JP2016082848A - Foreign object detector for non-contact power supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a foreign object detector for a non-contact power supply system, where the detector is easy to install on a power transmission coil case.SOLUTION: A foreign object detector for a non-contact power supply system includes an array type foreign object detection sensor 10 comprising a plurality of detection electrodes 21 to 26 arranged in an array shape on a single plane and a ground electrode 30 surrounding outer peripheries of the respective detection electrodes in an electrically connected state. The array type foreign object detection sensor 10 is installed on a power transmission coil case. Each of the array type foreign object detection sensor 10's detection electrodes 21 to 26 and ground electrode 30 has a non-induction coil shape. The existence of a foreign object is detected on the basis of variations in electrostatic capacitance between the detection electrodes 21 to 26 and ground electrode 30. The array type foreign object detection sensor 10 can cover a range wider than a range covered by a single foreign object detection sensor, making it possible to mitigate a load in performing installation on the power transmission coil case.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a foreign object detection device capable of detecting a foreign object that has entered a gap between a power transmission coil and a power receiving coil of a non-contact power supply transformer, and can detect a living organism such as a pet that has entered the gap.

Charging of batteries mounted on electric vehicles and plug-in hybrid vehicles uses an electric cable and connector, but in recent years, cable connection is not required to improve convenience and safety. Research on charging by a non-contact power feeding method is actively conducted in each country.
In this method, as shown in FIG. 16, a secondary coil (power receiving coil) 102 of a non-contact power supply transformer mounted on the floor back surface of the vehicle, and a primary coil (power transmission coil) 202 installed on the ground side. Power is supplied in a non-contact manner to a stopped vehicle from the ground side.
As shown in FIG. 17, the power transmission coil 202 is built in a resin coil case 90 and installed on the ground side. Similarly, the power receiving coil 102 is housed in a resin coil case and fixed to the rear surface of the vehicle floor.

In this charging method, foreign matter such as coins and cans may enter the gap between the power transmission coil 202 and the power reception coil 102. These foreign matters generate heat due to the magnetic flux at the time of non-contact power supply and cause an accident, and also reduce the efficiency of non-contact power supply.
Therefore, various methods for detecting foreign matter have been studied.
For example, Patent Document 1 below discloses a method for detecting a metallic foreign object by utilizing changes in characteristics such as power supply efficiency depending on the presence or absence of the metallic foreign object. Also known is a method of detecting a metallic foreign object by detecting a temperature change.

The present inventors have previously proposed a foreign object detection device that can detect not only hardware foreign objects but also small animals such as pets in the gap between the power receiving coil and the power transmission coil (Patent Document 2 below). ).
This foreign object detection device detects a foreign object by utilizing the fact that the capacitance between the electrodes of the foreign object detection sensor having electrodes spaced apart on a plane changes depending on the foreign object. Are arranged on the case of the power transmission coil to detect foreign matter that has entered the gap between the power transmission coil and the power reception coil.
FIG. 18 shows an example of the foreign object detection sensor. The foreign matter detection sensor includes a detection electrode 312 disposed at the center and a ground electrode 322 disposed at the outer periphery, and the detection electrode 312 and the ground electrode 322 are respectively in the electrode at the time of non-contact power feeding. Inductive currents in opposite directions are generated by the magnetic fluxes, and they cancel each other out to have a pattern (non-inductive coil shape) in which the induced current becomes zero.

  When the detection electrode 312 and the ground electrode 322 are formed of copper foil, as shown in FIG. 18, the open end of the pattern of the detection electrode 312 is connected by a resistor 313 to form a closed circuit, and the ground electrode 322 is opened. Although it is desirable to connect the ends with a resistor 323 to form a closed circuit, when the pattern of the detection electrode 312 and the ground electrode 322 is formed of silver paste or carbon paste, the closed circuit should be formed without using a resistor. Can do.

When a foreign substance exists on the foreign substance detection sensor, the capacitance between the detection electrode 312 and the ground electrode 322 increases. This increase in capacitance is detected as a decrease in the oscillation frequency of the oscillation circuit.
A plurality of foreign matter detection sensors are arranged side by side on the upper surface of the power transmission coil case 90 of FIG. If foreign matter detection sensors are connected in order to the oscillation circuit via a multiplexer or the like, it is possible to identify the foreign matter detection sensor in which a change in the oscillation frequency appears, and the location of the foreign matter. Can be identified.

JP 2013-59239 A Japanese Patent Application No. 2014-104681

However, the foreign object detection sensor proposed in Patent Document 2 is extremely small compared to the area of the power transmission coil case.
The foreign object detection sensor needs to be set to a size suitable for the object to be detected, but if the foreign object detection sensor proposed in Patent Document 2 is similarly increased in size according to the size of the power transmission coil case, A dead zone occurs in the center, and foreign objects cannot be detected properly.
Therefore, when using the foreign matter detection sensor of Patent Document 2, it is necessary to arrange a large number of foreign matter detection sensors on the power transmission coil case, and accordingly, the wiring work becomes complicated, and the foreign matter detection sensor is installed. There is a problem that a lot of time is taken.

  The present invention was devised in view of such circumstances, and a foreign object detection device for a non-contact power supply system that can detect not only hardware foreign objects but also living organisms and can be easily installed on a power transmission coil case. It is intended to provide.

The present invention is installed in a power transmission coil case in which a power transmission coil of a non-contact power supply transformer is incorporated, and detects a foreign matter that enters between the power reception coil case in which the power reception coil of the non-contact power supply transformer is incorporated and the power transmission coil case. A foreign matter detection apparatus having an array type foreign matter detection sensor having a plurality of detection electrodes arranged in an array on the same plane and a ground electrode surrounding each of the detection electrodes, and this array type foreign matter detection sensor Are installed in the power transmission coil case. The detection electrode and the ground electrode of the array type foreign object detection sensor each have a non-inductive coil shape, and the presence or absence of a foreign object is detected based on the change in capacitance between the detection electrode and the ground electrode.
Compared to a single foreign object detection sensor, the array type foreign object detection sensor can cover a wider area, and thus can reduce the burden on installation on the power transmission coil case. The number of connected foreign matter detection sensors (capacitors) included in the array-type foreign matter detection sensor is appropriately set in consideration of the detection target, the detection environment, and the like. An array-type foreign object detection sensor having a non-inductive coil-shaped detection electrode and a ground electrode does not adversely affect non-contact power supply even if it is arranged directly above a power transmission coil that is being supplied with power.

In the foreign matter detection device of the present invention, the ground electrodes of the array type foreign matter detection sensor are electrically connected to each other, and a plurality of capacitors each composed of the detection electrodes and the ground electrode are electrically connected in parallel. It is desirable that
Since the combined capacity of capacitors connected in parallel is larger than that of a single capacitor, it is convenient when a foreign object detection circuit is configured by adding a coil or the like.

In the foreign matter detection device of the present invention, a plurality of capacitors each including a detection electrode of the array type foreign matter detection sensor and a ground electrode surrounding each detection electrode may be electrically connected in series.
The combined capacitance of the capacitors connected in series is smaller than the capacitance of a single capacitor. However, if the number of capacitors connected is reduced or the inductance of the added coil is increased, foreign matter can be detected without hindrance.

In the foreign matter detection device of the present invention, a resonance circuit is configured by adding coils to a plurality of capacitors of the array type foreign matter detection sensor, and the presence or absence of foreign matter is detected by supplying alternating current of the resonance frequency to the resonance circuit.
When foreign matter is present on the array type foreign matter detection sensor, the characteristic at the resonance frequency changes. By observing the change, the presence or absence of foreign matter can be detected.

In the foreign object detection device of the present invention, it is desirable that the resonance circuit is a parallel resonance circuit.
In the parallel resonance circuit, the change in impedance due to the presence of foreign matter is generally larger than that in the series resonance circuit. Therefore, highly accurate foreign object detection is possible.
In the foreign object detection device of the present invention, the resonance circuit may be a series resonance circuit.

Moreover, in the foreign material detection apparatus of this invention, it is desirable to detect the presence or absence of a foreign material based on the change of the impedance of a resonance circuit.
The presence / absence of a foreign substance is detected based on the impedance value (| Z |) at the resonance frequency and the phase change.

Moreover, in the foreign material detection apparatus of this invention, you may make it include the array type foreign material detection sensor from which the number of connections of a capacitor differs in the several array type foreign material detection sensor installed in a power transmission coil case.
For example, the number of capacitors connected to the array type foreign matter detection sensor may be small in the array type foreign matter detection sensor arranged right above the power transmission coil, and may be increased in the array type foreign matter detection sensor placed at a position away from the power transmission coil. .

Moreover, in the foreign material detection apparatus of this invention, the foreign material detection by the array type | mold foreign material detection sensor installed in the area | region on the transmission coil of a power transmission coil case, and the foreign material by the array type | mold foreign material detection sensor installed in the other area | region of the power transmission coil case These detections may be performed independently.
Since the resonance frequency changes depending on whether the array type foreign matter detection sensor is installed in the area on the transmission coil of the power transmission coil case or in other areas, it is better to make the detection circuit independent for each area. .

Since the foreign object detection device of the present invention detects foreign objects based on the change in capacitance of the capacitors constituting the array type foreign object detection sensor, only the metallic foreign object is placed in the gap between the power transmission coil case and the power reception coil case. It is also possible to detect when a living organism has entered.
In addition, the array type foreign matter detection sensor can cover a wider range than a single foreign matter detection sensor, and therefore, the burden on installation on the power transmission coil case can be reduced.

The figure which shows an example of the array type | mold foreign material detection sensor (a some capacitor is connected in parallel) used with the foreign material detection apparatus of this invention The figure which shows the other example of an array type foreign material detection sensor The figure explaining the manufacturing method of an array type foreign material detection sensor The figure which shows the foreign material detection circuit provided with the parallel resonance circuit of an array type foreign material detection sensor, The figure which shows the foreign material detection circuit provided with the series resonance circuit of an array type foreign material detection sensor, The figure which shows the frequency characteristic (a) of a parallel resonance circuit, and the frequency characteristic (b) of a series resonance circuit The figure which shows the measured value of the change of the impedance and the phase by various foreign matters The figure which compared the phase difference data of a parallel resonance circuit and a series resonance circuit based on the measured value of FIG. The figure which compared the impedance data of a parallel resonant circuit and a series resonant circuit based on the measured value of FIG. The figure which shows the influence on impedance (a) and phase (b) by rain Diagram showing the effect of rain on foreign object detection The figure which shows the control system which controls non-contact electric power feeding based on the detection result of an array type foreign matter detection sensor FIG. 12 is a flowchart showing the operation of the control system of FIG. The figure which shows the difference in the frequency characteristic by the position on the power transmission coil case of the array type foreign matter detection sensor The figure which shows the array type | mold foreign material detection sensor (a some capacitor is connected in series) used with the foreign material detection apparatus of this invention Diagram showing a contactless power supply system for electric vehicles Diagram showing power transmission coil case A diagram showing a conventional foreign matter detection sensor

FIG. 1 shows an example of an array type foreign matter detection sensor 10 used in the foreign matter detection device of the present invention.
This array-type foreign matter detection sensor 10 has six detection electrodes 21, 22, 23, 24, 25, 26 arranged in a straight line at intervals on a plane, and outer peripheries of the detection electrodes 21-26. And a ground electrode 30 that is surrounded by an electrical connection. The detection electrodes 21 to 26 and the ground electrode 30 have a non-inductive coil shape.
In this array type foreign matter detection sensor 10, six foreign matter detection sensors (capacitors) each including detection electrodes 21 to 26 and a ground electrode 30 surrounding them are combined in an array, and adjacent detections are made. The ground electrode portions between the electrodes (21 and 22, 22 and 23, 23 and 24, 24 and 25, 25 and 26) are both foreign matter detection sensors as part of the ground electrode surrounding each of the adjacent detection electrodes. Shared.

The detection electrodes 21 to 26 are connected to the electric wire 40 in parallel. In addition, one end 50 of the electrically connected ground electrode 30 is led out for connection. (In FIG. 1, the ground electrode 30 is shown to be cut at the position of the lead-out line connecting the detection electrodes 21 to 26 to the electric wire 40. Not cut.)
This array type foreign matter detection sensor 10 corresponds to a configuration in which six capacitors arranged in a straight line are connected in parallel.

  The arrangement of the capacitors in the array type foreign object detection sensor 10 may be an arrangement as shown in FIGS. 2A, 2B, 2C, and 2D, or an arrangement of its rotating body or mirror image. In any case, the ground electrode surrounding the outer periphery of each detection electrode is electrically connected, and a plurality of capacitors included in the array type foreign object detection sensor 10 are connected in parallel.

  A plurality of the array type foreign matter detection sensors 10 are arranged on a power transmission coil case 90 shown in FIG. The detection electrodes 21 to 26 and the ground electrode 30 of the array type foreign object detection sensor 10 have a non-inductive coil shape, and no induced current is generated even when receiving magnetic flux during non-contact power feeding. Therefore, even if this array type foreign object detection sensor 10 is arranged at the position of the power transmission coil case 90 that is directly above the power transmission coil 202, there is no problem with non-contact power feeding.

This array type foreign matter detection sensor is produced as follows. 3A, 3B, and 3C are sectional views showing the manufacturing process.
A non-conductive substrate 80 such as an acrylic resin is prepared, and a conductive thin film 81 such as copper or ITO (transparent electrode material) is formed thereon. A photoresist 82 is applied thereon, and a repeated pattern of the array type foreign matter detection sensor is baked onto the photoresist 82 using photolithography (FIG. 3A).
Next, the exposed portion of the conductive thin film 81 is removed by wet etching or dry etching (FIG. 3B).
Next, the remaining photoresist 82 is removed. At this time, in order to prevent corrosion of the conductive thin film 81, the pattern of the conductive thin film 81 may be covered with a non-conductor 83 (FIG. 3C).
Further, the detection electrode and the ground electrode may be laminated by repeating the process of FIG. By laminating these electrodes, there is an advantage that electrical connection is facilitated and non-induction is facilitated.
Next, the array shape of the array type foreign matter detection sensor is separated from the substrate 80.
Thus, the array type foreign matter detection sensor is completed.

Next, a foreign matter detection circuit that detects foreign matter using an array type foreign matter detection sensor will be described.
As shown in FIGS. 4 and 5, a coil 62 is connected to the array type foreign object detection sensor 10 in which a plurality of capacitors are connected in parallel to form a resonance circuit, and an alternating current at the resonance frequency of this resonance circuit is supplied to the LCR meter 61. Supplied from the built-in oscillator. Then, the impedance value (| Z |) and phase of the resonance circuit are measured by the LCR meter 61. The oscillator may be independent from the LCR meter 61.

FIG. 4 shows a case where a coil 62 is connected in parallel to the array-type foreign object detection sensor 10 and a parallel resonance circuit is formed by the combined capacitance of the array-type foreign object detection sensor 10 in which a plurality of capacitors are connected in parallel and the inductance of the coil 62. Is shown. FIG. 5 shows a case where the coil 62 is connected in series to the array type foreign object detection sensor 10 and a series resonance circuit is configured by the combined capacitance of the array type foreign object detection sensor 10 and the inductance of the coil 62.
When there is no foreign object, the impedance value (1) and the phase (2) change in the parallel resonance circuit near the resonance frequency as shown in FIG. On the other hand, in the series resonance circuit, the impedance value (1) and the phase (2) change near the resonance frequency as shown in FIG.
When alternating current of resonance frequency is supplied to this resonance circuit, if foreign matter exists on the array type foreign matter detection sensor 10, resonance cannot be obtained, and the impedance value and phase are shown in FIGS. ) From the resonance state.

Figure 7 uses five types of foreign coins (one yen, ten yen, one hundred yen, one cent, 0.5 euro) as foreign objects, silver paper for cigarettes, and a water balloon (water capacity: 25 ml) as a biological substitute. When there is no foreign substance, and the impedance value at the resonance frequency and the phase angle measured when these foreign substances are present, the measured value in the parallel resonant circuit and the measured value in the series resonant circuit. It is shown separately.
Further, FIG. 8 compares the measured value (1) of the parallel resonant circuit with the measured value (2) of the series resonant circuit with respect to the phase difference based on the result of FIG. FIG. 9 compares the measured value (1) of the parallel resonant circuit and the measured value (1) of the series resonant circuit with respect to the rate of change in impedance based on the result of FIG.
8 and 9, it can be seen that the parallel resonant circuit of FIG. 4 has a larger rate of change due to foreign matter than the series resonant circuit of FIG. 5, and is desirable as a foreign matter detection circuit.

Further, the foreign object detection circuit (FIG. 4) including the parallel resonance circuit of the array type foreign object detection sensor 10 can perform appropriate foreign object inspection even in an environment where it rains.
FIG. 10 shows a state where minute water droplets such as drizzle float on the power transmission coil case 90 (Wet1), a state where water droplets such as raindrops float (Wet2), and a state where water is uniformly on the surface ( Wet 3) is created and the impedance (FIG. 10 (a)) and phase angle (FIG. 10 (b)) in each state and the Dry state (where no foreign matter is present) are detected by the foreign object detection circuit of FIG. The result of having measured the frequency characteristic of is shown. FIG. 10 shows that even if the power transmission coil case 90 gets wet in the rain, there is no significant change in the impedance value or phase.

FIG. 11 shows the ratio of change in impedance at the resonance frequency (FIG. 11 (a)) and phase difference (FIG. 11 (b)) in each of the states Wet1, Wet2, Wet3, and Dry when foreign matter is present. Shows how it changes depending on the foreign object. The foreign material shown in FIG. 7 is used. The four bar graphs displayed for each foreign object indicate the measurement results in the states of Dry, Wet1, Wet2, and Wet3 from the left.
From FIG. 11, it can be seen that foreign object detection is possible even when the power transmission coil case 90 gets wet in the rain. In addition, it can be seen that the change in the phase difference is more conspicuous, and the foreign object can be detected stably even in an environment wet with rain.

Next, an example of a control system for controlling the high-frequency power source for non-contact power supply based on the detection result of the array type foreign object detection sensor 10 will be described.
As shown in FIG. 12, this control system includes one or more array-type foreign matter detection sensors 10 installed on a power transmission coil case 90, an LCR meter 61 incorporating an oscillator, and a parallel resonance detected by the LCR meter 61. A foreign matter determination unit 64 that identifies the presence or absence of foreign matter from the impedance value and phase angle of the circuit, and a high-frequency power source that controls on / off of a high-frequency power source for contactless power supply (not shown) based on the identification result of the foreign matter determination unit 64 And a control unit 63.

The operation of this control system is shown in the flowchart of FIG.
The oscillator with the frequency set to the resonance frequency of the parallel resonance circuit including the array type foreign object detection sensor 10 is output from the oscillator built in the LCR meter 61 (St. 1).
The LCR meter 61 detects the phase and impedance of the parallel resonance circuit (St. 2), and outputs the detection result to the foreign matter determination unit 64.
The foreign matter determination unit 64 holds in advance the phase and impedance data at the resonance frequency of the resonance circuit in a state where no foreign matter is present, and the held data and the phase and impedance sent from the LCR meter 61 Are compared to determine whether or not a foreign object exists on the array type foreign object detection sensor 10 (St. 3). When it is determined that there is no foreign object (No in St. 3), the fact is notified to the high frequency power supply control unit 63, and the high frequency power supply control unit 63 turns on the high frequency power supply for noncontact power supply and performs noncontact power supply. (St. 4).
The LCR meter 61 continues to detect the phase and impedance of the parallel resonance circuit (St. 5), and continues to send the detection result to the foreign matter determination unit 64.

Each time the detection result is sent from the LCR meter 61, the foreign matter determination unit 64 compares the held phase and impedance data with the sent phase and impedance, and puts it on the array type foreign matter detection sensor 10. It is determined whether or not a foreign object exists (St. 6). If no foreign matter is present, St. 5 and St. The operation of 6 is repeated.
When the foreign matter determination unit 64 determines that there is a foreign matter (Yes in St. 6), the foreign matter determination unit 64 notifies the high frequency power supply control unit 63 of the fact, and the high frequency power supply control unit 63 performs contactless power supply. The high frequency power supply is turned off (St. 7), and a foreign object detection alarm is displayed (St. 8).
Also, if the foreign matter determination unit 64 determines that there is a foreign matter before the non-contact power feeding is started (Yes in St. 3), St. The process proceeds to 8, and a foreign object detection alarm is displayed.
After the display of the foreign object detection alarm, St. If the procedure from step 2 onward is repeated and there is no foreign matter on the array type foreign matter detection sensor 10, the high-frequency power source for non-contact power supply is turned on and non-contact power supply is performed.

  In this control system, the position of the array type foreign matter detection sensor 10 where foreign matter is present cannot be specified. When it is necessary to specify the position of the foreign matter, as described in Patent Document 2, St. 1, parallel resonant circuits that output alternating current may be sequentially connected using a multiplexer or the like so that the parallel resonant circuit determined by the foreign matter determination unit 64 as having a foreign object can be identified.

Since the cover range of the array-type foreign object detection sensor 10 on the power transmission coil case 90 is wider than that of a conventional foreign object detection sensor, the burden on installation on the power transmission coil case 90 can be reduced.
The number of capacitors connected in the array type foreign object detection sensor 10 can be appropriately selected according to the detection target, the detection environment, and the like. When it is necessary to specify the position of a foreign object, it is necessary to select the number of capacitor connections in consideration of the fact that the resolution of the position decreases if the number of capacitor connections is too large.

FIG. 14 shows the frequency characteristics of impedance and phase when the array type foreign object detection sensor 10 having the same number of connected capacitors is installed in the region 100 away from the power transmission coil 202 of the power transmission coil case 90 shown in FIG. 14 (a)) and impedance and phase frequency characteristics (FIG. 14 (b)) when installed at a position directly above the power transmission coil 202.
When installed at a position directly above the power transmission coil 202 (FIG. 14 (b)), because of the influence of the ferrite core of the power transmission coil 202, the position of the resonance frequency is compared with the characteristics of FIG. 14 (a). In addition, the impedance value at the resonance frequency is increased.
Such a difference in characteristics depending on the installation position of the array-type foreign object detection sensor 10 can be eliminated by changing the number of capacitors connected to the array-type foreign object detection sensor 10 according to the installation position.

  Further, the detection of foreign matter by the array type foreign matter detection sensor 10 installed in the region on the transmission coil 202 of the power transmission coil case 90 and the detection of foreign matter by the array type foreign matter detection sensor 10 installed in the other region 100 of the power transmission coil case 90. May be performed by independent foreign matter detection circuits.

In addition, this invention is not restricted to the structure shown here, A various deformation | transformation is possible. In FIG. 1 and FIG. 2, the number of capacitors included in the array type foreign object detection sensor 10 is six, but the number of capacitors connected may be other than six.
Here, an array type foreign matter detection sensor in which a plurality of capacitors are connected in parallel is shown. In this case, when configuring the resonance circuit of the array type foreign matter detection sensor, for example, the combined capacitance when n capacitors having a capacitance C ₀ of about 4 pF are connected in parallel is nC ₀ , and the resonance frequency is set to an appropriate level. Selection of a resonance coil for setting is easy.
However, as shown in FIG. 15, even when a plurality of capacitors included in the array type foreign matter detection sensor are connected in series, the number of connected capacitors is reduced so that the combined capacitance C ₀ / n does not become too small (FIG. 15). In this case, five capacitors are connected.) By using a resonance coil having a large inductance, foreign matter can be detected.

  The foreign object detection device of the present invention can be widely used for the safe implementation of non-contact power feeding of various moving bodies such as electric vehicles, plug-in hybrid vehicles, and automatic guided vehicles.

DESCRIPTION OF SYMBOLS 10 Array type foreign matter detection sensor 21 Detection electrode 22 Detection electrode 23 Detection electrode 24 Detection electrode 25 Detection electrode 26 Detection electrode 30 Ground electrode 40 Electric wire 50 Connection end 61 LCR meter 62 Coil 63 High frequency power supply control part 64 Foreign substance determination part 80 Substrate 81 Conductivity Thin film 82 Photo resist 83 Non-conductor 90 Power transmission coil case 102 Secondary coil (power receiving coil)
202 Primary coil (power transmission coil)
312 Detection electrode 313 Resistance 322 Ground electrode 323 Resistance

Claims (9)

A foreign object detection device that is installed in a power transmission coil case in which a power transmission coil of a non-contact power supply transformer is built in and detects a foreign material that enters between the power reception coil case in which the power reception coil of the non-contact power supply transformer is built in and the power transmission coil case Because
Having an array type foreign matter detection sensor comprising a plurality of detection electrodes arranged in an array on the same plane and a ground electrode surrounding the outer periphery of each of the detection electrodes;
One or more array type foreign matter detection sensors are installed in the power transmission coil case,
Each of the detection electrode and the ground electrode of the array type foreign matter detection sensor has a non-inductive coil shape,
A foreign matter detection device for a non-contact power feeding system, wherein presence or absence of foreign matter is detected based on a change in electrostatic capacitance between the detection electrode and the ground electrode.   2. The foreign matter detection device according to claim 1, wherein the ground electrodes of the array type foreign matter detection sensor are electrically connected to each other, and a plurality of capacitors configured by each of the detection electrodes and the ground electrode are provided. Foreign matter detection device for non-contact power supply system, characterized by being electrically connected in parallel.   2. The foreign matter detection device according to claim 1, wherein a plurality of capacitors including the detection electrode of the array-type foreign matter detection sensor and the ground electrode surrounding the detection electrode are electrically connected in series. A foreign matter detection device for a non-contact power feeding system.   4. The foreign matter detection device according to claim 2, wherein a coil is added to the plurality of capacitors of the array type foreign matter detection sensor to form a resonance circuit, and an alternating current having a resonance frequency is supplied to the resonance circuit. A foreign matter detection device for a non-contact power feeding system, wherein presence or absence of foreign matter is detected.   5. The foreign object detection device according to claim 4, wherein the resonance circuit is a parallel resonance circuit.   The foreign object detection device according to claim 4, wherein the resonance circuit is a series resonance circuit.   5. The foreign matter detection device according to claim 4, wherein the presence or absence of foreign matter is detected based on a change in impedance of the resonance circuit.   2. The foreign object detection device according to claim 1, wherein the array type foreign object detection sensors having different numbers of the detection electrodes are included in the plurality of array type foreign object detection sensors installed in the power transmission coil case. A foreign matter detection device for a non-contact power feeding system.   The foreign matter detection device according to claim 1, wherein the foreign matter is detected by the array-type foreign matter detection sensor installed in a region on the transmission coil of the power transmission coil case, and is installed in another region of the power transmission coil case. The foreign object detection device for a non-contact power feeding system, wherein the foreign object detection by the array type foreign object detection sensor is performed independently.