at the end of the main coil is pulled out of the main coil by inserting the wire at the end of the main coil into the notch formed in the magnetic body. Coil structure for power transmission of a contact power transmission device.
4. 2. The contactless power transmission device according to claim 1, wherein the magnetic flux changing portion is formed by providing a step in the normal direction of the magnetic material having the flat plate shape in a part of the main coil. Coil structure for power transmission.
5. 2. The contactless power transmission device according to claim 1, wherein the magnetic flux changing portion is formed by providing a step in a normal direction of the magnetic material in a part of the flat magnetic material. 3. Coil structure for power transmission.
6. A sub-coil that is connected to an end of an electric wire that forms the main coil and has a loop shape, and when exciting the main coil, the magnetic flux changing section is formed by exciting the sub-coil. The coil structure for electric power transmission of the non-contact electric power transmission apparatus of Claim 1.
7. The coil structure for power transmission of the non-contact power transmission device according to claim 6, wherein the main coil has an opening at the center, and the sub-coil is formed at the opening.

Images