JP2019213342A - Non-contact power transmission system - Google Patents

Abstract

To more surely prevent a transmission of power in a state where an excess positional deviation between a primary coil and a secondary coil occurs in a non-contact power transmission system detecting a relative position of a power transmission/reception coil by an imaging device.SOLUTION: In a non-contact power transmission system, a power transmission device 100 has an imaging device 103, and a power reception device 200 has patterns Pb and Pf recognizable by the imaging device 103. The patterns Pb and Pf have patterns different from each other and are arranged apart from each other around a secondary coil 201. An electronic control unit of the non-contact power transmission system matches, before starting the transmission of power, the patterns Pb and Pf recognized by the imaging device 103 to predetermined patterns, and permits the start of the transmission of the power when the match is successful with respect to both of the patterns Pb and Pf.SELECTED DRAWING: Figure 3

Description

  The present disclosure relates to a contactless power transmission system, and more particularly to a contactless power transmission system in which power is transmitted in a contactless manner from a primary coil of a power transmission device to a secondary coil of a power reception device.

  The IEC (International Electrotechnical Commission) 61980 series is an LPE (Low Power Excitation) method described below as a detection method of a relative position between a power transmission coil and a power reception coil (hereinafter also referred to as “relative position of the power transmission / reception coil”). And the low frequency signal (LF Signal) system is presented. In addition, the relative position of a power transmission / reception coil means the other position on the basis of one among a power transmission coil and a power reception coil.

  In the above LPE method, the relative position of the power transmission / reception coil is detected based on the received power when power transmission is performed with low power. However, such a detection method has the following problems. First, the accuracy of position detection becomes insufficient depending on the distance between the power transmission coil and the power reception coil (hereinafter also referred to as “inter-coil gap”). Secondly, the position cannot be detected unless the power transmission coil and the power reception coil are brought close to the extent that power transmission is possible.

  In the low-frequency signal system, the relative position of the power transmission / reception coil is detected through antenna wireless communication between the power transmission device and the power reception device. In such a detection method, the relative position of the power transmission / reception coil is detected by detecting a target signal with an antenna. However, there are a large number of electromagnetic waves (reflected waves, etc.) other than the signal of interest around the antenna, and erroneous detection may occur when such electromagnetic waves are detected by the antenna.

  In view of the above-described problems of each method presented by the IEC 61980 series, another method has been proposed. For example, Japanese Patent Laying-Open No. 2015-37336 (Patent Document 1) discloses an amount of positional deviation between a power transmission coil and a power reception coil using an imaging device (more specifically, 3 between the center positions of the power transmission coil and the power reception coil). A method for detecting (dimensional distance) is disclosed (particularly, refer to paragraph [0042] of Patent Document 1).

  JP 2013-154815 A (Patent Document 2), JP 2013-146154 A (Patent Document 3), JP 2013-146148 A (Patent Document 4), JP 2013-110822 A (Patent Document 2). Document 5) and Japanese Patent Application Laid-Open No. 2013-126327 (Patent Document 6) also disclose techniques related to non-contact power transmission.

JP 2015-37336 A JP2013-154815A JP2013-146154A JP2013-146148A JP 2013-110822 A JP 2013-126327 A

  In the non-contact power transmission system described in Patent Document 1, the three-dimensional distance between the center positions of the power transmission coil and the power reception coil is the amount of positional deviation between the power transmission coil and the power reception coil (hereinafter referred to as “the amount of positional deviation between coils”). ). The greater the three-dimensional distance between the center positions of the power transmission coil and the power reception coil, the greater the amount of positional deviation between the coils. However, it is difficult to accurately detect such a three-dimensional distance by the imaging apparatus. If power transmission is performed in a state where the power transmission coil and the power receiving coil are excessively misaligned due to erroneous detection of the amount of misalignment between the coils, the power transmission efficiency (the ratio of the received power to the transmitted power) is reduced. Inconvenience can occur.

  The present disclosure has been made in order to solve the above-described problem, and an object of the present disclosure is to provide a primary coil (power transmission coil) and a secondary coil in a non-contact power transmission system that detects a relative position of a power transmission / reception coil by an imaging device. This is to more reliably prevent power transmission in a state where the (power receiving coil) is excessively displaced.

  In the non-contact power transmission system of the present disclosure, power is transmitted in a non-contact manner from the primary coil of the power transmission device to the secondary coil of the power reception device. One of the power transmission device and the power receiving device includes an imaging device, and the other includes a first pattern and a second pattern that can be recognized by the imaging device. The first pattern and the second pattern are different from each other and are spaced apart from each other around the primary coil or the secondary coil. Then, the non-contact power transmission system according to the present disclosure collates each of the first pattern and the second pattern recognized by the imaging device with a predetermined pattern before starting the transmission of the power. When the verification is successful for both the second pattern and the second pattern, the start of power transmission is permitted.

  A pattern provided around the coil is recognized by the imaging device, and the recognized pattern and a predetermined pattern are collated (pattern collation), whereby the relative position between the primary coil and the secondary coil (coil It is possible to detect a misalignment amount). However, in pattern matching using only one pattern, the possibility that pattern recognition is hindered by dirt or scratches cannot be denied, and the possibility of erroneous detection increases. In the non-contact power transmission system of the present disclosure, before the power transmission is started, pattern matching is performed for each of the first pattern and the second pattern, and matching of a plurality of patterns (first pattern and second pattern) is successful. The primary coil and the secondary coil are excessively positioned by permitting the start of power transmission in that case (that is, not permitting the start of power transmission if any of the pattern matching fails). It is possible to more reliably prevent power transmission in a shifted state (more specifically, a state in which the amount of positional deviation between the coils exceeds the allowable range).

  In addition, since the first pattern and the second pattern have different patterns and are spaced apart from each other, the primary coil and the secondary coil are based on which pattern is recognized first by the imaging device. The relative positional relationship with the coil can be detected.

  According to the present disclosure, in the non-contact power transmission system that detects the relative position of the power transmission / reception coil by the imaging device, it is possible to more reliably transmit power in a state where the primary coil and the secondary coil are misaligned. It becomes possible to prevent.

1 is an overall configuration diagram of a contactless power transmission system according to an embodiment of the present disclosure. It is the figure which looked at the vehicle shown in FIG. 1 from the bottom. It is a figure which shows the cross-section of the power transmission apparatus and power receiving apparatus which were shown in FIG. It is the figure which looked at the power transmission apparatus shown in FIG.1 and FIG.3 from the top. It is the figure which looked at the power receiving apparatus shown in FIG.1 and FIG.3 from the bottom. It is a figure for demonstrating the method to detect the relative position of a power transmission / reception coil in the non-contact electric power transmission system which concerns on embodiment of this indication. It is a flowchart which shows electric power transmission control by the non-contact electric power transmission system which concerns on embodiment of this indication.

  Embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals and description thereof will not be repeated.

  Arrows F, B, R, L, U, and D in the drawings used below indicate directions with respect to the vehicle, arrow F is “forward”, arrow B is “rear”, and arrow R is “ "Right", arrow L indicates "left", arrow U indicates "up", and arrow D indicates "down". Hereinafter, the electronic control unit is referred to as “ECU”.

  FIG. 1 is an overall configuration diagram of a contactless power transmission system according to an embodiment of the present disclosure. The power transmission system 10 includes a charging facility 1 (ground unit) and a vehicle 2.

  The charging facility 1 includes a power transmission device 100, a power transmission ECU 150 that controls the power transmission device 100, and an AC power source 700 that supplies power to the power transmission device 100. The power transmission device 100 is installed on the ground F10 (for example, the floor of a parking lot). An example of the AC power supply 700 is a household power supply (for example, an AC power supply having a voltage of 200 V and a frequency of 50 Hz).

  The vehicle 2 includes a power receiving device 200, a power storage device 300 that is charged by the power received by the power receiving device 200, and a vehicle ECU 500 that controls the power receiving device 200. The power receiving device 200 is provided on the lower surface (road surface side) of the power storage device 300 installed on the lower surface F20 (under the floor) of the vehicle 2.

  Power storage device 300 includes, for example, a secondary battery (such as a lithium ion battery or a nickel metal hydride battery), a charging relay that is ON / OFF controlled by vehicle ECU 500, and a monitoring unit that monitors the state of power storage device 300 (both shown). Z)). The monitoring unit includes various sensors that detect the state (temperature, current, voltage, etc.) of power storage device 300, and outputs the detection result to vehicle ECU 500. Vehicle ECU 500 acquires the state of power storage device 300 (SOC (State Of Charge) or the like) based on the output of the monitoring unit. The charging relay is turned on (conductive state) when the power storage device 300 is charged by the power receiving device 200. The power storage device 300 supplies power to, for example, a vehicle drive device (such as an inverter and a drive motor) not shown. The vehicle 2 may be an electric vehicle that can run using only the electric power stored in the power storage device 300, or uses both the electric power stored in the power storage device 300 and the output of an engine (not shown). The vehicle may be a hybrid vehicle capable of traveling.

  The power transmission device 100 is configured to transmit power to the power reception device 200 in a non-contact manner through a magnetic field in a state where the vehicle 2 is aligned so that the power reception device 200 of the vehicle 2 faces the power transmission device 100. The power receiving device 200 receives the power from the power transmitting device 100 in a contactless manner. A non-contact (wireless) power transmission method is, for example, a magnetic field resonance method. However, the present invention is not limited to this, and other methods (such as an electromagnetic induction method) may be adopted.

  Each of the ECUs (power transmission ECU 150, vehicle ECU 500) includes an arithmetic device, a storage device, an input / output port, a communication port (all not shown), and the like. The arithmetic unit is configured by a microprocessor including, for example, a CPU (Central Processing Unit). The storage device includes a RAM (Random Access Memory) that temporarily stores data, and a storage (ROM (Read Only Memory), rewritable nonvolatile memory, and the like) that stores programs and the like. Various controls are executed by the arithmetic device executing the program stored in the storage device. In the power transmission ECU 150, for example, the power transmission control unit 151 and the detection unit 152 are realized by an arithmetic device and a program executed by the arithmetic device. Details of the power transmission control unit 151 and the detection unit 152 will be described later. Various controls are not limited to processing by software, and can be processed by dedicated hardware (electronic circuit).

  Charging facility 1 further includes a communication unit 160, and vehicle 2 further includes a communication unit 600. Communication units 160 and 600 are communication interfaces for performing wireless communication between charging facility 1 and vehicle 2. By performing wireless communication between the communication unit 160 of the charging facility 1 and the communication unit 600 of the vehicle 2, information can be exchanged between the power transmission ECU 150 and the vehicle ECU 500.

  The vehicle 2 further includes a display unit 400 that displays information and signals input from the vehicle ECU 500. Vehicle ECU 500 can notify the user through display unit 400. An example of the display unit 400 is a touch panel display. The display unit 400 may have a speaker function.

  FIG. 2 is a view of the vehicle 2 shown in FIG. 1 as viewed from below. Referring to FIG. 2, floor panel 21 and exhaust system 22 constituting a part of the vehicle body (underbody) are exposed on lower surface F <b> 20 of vehicle 2 in addition to power storage device 300 and power receiving device 200 described above. Yes. The exhaust system 22 includes, for example, an exhaust pipe, an exhaust purification device, and a muffler.

  Hereinafter, the configurations of the power transmission device 100 and the power reception device 200 will be described with reference to FIGS. FIG. 3 is a diagram illustrating a cross-sectional structure of the power transmission device 100 and the power reception device 200 illustrated in FIG. 1. FIG. 4 is a view of the power transmission device 100 shown in FIGS. 1 and 3 as viewed from above. FIG. 5 is a view of the power receiving device 200 shown in FIGS. 1 and 3 as viewed from below.

  With reference to FIG. 3 and FIG. 4, the power transmission device 100 includes a primary coil 101, a housing 102 that houses the primary coil 101, and an imaging device 103. In FIG. 4, the reference plane P11 is a plane (LR-UD plane) orthogonal to the axis in the front-rear direction (FB direction) and includes the coil center axis P10. The reference plane P12 is a plane (FB-UD plane) orthogonal to the axis in the left-right direction (LR direction) and includes the coil center axis P10. The coil central axis P10 is the central axis of the primary coil 101 and corresponds to the intersection line of the reference plane P11 and the reference plane P12.

  The primary coil 101 forms a resonance circuit that resonates at a transmission frequency (frequency of transmitted power). The Q value indicating the resonance strength of the resonance circuit is preferably 100 or more. In addition to the primary coil 101, the housing 102 further accommodates a ferrite plate (core of the primary coil 101), a metal plate for electromagnetic shielding, a circuit board, a monitoring unit, and the like (all not shown). ing. The circuit board includes a power converter (such as an AC / DC converter, an inverter, and a filter circuit) that performs a predetermined power conversion process on the power received from AC power supply 700 (FIG. 1). The monitoring unit also includes various sensors that detect the state (temperature, current, voltage, etc.) of the circuit board, and outputs the detection result to the power transmission ECU 150 (FIG. 1). The power transmission ECU 150 controls the power conversion unit so that AC power having a predetermined magnitude and frequency is supplied to the primary coil 101.

  The imaging device 103 is provided, for example, at the center of the upper surface of the housing 102 (near the coil central axis P10). The imaging device 103 includes a lens and an image sensor. The image sensor is disposed on the imaging surface, and light passing through the lens is converted into an electric signal by the image sensor. As the image sensor of the imaging device 103, for example, a complementary metal oxide semiconductor (CMOS) image sensor or a charge-coupled device (CCD) image sensor can be employed. In this embodiment, a fisheye lens is employed as the lens of the imaging device 103. As a result, a wide range (wide angle) space can be captured by the imaging device 103. The imaging device 103 captures the surrounding space to obtain image data (hereinafter referred to as “captured image”), and outputs the captured image to the power transmission ECU 150. In this embodiment, the power transmission device 100 includes one imaging device, but the power transmission device 100 may be provided with a plurality of imaging devices.

  With reference to FIG.3 and FIG.5, the power receiving apparatus 200 is the power receiving part 210, the board | substrate 220, the inclination parts 221, 222, the pattern Pb (1st pattern) which the several light emission parts Lb1-Lb11 form, And a pattern Pf (second pattern) formed by the plurality of light emitting portions Lf1 to Lf11. In FIG. 5, the reference plane P21 is a plane (LR-UD plane) orthogonal to the axis in the front-rear direction (FB direction) and includes the coil center axis P20. The reference plane P22 is a plane (FB-UD plane) perpendicular to the axis in the left-right direction (LR direction) and includes the coil center axis P20. The coil central axis P20 is the central axis of the secondary coil 201 and corresponds to the intersection line of the reference plane P21 and the reference plane P22.

  The power receiving unit 210 and the patterns Pb and Pf are installed on the lower surface of the substrate 220. One end of each of the inclined portions 221 and 222 is connected to the lower surface of the substrate 220. The substrate 220 and the inclined portions 221 and 222 may be formed integrally with each other. The pattern Pb and the pattern Pf are spaced apart from each other around the secondary coil 201. The pattern Pb and the pattern Pf are opposed to each other with the secondary coil 201 interposed therebetween. The pattern Pb is arranged behind the secondary coil 201 (B side), and the pattern Pf is arranged ahead of the secondary coil 201 (F side). Has been. In addition, an inclined portion 221 is provided behind the pattern Pb, and an inclined portion 222 is provided in front of the pattern Pf.

  Each of the inclined portions 221 and 222 is a plate-like member that is inclined with respect to the substrate 220, extends from the base end (connecting portion with the substrate 220) toward the power receiving portion 210, and receives power as the distance from the substrate 220 decreases. Approaching part 210. The tips of the inclined portions 221 and 222 are located in the vicinity of the patterns Pb and Pf, respectively. The inclined parts 221 and 222 protect the light emitting parts (the light emitting parts Lb1 to Lb11 and Lf1 to Lf11) constituting the patterns Pb and Pf, and can also be used for positioning of the respective light emitting parts.

  The power receiving unit 210 includes a secondary coil 201 and a housing 202 that houses the secondary coil 201. The secondary coil 201 constitutes a resonance circuit that resonates at the transmission frequency. The Q value indicating the resonance strength of the resonance circuit is preferably 100 or more. In addition to the secondary coil 201, the housing 202 further accommodates a ferrite plate (core of the secondary coil 201), a metal plate for electromagnetic shielding, a circuit board, a monitoring unit, and the like (all not shown). ing. The circuit board includes a filter circuit, a rectifier circuit, a smoothing capacitor, and the like. The monitoring unit includes various sensors that detect the state (temperature, current, voltage, etc.) of the circuit board, and outputs the detection result to the vehicle ECU 500 (FIG. 1). The AC power received by the secondary coil 201 is converted into DC power by the circuit board. As a result, DC power is supplied to the power storage device 300 (FIG. 1) as output power of the power receiving device 200.

  Each of the light emitting units Lb1 to Lb11 and Lf1 to Lf11 forming the patterns Pb and Pf is a light emitter that can be turned on and off, and the state (lighting / extinguishing) of each light emitting unit is controlled by the vehicle ECU 500. In this embodiment, an LED (light emitting diode) is employed as each light emitting unit, but other light emitters (incandescent light bulbs or the like) may be used.

  In this embodiment, as each of the patterns Pb and Pf, 10 or more (more specifically, 11) data (binary data) binarized according to the state (lighting / extinguishing) of each light emitting unit. A one-dimensional code consisting of In FIG. 5, among the light emitting portions Lb1 to Lb11 and Lf1 to Lf11, those with a pattern (dot pattern) indicate a light emitting portion that is lit, and those without a pattern indicate light emission that is turned off. Shows the part. When the light emitting unit that is lit is represented by “1” and the light emitting unit that is extinguished is represented by “0”, the pattern Pb is “01010001010” from right to left, and the pattern Pf is “01010101010” from right to left. " Thus, the pattern Pb and the pattern Pf have different patterns.

  When the patterns Pb and Pf are recognized by the imaging device 103, a light emitting unit that is lit among the light emitting units that form each of the patterns Pb and Pf is recognized. Each pattern consists of the number of light-emitting parts that are lit, the size of the light-emitting parts that are lit (the number of light-emitting parts that are lit continuously), and the gap between the light-emitting parts that are lit (lights The number of light-emitting parts that are extinguished between the light-emitting parts that are present). The patterns Pb and Pf are not limited to the patterns shown in FIG. 5 and can be changed as appropriate.

  In the power transmission system 10 according to this embodiment, the power transmission ECU 150 detects the relative position of the power transmission / reception coil (the relative position of the primary coil 101 and the secondary coil 201) before starting power transmission. In this embodiment, the reference (position) is such that the central axis of the primary coil 101 (coil central axis P10 shown in FIG. 4) and the central axis of the secondary coil 201 (coil central axis P20 shown in FIG. 5) coincide. With no deviation), the amount of displacement and the direction of displacement between the primary coil 101 and the secondary coil 201 are detected as the relative positions of the power transmitting and receiving coils.

  When the positional deviation amount between the primary coil 101 and the secondary coil 201 (inter-coil positional deviation amount) is within a predetermined allowable range, the power transmission ECU 150 starts power transmission, and the inter-coil positional deviation amount is If not within the allowable range, for example, as shown below, the primary coil 101 and the secondary coil 201 are aligned (position correction).

  The power transmission ECU 150 determines how the center axis of the secondary coil 201 is deviated from the center axis of the primary coil 101 (for example, the amount of misalignment between the primary coil 101 and the secondary coil 201 and the direction of misalignment). ) Is displayed on the display unit 400 (FIG. 1). The driver of the vehicle 2 operates the steering wheel, the accelerator, the brake (all not shown), etc. while referring to this display, and the deviation between the central axis of the primary coil 101 and the central axis of the secondary coil 201 is performed. The vehicle 2 can be moved so as to reduce the amount. The primary coil 101 and the secondary coil 201 can be aligned by repeating the detection of the relative position of the power transmission / reception coil and the movement of the vehicle 2 until the amount of positional deviation between the coils is within the allowable range. The movement of the vehicle 2 may be performed by automatic driving.

  When the amount of positional deviation between the coils is within the allowable range due to the above alignment (position correction), the power transmission ECU 150 starts transmitting electric power.

  Hereinafter, a method for detecting the relative position of the power transmission / reception coil will be discussed. The larger the three-dimensional distance between the center positions of the primary coil 101 and the secondary coil 201, the larger the amount of misalignment between the coils. Therefore, it is conceivable to detect such a three-dimensional distance as a parameter indicating the amount of misalignment between the coils. . However, it is difficult to accurately detect such a three-dimensional distance by the imaging device 103. If power transmission is performed in a state where the primary coil 101 and the secondary coil 201 are excessively misaligned due to erroneous detection of the amount of misalignment between the coils, inconveniences such as low power transmission efficiency may occur. .

  In view of the above, in the power transmission system 10 according to this embodiment, the pattern provided around the secondary coil 201 is recognized by the imaging device 103, and the recognized pattern is collated with a predetermined pattern ( By performing pattern matching, the relative position between the primary coil 101 and the secondary coil 201 is detected. However, in pattern matching using only one pattern, the surface of the light emitting part forming the pattern is soiled or scratched, or the light is blocked by the underfloor structure (floor panel 21, exhaust system 22, etc.) of the vehicle 2. Therefore, the possibility that the recognition of the pattern is hindered cannot be denied, and the possibility of erroneous detection increases. Therefore, the power transmission system 10 according to this embodiment employs a plurality of patterns Pb and Pf.

  In the power transmission system 10, the power transmission ECU 150 collates each pattern Pb and Pf recognized by the imaging device 103 with a predetermined pattern (pattern collation) before starting the transmission of power. When verification is successful for both Pf, the start of power transmission is permitted. Power transmission is not started in a period in which collation is not successful in at least one of the patterns Pb and Pf. As a result, power transmission is performed in a state where the primary coil 101 and the secondary coil 201 are excessively misaligned (more specifically, a state where the amount of misalignment between the coils exceeds the allowable range). It becomes possible to prevent more reliably.

  FIG. 6 is a diagram for explaining a method of detecting the relative position of the power transmission / reception coil in the power transmission system 10. In FIG. 6, ΔX indicates the amount of positional deviation in the front-rear direction (FB direction). The fact that the amount of positional deviation between the coils is within the allowable range means that the positional deviation amount ΔX in the front-rear direction (FB direction) and the positional deviation amount ΔY (not shown) in the left-right direction (LR direction) are each. It means that it is within the allowable range. ΔZ represents the gap between the coils. ΔZ is not directly related to alignment. However, since ΔZ correlates with a coupling coefficient between the primary coil 101 and the secondary coil 201, ΔZ may be detected using the imaging device 103. In addition to the imaging device 103, a distance sensor for detecting ΔZ may be provided.

  With reference to FIG. 6 together with FIG. 1, the power transmission device 100 starts monitoring by the imaging device 103 prior to power transmission. In such a situation, the vehicle 2 (and thus the power receiving device 200) approaches the power transmission device 100 to charge the power storage device 300. In the example illustrated in FIG. 6, the vehicle 2 enters the charging space where the power transmission device 100 is installed in a rearward direction and stops. Then, when the power receiving device 200 of the vehicle 2 approaches the power transmitting device 100, the pattern Pb (rear pattern) is within a range that can be recognized by the imaging device 103 before the pattern Pf (front pattern). In this case, power transmission ECU 150 determines that vehicle 2 is facing backward and stops in the charging space. Thus, the power transmission ECU 150 can detect the orientation of the vehicle 2 based on which of the patterns Pb and Pf is recognized by the imaging device 103 first. For example, in a charging facility that cannot be charged properly unless it stops in a charging space in a predetermined direction (forward or backward), if the target vehicle is determined to stop in a different direction, the direction of the vehicle is appropriate You may make it alert | report to a target vehicle that it is not.

  When the power receiving device 200 of the vehicle 2 further approaches the power transmitting device 100 and both the patterns Pb and Pf are within the range recognizable by the imaging device 103, pattern matching is performed for each of the patterns Pb and Pf. For pattern matching, first matching information and second matching information described below are used.

  Prior to pattern matching, the storage device of the power transmission ECU 150 stores in advance first matching information indicating the first pattern (pattern Pb) and second matching information indicating the second pattern (pattern Pf). For example, the first pattern determined for the charging facility 1, the first verification information indicating the second pattern, and the second verification information are stored in advance in the storage device of the power transmission ECU 150. The contents of one pattern and the second pattern (that is, what pattern is used for collation) may be notified to the vehicle 2. Further, before performing pattern matching, the contents of patterns Pb and Pf (that is, what patterns) are transmitted from vehicle 2 to charging facility 1, and first matching information and second matching information are generated in power transmission ECU 150. And may be stored in a storage device. In addition, the contents of the first pattern and the second pattern are transmitted to each of the charging facility 1 and the vehicle 2 by a server (not shown) that is communicably connected to both the charging facility 1 and the vehicle 2. It may be. In this case, in the vehicle 2, the vehicle ECU 500 controls the light emitting units Lb1 to Lb11 and Lf1 to Lf11 so that the first pattern and the second pattern are formed as the patterns Pb and Pf. The power transmission ECU 150 generates the first verification information and the second verification information indicating the first pattern and the second pattern, and stores them in the storage device.

  The power transmission ECU 150 executes pattern matching based on the first matching information and the second matching information in a predetermined area (hereinafter, also referred to as “pattern recognition area”) of the captured image acquired by the imaging device 103. Then, when the first pattern indicated by the first verification information exists in the pattern recognition area, it is determined that the verification of the first pattern (pattern Pb) has succeeded, and the second pattern indicated by the second verification information becomes the pattern recognition area. It is determined that the second pattern (pattern Pf) has been successfully verified. Such collation can be performed using a known image recognition technique. Note that the pattern recognition area may be a single area or two areas that are separated (area determined for each pattern).

  When collation is successful for both the first pattern (pattern Pb) and the second pattern (pattern Pf), it is determined that both the patterns Pb and Pf exist in the pattern recognition area. The presence of the patterns Pb and Pf in the pattern recognition area means that the amount of positional deviation between the coils is within an allowable range. For this reason, when collation is successful for both patterns Pb and Pf, the start of power transmission is permitted. On the other hand, if collation fails for at least one of the first pattern (pattern Pb) and the second pattern (pattern Pf), it is determined that at least one of the patterns Pb and Pf does not exist in the pattern recognition area. The fact that at least one of the patterns Pb and Pf does not exist in the pattern recognition area means that the amount of positional deviation between the coils exceeds the allowable range. For this reason, when collation fails about at least one of patterns Pb and Pf, the start of electric power transmission is not permitted. In this case, the power transmission ECU 150 determines the amount of displacement between the primary coil 101 and the secondary coil 201 and the direction of displacement (more specifically, how much the patterns Pb and Pf are in any direction with respect to the pattern recognition region. Is detected as a relative position of the power transmission / reception coil. Then, the power transmission ECU 150 prompts the vehicle 2 to execute the above-described alignment (position correction) by display, voice, communication, or the like.

  In the power transmission system 10 according to this embodiment, power transmission is started when collation is successful for both the first pattern and the second pattern. During power transmission, detection of the relative position of the power transmission / reception coil (hereinafter also simply referred to as “position detection”), detection of a metal foreign object (hereinafter also simply referred to as “foreign object detection”), Detection (hereinafter, also simply referred to as “intrusion detection”) is performed.

  In foreign object detection and intrusion detection, whether or not there are foreign objects (more specifically, metal foreign objects and animals) in the space between the primary coil 101 and the secondary coil 201 (hereinafter also referred to as “between coils”). Is judged. In the foreign object detection, it is determined whether or not a metal foreign object (such as a beverage can or a coin) exists between the coils. In the intrusion detection, it is determined whether a living body (for example, an animal such as a cat or a dog) has entered between the coils. In this embodiment, a method using the imaging device 103 is adopted as a foreign matter detection and intrusion detection method, and an image obtained using the imaging device 103 is analyzed in the power transmission ECU 150 to each of a metallic foreign matter and a living body intrusion. Is detected. For example, the imaging device 103 may monitor the space between the coils illuminated by the light-emitting portions that are lit among the light-emitting portions Lb1 to Lb11 and Lf1 to Lf11 that form the patterns Pb and Pf. In this case, when reflected light from the foreign object is detected by the imaging device 103, it may be determined that a metal foreign object exists between the coils. Further, based on the fact that the brightness of the space between the coils detected by the imaging device 103 changes according to the presence or absence of foreign matter, it may be determined whether or not foreign matter exists between the coils. Note that the foreign object detection and intrusion detection methods are not limited to those described above and are arbitrary, and other methods may be employed. For example, a foreign object detection coil may be provided in at least one of the power transmission device 100 and the power reception device 200.

  Referring to FIG. 1 again, power transmission ECU 150 includes a power transmission control unit 151 and a detection unit 152. The power transmission control unit 151 is configured to control power transmission. More specifically, the power transmission control unit 151 can adjust the power supplied from the primary coil 101 to the secondary coil 201 by controlling the power conversion unit in the housing 102 (FIG. 3). The detection unit 152 selects any of the pre-power transmission detection mode, the power transmission detection mode, and the non-detection mode according to the control signal from the power transmission control unit 151, and does not perform detection when the non-detection mode is selected. When another mode is selected, detection by the selected mode is executed, and the detection result is output to the power transmission control unit 151. Initially, the non-detection mode is selected. The detection mode before power transmission is selected before power transmission is started (during power transmission preparation), and the detection mode during power transmission is selected during power transmission (during power transmission). In this embodiment, the detection mode before power transmission and the detection mode during power transmission are set as follows.

  In the pre-power transmission detection mode, position detection is performed, and foreign object detection and intrusion detection are not performed. The method of position detection in the pre-power transmission detection mode (hereinafter also referred to as “first position detection”) is as described above, and the relative position of the power transmission / reception coil is detected through pattern verification based on the first verification information and the second verification information. Is done.

  In the power transmission detection mode, position detection, foreign object detection, and intrusion detection are executed. However, in position detection in the detection mode during power transmission (hereinafter also referred to as “second position detection”), power is transmitted and received through pattern matching based on only one of the first verification information and the second verification information (for example, only the first verification information). The relative position of the coil is detected. In the second position detection, patterns that are not the target of pattern matching (for example, the light emitting portions Lf1 to Lf11 that form the pattern Pf) may be turned off. Alternatively, the pattern recognition area may be limited to only an area corresponding to one pattern (for example, pattern Pb) while both patterns Pb and Pf (light emitting portions Lb1 to Lb11 and Lf1 to Lf11) are turned on. In the second position detection, if the collation is successful, the continuation of power transmission is permitted, and if the collation fails, the ongoing power transmission is stopped. In the foreign object detection, the coil is monitored, and power transmission is stopped when the presence of a metal foreign object is detected between the coils. In intrusion detection, between coils is monitored, and power transmission stops when a living body intrusion between the coils is detected.

  The detection mode before power transmission and the detection mode during power transmission are not limited to the above, and can be changed as appropriate. For example, in the pre-power transmission detection mode, foreign object detection and / or intrusion detection may be performed in addition to position detection. Then, transmission of power may be started when collation is successful for both patterns Pb and Pf and no foreign matter (such as a metallic foreign matter or a living body) exists between the coils.

  FIG. 7 is a flowchart showing power transmission control by the power transmission system 10 according to this embodiment. In FIG. 7, steps S11 to S15 (hereinafter simply referred to as “S11” to “S15”) are executed by the power transmission control unit 151 of the power transmission ECU 150. Steps S21 to S23 (hereinafter simply referred to as “S21” to “S23”) are executed by the detection unit 152 of the power transmission ECU 150.

  Referring to FIG. 7, the process of S11 is executed by establishing a wireless communication connection (for example, connection to a wireless LAN) between communication unit 160 of charging facility 1 and communication unit 600 of vehicle 2. Is done. In S11, the power transmission control unit 151 requests the detection unit 152 to perform detection before power transmission. Moreover, the power transmission control part 151 requests | requires alignment with the vehicle 2 after the process of S11 (S12).

  On the other hand, when the detection unit 152 receives the detection request before power transmission from the power transmission control unit 151, the detection unit 152 selects the detection mode before power transmission (S21). When the detection mode before power transmission is selected, the detection unit 152 executes first position detection (that is, highly accurate position detection using two patterns). More specifically, during the period in which the pre-power transmission detection mode is selected, the detection unit 152 performs collation for both the patterns Pb and Pf every time a predetermined time elapses or every time a predetermined condition is satisfied. Whether or not both of the patterns Pb and Pf exist in the recognition region) is output to the power transmission control unit 151.

  The power transmission control unit 151 receives the collation result from the detection unit 152. If the collation result is unsuccessful, the power transmission control unit 151 requests the vehicle 2 to perform alignment (position correction) again (S12). Is detected and the detection unit 152 is requested to detect during power transmission (S13). Moreover, the power transmission control part 151 starts the power transmission (electric power transmission) from the primary coil 101 to the secondary coil 201 after the process of S13 (S14). The power storage device 300 is charged by this power transmission.

  On the other hand, when the detection unit 152 receives the above detection request during power transmission from the power transmission control unit 151, the detection unit 152 selects the detection mode during power transmission (S22). When the power transmission detection mode is selected, the detection unit 152 performs second position detection (that is, simple positional deviation detection using one pattern), foreign object detection, and intrusion detection.

  More specifically, in a period when the detection mode during power transmission is selected, the detection unit 152 performs second position detection (for example, pattern Pb verification) every time a predetermined time has elapsed, and verification fails ( That is, when a positional deviation exceeding the allowable range is detected, a signal indicating that fact (hereinafter referred to as “first abnormality signal”) is transmitted to the power transmission control unit 151. Moreover, in the period when the detection mode during power transmission is selected, the detection unit 152 monitors between the coils. When detecting the presence of a metallic foreign object between the coils, the detection unit 152 transmits a signal indicating that fact (hereinafter referred to as “second abnormality signal”) to the power transmission control unit 151, and the living body enters between the coils. Is detected, a signal indicating that fact (hereinafter referred to as “third abnormality signal”) is transmitted to the power transmission control unit 151. When the power transmission control unit 151 receives any of the first to third abnormality signals during power transmission (that is, when an abnormality occurs during power transmission), the power transmission control unit 151 forcibly stops the current power transmission. Then, power transmission is terminated (S15).

  The power transmission control unit 151 also stops power transmission in progress and terminates power transmission even when a predetermined completion condition is satisfied during power transmission (that is, when power transmission is normally completed) (S15). Completion conditions can be set arbitrarily. For example, the completion condition may be satisfied when the SOC of power storage device 300 becomes equal to or higher than a predetermined SOC value during power transmission. The predetermined SOC value may be automatically set by the vehicle ECU 500 or the like, or may be set by the user. Further, the completion condition may be satisfied when the power transmission time (elapsed time from the start of power transmission) becomes longer than a predetermined value. Further, the completion condition may be satisfied when the user gives an instruction to stop power transmission during power transmission.

  In S <b> 15, the power transmission control unit 151 requests the detection unit 152 to end detection after terminating power transmission. Upon receiving this detection end request from the power transmission control unit 151, the detection unit 152 selects the non-detection mode and ends all detections (S23).

  In the process of FIG. 7, before the start of power transmission, the detection unit 152 captures the patterns Pb and Pf formed by the light emitting unit (hereinafter, may be referred to as “first mark”) by the imaging device 103. At the same time, the relative position between the primary coil 101 and the secondary coil 201 is detected using the imaged first mark (S21). On the other hand, during the transmission of power, the detection unit 152 captures the pattern Pb (hereinafter sometimes referred to as “second mark”) with the imaging device 103 and uses the captured second mark to perform the primary operation. The relative position between the coil 101 and the secondary coil 201 is detected (S22).

  When the imaging device 103 recognizes the first mark and the second mark, a light emitting unit that is lit among the light emitting units constituting each mark is recognized. Among the light emitting units constituting the first mark (patterns Pb and Pf), nine light emitting units are lit (light emitting units Lb2, Lb4, Lb8, Lb10, Lf2, Lf4, Lf6, Lf8, and Lf10). Among the light emitting units constituting the second mark (pattern Pb), four light emitting units are lit (light emitting units Lb2, Lb4, Lb8, and Lb10). That is, according to the process of FIG. 7 described above, before starting the power transmission, the relative position of the power transmission / reception coil is increased by using the first mark having a larger amount of information (the number of light-emitting parts that are lit) than the second mark. By detecting with accuracy, the primary coil 101 and the secondary coil 201 can be aligned with high accuracy.

  Further, during power transmission, the relative position of the power transmission / reception coil is detected using the second mark having a small amount of information. By monitoring the relative position of the power transmission / reception coil during power transmission, it is possible to determine whether or not a positional deviation exceeding the allowable range has occurred after the completion of the alignment. If alignment is performed with high accuracy before the start of power transmission, monitoring of the relative position of the power transmission / reception coil during power transmission can be appropriately performed even with the second mark having a small amount of information. When the second mark is used for position detection, the load of information processing for position detection is smaller than when the first mark is used. As described above, according to the power transmission system 10 according to this embodiment, the relative position of the power transmission / reception coil (and hence the positional deviation exceeding the allowable range) during power transmission without excessively increasing the information processing load. It is possible to appropriately monitor whether or not This facilitates other information processing (for example, information processing for foreign object detection) simultaneously with the position detection during power transmission.

  In the above-described embodiment, in the second position detection, pattern matching is performed only for the pattern Pb having a small number of light-emitting portions that are lit among the patterns Pb and Pf. By selecting the pattern Pb instead of the pattern Pf, the information processing load for detecting the second position can be reduced.

  When pattern matching is performed on one of the patterns Pb and Pf (hereinafter referred to as “target pattern”) in the second position detection, pattern matching may be performed not on the entire target pattern but on only a part thereof. For example, when the target pattern is the pattern Pf, among the light emitting units that form the pattern Pf, there are five light emitting units that are lit, but the pattern recognition area is narrowed down and only the four or three light emitting units are patterned. You may make it perform collation. By doing so, it is possible to reduce the load of information processing for the second position detection.

  The pattern used for pattern matching is not limited to the above one-dimensional code. For example, a two-dimensional code formed by a plurality of (for example, nine (= 3 × 3) or more) light emitting units arranged vertically and horizontally may be employed. Moreover, the display part which displays a pattern in a non-contact electric power transmission system is not restricted to a light emission part, A label etc. may be sufficient. A pattern printed on a label or the like may be recognized by the imaging device 103.

  In the above embodiment, the power transmission device 100 includes the imaging device 103, and the power reception device 200 includes the patterns Pb and Pf that can be recognized by the imaging device 103. However, the invention is not limited thereto, and the power receiving device 200 may include an imaging device, and the power transmission device 100 may include patterns (first pattern and second pattern) that can be recognized by the imaging device. Also in this case, if the first pattern and the second pattern have different patterns in the power transmission device 100 and are spaced apart from each other, which pattern is recognized first by the imaging device of the power reception device 200? Based on the above, the relative positional relationship between the primary coil 101 and the secondary coil 201 can be detected.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiment but by the scope of claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of claims.

  DESCRIPTION OF SYMBOLS 1 Charging equipment, 2 Vehicles, 10 Power transmission system, 21 Floor panel, 22 Exhaust system, 100 Power transmission device, 101 Primary coil, 102, 202 Case, 103 Imaging device, 150 Power transmission ECU, 151 Power transmission control unit, 152 Detection Unit, 160, 600 communication unit, 200 power receiving device, 201 secondary coil, 210 power receiving unit, 220 substrate, 221, 222 inclined unit, 300 power storage device, 400 display unit, 500 vehicle ECU, 700 AC power supply, Lb1 to Lb11, Lf1 to Lf11 Light emitting part, Pb, Pf pattern.

Claims (1)

A non-contact power transmission system in which power is transmitted in a non-contact manner from a primary coil of a power transmission device to a secondary coil of a power reception device,
One of the power transmission device and the power receiving device includes an imaging device, and the other includes a first pattern and a second pattern that can be recognized by the imaging device,
The first pattern and the second pattern have different patterns and are spaced apart from each other around the primary coil or the secondary coil,
Before starting transmission of the power, each of the first pattern and the second pattern recognized by the imaging device is collated with a predetermined pattern, and both the first pattern and the second pattern are checked. A non-contact power transmission system that permits the start of power transmission when verification is successful.

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