JP2019054730A - Foreign matter detection device, wireless power transmission device, and wireless power transmission system - Google Patents

Abstract

To provide a foreign matter detection device capable of widening the range where a foreign matter can be detected with high accuracy.SOLUTION: A foreign matter detection device includes a first coil, a second coil placed adjacently to the first coil and having the same winding direction as the first coil, and a foreign matter detection circuit. The foreign matter detection circuit outputs a first detection signal to one of the outside or inside terminal of the first coil, and outputs a second detection signal having a polarity, inverting the polarity of the first detection signal, to one of the outside or inside terminal of the second coil, i.e., the terminal on the same side as the first coil to which the first detection signal is outputted. One of the first detection signal flowing to the first coil and the second detection signal flowing to the second coil is made to flow clockwise, and the other is made to flow counter clockwise, thus generating a synthetic magnetic field across the first and second coils. Variation of impedance value of any one of the first and second coils, corresponding to change in the synthetic magnetic field caused by presence of a foreign matter, is then measured and a determination is made that there is a foreign matter in the neighborhood of the first and second coils on the basis of the variation.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a foreign object detection device that detects foreign objects such as metals and human bodies (animals) in the vicinity of a wireless power transmission device of a wireless power transmission system, for example. The present disclosure also relates to a wireless power transmission device and a wireless power transmission system including such a foreign object detection device.

  In recent years, various mobile devices such as mobile phones are becoming widespread, and the power consumption of mobile devices continues to increase due to improvements in functions and performance and diversification of contents. When the power consumption of a mobile device that operates with a battery of a predetermined capacity increases, the operation time of the mobile device becomes shorter. A wireless power transmission system has attracted attention as a technique for supplementing the limitation of battery capacity. The wireless power transmission system wirelessly transmits power from a power transmission device to a power reception device by electromagnetic induction between a power transmission coil of a wireless power transmission device (also referred to as a power transmission device) and a power reception coil of a wireless power reception device (also referred to as a power reception device). In particular, a wireless power transmission system using a resonant power transmission coil and a power reception coil can maintain high transmission efficiency even when the positions of the power transmission coil and the power reception coil are shifted from each other. Expected. Furthermore, the chargeable area can be further expanded by increasing the size of the power transmission coil or configuring an array in which a plurality of coils are arranged.

Japanese Patent No. 4525710 Japanese Patent No. 4780447 JP 2011-23496 A

  However, in such a conventional technique, a foreign object detection device capable of detecting a foreign object with high accuracy has been demanded.

A foreign object detection device according to an aspect of the present disclosure is provided.
A first coil that is wound, wherein one of the two terminals of the first conductor is an outer terminal disposed on the outside and the other is an inner terminal disposed on the inside;
The second conductor is disposed adjacent to the first coil and the winding direction is the same as that of the first coil, and one of the two terminals of the second conductor is an outer terminal disposed outside. A second coil that is an inner terminal disposed on the inner side,
The first detection signal having a first predetermined waveform is output to one of the outer terminal and the inner terminal of the first coil, and the terminal is on the same side as the first coil from which the first detection signal is output. A second detection signal having a second predetermined waveform having a polarity opposite to the polarity of the first predetermined waveform is output to one of the outer terminal and the inner terminal of the second coil;
One of the first detection signal flowing in the first coil and the second detection signal flowing in the second coil is caused to flow clockwise, the other is caused to flow counterclockwise, and the first coil and the first coil Generate a synthetic magnetic field that straddles between two coils,
Measuring the amount of change in the impedance value of either the first coil or the second coil corresponding to the change in the combined magnetic field caused by the presence or absence of foreign matter,
A foreign matter detection circuit that determines that there is a foreign matter in the vicinity of the first coil and the second coil when the amount of change in the impedance value exceeds a predetermined value.

  Note that these comprehensive or specific aspects may be realized by a system, method, integrated circuit, computer program, or recording medium. Any of the system, apparatus, method, integrated circuit, computer program, and recording medium may be used. It may be realized by various combinations.

  According to one aspect of the present disclosure, it is possible to provide a foreign object detection device that can detect a foreign object with high accuracy.

It is a block diagram which shows the foreign material detection apparatus which concerns on 1st Embodiment. It is a figure which shows the cross section of the detection coils 11a and 11b in the A1-A1 'line of FIG. 1, and the magnetic field produced | generated. It is a block diagram which shows the foreign material detection apparatus which concerns on the 1st modification of 1st Embodiment. It is a block diagram which shows the foreign material detection apparatus which concerns on the 2nd modification of 1st Embodiment. It is a block diagram which shows the foreign material detection apparatus which concerns on the 3rd modification of 1st Embodiment. It is a figure which shows operation | movement of the foreign material detection apparatus which concerns on 1st Embodiment. It is a top view which shows the detection coils 11a and 11b of the foreign material detection apparatus which concerns on the mounting example of 1st Embodiment. It is a top view which shows the detection coil 11a of the foreign material detection apparatus which concerns on a comparative example. It is a graph which shows the change rate of the inductance by the foreign materials 20a-20d of FIG.7 and FIG.8. It is a block diagram which shows the foreign material detection apparatus which concerns on the 4th modification of 1st Embodiment. It is a block diagram which shows the foreign material detection apparatus which concerns on the 5th modification of 1st Embodiment. It is a block diagram which shows the foreign material detection apparatus which concerns on the 6th modification of 1st Embodiment. It is a block diagram which shows the wireless power transmission system which concerns on 2nd Embodiment. It is a figure which shows a part of power transmission apparatus 30 of FIG. It is a figure which shows the cross section of the detection coils 11a and 11b and the power transmission coils 31a and 31b in the A2-A2 'line | wire of FIG. It is a figure which shows arrangement | positioning of the detection coils 11a-11d and the power transmission coil 31 of the wireless power transmission system which concerns on the 1st modification of 2nd Embodiment. It is a figure which shows the cross section of the detection coils 11a-11d and the power transmission coil 31 in the A3-A3 'line | wire of FIG. It is a figure which shows arrangement | positioning of the detection coils 11a-11d, power transmission coil 31A, and the receiving coil 41 of the wireless power transmission system which concerns on the 2nd modification of 2nd Embodiment. It is a figure which shows operation | movement of the power transmission apparatus which concerns on 2nd Embodiment. It is a block diagram which shows the wireless power transmission system which concerns on 3rd Embodiment. It is a figure which shows a part of power transmission apparatus 30A of FIG. It is a figure which shows the cross section of the power transmission coils 31a and 31b in the A4-A4 'line | wire of FIG. It is a figure which shows a part of power transmission apparatus of the wireless power transmission system which concerns on the 1st modification of 3rd Embodiment. It is a figure which shows a part of power transmission apparatus of the wireless power transmission system which concerns on the 2nd modification of 3rd Embodiment. It is a figure which shows a part of power transmission apparatus of the wireless power transmission system which concerns on the 3rd modification of 3rd Embodiment. It is a figure which shows a part of power transmission apparatus of the wireless power transmission system which concerns on the 4th modification of 3rd Embodiment. It is a figure which shows operation | movement of the power transmission apparatus which concerns on 2nd Embodiment and 3rd Embodiment. It is a figure which shows operation | movement of the power transmission apparatus which detects a foreign material before power transmission, and detects a foreign material in the middle of performing power transmission. It is the figure which showed the state in which the smart phone provided with the power receiving apparatus 200 was placed on the power transmission apparatus 100, for example. It is the figure which showed the parking lot provided with the wireless power system. It is a figure which shows the structural example of the wireless power transmission system which transmits electric power to the robot 1500 used in a hospital etc. non-contactedly from a wall. It is a top view which shows the detection coil 111 of the foreign material detection apparatus concerning patent document 1. FIG. It is a figure which shows the cross section of the detection coil 111 in the A11-A11 'line | wire of FIG. 32, and the magnetic field produced | generated. It is a top view which shows the detection coils 111a and 111b of the foreign material detection apparatus concerning patent document 2. FIG. It is a figure which shows the cross section of the detection coils 111a and 111b in the A12-A12 'line | wire of FIG. 34, and the magnetic field produced | generated.

(Knowledge that became the basis of this disclosure)
The present inventors have found that the following problems occur with respect to the wireless power transmission system described in the “Background Art” section.

  First, the definition of “foreign matter” will be described. In the present disclosure, “foreign matter” refers to a metal and a human body that generate heat due to power transmitted between the power transmission coil and the power reception coil when positioned near the power transmission coil or the power reception coil of the wireless power transmission system. Indicates an object such as (animal).

  In a wireless power transmission system, if a foreign object exists in a space where wireless power transmission is performed, the risk of the heat generation of the foreign object increases. Here, consider a case where the foreign matter is a metallic foreign matter. When power is transmitted wirelessly from the power transmission coil to the power reception coil, a magnetic field is generated by the current flowing through the power transmission coil. Due to the generated magnetic field, an eddy current flows on the surface of the foreign matter, so that the foreign matter generates heat. This heat generation may cause a temperature increase of several tens of degrees or more. For example, in the WPC (Wireless Power Consortium) standard (Qi standard), an upper limit of temperature rise is defined. Therefore, when power is transmitted wirelessly, it is desirable that foreign matter is not mixed between the power transmission coil and the power reception coil. In order to further improve safety, it is desirable to detect the presence or absence of foreign matter above the power transmission coil before starting power transmission. And it is desired to shift to the power transmission operation only when there is no foreign object and to remove the risk of heat generation in advance.

  Furthermore, for example, in order to further expand an area for charging a smart phone or the like, for example, there is a demand for expanding the range in which the power transmission coil can transmit power by increasing the size of the power transmission coil. With this demand, it is desired to expand the range in which foreign matter can be detected with high accuracy.

  Patent Document 1 discloses that one coil is shared as a power transmission coil and a detection coil, and a pulse is transmitted from the detection coil. Patent Document 1 discloses that a change in the voltage of the detection coil due to the reflected wave is detected to determine the presence or absence of a foreign object.

  Patent Document 2 discloses that foreign matter detection is performed by arranging two or more detection coils side by side in order to widen the range in which foreign matter can be detected. Further, Patent Document 2 discloses supplying currents of opposite phases to the transmission coil and the reception coil by using the stacked transmission coil (detection coil) and reception coil in order to detect foreign matter. ing. Thus, the signal transmitted from the transmission coil is not directly received by the reception coil, the reflected wave from the foreign object is received with high sensitivity, and the foreign object is detected.

  Patent Document 3 discloses a power transmission coil in a wireless power transmission system, not a detection coil that performs foreign object detection. The configuration of the power transmission coil is a power transmission coil unit configured to connect the conductive wires (also referred to as windings) of two adjacent power transmission coils so that the generated magnetic field has an opposite phase. By using the power transmission coil unit, it is possible to reduce leakage of the electromagnetic field at a distance from the power transmission coil unit during power transmission.

  However, as a result of investigating the magnetic field distribution of the detection coils of Patent Document 1 and Patent Document 2, it is difficult for the present inventors to widen the range in which foreign objects can be detected with high accuracy in Patent Document 1 and Patent Document 2. I understood that. Details will be described below.

  First, Patent Document 1 will be described.

  The detection coil of Patent Document 1 is a planar coil in which a winding is wound on a plane perpendicular to an axis passing through the center of the winding of the detection coil.

  FIG. 32 is a top view showing the detection coil 111 of the foreign object detection device according to Patent Document 1. FIG. FIG. 33 is a diagram obtained by analyzing the cross section of the detection coil 111 and the magnetic field distribution around the cross section along the line A11-A11 ′ in FIG. The foreign matter 120 existing in the vicinity of the detection coil 111 is detected by the foreign matter 120 interacting with the magnetic field generated around the detection coil 111 and the frequency and / or amplitude of the signal flowing through the detection coil 111 is changed. . For this reason, the range in which the foreign matter 120 can be detected by the detection coil 111 is approximately the range in which the winding of the detection coil 111 is wound. It is easy to detect the foreign matter 120 on the center of the winding of the detection coil 111, and as shown in FIGS. 32 and 33, it is difficult to detect the foreign matter 120 outside the outer periphery of the winding of the detection coil 111. Therefore, in Patent Document 1, since the magnetic field outside the outer periphery of the winding cannot be expanded, it is difficult to expand the range in which foreign matter can be detected with high accuracy.

  Next, Patent Document 2 will be described.

  In the planar flexible antenna of Patent Document 2, a plurality of detection coils are arranged side by side so that a group of detection coils composed of planar coils (a laminate of a plurality of planar coils) are adjacent to each other. Thus, the planar flexible antenna can expand the range in which foreign matter can be detected. Here, for the sake of simplification, a plurality of stacked detection coils, which are detection coil groups, are connected in parallel, and therefore can be combined and considered as one. Therefore, here, the detection coil group is treated as one detection coil.

  FIG. 34 shows two detection coils arranged adjacent to each other from among a plurality of detection coils arranged side by side in the flat flexible antenna according to Patent Document 2, and the upper surfaces of the selected two detection coils 111a and 111b. FIG.

  FIG. 35 is a diagram analyzing the cross section of the detection coils 111a and 111b and the magnetic field distribution around the cross section taken along the line A12-A12 'of FIG.

  From FIG. 35, it was found that the magnetic field between two adjacent detection coils 111a and 111b was very weak. The reason is that the directions of signals flowing in the two detection coils are the same direction (in-phase), so that the magnetic field between two adjacent detection coils repels. For this reason, the magnetic field between two adjacent detection coils is very weak. Therefore, in Patent Document 2, it is difficult to detect the foreign matter 120 between the two adjacent detection coils 111a and 111b.

  From the above, it has been found that in Patent Document 1 and Patent Document 2, it is difficult to widen the range in which foreign matter can be detected with high accuracy.

  From the above consideration, in order to widen the range in which a foreign object can be detected with high accuracy, the present inventors are adjacent even if a foreign object detection device in which a plurality of detection coils are arranged adjacent to each other as in Patent Document 2 is used. When a foreign object exists between the two detection coils, a new problem has been discovered that the foreign object cannot be detected.

  On the other hand, Patent Document 3 discloses a power transmission coil used in a wireless power transmission system, not a detection coil for detecting foreign matter. The configuration of the power transmission coil is a power transmission coil unit configured to connect the conductive wires of two adjacent power transmission coils so that the generated magnetic field has an opposite phase. The purpose of the power transmission coil unit is to reduce the leakage of the electromagnetic field far from the power transmission coil unit during power transmission.

  In a wireless power transmission system, when the distance between the power transmission coil and the power reception coil is fixed, power can be stably transmitted to the power reception coil without changing the magnetic field emitted from the power transmission coil as much as possible. Desired.

  Moreover, the power at the time of power transmission is, for example, 1 W to 50 kW. If foreign matter enters between two power transmission coils during power transmission, the foreign matter may generate heat.

  On the other hand, the power of the signal transmitted from the detection coil during operation can be, for example, 10 mW to 100 mW. Since the power of the signal transmitted from the detection coil is much smaller than the power at the time of power transmission (for example, about one thousandth or less of the power at the time of power transmission), there is no danger due to heat generation of foreign matter. Since the power transmission coil and the detection coil have different purposes, of course, the amount of output power is greatly different. For example, if power is transmitted without detecting a foreign object, the foreign object may generate heat as described above.

  Therefore, Patent Literature 3 does not have a focus on detecting a foreign object between two adjacent detection coils.

  Accordingly, there is a need for a foreign object detection device that can detect a foreign object between two adjacent detection coils and expand the range in which the foreign object can be detected with high accuracy.

  Based on the above considerations, the present inventors have arrived at each aspect disclosed below.

A foreign object detection device according to an aspect of the present disclosure is provided.
A first coil that is wound, wherein one of the two terminals of the first conductor is an outer terminal disposed on the outside and the other is an inner terminal disposed on the inside;
The second conductor is disposed adjacent to the first coil and the winding direction is the same as that of the first coil, and one of the two terminals of the second conductor is an outer terminal disposed outside. A second coil that is an inner terminal disposed on the inner side,
The first detection signal having a first predetermined waveform is output to one of the outer terminal and the inner terminal of the first coil, and the terminal is on the same side as the first coil from which the first detection signal is output. A second detection signal having a second predetermined waveform having a polarity opposite to the polarity of the first predetermined waveform is output to one of the outer terminal and the inner terminal of the second coil;
One of the first detection signal flowing in the first coil and the second detection signal flowing in the second coil is caused to flow clockwise, the other is caused to flow counterclockwise, and the first coil and the first coil Generate a synthetic magnetic field that straddles between two coils,
Measuring the amount of change in the impedance value of either the first coil or the second coil corresponding to the change in the combined magnetic field caused by the presence or absence of foreign matter,
A foreign matter detection circuit that determines that there is a foreign matter in the vicinity of the first coil and the second coil when the amount of change in the impedance value exceeds a predetermined value.

According to the above aspect,
The foreign object detection device includes the second coil that is disposed adjacent to the first coil and whose winding direction is the same as that of the first coil.
The first detection signal having the first predetermined waveform is output to one of the outer terminal and the inner terminal of the first coil, and is a terminal on the same side as the first coil from which the first detection signal is output. A second detection signal having a second predetermined waveform having a polarity opposite to the polarity of the first predetermined waveform is output to one of the outer terminal and the inner terminal of the second coil. Then, one of the first detection signal flowing through the first coil and the second detection signal flowing through the second coil is caused to flow clockwise and the other is caused to flow counterclockwise. Then, a synthetic magnetic field straddling between the first coil and the second coil is generated. Thereby, the magnetic field between two adjacent detection coils couple | bonds. Therefore, the magnetic field between two adjacent detection coils can be strengthened.
Then, the amount of change in the impedance value of either the first coil or the second coil corresponding to the change in the combined magnetic field caused by the presence or absence of foreign matter is measured. When the amount of change in the impedance value exceeds a predetermined value, it is determined that there is a foreign object in the vicinity of the first coil and the second coil. This not only widens the detection range of foreign objects by simply arranging a plurality of coils, but also strengthens the magnetic field between two adjacent detection coils so that it is between the adjacent first and second coils. Detect foreign objects.
As a result, the range in which foreign matter can be detected with high accuracy can be expanded.
Moreover, since the detection coil currently used can be used, the increase in the number of parts, a dimension, and manufacturing cost can be suppressed.

  Here, the impedance value is a voltage value, a current value, a frequency value, or the like of at least one of the first coil and the second coil. The impedance value may be an inductance value calculated from the voltage value, the current value, the frequency value, or the like, a calculated value such as a coupling coefficient value, or a Q value.

  The amount of change in the impedance value is the difference between the impedance value detected when there is no foreign object near the first coil or the second coil and the impedance value detected by the foreign object detection circuit. The amount of change.

  Here, the amount of change in the impedance value is measured, but the amount of change in the value such as the frequency and / or amplitude of the reflected signal from which the signal output by the first detection signal and the second detection signal returns is measured. You may measure.

  The definition of the amount of change in the impedance value, the change in the impedance value, the value of the reflected signal such as the frequency and / or amplitude is also applied to the content disclosed below.

First embodiment.
Hereinafter, the foreign object detection device according to the first embodiment of the present disclosure will be described with reference to the drawings.

  FIG. 1 is a block diagram showing a foreign object detection device according to the first embodiment. The foreign object detection device includes a plurality of detection coils 11 a and 11 b and a foreign object detection circuit 10. Hereinafter, the detection coil may be simply referred to as a coil. The plurality of detection coils 11a and 11b are wound with conductive wires adjacent to each other on one surface.

  As shown in FIG. 1, the detection coils 11 a and 11 b are wound with a conductive wire, and are arranged inside an outer terminal (marked with ●) arranged outside the wound conductive wire, and inside the wound conductive wire. Inner terminals (marked with ●). The outer terminal is a terminal that receives a detection signal of the foreign object detection circuit from the outside of the detection coil or a terminal that is connected to the ground. The outer terminal may be disposed anywhere as long as it is between the outer portion of the detection coil and the foreign object detection circuit or the ground. The inner terminal is a terminal that receives a detection signal of the foreign object detection circuit from the inner side of the detection coil or a terminal that is connected to the ground. The inner terminal may be disposed anywhere as long as it is between the inner portion of the detection coil and the foreign object detection circuit or the ground. Further, the outer terminal and the inner terminal may be a contact directly connected to the foreign object detection circuit and / or a contact directly connected to the ground. In that case, the terminal may not be clearly seen as shown in FIG. In the following embodiments, the outer terminal and the inner terminal will be described by omitting the terminal (● mark) in the case of a contact directly connected to the foreign object detection circuit and / or a contact directly connected to the ground.

  The foreign object detection circuit 10 transmits a detection signal having a predetermined waveform to two detection coils 11a and 11b adjacent to each other among the plurality of detection coils 11a and 11b (hereinafter may be referred to as “output”). A reflected signal generated by the detection signal being reflected by the two adjacent detection coils 11a and 11b is received, and based on the reflected signal, the presence or absence of foreign matter in the vicinity of the two adjacent detection coils 11a and 11b is detected. to decide. The detection signal includes a first detection signal flowing in one of the two adjacent detection coils 11a and 11b and a second detection signal flowing in the other of the two adjacent detection coils 11a and 11b. Including. When one of the first and second detection signals is flowing clockwise on the surface including the detection coils 11a and 11b, the other of the first and second detection signals is the detection coil 11a and It flows counterclockwise on the surface including 11b. That is, detection signals in opposite directions flow through two detection coils 11a and 11b adjacent to each other.

  According to FIG. 1, the plurality of detection coils 11a and 11b have the same winding direction on one surface. According to FIG. 1, the foreign object detection circuit 10 generates detection signals 1 and 2 having opposite polarities, and transmits the detection signals 1 and 2 simultaneously to two adjacent detection coils 11a and 11b.

  The detection signals 1 and 2 may each be an AC signal. Further, each of the detection signals 1 and 2 may be a pulse signal. The pulse signal may be monopolar or bipolar. When the detection signals 1 and 2 are, for example, sine waves, the foreign object detection circuit 10 generates the detection signals 1 and 2 so as to have a phase difference of 180 degrees, for example.

  FIG. 2 is a diagram showing a cross section of the detection coils 11a and 11b and a generated magnetic field along the line A1-A1 'of FIG. The foreign object detection circuit 10 determines the presence or absence of the foreign object 20 in the vicinity of the detection coils 11a and 11b by observing reflected signals from the detection coils 11a and 11b. As shown in FIG. 2, the detection coils 11a and 11b generate a magnetic field near the detection signals 1 and 2 transmitted from the foreign object detection circuit 10. At a certain moment, a counterclockwise current flows through the detection coil 11a, and a clockwise current flows through the detection coil 11b. Therefore, the + X side (right side) lead wire of the detection coil 11a and the -X side of the detection coil 11b ( The same current in the + Y direction flows through the lead wire on the left side. As a result, a combined magnetic field that spans the two coils is generated. At this time, if the foreign matter 20 exists between the detection coils 11a and 11b, a part of the magnetic field is blocked and a change occurs in the reflected signal. When the foreign substance 20 generates a capacitance between the detection coils 11a and 11b, the inductance of the detection coils 11a and 11b changes due to the capacitance, and the frequency of the reflected signal also changes accordingly. When the inductance of the detection coils 11a and 11b decreases, the frequency of the reflected signal increases. When the inductance of the detection coils 11a and 11b increases, the frequency of the reflected signal decreases. Further, when the foreign object 20 is heated by the induced current, the energy of the detection signals 1 and 2 is consumed, and the amplitude of the reflected signal is reduced. The change in the reflected signal is detected by measuring the reflected signal directly or by measuring a combined signal of the transmitted detection signal and the received reflected signal. The foreign object detection circuit 10 measures in advance the frequency and / or amplitude of the reflected signal when the foreign object 20 is not present in the vicinity of the detection coils 11a and 11b and stores it as a reference value, and a frequency and / or amplitude different from the reference value. When the reflection signal having the above is received, it is determined that the foreign object 20 exists.

  Here, the presence of the foreign object is determined based on the change in the frequency and / or amplitude of the received reflected signal. However, as described above, the presence of the foreign object may be determined based on the change in the impedance value. This also applies to the embodiments disclosed below.

  In the foreign matter detection apparatus of FIG. 1, the foreign matter detection circuit 10 generates detection signals 1 and 2 having opposite polarities so that detection signals in opposite directions flow through two detection coils 11a and 11b adjacent to each other. doing. On the other hand, as described below with reference to FIGS. 3 to 5, a foreign object detection circuit 10 </ b> A that generates one detection signal may be used. The detection signal generated by the foreign object detection circuit 10A is, for example, an AC signal or a pulse signal.

  FIG. 3 is a block diagram illustrating a foreign object detection device according to a first modification of the first embodiment. The plurality of detection coils 11a and 11b have the same winding direction on one surface. The foreign object detection circuit 10A generates one detection signal, transmits the detection signal as a first detection signal to one of the two detection coils 11a and 11b adjacent to each other, and the two detection coils 11a adjacent to each other. And the same detection signal is transmitted to the other of 11b as a second detection signal. Two detection coils 11a and 11b adjacent to each other are arranged such that when one of the first and second detection signals is flowing clockwise on the surface including the detection coils 11a and 11b, The other of the detection signals is connected to the foreign object detection circuit 10A so that it flows counterclockwise on the surface including the detection coils 11a and 11b. According to the foreign object detection device of FIG. 3, by making the connection of the detection coil 11a and the foreign object detection circuit 10A different from the connection of the detection coil 11b and the foreign object detection circuit 10A, the two detection coils 11a and 11b adjacent to each other are connected. Detection signals in opposite directions flow. According to the foreign object detection device of FIG. 3, the detection signal transmitted from the foreign object detection circuit 10A is divided into two, and the same detection signal is transmitted to the detection coils 11a and 11b, thereby synthesizing between the detection coils 11a and 11b. A magnetic field is generated to detect foreign matter existing between the detection coils 11a and 11b.

  FIG. 4 is a block diagram illustrating a foreign object detection device according to a second modification of the first embodiment. The foreign object detection device of FIG. 4 further includes at least one phase shifter 12. The plurality of detection coils 11a and 11b have the same winding direction on one surface. The foreign object detection circuit 10A generates one detection signal and transmits the one detection signal directly to one of the two adjacent detection coils 11a and 11b as the first detection signal. As a second detection signal via the phase shifter 12 to the other of the two detection coils 11a and 11b adjacent to each other. When the detection signal generated by the foreign object detection circuit 10A is a periodic signal (for example, an AC signal such as a sine wave) having a waveform inverted in the first half and the second half of each cycle, the phase shifter 12 is used. A detection signal substantially in phase (180 degrees) may be generated with respect to the detection signal generated by the foreign object detection circuit 10A. According to the foreign substance detection apparatus of FIG. 4, the use of the phase shifter 12 causes detection signals in opposite directions to flow through the two detection coils 11a and 11b adjacent to each other. According to the foreign object detection device of FIG. 4, the detection signal transmitted from the foreign object detection circuit 10A is divided into two, and the detection signal delayed by 180 degrees by the phase shifter 12 is transmitted to the detection coil 11b. A synthetic magnetic field is formed between the detection coils 11a and 11b, and foreign matter existing between the detection coils 11a and 11b is detected.

  FIG. 5 is a block diagram illustrating a foreign object detection device according to a third modification of the first embodiment. Two detection coils 11a and 11b adjacent to each other among the plurality of detection coils 11a and 11b have different winding directions on one surface. The foreign object detection circuit 10A generates one detection signal, transmits the detection signal as a first detection signal to one of the two detection coils 11a and 11b adjacent to each other, and the two detection coils 11a adjacent to each other. And the same detection signal is transmitted to the other of 11b as a second detection signal. According to the foreign object detection device of FIG. 5, the detection coils 11a and 11b have different winding directions on one surface, so that detection signals in opposite directions flow through the two detection coils 11a and 11b adjacent to each other. . 5, the detection signal transmitted from the foreign object detection circuit 10A is divided into two, and the same detection signal is transmitted to the detection coils 11a and 11b, thereby synthesizing between the detection coils 11a and 11b. A magnetic field is generated to detect foreign matter existing between the detection coils 11a and 11b.

  The operation of the foreign object detection device according to the first embodiment will be described with reference to FIG. 6 as an example.

  After the operation of the foreign object detection device is started (step S1), foreign object detection processing is executed (step S2). In the foreign object detection process, first, the first detection signal and the second detection signal (including the case where the first detection signal and the second detection signal are combined with one detection signal) are output from the foreign object detection circuit 10 to the first coil and the second coil. Send to. Then, one of the first detection signal (also referred to as detection signal 1) flowing through the first coil 11a and the second detection signal (also referred to as detection signal 2) flowing through the second coil 11b is caused to flow clockwise, while the other is A counter magnetic field is caused to flow counterclockwise to generate a synthetic magnetic field straddling between the first coil and the second coil (step S11: refer to the first embodiment as an example). The synthetic magnetic field changes depending on the presence or absence of foreign matter. Therefore, the reflected signal from which the signals transmitted by the first detection signal and the second detection signal return changes in accordance with the change in the synthetic magnetic field.

  The foreign object detection circuit 10 detects a change in the reflected signal that changes depending on the presence or absence of a foreign object (step S12).

  Next, the foreign matter detection circuit 10 determines whether or not the amount of change in the reflected signal corresponding to the change in the composite magnetic field caused by the presence or absence of foreign matter has exceeded a predetermined threshold (step S13). Here, the amount of change in the reflected signal is a value such as the frequency or amplitude of the reflected signal when there is no foreign object in the vicinity of the first coil and the second coil, and the frequency of the reflected signal detected by the foreign object detection circuit 10 during detection. Alternatively, a difference from a value such as amplitude is referred to as a change amount of the reflected signal. Next, the foreign object detection circuit 10 determines that there is a foreign object in the vicinity of the first coil and the second coil when the amount of change in the reflected signal exceeds a predetermined threshold (step S15). It is determined that there is no foreign object (step S14).

  When the change amount of the reflected signal does not exceed the predetermined threshold value, the foreign object detection circuit 10 transmits a signal having no foreign object to, for example, the power transmission device of the wireless power transmission device (step S3). Here, a signal without foreign matter is transmitted to the power transmission device, but it is not particularly limited as long as it is a device that requires information on the presence or absence of foreign matter regardless of the power transmission device.

  3 to 5 has an advantage that the detection signal output from the foreign object detection circuit 10A can be made one, and the circuit can be simplified. Moreover, according to the foreign substance detection apparatus of FIG.3 and FIG.4, it becomes possible to comprise several detection coils 11a and 11b with the same single component, and there exists an effect that the manufacturing cost of a product can be restrained low. . In addition, according to the foreign matter detection device of FIGS. 3 and 5, the foreign matter detection device is configured such that detection signals in opposite directions flow through the two detection coils 11a and 11b adjacent to each other without using a phase shifter. can do. According to the foreign object detection device of FIG. 5, when it is cheaper to prepare a detection coil in a different winding direction than to prepare a phase shifter, the foreign object detection device can be used without using a phase shifter. The manufacturing cost can be kept low.

  Next, the effect of the foreign object detection device according to the first embodiment will be described with reference to FIGS.

  FIG. 7 is a top view showing the detection coils 11a and 11b of the foreign object detection device according to the mounting example of the first embodiment. The foreign object detection device in FIG. 7 is an example of mounting the foreign object detection device in FIG. 3. The detection coils 11a and 11b had the same winding direction on one surface, and the outer diameter was 40 mm. Each of the detection coils 11a and 11b had 14 turns. The detection coils 11a and 11b were arranged with a distance of 42 mm between their centers Oa and Ob. A foreign object 20a or 20b made of iron having a rectangular parallelepiped size of 15 × 15 × 1 [mm] was disposed at the position of the center Oa of the detection coil 11a or between the detection coils 11a and 11b. The distance between the upper surfaces of the detection coils 11a and 11b and the lower surface of the foreign matter 20a or 20b was 4 mm. The ports P1 of the detection coils 11a and 11b are connected to a foreign object detection circuit that generates one detection signal. The detection coils 11a and 11b are connected to a foreign object detection circuit so that detection signals in opposite directions flow through the two detection coils 11a and 11b adjacent to each other.

  FIG. 8 is a top view showing the detection coil 11a of the foreign object detection device according to the comparative example. The foreign object detection device of FIG. 8 includes only the detection coil 11a of FIG. A foreign object 20c or 20d made of 15 × 15 × 1 [mm] rectangular parallelepiped iron was disposed at the position of the center Oa of the detection coil 11a or at the outer periphery of the detection coil 11a. The distance between the upper surface of the detection coil 11a and the lower surface of the foreign matter 20c or 20d was 4 mm. The port P2 of the detection coil 11a is connected to a foreign object detection circuit that generates one detection signal.

  FIG. 9 is a graph showing the rate of change in inductance due to the foreign objects 20a to 20d in FIGS. For the detection coils 11a and 11b in FIG. 7, the inductance (synthetic inductance) L1 when the foreign matter 20a or 20b is present was measured, and the inductance change rate ΔL1 from the inductance L01 when the foreign matter was not present was calculated. Similarly, for the detection coil 11a of FIG. 8, the inductance L2 when the foreign matter 20c or 20d is present was measured, and the inductance change rate ΔL2 from the inductance L02 when the foreign matter was not present was calculated.

ΔL1 = (L1−L01) / L01 × 100 [%]
ΔL2 = (L2−L02) / L02 × 100 [%]

  The inductance change rate ΔL1 due to the foreign matter 20a was 0.24%. The inductance change rate ΔL1 due to the foreign matter 20b was 2.16%. The inductance change rate ΔL2 due to the foreign matter 20c was 2.28%. The inductance change rate ΔL2 due to the foreign matter 20d was 1.40%. According to FIG. 9, in the foreign object detection device of FIG. 7, the change in inductance caused by the foreign object 20a at the position of the center Oa of the detection coil 11a is very small, but the foreign object 20b at the position between the detection coils 11a and 11b. It can be seen that the resulting inductance change is large. This is because the combined magnetic field of the two detection coils 11a and 11b is generated between the detection coils 11a and 11b as shown in FIG.

  When the detection signals flowing in the two detection coils 11a and 11b adjacent to each other are periodic signals (for example, AC signals such as a sine wave) having waveforms inverted in the first half and the second half of each cycle, the detection coil 11a It is possible to detect a foreign substance existing between the detection coils 11a and 11b by causing a current of a detection signal having a substantially opposite phase (180 degrees) to flow through the detection coils 11a and 11b. Here, “substantially opposite phase (180 degrees)” means a phase difference between two detection signals within a range in which foreign matter between two adjacent detection coils 11a and 11b can be detected. If the phase difference between the two detection signals is 180 ° ± 90 °, substantially the same effect can be obtained, but a preferable range is 180 ° ± 45 °.

  On the other hand, in the foreign matter detection device of FIG. 8, the inductance change caused by the foreign matter 20c located at the center Oa of the detection coil 11a is large, but the inductance change caused by the foreign matter 20d located at the outer periphery of the detection coil 11a is very large. I understand that it is small. For this reason, although it is possible to detect the foreign material in the position of the center Oa of the detection coil 11a, it is difficult to detect the foreign material in the position of the outer periphery of the detection coil 11a. Therefore, by combining a method for detecting a foreign substance at the center using one detection coil and a method for detecting a foreign substance between them using two detection coils, a foreign substance such as a metal is reliably detected. It becomes possible.

  As described above, according to the foreign object detection device according to the first embodiment, while suppressing an increase in the number of parts, dimensions, and manufacturing costs, the foreign object positioned between two adjacent detection coils can be further reduced. It is possible to provide a foreign object detection device that reliably detects.

  In addition, the foreign material detection apparatus according to the first embodiment detects a foreign material (foreign material 20b in FIG. 7) at a position between two adjacent detection coils, or at a position close to above or below this position. Can do. Furthermore, by detecting a detection signal for each individual detection coil and determining the presence or absence of foreign matter for each detection coil, the foreign matter at the center position of the detection coil, or at a position close to or above the center (FIG. 8). The foreign matter 20c) can be detected. By using these two foreign matter detection methods in combination, foreign matter can be detected in all regions where foreign matter may generate heat, including between detection coils and the center of the detection coil. As described in the second and third embodiments, the foreign object detection device according to the first embodiment includes wireless power transmission including one or more power transmission coils (an array of power transmission coils or a large power transmission coil). When applied to a device or a wireless power transmission system, it is an excellent configuration capable of reliably detecting foreign matter.

  Hereinafter, as described with reference to FIGS. 10 to 12, the foreign object detection apparatus may include three or more detection coils.

  FIG. 10 is a block diagram illustrating a foreign object detection device according to a fourth modification example of the first embodiment. The foreign object detection device of FIG. 10 includes three detection coils 11a to 11c, a foreign object detection circuit 10B, and a switch SW1. The three detection coils 11a to 11c are wound close to each other on one surface. In order for detection signals in opposite directions to flow through two detection coils (11a and 11b, 11b and 11c) adjacent to each other among the detection coils 11a to 11c, for example, the detection coil 11b includes the detection coil 11a and the detection coil 11a. It has a winding direction different from 11c. The foreign object detection circuit 10B generates one detection signal similarly to the foreign object detection circuit 10A of FIGS. 3 to 5, and further controls the switch SW1. The switch SW1 selectively connects the foreign object detection circuit 10B to two detection coils adjacent to each other among the detection coils 11a to 11c. Here, the detection coil 11b is always connected to the foreign object detection circuit 10B, and the switch SW1 selectively connects the foreign object detection circuit 10B to one of the detection coils 11a and 11c. Specifically, when the foreign matter detection circuit 10B is connected to the detection coil 11a by the switch SW1, the presence or absence of foreign matter between the detection coils 11a and 11b is detected, and the foreign matter detection circuit 10B is connected to the detection coil 11c by the switch SW1. In such a case, the presence / absence of foreign matter between the detection coils 11b and 11c is detected.

  FIG. 11 is a block diagram illustrating a foreign object detection device according to a fifth modification example of the first embodiment. The foreign object detection device of FIG. 11 includes four detection coils 11a to 11d, a foreign object detection circuit 10C, and switches SW2 and SW3. The four detection coils 11a to 11d are wound close to each other on one surface. In order to cause detection signals in opposite directions to flow through two detection coils (11a and 11b, 11b and 11c, 11c and 11d) adjacent to each other among the detection coils 11a to 11d, for example, the detection coils 11b and 11d Has a winding direction different from that of the detection coils 11a and 11c. The foreign object detection circuit 10C generates one detection signal similarly to the foreign object detection circuit 10A of FIGS. 3 to 5, and further controls the switches SW2 and SW3. The switches SW2 and SW3 selectively connect the foreign object detection circuit 10C to two adjacent detection coils among the detection coils 11a to 11d. When the foreign object detection circuit 10C is connected to the detection coils 11a and 11b, the presence or absence of a foreign object between the detection coils 11a and 11b is detected. When the foreign object detection circuit 10C is connected to the detection coils 11b and 11c, the detection coil When the presence or absence of foreign matter between 11b and 11c is detected and the foreign matter detection circuit 10C is connected to the detection coils 11c and 11d, the presence or absence of foreign matter between the detection coils 11c and 11d is detected.

  FIG. 12 is a block diagram illustrating a foreign object detection device according to a sixth modification example of the first embodiment. The plurality of detection coils are not limited to being arranged one-dimensionally as shown in FIGS. 10 and 11, but may be arranged two-dimensionally as shown in FIG. The foreign object detection device of FIG. 12 includes four detection coils 11a to 11d, a foreign object detection circuit 10D, switches SW4 and SW5, and a phase shifter 12. The four detection coils 11a to 11d are wound close to each other on one surface. In order to allow detection signals in opposite directions to flow through two detection coils adjacent to each other among the detection coils 11a to 11d, for example, the detection coils 11b and 11d have a winding direction different from that of the detection coils 11a and 11c. Have The foreign object detection circuit 10D generates one detection signal similarly to the foreign object detection circuit 10A of FIGS. 3 to 5, and further controls the switches SW4 and SW5. The foreign object detection circuit 10D generates a periodic detection signal (for example, an AC signal such as a sine wave) having a waveform inverted in the first half and the second half of each cycle. The switches SW4 and SW5 select the foreign object detection circuit 10D as two adjacent detection coils (11a and 11b, 11a and 11c, 11b and 11d, 11c and 11d, 11a and 11d) among the detection coils 11a to 11d. Connect to. When the foreign object detection circuit 10D is connected to the detection coils 11a and 11d, the detection signal transmitted to one detection coil 11a is substantially equal to the detection signal transmitted to the other detection coil 11d by the phase shifter 12. Thus, the phase is reversed (180 degrees). According to the foreign matter detection device of FIG. 12, the foreign matter detection circuit 10D is selectively connected to two adjacent detection coils among the plurality of detection coils 11a to 11d by the switches SW4 and SW5, The presence or absence of foreign matter in the vicinity of the detection coil can be determined. According to the foreign object detection apparatus of FIG. 12, a plurality of positions (positions between two adjacent detection coils) where foreign objects can be detected are two-dimensionally distributed.

  10 to 12, when three or more detection coils are arranged, by using at least one switch, a simple configuration and adjacent to each other among the plurality of detection coils. Foreign matter between the two detection coils can be detected.

  According to the foreign object detection device of FIG. 12, it is possible to detect a foreign object between two adjacent detection coils among a plurality of detection coils in a two-dimensional manner with a simple configuration.

  Even when the foreign object detection device includes five or more detection coils, the foreign object detection circuit is made up of a plurality of detection coils by increasing the number of detection coils connected to the switch as in the foreign object detection device of FIGS. Can be selectively connected to two adjacent detection coils. For example, the detection coils having the first winding direction (11a and 11c in FIG. 11, 11a and 11d in FIG. 12) are switched by the first switch (SW2 in FIG. 11, SW5 in FIG. 12), and the second winding is performed. The detection coils having the rotation direction (11b and 11d in FIG. 11 and 11b and 11c in FIG. 12) may be switched by a second switch (SW3 in FIG. 11, SW4 in FIG. 12). Instead, the foreign object detection device may include three or more switches as necessary.

  10 to 12, in order to allow detection signals in opposite directions to flow through two detection coils adjacent to each other among a plurality of detection coils, winding of some detection coils is performed. Although the direction is different from the winding direction of the other detection coils, the present invention is not limited to this. For this purpose, FIG. 1 (when the foreign object detection circuit generates a plurality of detection signals having opposite polarities to each other), FIG. 3 (when the connection between the plurality of detection coils and the foreign object detection circuit is different), FIG. 4 (when using a phase shifter), or a combination thereof can be used.

Second embodiment.
FIG. 13 is a block diagram illustrating a wireless power transmission system according to the second embodiment. The wireless power transmission system in FIG. 13 includes a power transmission device 30 and a power reception device 40. The power transmission device 30 includes a foreign object detection circuit 10, detection coils 11a and 11b, power transmission coils 31a and 31b, power transmission circuits 32a and 32b, a communication circuit 33, and a control circuit 34. The power transmission circuits 32a and 32b generate high frequency power. The control circuit 34 of the power transmission device 30 controls the foreign object detection circuit 10, the power transmission circuits 32 a and 32 b, and the communication circuit 33. The power receiving device 40 includes a power receiving coil 41, a power receiving circuit 42, a communication circuit 43, a control circuit 44, and a load device 45. The control circuit 44 of the power receiving device 40 controls the power receiving circuit 42 and the communication circuit 43. The power transmission device 30 includes the foreign matter detection device (foreign matter detection circuit 10, detection coils 11a and 11b) shown in FIG. 1, and can detect foreign matter in the vicinity of the power transmission coils 31a and 31b.

  FIG. 14 is a diagram illustrating a part of the power transmission device 30 in FIG. 13. FIG. 14 shows the positional relationship on the XY plane of the detection coils 11a and 11b and the power transmission coils 31a and 31b. FIG. 15 is a view showing a cross section of the detection coils 11a and 11b and the power transmission coils 31a and 31b along the line A2-A2 'of FIG. As shown in FIG. 15, the detection coils 11 a and 11 b and the power transmission coils 31 a and 31 b may be provided on the magnetic substrate 51, and the power transmission device 30 may be provided in the housing 52. The housing 52 is formed of a material that allows an electromagnetic field to pass, such as plastic. For simplification of illustration, the magnetic substrate 51, the casing 52, and other circuits are omitted in FIG. 14, and each circuit in the power transmission device 30 is omitted in FIG. In the power transmission device 30 of FIG. 13, for example, the detection coil 11a is provided outside the outer periphery of the power transmission coil 31a, and the detection coil 11b is provided outside the outer periphery of the power transmission coil 31b. That is, one detection coil is provided in one power transmission coil. This makes it possible to reliably detect the foreign object 20 that may generate heat in the vicinity of the power transmission coils 31a and 31b. By arranging the detection coils 11a and 11b and the power transmission coils 31a and 31b on the same surface, there is an effect that the power transmission device 30 itself can be thinned. Furthermore, according to the configuration of FIG. 13, the foreign object 20 can be detected independently of the power transmission operation by separately providing the power transmission coil and the detection coil. That is, there is an effect that the foreign object 20 can be detected even during power transmission.

  The frequency of the detection signals 1 and 2 may be the same as or different from the frequency at which power is transmitted. When the power transmission frequency is, for example, 100 kHz to 200 kHz, the frequencies of the detection signals 1 and 2 may be the same or higher, for example, 100 kHz to 2 MHz.

  14 and 15, the example in which the detection coils 11a and 11b and the power transmission coils 31a and 31b are arranged on the same surface has been described. However, the present invention is not limited to this, and the detection coils 11a and 11b are not limited to the power transmission coil 31a. And 31b (between the power transmission coils 31a and 31b and the casing 52). As a result, there is an advantage that the sensitivity for detecting foreign matter is improved. Moreover, the detection coils 11a and 11b may be provided under the power transmission coils 31a and 31b (between the power transmission coil 31a and the magnetic substrate 51). Thereby, there exists an advantage that the efficiency of the wireless power transmission by the power transmission coils 31a and 31b improves.

  In FIGS. 13 to 15, an example including two power transmission coils 31 a and 31 b is shown as an example, but the present invention is not limited to this, and the power transmission device may include three or more power transmission coils.

  FIG. 16 is a diagram illustrating an arrangement of the detection coils 11 a to 11 d and the power transmission coil 31 of the wireless power transmission system according to the first modification of the second embodiment. FIG. 16 shows the positional relationship between the detection coils 11a to 11d and the power transmission coil 31 on the XY plane. FIG. 17 is a diagram illustrating a cross section of the detection coils 11a to 11d and the power transmission coil 31 taken along the line A3-A3 'of FIG. For simplification of illustration, the magnetic substrate 51, the casing 52, and other circuits are omitted in FIG. 16, and each circuit in the power transmission apparatus is omitted in FIG. 16 and 17 show an example in which a plurality of smaller detection coils 11 a to 11 d are arranged on one large power transmission coil 31. In this case, the detection coils 11 a to 11 d are arranged on one surface parallel to the power transmission coil 31 above the power transmission coil 31. As described above, by using the plurality of detection coils 11 a to 11 d smaller than the power transmission coil 31, there is an effect that the small foreign matter 20 can be detected with respect to the power transmission coil 31. Furthermore, according to the configuration of FIGS. 16 and 17, the foreign object 20 can be detected independently of the power transmission operation by separately providing the power transmission coil and the detection coil as in FIG. 13. That is, there is an effect that the foreign object 20 can be detected even during power transmission.

  FIG. 18 is a diagram illustrating an arrangement of the detection coils 11a to 11d, the power transmission coil 31A, and the power reception coil 41 of the wireless power transmission system according to the second modification of the second embodiment. The power transmission coil (and the power reception coil) is not limited to those wound on a plane as shown in FIGS. For example, as illustrated in FIG. 18, the power transmission device and the power reception device may include a power transmission coil 31 </ b> A and a power reception coil 41 </ b> A that are coils wound in a cylindrical shape (solenoid coil). For simplification of illustration, in FIG. 18, the detection coils 11 a to 11 d of the power transmission device, the power transmission coil 31 </ b> A, and other components of the casing 52 are omitted, and other components of the power reception coil 41 </ b> A of the power reception device are omitted. Omitted. The power transmission coil 31 </ b> A and the power reception coil 41 </ b> A have a longitudinal direction along the X axis, are provided in parallel, and are electromagnetically coupled to each other. The detection coils 11a to 11d are arranged on one surface that is in contact with the upper end (the end in the + Z direction) of the power transmission coil 31A. Since the power transmission coil 31A is a solenoid coil, the electromagnetic fields at both ends in the direction along the X axis of the power transmission coil 31A are strengthened. For this reason, there exists a possibility that the foreign material which exists in the both ends of 31 A of power transmission coils may generate | occur | produce heat. On the contrary, in the vicinity of the center in the direction along the X axis of the power transmission coil 31 </ b> A, heat is not generated much even if foreign matter is present. Therefore, as illustrated in FIG. 18, the detection coils 11 a to 11 d may be disposed at both ends of the power transmission coil 31 </ b> A, and the detection coils may not be disposed at places other than both ends. As shown in FIG. 18, by arranging the detection coils 11a to 11d, it is possible to reliably detect foreign substances that may generate heat while reducing the number of detection coils, leading to cost reduction. There is. Similarly to the example of FIGS. 16 and 17, by using a plurality of detection coils 11 a to 11 d that are smaller than the power transmission coil 31 </ b> A, it is possible to detect a small foreign object 20 with respect to the power transmission coil 31 </ b> A. There is. Furthermore, according to the configuration of FIG. 18, as in FIG. 13, it is possible to detect a foreign object independently of the power transmission operation by separately providing the power transmission coil and the detection coil. That is, there is an effect that foreign matter can be detected even during power transmission.

  In 2nd Embodiment, although the detection coil was provided along the upper surface of the housing | casing 52 of a power transmission apparatus, a detection coil may be provided in the arbitrary places where the magnetic field generated by the power transmission coil passes, for example, You may wind along the arbitrary places on the surface surrounding a power transmission coil.

  The power transmission device has an effect of preventing danger by detecting foreign matter using the foreign matter detection device of the present embodiment even during power transmission.

  The operation of the foreign object detection device according to the second embodiment will be described with reference to FIG. 19 as an example.

  After starting the operation of the power transmission device (step S21), the foreign matter detection process during power transmission (step S22) is executed while power is transmitted (steps S24 to S25). In the foreign matter detection process during power transmission, first, a detection signal is transmitted from the foreign matter detection circuit 10 (step S31), and a change in reflected signal is detected (step S32) and reflected by the method described in the first embodiment. It is determined whether or not the change amount of the signal exceeds a predetermined threshold (step S33). If it is determined that there is a foreign object (step S35), the power transmission is stopped (step S23), and the operation of the power transmission device is terminated (step S27). If it is determined that there is no foreign object (step S34), it is determined in step S33 of the foreign object detection process during power transmission (step S22) that there is a foreign object (intrusion of foreign object is detected and power transmission is stopped). Alternatively, the foreign matter detection process during power transmission (step S22) is continued until the power transmission operation is completed (step S26) and the power transmission device is turned off. It is also possible to transmit a detection signal (step S31) after waiting for a predetermined time after it is determined that there is no foreign object (step S34). As a result, unnecessary power consumption can be suppressed.

  When it is determined that there is no foreign object again after power transmission described above and power transmission is started, the power transmission circuit and the first power transmission are determined from the electrical connection between the foreign object detection circuit and the first power transmission coil and the second power transmission coil. The power transmission may be started by switching to an electrical connection between at least one of the coil (first coil) and the second power transmission coil (second coil).

  In addition, when it is determined that there is no foreign matter and power transmission starts, power transmission may be performed using two power transmission coils (may be the first coil and the second coil) arranged adjacent to each other. Is possible. Accordingly, there is an effect that power can be transmitted to a power receiving coil larger than one power transmitting coil. In this case, the direction of the AC power flowing through the two power transmission coils is preferably the same.

Third embodiment.
FIG. 20 is a block diagram showing a wireless power transmission system according to the third embodiment. The wireless power transmission system of FIG. 20 includes a power transmission device 30A and a power reception device 40. The power transmission device 30A includes the foreign object detection circuit 10, power transmission coils 31a and 31b, power transmission circuits 32a and 32b, a communication circuit 33, a control circuit 34A, and a switch circuit 35. The control circuit 34A of the power transmission device 30A controls the foreign object detection circuit 10, the power transmission circuits 32a and 32b, the communication circuit 33, and the switch circuit 35. The power receiving device 40 in FIG. 20 is the same as the power receiving device 40 in FIG. 13. In the power transmission device 30A, the power transmission coils 31a and 31b are also operated as the detection coils 11a and 11b in FIG. That is, the power transmission coils 31a and 31b are shared for power transmission and for foreign object detection. The switch circuit 35 connects at least one power transmission circuit 32a and 32b to at least one of the plurality of power transmission coils 31a and 31b, or connects the foreign object detection circuit 10 adjacent to each other among the plurality of power transmission coils 31a and 31b. Connect to two power transmission coils. When at least one power transmission circuit 32a and 32b is connected to at least one of the plurality of power transmission coils 31a and 31b, power can be transmitted from the power transmission device 30A to the power reception device 40. When the foreign object detection circuit 10 is connected to two power transmission coils adjacent to each other among the plurality of power transmission coils 31a and 31b, the foreign material between the two power transmission coils adjacent to each other can be detected. Thereby, the detection coils 11a and 11b of FIG. 13 can be reduced, and the cost can be reduced by reducing the number of parts. Furthermore, since a coil, which is a relatively large component, can be shared, the power transmission device can be reduced in size, weight, and thickness, and the width of the design can be increased.

  FIG. 21 is a diagram illustrating a part of the power transmission device 30A of FIG. FIG. 21 shows the positional relationship on the XY plane of the power transmission coils 31a and 31b. FIG. 22 is a diagram showing a cross section of the power transmission coils 31a and 31b along the line A4-A4 'of FIG. For simplification of illustration, in FIG. 21, the magnetic substrate 51, the casing 52, and other circuits are omitted, and in FIG. 22, each circuit in the power transmission device 30A is omitted. The plurality of power transmission coils 31a and 31b have the same winding direction on one surface and are wound close to each other. The foreign object detection circuit 10 generates detection signals 1 and 2 having a predetermined waveform. When the detection signals 1 and 2 are, for example, sine waves, the foreign object detection circuit 10 generates the detection signals 1 and 2 so as to have a phase difference of 180 degrees, for example. By setting the phase difference between the two detection signals transmitted from the foreign object detection circuit 10 to 180 degrees, a synthetic magnetic field is formed between the two detection coils, thereby enabling detection of the foreign object existing between the coils 11a and 11b. Yes. The switch circuit 35 includes switches SW11 and SW12. The switch SW11 connects the power transmission coil 31a to the power transmission circuit 32a or the foreign object detection circuit 10. That is, the switch SW11 connects the power transmission coil 31a to the foreign object detection circuit 10 when detecting a foreign object, and connects the power transmission coil 31a to the power transmission circuit 32a when transmitting power. Similarly, the switch SW12 connects the power transmission coil 31b to the foreign object detection circuit 10 when detecting a foreign object, and connects the power transmission coil 31b to the power transmission circuit 32b when transmitting power. Thereby, the power transmission coils 31a and 31b can be shared for power transmission and for foreign object detection. As described above, according to the configurations of FIGS. 20 to 22, the detection coil and the power transmission coil can be configured by the same single component, and the manufacturing cost of the power transmission device and the wireless power transmission system can be kept low. There is an effect.

  When the power transmission coils 31a and 31b are used for foreign object detection, in order to allow detection signals in opposite directions to flow through the two power transmission coils 31a and 31b adjacent to each other, similarly to the foreign object detection device of FIGS. A foreign object detection circuit 10A that generates one detection signal may be used.

FIG. 23 is a diagram illustrating a part of the power transmission device of the wireless power transmission system according to the first modification of the third embodiment. The foreign object detection circuit 10A and the power transmission coils 31a and 31b in FIG. 23 are configured similarly to the foreign object detection circuit 10A and the detection coils 11a and 11b in FIG. The power transmission coils 31a and 31b have the same winding direction on one surface. The two power transmission coils 31a and 31b adjacent to each other are arranged such that when one of the first and second detection signals flows clockwise on the surface including the power transmission coils 31a and 31b, The other of the detection signals is connected to the foreign object detection circuit 10A via the switch circuit 35 so as to flow counterclockwise on the surface including the power transmission coils 31a and 31b. According to the power transmission device of FIG. 3, the connection between the power transmission coil 31 a and the foreign object detection circuit 10 </ b> A is different from the connection between the power transmission coil 31 a and the foreign object detection circuit 10 </ b> A. A detection signal in the reverse direction flows. According to the power transmission device of FIG. 23, the detection signal transmitted from the foreign object detection circuit 10A is divided into two, and the same detection signal is transmitted to the power transmission coils 31a and 31b. And detects a foreign object existing between the power transmission coils 31a and 31b.

  FIG. 24 is a diagram illustrating a part of the power transmission device of the wireless power transmission system according to the second modification of the third embodiment. The foreign object detection circuit 10A, power transmission coils 31a and 31b, and the phase shifter 12 in FIG. 24 are configured in the same manner as the foreign object detection circuit 10A, detection coils 11a and 11b, and the phase shifter 12 in FIG. The power transmission coils 31a and 31b have the same winding direction on one surface. The foreign object detection circuit 10A generates one detection signal, and transmits the one detection signal directly to one of the two adjacent power transmission coils 31a and 31b as the first detection signal. Is transmitted as a second detection signal to the other of the two power transmission coils 31a and 31b adjacent to each other via the phase shifter 12. According to the power transmission device of FIG. 24, by using the phase shifter 12, detection signals in opposite directions flow through the two power transmission coils 31a and 31b adjacent to each other. According to the power transmission device of FIG. 24, the detection signal transmitted from the foreign object detection circuit 10A is distributed into two, and the detection signal whose phase is delayed by 180 degrees by the phase shifter 12 is transmitted to the power transmission coil 31b. A synthetic magnetic field is formed between the coils 31a and 31b, and foreign matter existing between the power transmission coils 31a and 31b is detected.

  FIG. 25 is a diagram illustrating a part of a power transmission device of a wireless power transmission system according to a third modification of the third embodiment. The foreign object detection circuit 10A and the power transmission coils 31a and 31b in FIG. 25 are configured similarly to the foreign object detection circuit 10A and the detection coils 11a and 11b in FIG. Two power transmission coils 31a and 31b adjacent to each other among the plurality of power transmission coils 31a and 31b have different winding directions on one surface. The foreign object detection circuit 10A generates one detection signal, transmits the detection signal as a first detection signal to one of the two power transmission coils 31a and 31b adjacent to each other, and the two power transmission coils 31a adjacent to each other. And the same detection signal is transmitted to the other of 31b as a 2nd detection signal. According to the power transmission device of FIG. 25, since the power transmission coils 31a and 31b have different winding directions on one surface, detection signals in opposite directions flow through the two power transmission coils 31a and 31b adjacent to each other. According to the power transmission device in FIG. 25, the detection signal transmitted from the foreign object detection circuit 10A is divided into two, and the same detection signal is transmitted to the power transmission coils 31a and 31b, whereby the combined magnetic field is transmitted between the power transmission coils 31a and 31b. And detects a foreign object existing between the power transmission coils 31a and 31b.

  23 to 25, there is an advantage that the detection signal output from the foreign object detection circuit 10A can be made one, and the circuit can be simplified. According to the power transmission device of FIGS. 23 to 25, the power transmission coils 31a and 31b can be shared for power transmission and foreign object detection, similarly to the power transmission device 30A of FIG. According to the power transmission device of FIGS. 23 to 25, the detection coil and the power transmission coil can be configured with the same single component, similarly to the power transmission device 30A of FIG. 20, and the power transmission device or the wireless power transmission system can be manufactured. There is an effect that the cost can be kept low.

  FIG. 26 is a diagram illustrating a part of a power transmission device of a wireless power transmission system according to a fourth modification of the third embodiment. The power transmission device according to the third embodiment may include three or more power transmission coils in order to be used as a detection coil in the same manner as the foreign object detection device of FIGS. The foreign object detection circuit 10B and power transmission coils 31a to 31c in FIG. 26 are configured in the same manner as the foreign object detection circuit 10B and detection coils 11a to 11c in FIG. In the power transmission device of FIG. 26, the switch circuit 25A includes three switches SW11 to SW13. The switch circuit 35A connects at least one power transmission circuit 32a to 32c to at least one of the plurality of power transmission coils 31a to 31c, or adjoins the foreign object detection circuit 10B to each other among the plurality of power transmission coils 31a to 31c. Connect to two power transmission coils. According to the power transmission device of FIG. 26, similarly to the power transmission device 30A of FIG. 20, the power transmission coils 31a to 31c can be shared for power transmission and foreign object detection.

  According to the foreign object detection device of FIG. 26, in order to allow detection signals in opposite directions to flow through two power transmission coils adjacent to each other among the plurality of power transmission coils, the winding direction of some of the power transmission coils is different. However, the present invention is not limited to this. For this purpose, FIG. 1 (when the foreign object detection circuit generates a plurality of detection signals having opposite polarities), FIG. 3 (when the connection between the plurality of power transmission coils and the foreign object detection circuit is different), FIG. 4 (when using a phase shifter), or a combination thereof can be used.

  In the power transmission device, the foreign object detection circuit and the power transmission coil may be configured in the same manner as the foreign object detection circuit and the detection coil in FIG.

  Even when the foreign object detection device includes five or more power transmission coils, by increasing the number of power transmission coils connected to the switch, the foreign object detection circuit includes a plurality of power transmission coils as in the foreign object detection device of FIGS. 11 and 12. Can be selectively connected to two power transmission coils adjacent to each other. For example, a power transmission coil having a first winding direction may be switched by a first switch, and a power transmission coil having a second winding direction may be switched by a second switch. Instead, the foreign object detection device may include three or more switches as necessary.

  In the modified examples of FIGS. 23 to 26, the sectional view is omitted, but is the same as FIG. 22, and the same effect can be obtained.

  The power transmission devices according to the second and third embodiments have an effect of preventing danger by detecting foreign matters using the foreign matter detection device of the present embodiment. Specifically, the operation will be described with reference to FIG. 27 as an example.

  After the operation of the power transmission apparatus is started (step S41), a foreign object detection process before power transmission (step S42) is executed. The foreign object detection process before power transmission in FIG. 27 is the same as the foreign object detection process in FIG. In the foreign object detection processing before power transmission, first, a detection signal is transmitted from the foreign object detection circuit 10 (step S51), and a change in the reflected signal is detected (step S52) and reflected by the method described in the first embodiment. It is determined whether or not the amount of change in the signal exceeds a predetermined threshold (step S53). When it is determined that there is no foreign object (step S54), power transmission is started (step S43), and power transmission is continued until power transmission is completed (steps S43 to S46). If it is determined that there is a foreign object (step S55), the foreign object detection process before power transmission (until the foreign object detection process (step S42) determines that there is no foreign object or until the power transmission device is turned off. Step S42) is continued. In addition, after continuing the foreign object detection processing before power transmission (step S42) until a predetermined time, if there is still a foreign object, the power transmission device can be turned off. As a result, unnecessary power consumption can be suppressed.

  As described above, the detection of foreign matters using the foreign matter detection device has an effect of preventing danger.

  Further, in the power transmission device, there is an effect that it is possible to further prevent danger by detecting foreign matter before power transmission and detecting foreign matter even during power transmission. Specifically, as an example, the operation will be described with reference to FIG.

  After the operation of the power transmission device is started (step S21), the foreign object detection process before power transmission (step S61: the same as step S42 in FIG. 27) is performed, and then power transmission is started (step S24) and the foreign object detection process during power transmission ( Step S22: The same as step S22 in FIG. 19 is performed. Here, the operations in steps S21 to S27 in FIG. 28 are the same as those in steps S21 to S27 in FIG. 19, and the operation in step S61 in FIG. 28 is the same as step S42 in FIG.

  According to the power transmission process of FIG. 28, it is possible to detect foreign matters before power transmission, detect contamination of foreign matters even during power transmission, and stop power transmission, thereby further improving the safety.

Modified example.
In the accompanying drawings, the detection coil and the power transmission coil are shown as a circular coil or a rectangular coil. However, the present invention is not limited to these, and a square, a rectangle, an ellipse, an ellipse, and other coil shapes are also possible.

  In the second and third embodiments, a configuration in which the power transmission devices 30 and 30A and the power reception device 40 include the communication circuits 33 and 43 is described as an example, but the configuration is not limited thereto. One of the power transmission device 30 and the power reception device 40 includes a transmission circuit, and the other includes a reception circuit. As a result, the circuit configuration is simplified, and the cost can be reduced. In addition, when transmitting and receiving power of a predetermined value, there is no need for communication, and a configuration not including the communication circuits 33 and 43 is possible. Thereby, there is an effect of cost reduction by reducing the communication circuit.

  In the second and third embodiments, in the power transmission devices 30 and 30A, the communication circuit 33 is connected to the power transmission coils 31a and 31b, and communication is performed using the power transmission coils 31a and 31b. However, it is not limited to this. For example, a configuration in which the communication circuit 33 is connected to another antenna or another coil is also possible. Similarly, the power receiving device 40 is configured to perform communication using the power receiving coil 41, but is not limited thereto. For example, a configuration in which the communication circuit 43 is connected to another antenna or another coil is also possible.

  In the second and third embodiments, the example in which the power transmission circuits 32a and 32b are connected to the power transmission coils 31a and 31b, respectively, has been described. However, the present invention is not limited to this. A configuration connected to both 31a and 31b is also possible. Thereby, it leads to the reduction of cost by reducing the number of power transmission circuits. A configuration in which one power transmission circuit is selectively connected to one of the power transmission coils 31a and 31b via a switch is also possible. Thereby, by supplying electric power only to a power transmission coil that requires power transmission, there is an advantage that energy waste is reduced and transmission efficiency is improved.

  In the second and third embodiments, the magnetic substrate 51 has a larger area than the region where the detection coils 11a and 11b and the power transmission coils 31a and 31b are arranged. Thereby, with respect to the detection coils 11a and 11b and the power transmission coils 31a and 31b, there is an effect that it is possible to reduce the influence from the metal or the like (for example, the upper plate of a metal desk) arranged on the lower side of the coils. is there. In addition, although the example using one large area magnetic substrate 51 was demonstrated in FIG. 15, it is not restricted to this, You may provide a separate magnetic substrate for every group of a power transmission coil and a detection coil. Good. Thereby, it becomes possible to reduce the magnetic body of an unnecessary location and there exists an advantage that member cost can be reduced.

(Other embodiments)
The technology of the present disclosure is not limited to the above-described embodiment, and various modifications can be made. Hereinafter, examples of other embodiments of the wireless power transmission device including the above-described foreign object detection device, and the wireless power transmission system including the wireless power transmission device and the wireless power reception device will be described.

  FIG. 29 is a diagram illustrating a state in which, for example, a smart phone 62 including a power receiving device is placed on the power transmitting device 61. The power transmission device 61 includes the foreign matter detection device. Before starting the power transmission, the foreign object detection device determines whether there is a foreign object on the power transmission device 61. As a result, when it is determined that there is no foreign object on the power transmission device 61, the power transmission circuit wirelessly transmits AC power to the power reception device of the smart phone 62. The power transmission device 61 and the power receiving device of the smart phone 62 constitute a wireless power system.

  As a result, foreign matter is detected before power transmission is started, so that the risk of heat generation of the foreign matter can be prevented.

  Moreover, in the power transmission device, even during power transmission, danger can be prevented by detecting the foreign material using the foreign material detection device.

  FIG. 30 is a diagram showing a parking lot equipped with a wireless power system. The vehicle 72 includes a power receiving device including a power receiving coil 72a. In addition, a power transmission device 71 is provided in a cage standing substantially perpendicular to the road, for example, a car stop. The power transmission device 71 includes the foreign matter detection device. The power transmission coil 71a is embedded in the road, and is connected to the power transmission device 71 by an electric cable.

  Before the power transmission device 71 starts power transmission, the foreign matter detection device determines the presence or absence of foreign matter on the power transmission coil 71a. As a result, when it is determined that there is no foreign object on the power transmission coil 71a and the positioning of the power reception coil 72a and the power transmission coil 71a of the vehicle 72 is completed, a high frequency is transmitted from the power transmission device 71 to the power transmission coil 71a via an electric cable. Power is sent. Then, high frequency power is transmitted wirelessly from the power transmission coil 71a to the power reception coil 72a.

  As a result, foreign matter is detected before power transmission is started, so that the risk of heat generation of the foreign matter can be prevented.

  Moreover, in the power transmission device 71, even during power transmission, danger can be prevented in advance by detecting the foreign material using the foreign material detection device.

  FIG. 31 is a diagram illustrating a configuration example of a wireless power transmission system that transmits power from a wall 80 to a robot 90 used in a hospital or the like in a contactless manner. In this example, a DC power source 81 and a power transmission device 82 are embedded in the wall 80. The power transmission device 82 includes, for example, a control circuit 83, a power transmission circuit 84, a power transmission coil 85, a foreign object detection circuit 86, and a detection coil 87. The power transmission device 82 is configured similarly to the power transmission device 30 of FIG. The robot 90 includes a power receiving device 91 including a power receiving coil 92 and a power receiving circuit 93. The power receiving device 91 may be configured similarly to the power receiving device 40 of FIG. The robot 90 further includes a secondary battery 94, a driving electric motor 95, and a plurality of wheels 96 for movement.

  With such a system, for example, electric power can be transmitted from the wall 80 to the robot 90 in the hospital in a non-contact manner, and charging can be performed automatically without the assistance of a person.

  As a result, foreign matter is detected before power transmission is started, so that the risk of heat generation of the foreign matter can be prevented.

  Moreover, in the power transmission device, even during power transmission, danger can be prevented by detecting the foreign material using the foreign material detection device.

  The embodiments disclosed herein are illustrative in all respects and are not intended to be limiting. The scope of the present disclosure is determined not by the above description but by the claims, and is intended to include all aspects including meanings equivalent to the claims and modifications within the scope.

  A wireless power transmission device and a wireless power transmission system including a foreign object detection device and a detection coil according to an aspect of the present disclosure have the following configurations.

The foreign object detection device according to the first aspect of the present disclosure includes:
A first coil that is wound, wherein one of the two terminals of the first conductor is an outer terminal disposed on the outside and the other is an inner terminal disposed on the inside;
The second conductor is disposed adjacent to the first coil and the winding direction is the same as that of the first coil, and one of the two terminals of the second conductor is an outer terminal disposed outside. A second coil that is an inner terminal disposed on the inner side,
The first detection signal having a first predetermined waveform is output to one of the outer terminal and the inner terminal of the first coil, and the terminal is on the same side as the first coil from which the first detection signal is output. A second detection signal having a second predetermined waveform having a polarity opposite to the polarity of the first predetermined waveform is output to one of the outer terminal and the inner terminal of the second coil;
One of the first detection signal flowing in the first coil and the second detection signal flowing in the second coil is caused to flow clockwise, the other is caused to flow counterclockwise, and the first coil and the first coil Generate a synthetic magnetic field that straddles between two coils,
Measuring the amount of change in the impedance value of either the first coil or the second coil corresponding to the change in the combined magnetic field caused by the presence or absence of foreign matter,
A foreign matter detection circuit that determines that there is a foreign matter in the vicinity of the first coil and the second coil when the amount of change in the impedance value exceeds a predetermined value.

According to the above aspect,
The foreign object detection device includes the second coil and a foreign object detection circuit which are arranged adjacent to the first coil and whose winding direction is the same as that of the first coil.
The foreign object detection circuit outputs a first detection signal having the first predetermined waveform to one of the outer terminal or the inner terminal of the first coil, and the first coil from which the first detection signal is output. A second detection signal having a second predetermined waveform having a polarity opposite to the polarity of the first predetermined waveform is output to one of the outer terminal and the inner terminal of the second coil, which is the same terminal.
Then, one of the first detection signal flowing through the first coil and the second detection signal flowing through the second coil is caused to flow clockwise and the other is caused to flow counterclockwise.
Then, a synthetic magnetic field straddling between the first coil and the second coil is generated.
Then, the amount of change in the impedance value of either the first coil or the second coil corresponding to the change in the combined magnetic field caused by the presence or absence of foreign matter is measured.
When the amount of change in the impedance value exceeds a predetermined value, it is determined that there is a foreign object in the vicinity of the first coil and the second coil.
As a result, it is possible to detect the foreign matter between the adjacent first coil and the second coil, and to expand the range in which the foreign matter can be detected with high accuracy.
Moreover, since the said 1st coil and said 2nd coil currently used can be used as it is, the increase in the number of parts, a dimension, and manufacturing cost can be suppressed.
Moreover, since the said 1st coil and the said 2nd coil can be comprised with the same component, the cost of a foreign material detection apparatus can be held down low.

The foreign object detection device according to the second aspect of the present disclosure is the foreign object detection device according to the first aspect of the present disclosure.
Each of the first coil and the second coil is arranged in parallel.

According to the above aspect,
By disposing each of the first coil and the second coil in parallel, the magnetic field distribution emitted from the first coil and the second coil becomes uniform, and foreign matter can be detected with high accuracy.

The foreign object detection device according to the third aspect of the present disclosure is the foreign object detection device according to any one of the first aspect or the second aspect of the present disclosure.
The first detection signal and the second detection signal are AC signals or pulse signals.

According to the above aspect,
The case where the AC signal is used for the first detection signal and the second detection signal is applied when there is a relatively large amount of foreign matter and / or when it is used for a long time. Since the power of the AC signal gradually fluctuates, the burden on the first coil and the second coil can be reduced when the AC signal is continuously used for a long time. Further, when pulse signals are used for the first detection signal and the second detection signal, they are applied when there is relatively little intrusion of foreign matter. The pulse signal is easy to make an intermittent signal, and it is possible to detect foreign matters while reducing power consumption.

The foreign object detection device according to the fourth aspect of the present disclosure is the foreign object detection device according to any one of the first to third aspects of the present disclosure.
The foreign object detection circuit outputs the first detection signal and the second detection signal simultaneously to the first coil and the second coil.

According to the above aspect,
Since there is no phase shift between the first detection signal and the second detection signal, the magnetic field distribution emitted from the first coil and the second coil is uniform, and foreign matter can be detected with high accuracy.

The foreign object detection device according to the fifth aspect of the present disclosure is the foreign object detection device according to any one of the first to fourth aspects of the present disclosure.
Three or more coils including the first coil and the second coil and having the same structure as the first coil and the second coil;
And at least one switch for performing electrical connection between the first coil and the second coil and the foreign object detection circuit among the three or more coils,
The foreign object detection circuit uses the at least one switch to output the first coil as two adjacent coils from among the three or more coils before outputting the first detection signal and the second detection signal. And the second coil is selected.

According to the above aspect,
Since the three or more coils are arranged and the combination of the first coil and the second coil can be freely selected from the three or more coils, the range for detecting foreign matter can be further expanded.

The foreign object detection device according to the sixth aspect of the present disclosure is the foreign object detection device according to any one of the first to fifth aspects of the present disclosure.
The power of the first detection signal and the power of the second detection signal are 10 mW to 100 mW.

  According to the said aspect, a foreign material can be detected with low electric power.

A power transmission device according to a seventh aspect of the present disclosure is a foreign object detection device according to any one of the first to sixth aspects of the present disclosure.
A power transmission coil;
A power transmission circuit that transmits high-frequency power to the power transmission coil.

According to the above aspect,
Since the foreign object detection device capable of expanding the range in which foreign objects can be detected with high accuracy is provided, the range in which the power transmission circuit transmits high-frequency power can be expanded.
In addition, since both the first coil, the second coil, and the power transmission coil are provided, the intrusion of the foreign matter can be detected even when high-frequency power is transmitted, so that the heat generation of the foreign matter can be prevented.

A power transmission device according to an eighth aspect of the present disclosure is the power transmission device according to the seventh aspect of the present disclosure.
A housing having the power transmission coil disposed therein,
A housing having the power transmission coil disposed therein,
The outer periphery of each of the first coil and the second coil is smaller than the outer periphery of the power transmission coil,
The first coil and the second coil are disposed between the main surface of the casing and the power transmission coil.

According to the above aspect,
Since the outer periphery of each of the first coil and the second coil is smaller than the outer periphery of the power transmission coil, even a foreign object relatively smaller than the power transmission coil can be detected.

A power transmission device according to a ninth aspect of the present disclosure is the power transmission device according to the seventh aspect of the present disclosure.
At least one of the first coil and the second coil is used as the power transmission coil.

According to the above aspect,
Since at least one of the first coil and the second coil is used as the power transmission coil, the cost can be reduced. Further, the apparatus can be reduced in thickness and weight.

The power transmission device according to the tenth aspect of the present disclosure is the power transmission device according to any one of the seventh to ninth aspects of the present disclosure.
The power of the first detection signal and the power of the second detection signal are smaller than the high frequency power.

The power transmission device according to the eleventh aspect of the present disclosure is the power transmission device according to any one of the seventh to tenth aspects of the present disclosure.
After the foreign object detection circuit determines that there is no foreign object in the vicinity of the first coil and the second coil, a control circuit for transmitting the high-frequency power to the power transmission circuit is provided.

A wireless power transmission system according to a twelfth aspect of the present disclosure is provided.
A wireless power transmission device according to any one of the seventh to eleventh aspects of the present disclosure;
A wireless power receiving apparatus.

A foreign object detection device according to a thirteenth aspect of the present disclosure is provided.
A first coil wound, wherein one of the two terminals of the first conductor is an outer terminal disposed on the outside and the other is an inner terminal disposed on the inside;
The second conductor is disposed adjacent to the first coil and the winding direction is the same as that of the first coil, and one of the two second conductors is an outer terminal disposed outside. A second coil which is an inner terminal disposed on the inner side;
A detection signal having a predetermined waveform is applied to one of the outer terminal and the inner terminal of the first coil, and to the outer terminal or the inner terminal of the second coil, which is a terminal on a different side from the first coil. Output to the other,
One of the detection signal flowing through the first coil and the detection signal flowing through the second coil is caused to flow clockwise, and the other is caused to flow counterclockwise, and between the first coil and the second coil. To generate a synthetic magnetic field across
Measuring the amount of change in the impedance value of either the first coil or the second coil corresponding to the change in the combined magnetic field caused by the presence or absence of foreign matter,
A foreign matter detection circuit that determines that there is a foreign matter in the vicinity of the first coil and the second coil when the amount of change in the impedance value exceeds a predetermined value.

According to the above aspect,
The foreign object detection device includes the second coil and a foreign object detection circuit which are arranged adjacent to the first coil and whose winding direction is the same as that of the first coil.
The foreign object detection circuit transmits the detection signal having the predetermined waveform to one of the outer terminal or the inner terminal of the first coil and the second coil that is a terminal on a different side from the first coil. Output to the other of the outer terminal or the inner terminal.
Then, one of the first detection signal flowing through the first coil and the second detection signal flowing through the second coil is caused to flow clockwise and the other is caused to flow counterclockwise.
Then, a synthetic magnetic field straddling between the first coil and the second coil is generated.
Then, the amount of change in the impedance value of either the first coil or the second coil corresponding to the change in the combined magnetic field caused by the presence or absence of foreign matter is measured.
When the amount of change in the impedance value exceeds a predetermined value, it is determined that there is a foreign object in the vicinity of the first coil and the second coil.
As a result, it is possible to detect the foreign matter between the adjacent first coil and the second coil, and to expand the range in which the foreign matter can be detected with high accuracy.
Moreover, since the said 1st coil and said 2nd coil currently used can be used, the increase in a number of parts, a dimension, and manufacturing cost can be suppressed.
Moreover, since the said 1st coil and the said 2nd coil can be comprised with the same component, the cost of a foreign material detection apparatus can be held down low.
Further, since the detection signal output to the one coil and the second coil may be one signal, the circuit can be simplified.

A foreign object detection device according to a fourteenth aspect of the present disclosure is the foreign object detection device according to the thirteenth aspect of the present disclosure.
Each of the first coil and the second coil is arranged in parallel.

  According to the said aspect, the effect similar to a 2nd aspect can be acquired.

The foreign object detection device according to the fifteenth aspect of the present disclosure is the foreign object detection device according to any one of the thirteenth aspect or the fourteenth aspect of the present disclosure.
The detection signal flowing through the first coil and the detection signal flowing through the second coil are alternating current signals or pulse signals.

  According to the said aspect, the effect similar to a 3rd aspect can be acquired.

The foreign object detection device according to the sixteenth aspect of the present disclosure is the foreign object detection device according to any one of the thirteenth to fifteenth aspects of the present disclosure.
Three or more coils including the first coil and the second coil, the coils having the same structure as the first coil and the second coil;
And at least one switch for performing electrical connection between the first coil and the second coil and the foreign object detection circuit among the three or more coils,
The foreign object detection circuit selects the first coil and the second coil as two adjacent coils from among the three or more coils using the at least one switch before outputting the detection signal. .

  According to the said aspect, the effect similar to a 5th aspect can be acquired.

The foreign object detection device according to the seventeenth aspect of the present disclosure is the foreign object detection device according to any one of the thirteenth to sixteenth aspects of the present disclosure.
The power of the detection signal is 10 mW to 100 mW.

  According to the said aspect, the effect similar to a 6th aspect can be acquired.

A power transmission device according to an eighteenth aspect of the present disclosure includes a foreign matter detection device according to any one of the thirteenth to seventeenth aspects of the present disclosure;
A power transmission coil;
A power transmission circuit that transmits high-frequency power to the power transmission coil.

  According to the said aspect, the effect similar to a 7th aspect can be acquired.

A power transmission device according to a nineteenth aspect of the present disclosure is the power transmission device according to the eighteenth aspect of the present disclosure.
A housing having the power transmission coil disposed therein,
A housing having the power transmission coil disposed therein,
The outer periphery of each of the first coil and the second coil is smaller than the outer periphery of the power transmission coil,
The first coil and the second coil are disposed between the main surface of the casing and the power transmission coil.

  According to the above aspect, the same effect as in the eighth aspect can be obtained.

The power transmission device according to the twentieth aspect of the present disclosure is the power transmission device according to the eighteenth aspect of the present disclosure.
At least one of the first coil and the second coil is used as the power transmission coil.

  According to the above aspect, the same effect as in the ninth aspect can be obtained.

The power transmission device according to the twenty-first aspect of the present disclosure is the power transmission device according to any one of the eighteenth to twentieth aspects of the present disclosure.
The power of the first detection signal and the power of the second detection signal are smaller than the high frequency power.

The power transmission device according to the twenty-second aspect of the present disclosure is the power transmission device according to any one of the eighteenth to twenty-first aspects of the present disclosure.
After the foreign object detection circuit determines that there is no foreign object in the vicinity of the first coil and the second coil, a control circuit for transmitting the high-frequency power to the power transmission circuit is provided.

A wireless power transmission system according to a twenty-third aspect of the present disclosure includes:
A wireless power transmission device according to any one of the 18th to 22nd aspects of the present disclosure;
A wireless power receiving apparatus.

A foreign object detection device according to a twenty-fourth aspect of the present disclosure is provided.
A first coil that is wound, wherein one of the two terminals of the first conductor is an outer terminal disposed on the outside and the other is an inner terminal disposed on the inside;
The second conductor is disposed adjacent to the first coil and has a winding direction opposite to that of the first coil. One of the two terminals of the second conductor is an outer terminal disposed outside. A second coil that is an inner terminal disposed on the inner side,
A detection signal having a predetermined waveform is applied to one of the outer terminal and the inner terminal of the first coil, and to the outer terminal or the inner terminal of the second coil, which is a terminal on the same side as the first coil. Output to one side,
One of the detection signal flowing through the first coil and the detection signal flowing through the second coil is caused to flow clockwise, and the other is caused to flow counterclockwise, and between the first coil and the second coil. To generate a synthetic magnetic field across
Measuring the amount of change in the impedance value of either the first coil or the second coil corresponding to the change in the combined magnetic field caused by the presence or absence of foreign matter,
A foreign matter detection circuit that determines that there is a foreign matter in the vicinity of the first coil and the second coil when the amount of change in the impedance value exceeds a predetermined value.

According to the above aspect,
The foreign object detection device includes the second coil and a foreign object detection circuit which are disposed adjacent to the first coil and whose winding direction is opposite to the first coil.
The foreign object detection circuit sends a detection signal having a predetermined waveform to one of the outer terminal or the inner terminal of the first coil and the outer side of the second coil which is a terminal on the same side as the first coil. Output to either the terminal or the inner terminal.
Then, one of the first detection signal flowing through the first coil and the second detection signal flowing through the second coil is caused to flow clockwise and the other is caused to flow counterclockwise.
Then, a synthetic magnetic field straddling between the first coil and the second coil is generated.
Then, the amount of change in the impedance value of either the first coil or the second coil corresponding to the change in the combined magnetic field caused by the presence or absence of foreign matter is measured.
When the amount of change in the impedance value exceeds a predetermined value, it is determined that there is a foreign object in the vicinity of the first coil and the second coil.
As a result, it is possible to detect the foreign matter between the adjacent first coil and the second coil, and to expand the range in which the foreign matter can be detected with high accuracy.
Moreover, since the said 1st coil and said 2nd coil currently used can be used, the increase in a number of parts, a dimension, and manufacturing cost can be suppressed.
Further, since the detection signal output to the one coil and the second coil may be one signal, the circuit can be simplified.

A foreign object detection device according to a twenty-fifth aspect of the present disclosure is the foreign object detection device according to the twenty-fourth aspect of the present disclosure.
Each of the first coil and the second coil is arranged in parallel.

  According to the said aspect, the effect similar to a 2nd aspect can be acquired.

The foreign object detection device according to a twenty-sixth aspect of the present disclosure is the foreign object detection device according to any one of the twenty-fourth aspect or the twenty-fifth aspect of the present disclosure.
The detection signal flowing through the first coil and the detection signal flowing through the second coil are alternating current signals or pulse signals.

  According to the said aspect, the effect similar to a 3rd aspect can be acquired.

The foreign object detection device according to a twenty-seventh aspect of the present disclosure is the foreign object detection device according to any one of the twenty-fourth to twenty-sixth aspects of the present disclosure.
Three or more coils including the first coil and the second coil, the coils having the same structure as the first coil and the second coil;
And at least one switch for performing electrical connection between the first coil and the second coil and the foreign object detection circuit among the three or more coils,
The foreign object detection circuit selects the first coil and the second coil as two adjacent coils from among the three or more coils using the at least one switch before outputting the detection signal. .

  According to the said aspect, the effect similar to a 5th aspect can be acquired.

The foreign object detection device according to the twenty-eighth aspect of the present disclosure is the foreign object detection device according to any one of the twenty-fourth to twenty-seventh aspects of the present disclosure.
The power of the detection signal is 10 mW to 100 mW.

  According to the said aspect, the effect similar to a 6th aspect can be acquired.

A power transmission device according to a twenty-ninth aspect of the present disclosure is a foreign object detection device according to any one of the twenty-fourth to twenty-eighth aspects of the present disclosure;
A power transmission coil;
A power transmission circuit that transmits high-frequency power to the power transmission coil.

  According to the said aspect, the effect similar to a 7th aspect can be acquired.

The power transmission device according to the thirtieth aspect of the present disclosure is the power transmission device according to the twenty-ninth aspect of the present disclosure,
A housing having the power transmission coil disposed therein,
A housing having the power transmission coil disposed therein,
The outer periphery of each of the first coil and the second coil is smaller than the outer periphery of the power transmission coil,
The first coil and the second coil are disposed between the main surface of the casing and the power transmission coil.

  According to the above aspect, the same effect as in the eighth aspect can be obtained.

A power transmission device according to a thirty-first aspect of the present disclosure is the power transmission device according to the twenty-ninth aspect of the present disclosure.
At least one of the first coil and the second coil is used as the power transmission coil.

  According to the above aspect, the same effect as in the ninth aspect can be obtained.

The power transmission device according to the thirty-second aspect of the present disclosure is the power transmission device according to any one of the twenty-ninth to thirty-first aspects of the present disclosure.
The power of the first detection signal and the power of the second detection signal are smaller than the high frequency power.

The power transmission apparatus according to the thirty-third aspect of the present disclosure is the power transmission apparatus according to any one of the twenty-ninth to thirty-second aspects of the present disclosure.
After the foreign object detection circuit determines that there is no foreign object in the vicinity of the first coil and the second coil, a control circuit for transmitting the high-frequency power to the power transmission circuit is provided.

A wireless power transmission system according to a thirty-fourth aspect of the present disclosure includes:
A wireless power transmission device according to any one of the 29th to 33rd aspects of the present disclosure;
A wireless power receiving apparatus.

A foreign object detection device according to a thirty-fifth aspect of the present disclosure includes:
A first coil that is wound, wherein one of the two terminals of the first conductor is an outer terminal disposed on the outside and the other is an inner terminal disposed on the inside;
The second conductor is disposed adjacent to the first coil and the winding direction is the same as that of the first coil, and one of the two terminals of the second conductor is an outer terminal disposed outside. A second coil that is an inner terminal disposed on the inner side,
A foreign matter detection circuit for outputting a first detection signal having a first predetermined waveform to one of the outer terminal or the inner terminal of the first coil;
The output of the first detection signal is applied to one of the outer terminal and the inner terminal of the second coil on the same side as the first coil from which the first detection signal is output. A phase shifter that converts and outputs a second detection signal having a second predetermined waveform having a polarity reversed from
One of the first detection signal flowing through the first coil and the second detection signal flowing through the second coil flows clockwise, and the other flows counterclockwise. The first coil and the second coil A synthetic magnetic field that spans
The foreign object detection circuit
Measuring the amount of change in the impedance value of either the first coil or the second coil corresponding to the change in the combined magnetic field caused by the presence or absence of foreign matter,
When the change amount of the impedance value exceeds a predetermined value, it is determined that there is a foreign object in the vicinity of the first coil and the second coil adjacent to each other.

According to the above aspect,
The foreign object detection device includes the second coil that is disposed adjacent to the first coil and whose winding direction is the same as that of the first coil.
In addition, a foreign matter detection circuit is provided that outputs a first detection signal having a first predetermined waveform to one of the outer terminal and the inner terminal of the first coil.
The first detection signal output to the first predetermined waveform is output to one of the outer terminal and the inner terminal of the second coil on the same side as the first coil from which the first detection signal is output. A phase shifter that converts and outputs a second detection signal having a second predetermined waveform having a polarity inverted from that of the first polarity.
The foreign matter detection circuit causes one of the first detection signal flowing through the first coil and the second detection signal flowing through the second coil to flow clockwise and the other to flow counterclockwise. . Then, a synthetic magnetic field straddling between the first coil and the second coil is generated.
The foreign object detection circuit measures the amount of change in the impedance value of either the first coil or the second coil corresponding to the change in the combined magnetic field caused by the presence or absence of a foreign object.
When the amount of change in the impedance value exceeds a predetermined value, it is determined that there is a foreign object in the vicinity of the first coil and the second coil adjacent to each other.
As a result, it is possible to detect the foreign matter between the adjacent first coil and the second coil, and to expand the range in which the foreign matter can be detected with high accuracy.
Moreover, since the said 1st coil and said 2nd coil currently used can be used, the increase in a number of parts, a dimension, and manufacturing cost can be suppressed.
Moreover, since the said 1st coil and the said 2nd coil can be comprised with the same component, the cost of a foreign material detection apparatus can be held down low.
The second detection signal is used by inverting the polarity of the first detection signal by the phase shifter. Therefore, since the signal output from the foreign object detection circuit is only the first detection signal, the circuit can be simplified.

A foreign object detection device according to a thirty-sixth aspect of the present disclosure is the foreign object detection device according to the thirty-fifth aspect of the present disclosure.
Each of the first coil and the second coil is arranged in parallel.

  According to the said aspect, the effect similar to a 2nd aspect can be acquired.

The foreign object detection device according to the thirty-seventh aspect of the present disclosure is the foreign object detection device according to any one of the thirty-fifth aspect and the thirty-sixth aspect of the present disclosure.
The first detection signal and the second detection signal are AC signals or pulse signals.

  According to the said aspect, the effect similar to a 3rd aspect can be acquired.

The foreign object detection device according to the thirty-eighth aspect of the present disclosure is the foreign object detection device according to any one of the 35th to 37th aspects of the present disclosure.
A plurality of coils including at least one set of the first coil, the second coil, and the phase shifter;
And at least one switch for making an electrical connection between the at least one set and the foreign object detection circuit,
The foreign object detection circuit selects the at least one set from the plurality of coils using the at least one switch before outputting the detection signal.

  According to the above aspect, it is possible to further expand the range for detecting foreign matter by switching the switch.

  The foreign object detection device according to the 39th aspect of the present disclosure is the foreign object detection device according to any one of the 35th to 38th aspects of the present disclosure, wherein the power of the detection signal is 10 mW to 100 mW.

  According to the said aspect, the effect similar to a 6th aspect can be acquired.

A power transmission device according to a 40th aspect of the present disclosure is a foreign object detection device according to any one of the 35th to 39th aspects of the present disclosure;
A power transmission coil;
A power transmission circuit that transmits high-frequency power to the power transmission coil.

  According to the said aspect, the effect similar to a 7th aspect can be acquired.

The power transmission device according to the forty-first aspect of the present disclosure is the power transmission device according to the forty-first aspect of the present disclosure.
A housing having the power transmission coil disposed therein,
A housing having the power transmission coil disposed therein,
The outer periphery of each of the first coil and the second coil is smaller than the outer periphery of the power transmission coil,
The first coil and the second coil are disposed between the main surface of the casing and the power transmission coil.

  According to the above aspect, the same effect as in the eighth aspect can be obtained.

A power transmission device according to a forty-second aspect of the present disclosure is the power transmission device according to the forty-second aspect of the present disclosure.
A housing having the power transmission coil disposed therein,
The outer periphery of each of the first coil and the second coil is smaller than the outer periphery of the power transmission coil,
The first coil and the second coil are disposed between the main surface of the casing and the power transmission coil.

  According to the above aspect, the same effect as in the eighth aspect can be obtained.

A power transmission device according to a forty-third aspect of the present disclosure is the power transmission device according to the forty-third aspect of the present disclosure.
At least one of the first coil and the second coil is used as the power transmission coil.

  According to the above aspect, the same effect as in the ninth aspect can be obtained.

In the power transmission device according to the 44th aspect of the present disclosure, the power transmission device according to any one of the 40th to 43rd aspects of the present disclosure,
The power of the first detection signal and the power of the second detection signal are smaller than the high frequency power.

In the power transmission device according to the 45th aspect of the present disclosure, the power transmission device according to any one of the 40th to 44th aspects of the present disclosure,
After the foreign object detection circuit determines that there is no foreign object in the vicinity of the first coil and the second coil, a control circuit for transmitting the high-frequency power to the power transmission circuit is provided.

A wireless power transmission system according to a 46th aspect of the present disclosure includes:
A wireless power transmission device according to any one of the 40th to 45th aspects of the present disclosure;
A wireless power receiving apparatus.

A foreign matter detection device according to a 47th aspect of the present disclosure is:
A first coil wound with a conducting wire;
A second coil disposed adjacent to the first coil and wound with a conducting wire;
A first detection signal having a first predetermined waveform is output to the first coil; a second detection signal having a second predetermined waveform is output to the second coil; and the first detection signal flowing through the first coil; Causing one of the second detection signals flowing in the second coil to flow clockwise, the other to flow counterclockwise, and generating a combined magnetic field straddling between the first coil and the second coil,
Measuring the amount of change in the impedance value of either the first coil or the second coil corresponding to the change in the combined magnetic field caused by the presence or absence of foreign matter,
A foreign object detection circuit that determines that there is a foreign object in the vicinity of the first coil and the second coil adjacent to each other when the amount of change in the impedance value exceeds a predetermined value.

According to the above aspect,
The foreign object detection device includes a second coil that is disposed adjacent to the first coil around which the conducting wire is wound and on which the conducting wire is wound.
The foreign object detection circuit outputs a first detection signal having the first predetermined waveform to the first coil, and outputs a second detection signal having the second predetermined waveform to the second coil.
Then, one of the first detection signal flowing through the first coil and the second detection signal flowing through the second coil is caused to flow clockwise and the other is caused to flow counterclockwise.
Then, a synthetic magnetic field straddling between the first coil and the second coil is generated.
Then, the amount of change in the impedance value of either the first coil or the second coil corresponding to the change in the combined magnetic field caused by the presence or absence of foreign matter is measured.
When the amount of change in the impedance value exceeds a predetermined value, it is determined that there is a foreign object in the vicinity of the first coil and the second coil.
As a result, it is possible to detect the foreign matter between the adjacent first coil and the second coil, and to expand the range in which the foreign matter can be detected with high accuracy.
Moreover, since the said 1st coil and said 2nd coil currently used can be used, the increase in a number of parts, a dimension, and manufacturing cost can be suppressed.

A foreign object detection device according to a 48th aspect of the present disclosure is the foreign object detection device according to the 47th aspect of the present disclosure.
Each of the first coil and the second coil is arranged in parallel.

According to the above aspect,
By disposing each of the first coil and the second coil in parallel, the magnetic field distribution emitted from the first coil and the second coil becomes uniform, and foreign matter can be detected with high accuracy.

A foreign object detection device according to a 49th aspect of the present disclosure is the foreign object detection device according to any one of the 47th aspect or the 48th aspect of the present disclosure,
The first detection signal and the second detection signal are AC signals or pulse signals.

According to the above aspect,
The case where the AC signal is used for the first detection signal and the second detection signal is applied when there is a relatively large amount of foreign matter and / or when it is used for a long time. Since the power of the AC signal gradually fluctuates, the burden on the first coil and the second coil can be reduced when the AC signal is continuously used for a long time. Further, when pulse signals are used for the first detection signal and the second detection signal, they are applied when there is relatively little intrusion of foreign matter. The pulse signal is easy to make an intermittent signal, and it is possible to detect foreign matters while reducing power consumption.

The foreign object detection device according to the 50th aspect of the present disclosure is the foreign object detection device according to any one of 47th to 49th aspects of the present disclosure.
The foreign object detection circuit outputs the first detection signal and the second detection signal simultaneously to the first coil and the second coil.

According to the above aspect,
Since there is no phase shift between the first detection signal and the second detection signal, the magnetic field distribution emitted from the first coil and the second coil is uniform, and foreign matter can be detected with high accuracy.

The foreign object detection device according to the 51st aspect of the present disclosure is the foreign object detection device according to any one of 47th to 50th aspects of the present disclosure.
Three or more coils including the first coil and the second coil and having the same structure as the first coil and the second coil;
And at least one switch for performing electrical connection between the first coil and the second coil and the foreign object detection circuit among the three or more coils,
The foreign object detection circuit uses the at least one switch to output the first coil as two adjacent coils from among the three or more coils before outputting the first detection signal and the second detection signal. And the second coil is selected.

According to the above aspect,
Since the three or more coils are arranged and the combination of the first coil and the second coil can be freely selected from the three or more coils, the range for detecting foreign matter can be further expanded.

The foreign object detection device according to the 52nd aspect of the present disclosure is the foreign object detection device according to any one of 47th to 51st aspects of the present disclosure.
The power of the first detection signal and the power of the second detection signal are 10 mW to 100 mW.

  According to the said aspect, a foreign material can be detected with low electric power.

A power transmission device according to a 53rd aspect of the present disclosure includes a foreign object detection device according to any one of 47th to 52nd aspects of the present disclosure,
A power transmission coil;
A power transmission circuit that transmits high-frequency power to the power transmission coil.

According to the above aspect,
Since the foreign object detection device capable of expanding the range in which foreign objects can be detected with high accuracy is provided, the range in which the power transmission circuit transmits high-frequency power can be expanded.
In addition, since both the first coil, the second coil, and the power transmission coil are provided, the intrusion of the foreign matter can be detected even when high-frequency power is transmitted, so that the heat generation of the foreign matter can be prevented.

The power transmission device according to the 54th aspect of the present disclosure is the power transmission device according to the 53rd aspect of the present disclosure,
A housing having the power transmission coil disposed therein,
A housing having the power transmission coil disposed therein,
The outer periphery of each of the first coil and the second coil is smaller than the outer periphery of the power transmission coil,
The first coil and the second coil are disposed between the main surface of the casing and the power transmission coil.

According to the above aspect,
Since the outer periphery of each of the first coil and the second coil is smaller than the outer periphery of the power transmission coil, even a foreign object relatively smaller than the power transmission coil can be detected.

A power transmission device according to a 55th aspect of the present disclosure is the power transmission device according to the 53rd aspect of the present disclosure,
At least one of the first coil and the second coil is used as the power transmission coil.

According to the above aspect,
Since at least one of the first coil and the second coil is used as the power transmission coil, the cost can be reduced. Further, the apparatus can be reduced in thickness and weight.

In the power transmission device according to the 56th aspect of the present disclosure, the power transmission device according to any one of the 53rd to 55th aspects of the present disclosure,
The power of the first detection signal and the power of the second detection signal are smaller than the high frequency power.

The power transmission device according to the 57th aspect of the present disclosure is the power transmission device according to any one of the 53rd to 56th aspects of the present disclosure,
After the foreign object detection circuit determines that there is no foreign object in the vicinity of the first coil and the second coil, a control circuit for transmitting the high-frequency power to the power transmission circuit is provided.

A wireless power transmission system according to a 58th aspect of the present disclosure includes:
A wireless power transmission device according to any one of the 53rd to 57th aspects of the present disclosure;
A wireless power receiving apparatus.

According to the foreign matter detection device according to the 59th aspect of the present disclosure,
A foreign matter detection device comprising a plurality of coils and a foreign matter detection circuit,
The plurality of coils are wound close to each other on one surface,
The foreign object detection circuit
A detection signal having a predetermined waveform is transmitted to two adjacent coils of the plurality of coils,
Receiving a reflected signal generated by the detection signal being reflected by the two adjacent coils;
Based on the reflected signal, determine the presence or absence of foreign matter in the vicinity of the two adjacent coils,
The detection signal includes a first detection signal that flows through one of the two adjacent coils, and a second detection signal that flows through the other of the two adjacent coils. And when one of the second detection signals flows clockwise on the surface, the other of the first and second detection signals flows counterclockwise on the surface.

According to the foreign object detection device according to the 60th aspect of the present disclosure, in the foreign object detection device according to the 59th aspect,
Each of the first and second detection signals is an AC signal.

According to the foreign matter detection device according to the 61st aspect of the present disclosure, in the foreign matter detection device according to the 59th aspect,
Each of the first and second detection signals is a pulse signal.

According to the foreign matter detection device according to the 62nd aspect of the present disclosure, in the foreign matter detection device according to one of the 59th to 61st aspects,
The plurality of coils have the same winding direction on the surface,
The first and second detection signals have opposite polarities,
The foreign object detection circuit generates the first and second detection signals and simultaneously transmits the first and second detection signals to the two adjacent coils.

According to the foreign matter detection device according to the 63rd aspect of the present disclosure, in the foreign matter detection device according to one of the 59th to 61st aspects,
The plurality of coils have the same winding direction on the surface,
The foreign object detection circuit generates one detection signal, transmits the one detection signal as the first detection signal to one of the two adjacent coils, and the two adjacent coils. And transmitting the one detection signal to the other of the two as the second detection signal,
The two adjacent coils are such that when one of the first and second detection signals is flowing clockwise on the surface, the other of the first and second detection signals is the above. The foreign matter detection circuit is connected so as to flow counterclockwise on the surface.

According to the foreign matter detection device according to the sixty-fourth aspect of the present disclosure, in the foreign matter detection device according to one of the 59th to 61st aspects,
The foreign object detection device further includes at least one phase shifter,
The plurality of coils have the same winding direction on the surface,
The foreign object detection circuit generates one periodic detection signal having a waveform inverted in the first half and the second half of each cycle, and the one detection signal is directly applied to one of the two adjacent coils. The first detection signal is transmitted, and the one detection signal is transmitted to the other of the two adjacent coils as the second detection signal via the phase shifter.

According to the foreign matter detection device according to the 65th aspect of the present disclosure, in the foreign matter detection device according to one of the 59th to 61st aspects,
Two adjacent coils of the plurality of coils have different winding directions on the surface,
The foreign object detection circuit generates one detection signal, transmits the one detection signal as the first detection signal to one of the two adjacent coils, and the two adjacent coils. The other detection signal is transmitted as the second detection signal.

According to the foreign matter detection device according to the 66th aspect of the present disclosure, in the foreign matter detection device according to one of the 59th to 65th aspects,
The foreign object detection device further includes at least one first switch that selectively connects the foreign object detection circuit to two adjacent coils of the plurality of coils.

According to the wireless power transmitting apparatus according to the 67th aspect of the present disclosure.
A foreign object detection device according to one of the 59th to 65th aspects is provided.

According to the wireless power transmitting apparatus according to the 68th aspect of the present disclosure, in the wireless power transmitting apparatus according to the 67th aspect,
The wireless power transmission device
At least one power transmission circuit for generating high-frequency power;
A second switch connecting the at least one power transmission circuit to at least one of the plurality of coils, or connecting the foreign object detection circuit to two adjacent coils of the plurality of coils;
And a control circuit for controlling the second switch.

According to the wireless power transmission system according to the 69th aspect of the present disclosure,
A wireless power transmitting apparatus according to a 67th or 68th aspect;
A wireless power receiving apparatus.

  The foreign object detection device, the wireless power transmission device, and the wireless power transmission system of the present disclosure are useful for reliably detecting a foreign material in the vicinity of the power transmission coil or the power reception coil when wirelessly transmitting power to a mobile device, an EV vehicle, or the like. It is.

10, 10A to 10D ... Foreign matter detection circuit,
11a to 11d: detection coil,
12 ... Phase shifter,
20, 20a-20d ... foreign matter,
30, 30A ... power transmission device,
31, 31a-31c, 31A ... power transmission coil,
32a to 32c ... power transmission circuit,
33. Communication circuit,
34, 34A ... control circuit,
35 ... Switch circuit,
40. Power receiving device,
41 ... Receiving coil,
42. Power receiving circuit,
43. Communication circuit,
44 ... control circuit,
45 ... load device,
51 ... Magnetic substrate,
52 ... Case,
61 ... Power transmission device,
62 ... Smartphone,
71 ... power transmission device,
71a ... power transmission coil,
72 ... Smartphone,
72a ... receiving coil,
80 ... the wall,
81 ... DC power supply,
82 ... power transmission device,
83. Control circuit,
84 ... power transmission circuit,
85 ... power transmission coil,
86 ... Foreign object detection circuit,
87: Detection coil,
90 ... Robot,
91 ... Power receiving device,
92 ... Receiving coil,
93 ... Receiving circuit,
94 ... secondary battery,
95: Electric motor for driving,
96 ... wheels,
SW1 to SW5, SW11, SW12 ... switches.

Claims (13)

A plurality of detection coils of three or more wound around each other and arranged adjacent to each other;
A foreign matter detection circuit for determining the presence or absence of foreign matter in the vicinity of at least one of the plurality of detection coils;
A switch circuit that selectively connects any first detection coil and second detection coil adjacent to each other among the plurality of detection coils to the foreign object detection circuit;
The first detection coil and the second detection coil are connected in parallel to the foreign object detection circuit via the switch circuit,
The foreign object detection circuit includes:
A first detection signal having a predetermined waveform is caused to flow clockwise through the first detection coil via the switch circuit, and at the same time, a second detection signal having the same waveform as that of the first detection signal is supplied to the first detection coil. Causing the second detection coil to flow counterclockwise, thereby generating a composite magnetic field straddling between the first detection coil and the second detection coil;
Either of the first detection coil or the second detection coil according to a change in the combined magnetic field caused by the presence or absence of a foreign matter with reference to the impedance value of the first detection coil or the second detection coil when no foreign matter is present Measure the amount of change in either impedance value,
When the amount of change in the impedance value exceeds a predetermined value, it is determined that there is a foreign object in the vicinity of the first detection coil and the second detection coil.
Foreign object detection device. Each of the first detection coil and the second detection coil is arranged in parallel.
The foreign object detection device according to claim 1. The first detection signal and the second detection signal are alternating current signals or pulse signals,
The foreign object detection device according to claim 1 or 2. The first detection coil includes a first conducting wire wound along the surface, and one of the two terminals of the first conducting wire is an outer terminal arranged on the outer side, and the other is arranged on the inner side. Inner terminal,
The second detection coil includes a second conductive wire wound in the same direction as the first detection coil along the surface, and one of the two terminals of the second conductive wire is disposed outside. A terminal, the other is an inner terminal arranged inside,
The foreign object detection circuit generates the first detection signal and the second detection signal, inputs the first detection signal to one of an outer terminal and an inner terminal of the first detection coil, and the first detection signal is The second detection signal is input to one of an outer terminal and an inner terminal of the second detection coil on the same side as the input terminal of the first detection coil.
The foreign object detection device according to claim 1. The first detection coil includes a first conducting wire wound along the surface, and one of the two terminals of the first conducting wire is an outer terminal arranged on the outer side, and the other is arranged on the inner side. Inner terminal,
The second detection coil includes a second conductive wire wound in the same direction as the first detection coil along the surface, and one of the two terminals of the second conductive wire is disposed outside. A terminal, the other is an inner terminal arranged inside,
The foreign object detection circuit generates one common detection signal having a predetermined waveform, and inputs the common detection signal as the first detection signal to one of an outer terminal and an inner terminal of the first detection coil. The common detection signal is input as the second detection signal to one of the outer terminal and the inner terminal of the second detection coil on the side opposite to the terminal of the first detection coil to which the detection signal is input.
The foreign object detection device according to claim 1. The first detection coil includes a first conducting wire wound along the surface, and one of the two terminals of the first conducting wire is an outer terminal arranged on the outer side, and the other is arranged on the inner side. Inner terminal,
The second detection coil includes a second conductive wire wound in a direction opposite to the first detection coil along the surface, and one of the two terminals of the second conductive wire is disposed outside. An outer terminal, the other is an inner terminal disposed inside,
The foreign object detection circuit generates one common detection signal having a predetermined waveform, and inputs the common detection signal as the first detection signal to one of an outer terminal and an inner terminal of the first detection coil. The common detection signal is input as the second detection signal to one of the outer terminal and the inner terminal of the second detection coil on the same side as the terminal of the first detection coil to which the detection signal is input.
The foreign object detection device according to claim 1. The first detection coil includes a first conducting wire wound along the surface, and one of the two terminals of the first conducting wire is an outer terminal arranged on the outer side, and the other is arranged on the inner side. Inner terminal,
The second detection coil includes a second conductive wire wound in the same direction as the first detection coil along the surface, and one of the two terminals of the second conductive wire is disposed outside. A terminal, the other is an inner terminal arranged inside,
The foreign object detection device further includes at least one phase shifter,
The first detection coil, the second detection coil and the phase shifter are connected in parallel to the foreign object detection circuit via the switch circuit,
The foreign object detection circuit generates one common detection signal having a predetermined waveform, and inputs the common detection signal as the first detection signal to one of an outer terminal and an inner terminal of the first detection coil. The common detection signal is detected by the second detection coil via the phase shifter on one of the outer terminal and the inner terminal of the second detection coil on the same side as the terminal of the first detection coil to which the detection signal is input. Input as a signal,
The foreign object detection device according to claim 1. A foreign object detection device according to claim 1;
A power transmission coil;
A power transmission circuit for inputting high-frequency power to the power transmission coil,
Wireless power transmission device. The power transmission coil includes a housing disposed inside,
The outer periphery of each of the first detection coil and the second detection coil is smaller than the outer periphery of the power transmission coil,
The first detection coil and the second detection coil are disposed between a main surface of the housing and the power transmission coil,
The wireless power transmission apparatus according to claim 8. At least one of the plurality of detection coils is shared with the power transmission coil;
The wireless power transmission apparatus according to claim 8. The power of the first detection signal and the power of the second detection signal are smaller than the high frequency power,
The wireless power transmission apparatus according to claim 8. A control circuit for transmitting the high-frequency power to the power transmission circuit after the foreign object detection circuit determines that there is no foreign object in the vicinity of the plurality of detection coils;
The wireless power transmission apparatus according to claim 8. A wireless power transmission device according to one of claims 8 to 12,
A wireless power receiving device,
Wireless power transmission system.

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