JP2014117085A - Non-contact electric power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact electric power supply device capable of properly detecting foreign objects existing on a surface of a housing for housing a coil.SOLUTION: A non-contact power supply system includes: a reader unit for optically reading an upper surface 121 of a housing 120 for housing a power transmission coil, which faces a power reception coil; and a foreign object detection part which detects foreign objects existing on the upper surface 121 of the housing 120. In the housing 120, an identification code 122 which is optically readable is disposed on the upper surface 121 of the housing 120. The foreign object detection part detects the foreign objects existing on the upper surface 121 of the housing 120 on the basis of the reading result of the identification code 122 which is read by the reader unit.

Description

  The present invention relates to a non-contact power feeding device.

  2. Description of the Related Art Conventionally, a non-contact power feeding device that supplies power in a non-contact manner by magnetic coupling of a pair of coils is known (see, for example, Patent Document 1), and is applied to an electric vehicle such as an electric vehicle. For example, one coil connected to an AC power source is installed in a parking space such as a power supply stand, and the other coil connected to a battery is installed in an electric vehicle. And by using the coil on the parking space side as the primary coil and the coil on the electric vehicle side as the secondary coil, the AC power source on the parking space side is transferred to the battery on the vehicle side via one coil and the other coil. Power can be supplied.

JP 2011-72074 A

  By the way, when used in such a non-contact power feeding device, the coil is placed in a target location in a state of being housed in the housing, but since it is used outdoors, unintentionally, Foreign matter such as iron may be present on the surface. If power is supplied in such a state, the foreign matter may be heated by the magnetic flux generated in the coil.

  This invention is made | formed in view of this situation, The objective is to detect appropriately the foreign material which exists on the surface of the housing | casing which accommodates a coil in a non-contact electric power feeder.

  In order to solve such a problem, the present invention provides a reading unit that optically reads the surface of a housing that houses therein a first coil that is magnetically coupled to the second coil, and the surface of the housing. And a detection unit for detecting foreign matter to be detected. Here, the housing is provided with an optically readable identification code on the surface of the housing, and the detection unit exists on the surface of the housing based on the result of reading the identification code by the reading unit. Detect foreign objects.

  According to the present invention, when a foreign object is present, the identification code cannot be read by the foreign object. Therefore, the presence of the foreign object can be effectively detected by referring to the reading result of the identification code. it can.

Block diagram schematically showing the configuration of the non-contact power supply system A top view schematically showing a state of a housing that houses a power transmission coil installed in a parking space Explanatory drawing of the power transmission coil housed in the housing Explanatory drawing which shows the relationship between a reading unit and the housing | casing which accommodates a receiving coil. Illustration of identification code consisting of unit codes of the same size Explanatory drawing which shows the relationship between a reading unit and the housing | casing which accommodates a receiving coil. Top view schematically showing the state of a housing that houses a power transmission coil installed in a parking space

(First embodiment)
FIG. 1 is a block diagram schematically showing the configuration of the non-contact power feeding system according to this embodiment. The non-contact power supply system includes a power supply device 100 that is a ground-side unit, and an electric vehicle (hereinafter simply referred to as “vehicle”) 200 that includes the vehicle-side unit. The non-contact power supply system is a system that supplies power from the power supply apparatus 100 in a non-contact manner and charges a battery 28 provided in the vehicle 200 (non-contact power supply apparatus).

  The power supply apparatus 100 is installed in a charging stand or the like provided with a parking space for the vehicle 200 and supplies power to the vehicle 200. The power supply apparatus 100 is mainly configured by a power control unit 11, a power transmission coil 12, a wireless communication unit 14, and a control unit 15.

The power control unit 11 is a circuit for converting AC power transmitted from the AC power source 300 into high-frequency AC power and transmitting the power to the power transmission coil 12. The power control unit 11 includes a rectification unit 111, a PFC (Power Factor Correction) circuit 112, an inverter 113, and a sensor 114.

  The rectifying unit 111 is electrically connected to the AC power supply 300 and rectifies output AC power from the AC power supply. The PFC circuit 112 is a circuit for improving the power factor by shaping the output waveform from the rectifying unit 111, and is connected between the rectifying unit 111 and the inverter 113. The inverter 113 is a power conversion device including a switching element such as a smoothing capacitor and IGBT, a PWM control circuit, and the like. The inverter 113 converts DC power into high-frequency AC power based on a control signal from the control unit 15, and To supply. The sensor 114 is connected between the PFC circuit 112 and the inverter 113 and detects current and voltage.

  The power transmission coil 12 is a coil for supplying electric power in a non-contact manner to the power reception coil 22 on the vehicle 200 side, and has a structure in which a conductive wire made of a conductor such as metal is spirally wound in a predetermined plane. doing. The power transmission coil 12 is provided at a target location such as a parking space where the vehicle 200 is parked, and faces the lower side of the power receiving coil 22 on the vehicle 200 side when the vehicle 200 is parked at a specified position in the parking space.

  The wireless communication unit 14 performs bidirectional communication with the wireless communication unit 24 provided on the vehicle 200 side. Since the communication frequency between the wireless communication unit 14 and the wireless communication unit 24 is set to a frequency higher than the frequency used in the vehicle peripheral device such as intelligence ski, the wireless communication unit 14 and the wireless communication unit 24 Even if it communicates between, vehicle peripheral devices are hard to receive the interference by the said communication. For communication between the wireless communication unit 14 and the wireless communication unit 24, for example, various wireless LAN methods are used, and communication methods suitable for long distances are used.

  The control unit 15 has a function of controlling the power supply apparatus 100. For example, the control unit 15 controls the power control unit 11, the power transmission coil 12, and the wireless communication unit 14. The control unit 15 transmits a control signal to start power supply to the vehicle 200 side or receives power from the vehicle 200 side through communication between the wireless communication unit 14 and the wireless communication unit 24. Receive control signals. The control unit 15 performs switching control of the inverter 113 based on the detection current of the sensor 114 and controls electric power supplied from the power transmission coil 12. As the control unit 15, a microcomputer mainly composed of a CPU, a ROM, a RAM, and an I / O interface can be used.

Moreover, in the relationship with this embodiment, the control part 15 is provided with the foreign material detection part 150, when this is caught functionally. The foreign object detection unit 150 detects a foreign object existing between the power transmission coil 12 and the power reception coil 22 based on information output from the vehicle 200 side through communication between the wireless communication unit 14 and the wireless communication unit 24. I do. Details of the foreign object detection method will be described later.

  The vehicle 200 includes a power receiving coil 22, a reading unit 23, a wireless communication unit 24, a charging control unit 25, a rectifying unit 26, a relay unit 27, a battery 28, an inverter 29, a motor 30, and a notification unit. 32.

  The power receiving coil 22 is a coil for receiving power in a non-contact manner from the power transmitting coil 12 on the power supply apparatus 100 side, and has a structure in which a conductive wire made of a conductor such as metal is wound in a spiral shape. The power receiving coil 22 is provided at a target location, for example, between the rear wheels on the bottom surface (chassis) or the like of the vehicle 200, and when the vehicle 200 is parked at a specified position in the parking space, It faces the upper side of the power transmission coil 12.

  The reading unit 23 optically reads an identification code 122 described later, and outputs a signal indicating the reading result to the charging control unit 25. The reading unit 23 includes, for example, an imaging circuit such as a camera and an image processing circuit that processes an image signal from the imaging circuit. In addition to the image pickup circuit, the reading unit 23 may use an infrared unit that outputs infrared rays and receives the reflected light, and a known technique can be applied.

  The wireless communication unit 24 performs bidirectional communication with the wireless communication unit 14 provided on the power supply apparatus 100 side.

  The rectifying unit 26 is connected to the power receiving coil 22 and is configured by a rectifying circuit that rectifies AC power received by the power receiving coil 22 into direct current.

  The relay unit 27 includes a relay switch that is turned on and off under the control of the charging control unit 25. The relay unit 27 can disconnect the high-power system including the battery 28 from the low-power system of the power receiving coil 22 and the rectifying unit 26 serving as a charging circuit unit by turning off the relay switch.

  The battery 28 is a power source of the vehicle 200 and is configured by electrically connecting a plurality of secondary batteries, for example.

  The inverter 29 is a power conversion device that includes a switching element such as an IGBT, a PWM control circuit, and the like. The inverter 29 converts the DC power output from the battery 28 into AC power based on the control signal, and converts the AC power to the motor 30. Supply. The motor 30 is composed of, for example, a three-phase AC motor, and is a drive source for driving the vehicle 200.

  The notification unit 32 includes a warning lamp, a display of a navigation system, a speaker, and the like, and is arranged on an instrument panel or the like in the vehicle interior. The notification unit 32 outputs light, an image, sound, or the like to the user based on the control by the charging control unit 25.

  The charging control unit 25 has a function of controlling charging of the battery 28. For example, the charging control unit 25 receives a control signal for starting power supply from the power supply apparatus 100 side or supplies a control signal for receiving power through communication between the wireless communication unit 24 and the wireless communication unit 14. Or transmitted to the device 100 side. In addition, the charging control unit 25 transmits a reading result by the reading unit 23 to the power feeding apparatus 100 side through communication between the wireless communication unit 24 and the wireless communication unit 14.

  Although not shown, the charging control unit 25 is connected to a controller that controls the entire vehicle 200 via a CAN communication network. The controller manages the switching control of the inverter 29 and the state of charge (SOC) of the battery 28. When the charging control unit 25 determines full charging based on the SOC of the battery 28 obtained from the controller, the charging control unit 25 transmits a control signal to the power supply apparatus 100 to end charging.

  In the non-contact power feeding system according to the present embodiment, high-frequency power is transmitted between the power transmission coil 12 and the power receiving coil 22 in a non-contact state by electromagnetic induction. That is, when a voltage is applied to the power transmission coil 12 that is the primary coil, magnetic coupling occurs between the power transmission coil 12 and the power reception coil 22 that is the secondary coil, and power is transmitted from the power transmission coil 12 to the power reception coil 22. Supplied.

  In this non-contact power supply system, when the power transmission coil 12 on the power supply apparatus 100 side and the power reception coil 22 on the vehicle 200 side are installed at a target location, they are placed inside the casing from the viewpoint of coil protection and security. Contained.

  FIG. 2 is a top view schematically showing the state of the housing 120 that houses the power transmission coil 12 installed in the parking space. The power transmission coil 12 on the power feeding apparatus 100 side is disposed in the parking space in a state of being housed inside the housing 120. The power transmission coil 12 is housed so that a spiral coil portion is parallel to the upper surface 121 of the housing 120, and the upper surface 121 of the housing 120 faces the power receiving coil 22, which is a counterpart coil, during power feeding. Become. For this reason, the device 120 on the power transmission coil 12 side installed in the parking space is devised for detecting foreign matter present on the upper surface 121 thereof.

  Specifically, an optically detectable identification code 122 is disposed on the upper surface 121 of the housing 120. The identification code 122 may be arranged by drawing a predetermined code on a sheet-like member by printing or the like, and affixing the sheet-like member to the upper surface 121 of the casing 120. You may arrange | position by drawing a code | cord | chord directly on the upper surface 121 of this.

  The identification code 122 is configured by two-dimensionally arranging a plurality of unit codes 122a and 122b. The individual unit codes 122 a and 122 b function as a minimum unit code that can be recognized by the reading unit 23. For example, as the unit codes 122a and 122b, a one-dimensional code such as a bar code, a two-dimensional code such as a QR code (registered trademark), and other codes can be widely used. Here, the individual unit codes 122a and 122b may be configured by codes including information of the same content (that is, codes having the same pattern). However, in the present embodiment, the unit codes 122a and 122b are arranged. It is composed of a code including information indicating a position on the upper surface 121 of the housing 120.

  Here, the heating energy received by the foreign matter by the magnetic flux is in an environment where the foreign material has the same material (permeability, conductivity) and size (projected area in the direction of the magnetic flux), and the output condition (frequency) of the power transmission coil 12 is the same. Then, it is known that it is proportional to the square of magnetic flux density. That is, on the upper surface 121 of the housing 120, the larger the magnetic flux density of the magnetic flux generated in the power transmission coil 12, the greater the heating energy received by the foreign matter by the magnetic flux, that is, the heat generation of the foreign matter.

  FIG. 3A is an explanatory diagram schematically showing the state of the power transmission coil 12 housed in the housing 120, and FIG. 3B shows the distance L and magnetic flux from the coil center toward the radially outer side. It is explanatory drawing which shows the relationship with the density H. FIG. In the drawing, Cin represents a distance L corresponding to the innermost circumference of the coil, and Cout represents a distance L corresponding to the outermost circumference of the coil. As shown in the figure, the magnetic flux density H increases as the coil region increases. In the coil region, the magnetic flux density H increases from the inner peripheral side to the outer peripheral side of the coil and decreases through a maximum. ing.

  In the present embodiment, the size of the unit codes 122a and 122b is set according to the magnetic flux density of the power transmission coil 12 for the individual unit codes 122a and 122b. Specifically, from the viewpoint of setting the foreign matter detection capability (resolution) high at a position where the heat generation (magnetic flux density) of the foreign matter is assumed to be large, the region corresponding to the power transmission coil 12 has a small unit code. 122a is arranged, and in a region not corresponding to the power transmission coil 12, a large unit code 122b having a size larger than the small size is arranged. In other words, the identification code 122 is composed of a circular region composed of a plurality of large unit codes 122b and an annular region located outside thereof and composed of a plurality of small unit codes 122a. It is configured.

  FIG. 4 is an explanatory diagram showing the relationship between the reading unit 23 and the housing 220 that houses the power receiving coil 22. Similarly to the power transmission coil 12, the power reception coil 22 is disposed on the bottom surface side of the vehicle 200 while being housed inside the housing 220. Here, the power receiving coil 22 is accommodated such that the spiral coil portion is parallel to the lower surface of the housing 220. The reading unit 23 that reads the identification code 122 is arranged on the lower surface of the housing 220 so as to correspond to the center position of the power receiving coil 22. Thereby, when the vehicle 200 is parked at the specified position of the parking space, the reading unit 23 faces the upper side of the housing 220 that houses the power transmission coil 12. The reading range of the reading unit 23 is set so as to include the identification code 122 arranged on the upper surface 121 of the housing 120.

  In the non-contact power supply system having such a configuration, the foreign object detection unit 150 performs foreign object detection prior to the power supply operation when supplying power from the power supply apparatus 100 to the vehicle 200. Specifically, the foreign object detection unit 150 instructs the charging control unit 25 to perform a reading operation by the reading unit 23 through communication between the wireless communication unit 24 and the wireless communication unit 14. The charging control unit 25 optically reads the upper surface 121 of the casing 120 on the power transmission coil 12 side by the reading unit 23. When the reading unit 23 completes the reading of the upper surface 121 of the housing 120, the reading unit 23 acquires information regarding the unit codes 122 a and 122 b included in the identification code 122 arranged on the upper surface 121, and this is output to the charging control unit 25. The The charging control unit 25 outputs the information acquired from the reading unit 23 to the foreign object detection unit 150 through communication between the wireless communication unit 24 and the wireless communication unit 14.

  The foreign object detection unit 150 detects a foreign object present on the upper surface 121 of the housing 120 based on the reading result of the identification code 122, that is, information on the plurality of unit codes 122a and 122b. Specifically, when there is a foreign object on the upper surface 121 of the housing 120, the unit codes 122a and 122b cannot be read in the range where the foreign object exists. Therefore, the foreign object detection unit 150 holds the information of the identification code 122 as reference data in advance, and compares this with the actually read information. When the foreign object detection unit 150 determines that any one of the unit codes 122a and 122b has not been read, the foreign object detection unit 150 determines that there is a foreign object.

  Further, the foreign matter detection unit 150 identifies position information regarding the unit codes 122a and 122b that are not read based on position information regarding the surrounding unit codes 122a and 122b. Thereby, not only the presence / absence of a foreign substance but also its position can be detected. Further, the foreign object detector 150 can detect a plurality of foreign objects when there are a plurality of unit codes 122a and 122b that have not been read. However, when there are a plurality of unit codes 122a and 122b that are not read and these positions are adjacent to each other, the foreign object detection unit 150 sets a plurality of unit codes 122a and 122b that satisfy these conditions as one unit. It can be detected as a foreign object. With such a recognition method, the foreign object detection unit 150 can detect the size of the foreign object from the range of the unit codes 122a and 122b that are not read.

  When the foreign object detection unit 150 determines the presence of the foreign object, the foreign object detection unit 150 prohibits the start of charging, restricts the output from the power transmission coil 12 during the power feeding operation, and the wireless communication unit 14 and the wireless communication unit 24 The notification unit 32 of the vehicle 200 is operated. However, the foreign object detection unit 150 may perform the above-described operation only for a foreign object whose size is equal to or greater than a foreign object determination value that defines a predetermined size. Further, since the magnetic flux density is higher in the region corresponding to the small unit code 122a, the foreign matter detection unit 150 sets the foreign matter determination value for determining the foreign matter in the region of the large unit code 122b as the small unit. It may be set to a value larger than the foreign substance determination value for determining the foreign substance in the area of the code 122a.

  As described above, the non-contact power feeding system according to the present embodiment exists on the upper surface 121 of the housing 120 and the reading unit 23 that optically reads the upper surface 121 of the housing 120 that houses the power transmission coil 12 facing the power receiving coil 22. A foreign matter detection unit 150 that detects foreign matter to be detected. Here, the housing 120 is provided with an optically readable identification code 122 on the upper surface 121 of the housing 120. Further, the foreign matter detection unit 150 detects foreign matter present on the upper surface 121 of the housing 120 based on the reading result of the identification code 122 by the reading unit 23.

  According to such a configuration, when there is a foreign object, the identification code 122 cannot be read by the foreign object. Therefore, the presence of the foreign object is effectively detected by referring to the reading result of the identification code 122. be able to.

  In the present embodiment, the identification code 122 is composed of a plurality of unit codes 122a and 122b arranged two-dimensionally, and the unit codes 122a and 122b according to the magnetic flux density of the magnetic flux generated in the power transmission coil 12. The size of each is set.

  According to such a configuration, since the heating energy for the foreign matter differs depending on the magnitude of the magnetic flux density, the resolution for detecting the foreign matter can be appropriately set according to the heating energy. In the above-described embodiment, the unit codes 122a and 122b having two types of sizes are used. However, a plurality of types of sizes such as three and four are prepared and arranged according to the magnetic flux density. May be. Further, as shown in FIG. 5, the identification code 122 may be composed of only one unit code 122a. In this case, the identification code 122 may be arranged over the entire upper surface 121 of the housing 120, but as shown in the figure, the identification code 122 may be arranged within a range where it is deemed necessary to detect a foreign object. In the example shown in FIG. 5, the identification code 122 made up of the unit code 122a is formed so as to be enlarged toward the inner peripheral side in the radial direction from the region of the unit code 122a shown in FIG.

  In the present embodiment, the unit codes 122a and 122b include information indicating the position on the upper surface 121 of the housing 120 where the unit codes 122a and 122b are arranged.

  According to such a configuration, the position of the foreign object can be specified by referring to the position information from the reading result of the identification code 122. Further, since the individual unit codes 122a and 122b include position information, it is possible to specify the location of the foreign matter without requiring accurate alignment between the reading unit 23 and the identification code 122. Have.

  In the present embodiment, the foreign object detection unit 150 recognizes the size of the foreign object according to the reading results of the plurality of unit codes 122a and 122b forming the identification code 122.

  According to such a configuration, it is possible to recognize not only the presence of foreign matter but also the size of the foreign matter from the continuity of the plurality of unit codes 122a and 122b.

  In the present embodiment, the reading unit 23 is disposed on the power receiving coil 22 side.

  Since the power receiving coil 22 faces the power transmitting coil 12 during power feeding, by arranging the reading unit 23 on the power receiving coil 22 side, the upper surface 121 of the housing 120 can be effectively read during power feeding. It becomes.

  In the present embodiment, the reading unit 23 is disposed at the center position of the power receiving coil 22 wound in a spiral shape.

  According to this configuration, since the reading unit 23 is arranged in a region where the influence of the magnetic flux is small, the magnetic influence on the reading unit 23 can be suppressed.

  In the present embodiment, since the reading range of the reading unit 23 is set to include the entire area of the identification code 122, the reading unit 23 is fixedly arranged. However, as shown in FIG. 6, the reading range of the reading unit 23 is set to be smaller than the entire area of the identification code 122, and the entire area of the identification code 122 is scanned by rotating the reading unit 23. Also good.

(Second Embodiment)
FIG. 7 is an explanatory diagram showing a form of the identification code 122 according to the second embodiment. In the present embodiment, the identification code 122 is configured by two-dimensionally arranging a plurality of blocks. Each block is composed of unit codes 122a and 122b having the same size arranged one-dimensionally or two-dimensionally, and in the present embodiment, it corresponds to two types of unit codes 122a and 122b having different sizes. These two types of blocks are arranged. Here, each of the unit codes 122a and 122b included in the same block may include unique position information. However, since each of the unit codes 122a and 122b has the same position information, the foreign substance can be detected in units of blocks. Good.

  According to such a configuration, it is not necessary to create the identification code 122 with a predetermined shape, and the identification code 122 can be created with a block shape and a combination thereof. Can be applied. The shape of each block is not limited to a quadrangle, and various shapes can be used. For example, the circular identification code 122 shown in the first embodiment described above may be realized by a plurality of blocks partitioned along the radial direction.

  In this embodiment, each block is composed of a plurality of unit codes 122a and 122b, but each block may be realized by one unit code (for example, QR code (registered trademark)). In this case, the foreign object detection unit 150 can determine the presence and size of the foreign object based on the number of reading errors of information forming the unit code. Also, in this determination, the determination value for recognizing a foreign object is varied according to the magnetic flux density from the viewpoint of setting a high foreign substance detection capability (resolution) at a position where the magnetic flux density is assumed to be large. Also good.

Further, in each of the above-described embodiments, the identification code 122 is disposed in the housing 120 that houses the power transmission coil 12 disposed on the ground side. For example, if the power receiving coil 22 is disposed on the ceiling of the vehicle 200 and the power transmitting coil 12 is disposed so as to face the power receiving coil 22, the identification code 122 is disposed on the housing that houses the power receiving coil 22. Also good. However, from the viewpoint of detecting foreign matter, the foreign matter sensor 16 may be applied to each of the housings that accommodate individual coils, with respect to the pair of coils facing each other. The main operation of foreign object detection is
The charging control unit 25 on the vehicle 200 side may execute this.

  The unit on the vehicle 200 side of the non-contact power feeding system is mounted on an electric vehicle, but may be a vehicle such as a hybrid vehicle.

  The contactless power supply system to which the contactless power supply device of the present invention is applied has been described above. However, the present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the invention. Needless to say.

DESCRIPTION OF SYMBOLS 100 Electric power feeder 11 Power control part 12 Power transmission coil 120 Case 121 Upper surface 122 Identification code 122a Unit code 122b Unit code 14 Wireless communication part 15 Control part 16 Foreign substance sensor 160 Sensor unit 161 Light emission part 162 Light reception part 200 Vehicle 22 Power reception coil 220 Case Body 23 Reading unit 24 Wireless communication unit 25 Charging control unit 26 Rectification unit 27 Relay unit 28 Battery 29 Inverter 30 Motor 32 Notification unit

Claims (6)

In a non-contact power feeding device that performs non-contact power supply between the first coil and the second coil by magnetic coupling,
A housing that houses the first coil and is installed at a predetermined destination;
A reading unit that optically reads the surface of the housing facing the second coil during power feeding;
A detection unit for detecting foreign matter present on the surface of the housing,
The housing is provided with an optically readable identification code on the surface of the housing,
The non-contact power feeding apparatus according to claim 1, wherein the detection unit detects a foreign substance existing on a surface of the housing based on a reading result of the identification code by the reading unit.   The identification code is composed of a plurality of unit codes arranged two-dimensionally, and the size of the unit code is set according to the magnetic flux density of the magnetic flux generated in the first coil. The non-contact electric power feeder according to claim 1 characterized by things.   The contactless power supply device according to claim 1, wherein the unit code includes information indicating a position on a surface of the housing where the unit code is arranged.   The non-contact power feeding device according to claim 2, wherein the detection unit recognizes the size of the foreign matter according to a reading result of a plurality of unit codes constituting the identification code.   The non-contact power feeding apparatus according to claim 1, wherein the reading unit is disposed on the second coil side. The second coil has a spirally wound structure,
The non-contact power feeding apparatus according to claim 5, wherein the reading unit is disposed at a center position of the second coil.

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