JP2015104161A - Non-contact power transmission device and non-contact power transmission system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact power transmission device and a non-contact power transmission system that have a metal detection coil, the device and system being able to satisfactorily detect a metal foreign matter while preventing erroneous detection of a vehicle as metal foreign matter.SOLUTION: A non-contact power transmission device (power transmission device 200) comprises: a detecting part (detecting circuit 232) that detects output from a metal detection coil; and a control part 234 that, when a power receiving device (power receiving part 120) and a power transmission device 200 (power transmission part 210) mounted in a vehicle 100 are positioned to each other, controls a warning part 233 such that when output from the metal detection coil drops below a reference value, a warning operation is performed. When a vehicle 100 is located within a predetermined range from the power transmission device 200, the reference value is set lower than that when the vehicle 100 is located outside the predetermined range from the power transmission device 200.

Description

  The present invention relates to a contactless power transmission device and a contactless power transmission system.

  Conventionally, various proposals have been made for contactless power transmission devices and systems. For example, JP 2012-016125 A describes a power transmission device in which a plurality of metal detection coils are mounted in an array on the surface of the power transmission device.

JP 2012-016125 A JP 2011-160600 A JP 2010-252498 A JP2013-017247A JP2013-154815A JP2013-146154A JP2013-146148A JP 2013-110822 A JP 2013-126327 A

  In order to detect a metal foreign object using a metal detection coil, the following method can be considered. For example, when the power reception device is located above the power transmission device, a plurality of metal detection coils are arranged on the upper surface of the power transmission device. During non-contact power transmission, an electromagnetic field is generated from the power transmission device. At this time, if there is a metal foreign object near the metal detection coil, the inductance value (L value) of the metal detection coil changes. As a result, the induced voltage, current, and the like generated in the metal detection coil during non-contact power transmission are different (change) from when there is no metal foreign object. By utilizing this change, a metallic foreign object can be detected.

  Non-contact power transmission can be used to charge a vehicle battery. In that case, for example, the power reception device is provided in the vehicle, and the power transmission device is provided on the ground. The vehicle approaches the power transmission device by positioning the power transmission device and the power reception device for non-contact power transmission. Here, since the vehicle includes many metal parts, the metal detection coil may determine the vehicle itself as a metal foreign object.

  An object of the present invention is a non-contact power transmission apparatus and a non-contact transmission system provided with a metal detection coil, which can detect a metal foreign object well while suppressing misidentification of the vehicle as a metal foreign object. An apparatus and a contactless transmission system are provided.

  In summary, the present invention relates to a non-contact power transmission device, in which when a positioning unit that detects an output of a metal detection coil and a power receiving device mounted on a vehicle and a non-contact power transmission device are aligned, the metal And a control unit that controls the warning unit so as to perform a warning operation when the output of the detection coil falls below a reference value. The reference value is set lower when the vehicle is positioned inside the predetermined range from the non-contact power transmission device than when the vehicle is positioned outside the predetermined range from the non-contact power transmission device.

  If there is metal around the non-contact power transmission device, the output of the metal detection coil decreases, and the output falls below the reference value. The warning operation that is performed when the output of the metal detection coil falls below the reference value is an operation that is performed when a metal foreign object is detected. According to the vehicle having the above configuration, when the vehicle is located inside the predetermined range from the non-contact power transmission device (that is, the vehicle is close to the non-contact power transmission device), the vehicle is located outside the predetermined range from the non-contact power transmission device (that is, The reference value is set lower than when the vehicle is far from the non-contact power transmission device. Since the reference is appropriately set, even when the vehicle is near the non-contact power transmission device, it is possible to prevent the warning operation from being performed due to the influence of metal parts included in the vehicle. That is, it is possible to prevent a metal part or the like included in the vehicle from being erroneously detected as a metal foreign object.

  Preferably, when the alignment is performed, the control unit controls the non-contact power transmission device so that the metal foreign object detection is temporarily stopped when the vehicle enters a predetermined range, and the metal foreign object detection is performed after the alignment is completed. The contactless power transmission device is controlled to resume.

  When the vehicle is in the vicinity of the non-contact power transmission device and alignment is performed, the output of the metal detection coil may be changed every moment due to the influence of the metal parts approaching the non-contact power transmission device together with the vehicle. In that case, it is difficult to accurately determine the presence or absence of a metal foreign object from the change in the output of the metal detection coil, and erroneous detection may occur. According to the above configuration, when the vehicle is in the vicinity of the non-contact power transmission device and alignment is performed, the metallic foreign object detection is temporarily stopped. Thereby, it can prevent that a misdetection arises.

  Alternatively, preferably, the control unit controls the non-contact power transmission device so as to continue detecting the metal foreign object even when the vehicle enters the predetermined range, and performs a warning operation when the metal foreign object is detected. Control the warning section.

According to this configuration, the metallic foreign object can be detected even before the alignment is completed.
Preferably, the non-contact power transmission device further includes a power transmission coil, a power supply device that supplies power to the power transmission coil, and a communication unit that communicates with the vehicle. The control unit controls the power supply device so as to supply weak power to the power transmission coil, and when a metal foreign object is detected before alignment, notifies the vehicle of the presence of the metal foreign object when communication is established. To control the communication unit.

  According to this configuration, metal foreign matter detection can be performed using a weak current supplied to the power transmission coil for alignment. That is, an output can be generated in the metal detection coil by an electromagnetic field generated by supplying a weak current to the power transmission coil.

  Preferably, when the alignment is completed, the control unit controls the power supply device so that electric power larger than weak electric power is supplied to the power transmission coil to transmit power to the vehicle, and when a metal foreign object is detected during power transmission, The power supply device is controlled to stop the power supply.

  According to this configuration, for example, during the charging, metal foreign matter detection can be performed using the power for charging.

  In another aspect, the present invention is a contactless power transmission system. The non-contact power transmission system includes a non-contact power transmission device, a power reception device mounted on a vehicle, a detection unit that detects an output of a metal detection coil, and a positioning between the power reception device and the non-contact power transmission device. And a control unit that controls the warning unit so as to perform a warning operation when the output of the metal detection coil falls below a reference value. The reference value is set lower when the vehicle is positioned inside the predetermined range from the non-contact power transmission device than when the vehicle is positioned outside the predetermined range from the non-contact power transmission device.

  Even with the power transmission system having the above-described configuration, it is possible to prevent a metal part or the like included in the vehicle from being erroneously detected as a metal foreign object.

  According to the present invention, in a non-contact power transmission apparatus and a non-contact transmission system provided with a metal detection coil, a non-contact power transmission apparatus that can detect a metal foreign object well while suppressing misidentification of the vehicle as a metal foreign object. It is possible to provide a contactless transmission system.

It is a figure for demonstrating schematic structure of an electric power transmission system. It is a figure for demonstrating schematic structure of a vehicle. It is a figure for demonstrating the principle of a metal foreign material detection (metal foreign material sensor). It is a flowchart for demonstrating the process performed in non-contact charge. It is a flowchart for demonstrating the process performed in the non-contact charge including the temporary stop of a metal foreign material detection operation. It is a flowchart for demonstrating the process performed when a metal foreign material is detected before vehicle proximity. It is a flowchart for demonstrating the process performed when a metal foreign material is detected during charge. It is a figure for demonstrating the reference value in each metal foreign material detection operation | movement in the case of non-contact charge.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is a diagram for explaining a schematic configuration of the power transmission system 10. In the power transmission system 10, power transmission is performed in a contactless manner from the power transmission device 200 (that is, the infrastructure side) that is a contactless power transmission device to the power receiving unit 120 of the vehicle 100. Thereby, for example, contactless charging of vehicle 100 is performed.

  The vehicle 100 is, for example, an electric vehicle or a hybrid vehicle that can travel with electric energy. Vehicle 100 includes a camera 110, a power reception unit 120, a battery 130, and a communication unit 140. An image captured by the camera 110 can be confirmed by the occupant, and the user can perform alignment between the vehicle 100 and the power transmission device 200 using the image. The power receiving unit 120 receives the power from the power transmission device 200 in a contactless manner. The power receiving unit 120 includes a coil for receiving power (power receiving coil). Battery 130 is used as a power source of vehicle 100. The communication unit 140 is used to communicate with the communication unit 240 (for example, wireless communication).

  The power transmission device 200 is a device for sending electric power in a non-contact manner. The power transmission device 200 includes a power transmission unit 210, a metal detection coil unit 220, and a power supply stand 230. The power transmission unit 210 includes a coil for power transmission (power transmission coil). The power supply stand 230 includes a power supply device 231, a detection circuit 232, a warning unit 233, and a control unit 234. The power supply device 231 generates power (AC power) that can be contactlessly transmitted and supplies the power to the power transmission unit 210. The communication unit 240 is used for communicating with the communication unit 140. The control unit 234 controls the components included in the power transmission device 200. The control unit 234 can also control the vehicle 100 using the communication unit 240.

  The warning unit 233 performs a warning operation. The warning operation is an operation for notifying the vehicle 100 and the user of information related to the metal foreign object. The warning operation may be realized by cooperation between the warning unit 233 and the control unit 234. For example, the warning unit 233 includes an alarm device (not shown). In that case, the alarm is activated to inform the user of the presence of the metal foreign object. Warning operations include notification to the user that a metal foreign object has been detected (discovered), notification to the user to prompt removal of the metal foreign object, notification to the user that charging has been interrupted due to the presence of the metal foreign object, etc. Including various actions.

  In the non-contact charging, alignment is performed so that the power receiving coil included in the power receiving unit 120 of the vehicle 100 and the power transmitting coil included in the power transmitting unit 210 of the power transmitting device 200 face each other. In the aligned state (completed), power transmission is performed in a non-contact manner from the power transmission unit 210 (the power transmission coil) to the power reception unit 120 (the power reception coil) via the electromagnetic field.

  A capacitor is connected to each of the power transmission coil and the power reception coil, and is designed to resonate at the transmission frequency. The Q value indicating the resonance intensity is preferably 100 or more.

  If there is a metal foreign object between the power reception unit 120 and the power transmission unit 210, there is a possibility of affecting power transmission. For example, a part of electric power used for electric power transmission may be consumed by a metal foreign material. In that case, problems such as a decrease in power transmission efficiency and heat generation of metal foreign matter occur. In the power transmission system 10, a metal detection coil unit 220 and a detection circuit 232 are used to detect metal foreign matter that has entered between the power reception unit 120 and the power transmission unit 210. As will be described later with reference to FIG. 3, the metal detection coil unit 220 includes a plurality of metal detection coils (sometimes referred to as “scan coils” in the embodiments). The metal detection coil unit 220 only needs to be arranged so as to be able to detect a metal foreign object, and as an example, the metal detection coil unit 220 is arranged on the upper part of the power transmission unit 210 as shown in FIG. The detection circuit 232 functions as a detection unit that detects a voltage or current generated in the metal detection coil unit 220. Metal foreign object detection using the metal detection coil unit 220 and the detection circuit 232 will be described in detail later with reference to FIG.

  FIG. 2 is a diagram for explaining a schematic configuration of the vehicle 100. The vehicle 100 includes an ECU (Electric Control Unit) 160 that is a control unit that controls components included in the vehicle 100. The vehicle 100 is a so-called hybrid vehicle. Therefore, vehicle 100 includes a hybrid travel mechanism. ECU 160 can also control power transmission device 200 in FIG. 1 using communication unit 140.

  The hybrid travel mechanism can drive the drive wheels 134 by the internal combustion engine (engine) 133 and the motor generators MG1, MG2. Power split device 132 is coupled to engine 133 and M motor generators MG1 and MG2, and distributes power between them. The rotation shaft of motor generator MG2 is coupled to drive wheel 134 by a reduction gear and an operation gear (not shown). Further, the electric power stored in power storage device (battery) 130 is converted into electric power for driving motor generators MG1 and MG2 by PCU (Power Control Unit) 131. The electric power generated by motor generators MG1 and MG2 may be converted into electric power for charging battery 130 by PCU 131. The electric power of the battery 130 is used, for example, for auxiliary equipment other than the hybrid running.

  Vehicle 100 includes a power receiving unit 120. The power receiving unit 120 includes a power receiving coil 121, a capacitor 122, a power converter 123, and a power measuring unit 124. The power reception coil 121 receives the power from the power transmission coil in the power transmission unit 210 of FIG. 1 in a non-contact manner. The capacitor 122 is connected to the power receiving coil 121. The power receiving coil 121 and the capacitor 122 are designed to resonate at the transmission frequency. The power conversion device 123 converts the power received by the power receiving coil 121 into power suitable for charging the battery 130. The power measuring unit 124 can measure the power at the power receiving unit 120. As an example, the power measurement unit 124 measures the power sent from the power converter 123 to the battery 130 as shown in FIG.

  The ECU 160 may determine whether or not the power receiving unit 120 (the power receiving coil 121) and the power transmitting unit 210 of the power transmitting apparatus 200 illustrated in FIG. 1 are properly aligned based on the measurement result of the power measuring unit 124. it can. In the alignment, for example, if the reception level of the weak power transmitted from the power transmission unit 210 to the power reception unit 120 is at or near the maximum, it is determined that the alignment is appropriately performed.

  The communication unit 140 communicates with the outside of the vehicle 100. For example, the communication unit 140 performs wireless communication with the communication unit 240 of FIG.

  Vehicle 100 also includes a warning unit 150. The warning unit 150 performs a warning operation to the user in response to the warning operation of the power transmission device 200 of FIG. The warning operation is performed using, for example, a display device or a speaker (not shown).

  With the above configuration, vehicle 100 can charge battery 130 (that is, contactless charging) by receiving electric power from power transmission device 200 shown in FIG. 1 in a contactless manner. For non-contact charging, communication between the vehicle 100 and the power transmission device 200 is used.

  FIG. 3 is a diagram for explaining the principle of metal foreign object detection (so-called “metal foreign object sensor”) using the metal detection coil unit 220 and the detection circuit 232. The power transmission unit 210 is configured by accommodating a power transmission coil, a capacitor, and the like in a case (bobbin), for example. The power transmission unit 210 is supplied with power from the power supply device 231. The metal detection coil unit 220 includes a plurality of scan coils 221. The scan coil 221 is, for example, a planar coil antenna, and the scan coils 221 are arranged on the same plane. The metal detection coil unit 220 can also be said to be an antenna coil array. When the metal detection coil unit 220 is placed in an electromagnetic field, an induced voltage or an induced current (that is, an induced output) is generated in each scan coil 221 in accordance with the state or the like of the electromagnetic field strength or distribution. The induction output is sent to the detection circuit 232 and detected. The detection result P of the detection circuit 232 is used in a non-contact power supply system (for example, the power transmission system 10 in FIG. 1).

  Specifically, the detection result P of the detection circuit 232 is sent to the control unit 234 (FIG. 1). The control unit 234 determines the presence or absence of a metallic foreign object based on the detection result of the detection circuit 232. The determination of the presence or absence of a metallic foreign object based on the detection result can be explained as follows. When power is transmitted from the power transmission unit 210, an induction output is generated in each scan coil 221. At this time, if a metal foreign object exists near the scan coil 221, the L value of the scan coil 221 changes (for example, decreases). As a result, the induction output at the scan coil 221 changes (for example, decreases). By using this change, the presence or absence of a metal foreign object is determined. It is also determined which scan coil 221 is near the metal foreign object, that is, the position of the metal foreign object. Based on these determinations, metallic foreign matter detection is performed. When a metal foreign object exists, the warning operation using the warning unit 233 as described above is performed in the power transmission system 10 of FIG. In addition, non-contact charging may be suspended (or stopped).

  Whether or not there is a metallic foreign object is determined by comparing at least one of the induced voltage and the induced current, that is, the value of the induced output and the reference value. Specifically, when the guidance output falls below the reference value, it is determined that there is a metal foreign object, and a warning operation is performed. If the guidance output is greater than or equal to the reference value, it is determined that there is no metallic foreign matter.

  For example, the L value of the scan coil 221 when there is a metal piece in the vicinity of the scan coil 221 is lower than the L value of the scan coil 221 when there is no metal piece. Accordingly, the induced voltage and induced current of the scan coil 221 when there is a metal piece in the vicinity of the scan coil 221 are larger than the induced voltage and induced current of the scan coil 221 when there is no metal piece in the vicinity of the scan coil 221. Lower.

  The determination of whether or not there is a metal foreign object (metal foreign object detection operation) has the following problems. In general, a vehicle includes many metal parts. Therefore, when the vehicle approaches the scan coil, the L value of the scan coil decreases, and the induced voltage and induced current decrease. As a result, in the metal foreign object detection operation, there is a possibility that the vehicle itself is misidentified as a metal foreign object.

  Referring to FIG. 1 again, in power transmission system 10 according to the present embodiment, metal foreign object detection operation is performed based on the positional relationship between vehicle 100 (power receiving unit 120) and power transmission device 200 (power transmission unit 210). The reference value at is set appropriately. Specifically, when vehicle 100 is located outside a predetermined range from power transmission device 200, the first reference value is adopted as the reference value. On the other hand, when the vehicle 100 is located inside the predetermined range from the power transmission device 200, a second reference value lower than the first reference value is employed.

  By setting the second reference value lower than the first reference value, even if the vehicle 100 comes close to the scan coil and the induction output (at least one of the induction voltage and the induction current) decreases, the vehicle 100 is made of a metal foreign object. It can be determined that the warning operation is started.

  In the embodiment, a range outside predetermined range from power transmission device 200 by vehicle 100 is referred to as a first reference range, and a metal foreign object detection operation at the first reference value is referred to as “MODE1”. A range outside the predetermined range of power transmission device 200 by vehicle 100 is referred to as a second reference range, and a metallic foreign object detection operation in this second reference range is referred to as “MODE2”.

  The inside of the predetermined range is a range in which the change in the induction output of the scan coil due to the influence of the metal parts of the vehicle 100 is relatively large. For example, the vehicle 100 is close to the power transmission unit 210 of the power transmission device 200. is there. For example, if the positional relationship is such that at least a part of the bottom surface of the vehicle 100 overlaps the power transmission unit 210, it can be said that the vehicle 100 is close.

  FIG. 4 is a flowchart for explaining processing executed to perform non-contact charging of the vehicle. The “infrastructure (power transmission device) side” in FIG. 4 represents processing executed by the power transmission device 200 (FIG. 1), and “vehicle side” shows processing executed by the vehicle 100 (FIG. 1). Processing executed on the infrastructure side is performed by the control unit 234 (FIG. 1). Processing executed on the vehicle side is performed by ECU 160 (FIG. 2).

  Referring to FIG. 4, first, on the infrastructure side, the power stand is set to ON (step S101). This setting is performed by a user operation, for example. As a result, the power supply device 231 and the detection circuit 232 are placed in an operable state.

  On the vehicle side, the non-contact switch of the vehicle is set to ON. This setting is also performed by a user operation or the like, for example. As a result, the vehicle is placed in a non-contact chargeable state. In FIG. 2, the non-contact chargeable state means that the battery 130 can be charged by the power (charged power) received by the power receiving unit 120.

  On the infrastructure side, after the process of step S101 is executed, small power is supplied to the power transmission coil (step S102). The low power is a power (so-called weak power) that is considerably smaller than the charging power supplied to the power transmission coil for non-contact charging. In the present embodiment, the low power is also used to perform the metallic foreign object detection operation and the positioning of the power receiving device (power receiving unit 120) and the power transmitting device 200. Specifically, the vehicle 100 performs alignment with the power transmission device 200 based on the received voltage when the small power from the power transmission coil is received. On the other hand, an induced voltage and an induced current are generated in the scan coil by an alternating magnetic field formed around the power transmission coil. After the process of step S102 is executed, the process proceeds to step S103.

  On the infrastructure side, a metal foreign object detection operation is started in step S103. The metal foreign object detection operation here is “MODE1”, and the reference value is set to the first reference value. After the process of step S103 is executed, wireless communication between the infrastructure side and the vehicle side is performed.

  On the infrastructure side, in step S104, it is determined whether or not wireless communication with the vehicle side has been established. If wireless communication has been established (YES in step S104), the process proceeds to step S105. On the other hand, when the wireless communication is not established (NO in step S104), the process of step S104 is repeatedly executed until the wireless communication is established. In addition, when the magnitude | size of the small electric power used for metal foreign material detection operation and the magnitude | size of the small electric power used for alignment are different, after the process of step S104 is performed, the electric power supplied to the power transmission coil is The power for the metal foreign object detection operation may be changed to the power for alignment.

  On the vehicle side, in step S202, it is determined whether or not wireless communication with the infrastructure side has been established. If wireless communication has been established (YES in step S202), the process proceeds to step S203. On the other hand, when the wireless communication is not established (NO in step S202), the process of step S202 is repeatedly executed until the wireless communication is established.

  On the vehicle side, position detection is started (step S203). That is, position detection using the camera 110 (FIG. 1) and position detection based on the received level of weak power are performed. After the position detection is started, the vehicle moves closer to the infrastructure by a user operation or the like.

  On the vehicle side, in step S204, it is determined whether the vehicle is close to the infrastructure. If the vehicle is close (YES in step S204), the process proceeds to step S205. On the other hand, if the vehicle is not close to the infrastructure (NO in step S204), the process of step S204 is repeatedly executed until the vehicle is close to the infrastructure. Information on whether or not the vehicle is in close proximity is sent to the infrastructure side by wireless communication.

  On the infrastructure side, in step S105, based on the information sent from the vehicle side, it is determined whether or not the vehicle is close to the infrastructure. If the vehicle is close (YES in step 105), the process proceeds to step S106. On the other hand, when the vehicle does not approach (NO in step S105), the process of step S105 is repeatedly executed until the vehicle approaches.

  On the infrastructure side, in step S106, the metal foreign object detection is continued, the metal foreign object detection operation is switched to “MODE2”, and the reference value is set to the second reference value.

  On the vehicle side, in step S205, it is determined whether or not the vehicle is stopped, that is, whether or not the alignment is completed. For example, if the vehicle is in a READY-OFF state (incapable of traveling) or the shift position is set to P (Parking) by a user operation or the like, it is determined that the vehicle is stopped. If the vehicle is stopped (YES in step S205), the process proceeds to step S206. On the other hand, when the vehicle is not stopped (NO in step S205), the process of step S205 is repeatedly executed until the vehicle stops. Vehicle stop information is sent to the infrastructure side by wireless communication.

  On the infrastructure side, in step S107, it is confirmed that the vehicle is stopped based on information sent from the vehicle side.

  On the vehicle side, a charge start command is issued in step S206. The charge start command is sent to the infrastructure side by wireless communication.

  On the infrastructure side, in step S108, transmission of charging power is started based on information sent from the vehicle side.

On the vehicle side, in step S207, reception of charging power is started.
Thereafter, charging is completed in step S109 on the infrastructure side, and charging is completed in step S208 on the vehicle side.

  According to the flowchart of FIG. 4, the metal foreign object detection operation is set to “MODE1” before approaching the vehicle, and is set to “MODE2” after approaching the vehicle. Therefore, it is possible to detect the metal foreign object well without erroneously detecting the vehicle as the metal foreign object.

  Note that, in the metal foreign object detection operation, determination based on the rate of change of the scan coil induction output may be employed in addition to the determination of whether the scan coil induction output is lower than the reference value.

  Depending on the type of the vehicle 100, the change mode of the L value of the scan coil varies. As a result, if the vehicle is close to the power transmission device and the vehicle is moving, the presence or absence of a metallic foreign object cannot be accurately determined due to fluctuations in the induction output, and erroneous detection may occur. Therefore, it is conceivable to temporarily stop the metal foreign object detection operation when the vehicle is close to the power transmission device.

  FIG. 5 is a flowchart for explaining processing executed in non-contact charging including temporary suspension of the metallic foreign object detection operation. Steps S301 to S303 on the infrastructure side and steps S401 to S406 on the vehicle side in FIG. 5 are the same as steps S101 to S103 on the infrastructure side and steps S201 to S206 on the vehicle side in FIG.

  Referring to FIG. 5, it is determined in step S304 whether or not a metallic foreign object has been detected. This determination is a determination of whether or not a metal foreign object has been detected before the vehicle approaches. If no metal foreign object is detected (NO in step S304), the process proceeds to step S305. On the other hand, if a metallic foreign object is detected (YES in step S304), the process proceeds to step S304A. Step S304A will be described later with reference to FIG.

  On the infrastructure side, in step S305, it is determined whether or not wireless communication with the vehicle side has been established. If wireless communication has been established (YES in step S305), the process proceeds to step S306. On the other hand, when wireless communication is not established (NO in step S305), the process of step S305 is repeatedly executed. Also, after the process of step S304A is executed, the process proceeds to step S306.

  On the infrastructure side, in step S306, it is determined whether or not the vehicle is close to the infrastructure. If the vehicle is close (YES in step S306), the process proceeds to step S307. On the other hand, when the vehicle does not approach (NO in step S306), the process of step S306 is repeatedly executed until the vehicle approaches.

  On the infrastructure side, the metal foreign object detection operation is interrupted in step S307. Thereafter, in step S308, it is confirmed that the vehicle is stopped.

  On the infrastructure side, the metal foreign object detection operation is resumed in step S309. The metal foreign object detection operation at this time is “MODE2”, and the reference value is set to the second reference value.

  On the infrastructure side, charging is started in step S310. Similarly, on the vehicle side, charging is started in step S407. Processing executed after charging is started (during charging) will be described later with reference to FIG.

  According to the flowchart of FIG. 5, the metal foreign object detection operation is interrupted (temporarily stopped) until the vehicle stops after the vehicle approaches. No false positives occur during the pause.

  FIG. 6 is a flowchart for explaining the process executed in step S304A of FIG.

  Referring to FIG. 6, the infrastructure side determines whether or not wireless communication has been established in step S501. If wireless communication has been established (YES in step S501), the process proceeds to step S502. On the other hand, when wireless communication is not established (NO in step S501), the process of step S501 is repeatedly executed.

  Further, on the infrastructure side, in step S502, the detection of the metal foreign object, that is, the presence of the metal foreign object is notified from the infrastructure side to the vehicle side. Thereby, the presence of the metal foreign object is notified before the vehicle approaches.

Thereafter, on the infrastructure side, the metal foreign object detection operation is continued in step S503.
In step S603, the vehicle side receives information sent from the infrastructure side and notifies the occupant (driver) of the presence of the metal foreign object. The warning operation of the warning unit 233 in FIG. 1 or the warning unit 150 in FIG. 2 is used for notifying the passenger. In this step S603, the metal foreign object detection operation is performed by the weak electric power for positioning, and the problem of heat generation of the metal foreign object hardly occurs. Further, since charging is not yet performed, there is no problem of reduction in power transmission efficiency during charging. In spite of these problems, if the start of alignment is stopped or the user has to get off and remove the metal foreign object, the convenience is impaired. In order to avoid this, in the warning operation in step S603, the user is notified of the presence of the metal foreign object, but it is preferable not to prompt the user to remove the metal foreign object.

  On the vehicle side, in step S604, position detection is started, and then alignment is started. In step S605, after the alignment operation (parking operation) is continued, the vehicle stops in step S606, and the alignment is completed.

  On the vehicle side, when the alignment is completed, the charging (starting) operation is interrupted in step S607. Then, in step S608, a notification for prompting the user (driver) to remove the metallic foreign object and a notification of interruption of the charging (starting) operation are made. Thereby, a metal foreign material is removed by the user, for example.

  According to the flowchart of FIG. 6, when a metal foreign object is detected before approaching the vehicle, the presence of the metal foreign object is notified to the user before alignment is performed. Therefore, the user can make preparations for charging such as removal of metal foreign objects.

  FIG. 7 is a flowchart for explaining processing executed when a metallic foreign object is detected during charging. Steps S701 and S702 on the infrastructure side and steps S801 and S802 on the vehicle side in FIG. 7 are the same as steps S309 and S310 on the infrastructure side and steps S406 and S407 on the vehicle side in FIG.

  When charging is started, on the infrastructure side, the metal foreign object detection operation is switched to “MODE2-2” in step S703. “MODE2-2” is an adaptation of the reference value in the metallic foreign object detection operation to the inductive output level of the scan coil with respect to the charging power. This will be described later with reference to FIG.

  On the infrastructure side, in step S704, it is determined whether a metal foreign object has been detected. If a metallic foreign object is detected (YES in step S704), the process proceeds to step S705. On the other hand, if no metal foreign object is detected (NO in step S704), the process proceeds to step S705.

  In step S705, it is determined whether charging is complete. If charging is complete (YES in step S705), the processing in the flowchart ends. On the other hand, when the charging is not completed (NO in step S705), the process returns to step S704 again.

  On the infrastructure side, charging is interrupted in step S706. On the other hand, the metal foreign object detection operation is continued. Information on charging interruption is sent to the vehicle side. Note that weak power is supplied to the power transmission coil in order to continue the metal foreign object detection operation even if the charging is interrupted.

  On the vehicle side, in step S803, in response to the information from the infrastructure side, the user is notified of the interruption of charging and the notification for prompting the removal of the metallic foreign object. For the notification to the user, the warning operation of the warning unit 233 in FIG. 1 or the warning unit 150 in FIG. 2 is used. The user who has received the notification can get off the vehicle and remove the metallic foreign object, for example.

  On the infrastructure side, in step S707, it is determined whether or not the metal foreign matter has been removed. If the metal foreign object has been removed (YES in step S707), the process proceeds to step S708. On the other hand, when the metal foreign matter is not removed (NO in step S707), the process of step S707 is repeatedly executed.

  The infrastructure side waits for charging in step S708. Charging standby information is sent to the vehicle side.

  On the vehicle side, in step S805, the charging resumption determination is made in response to the charging standby information from the infrastructure side. The determination of resuming charging can be performed by a user operation of a user who thinks that charging may be resumed because the metal foreign object has been removed, for example. The decision to resume charging is sent to the infrastructure side. Thereafter, charging is resumed in step S806.

  On the infrastructure side, in step S709, charging is resumed upon receiving a charge resumption determination from the vehicle side. That is, the power supplied to the power transmission coil is returned from the weak power to the charging power.

  Thereafter, charging is completed in step S710 on the infrastructure side, and charging is completed in step S807 on the vehicle side.

  According to the flowchart of FIG. 7, when a metal foreign object is detected during charging, charging is interrupted and the presence of the metal foreign object is notified to the user. Thereby, the fall of the charging efficiency by presence of a metal foreign material, for example is prevented. Further, during charging, the reference value in the metal foreign object detection operation is set to an appropriate value corresponding to the charging power. Thereby, a metal foreign object can be detected appropriately.

  As described above, in the power transmission system 10 (FIG. 1) according to the embodiment, different reference values are set in the metal foreign object detection operation. Specifically, the reference value in the metallic foreign object detection operation (MODE 1) when the vehicle is close to the power transmission device (positioned inside the predetermined range) is not close to the power transmission device (positioned outside the predetermined range). ), A value higher than the reference value in the metallic foreign object detection operation (MODE 2) is set. Also, when the power supplied to the power transmission coil is small power (weak power or weak current) (MODE1 or MODE2), the power supplied to the power transmission coil is larger than the small power. A higher reference value is set for the metallic foreign matter detection operation (MODE2-2).

  Since the charging power is stronger than the small power, the strength of the electromagnetic field formed around the power transmission device 200 is increased. As a result, the induced voltage induced in the scan coil is also increased.

  FIG. 8 is a diagram for explaining the reference values in each metal foreign object detection operation, MODE1, MODE2, and MODE2-2 at the time of non-contact charging. In the graph of FIG. 8, the horizontal axis represents time (t), and the vertical axis represents the scan coil induction output (for example, induction voltage (V)). This graph shows how the mode of the metal foreign object detection operation is switched in the order of MODE1, MODE2, and MODE2-2 as time passes.

  Referring to FIG. 8, first, during time t0 to t1, since the vehicle is away from the power transmission device, the metallic foreign object detection operation in MODE 1 is performed. Small electric power (for example, a weak current) is supplied to the power transmission coil. This state corresponds to, for example, step S303 in FIG. Here, the reference value in MODE 1 is referred to as a first reference value. The first reference value is a value of the induction output that is expected to be generated in the scan coil when there is no metal foreign object. At this time, if a metallic foreign object jumps near the power transmission device 200, the induced voltage becomes lower than the first reference value. Thereby, a metallic foreign material can be detected.

  In addition, since the metal foreign object detection operation is interrupted between the times t1 and t2, it is not necessary to set the reference value. This state corresponds to, for example, steps S307 to S308 in FIG.

  Between times t2 and t3, the vehicle is in close proximity to the power transmission device, so the metal foreign object detection operation in MODE2 is performed. Weak power is supplied to the power transmission coil. This state corresponds to, for example, step S309 in FIG. Here, the reference value in MODE 2 is referred to as a second reference value. Therefore, when the second reference value is set, the guidance output does not become smaller than the second reference value even if the vehicle approaches. That is, there is no possibility that the vehicle is erroneously detected as a metal foreign object. In this way, when the metal foreign object jumps in the vicinity of the power transmission device 200 in the state where the vehicle 100 is close, the induced voltage becomes lower than the second reference value. Thereby, a metallic foreign material can be detected.

  After time t3, since the alignment between the vehicle and the power transmission device is completed and charging is performed, the metallic foreign object detection operation in MODE2-2 is performed. High power for charging is supplied to the power transmission coil. This state corresponds to, for example, step S703 in FIG. The reference value in MODE2-2 is referred to herein as the third reference value. The third reference value is higher than the first reference value and the second reference value.

  Finally, embodiments of the present invention will be summarized. 1 to 3, the non-contact power transmission device (power transmission device 200) according to the embodiment includes a detection unit (detection circuit 232) that detects the output of the metal detection coil (scan coil 221), and the vehicle 100. When the positioning of the power receiving device (power receiving unit 120) and the power transmitting device 200 (the power transmitting unit 210) mounted thereon is performed, if the output of the metal detection coil (scan coil 221) falls below a reference value, a warning operation is performed. And a control unit 234 for controlling the warning unit 233 so as to be implemented. The reference value is set lower when vehicle 100 is positioned inside the predetermined range from power transmission device 200 than when vehicle 100 is positioned outside the predetermined range from power transmission device 200.

  Preferably, as shown in FIG. 5, when positioning is performed, control unit 234 controls power transmission device 200 so that metallic foreign object detection is temporarily stopped when vehicle 100 enters a predetermined range (step). S307), the power transmission apparatus 200 is controlled so that the metallic foreign object detection is resumed after the alignment is completed (step S309).

  Alternatively, preferably, as shown in FIG. 4, control unit 234 controls power transmission device 200 so that metal foreign object detection is continued even if vehicle 100 enters inside a predetermined range (step S106), and metal foreign object When a warning is detected, the warning unit 233 is controlled to perform a warning operation.

  Preferably, as illustrated in FIG. 3, the power transmission device 200 includes a power transmission coil (power transmission unit 210), a power supply device 231 that supplies power to the power transmission coil (power transmission unit 210), and a communication unit that communicates with the vehicle 100 ( And a communication unit 240) of FIG. For example, as illustrated in FIGS. 5 and 6, the control unit 234 controls the power supply device 231 to supply weak power to the power transmission coil for alignment and metal detection (step S302), and before alignment. When a metal foreign object is detected (YES in step S304), the communication unit is controlled to notify the vehicle of the presence of the metal foreign object when communication is established (step S502).

  Preferably, for example, as shown in FIGS. 5 and 7, control unit 234 controls the power supply device so that, when alignment is completed, power larger than weak power is supplied to the power transmission coil and transmitted to the vehicle (step). S310) When a metallic foreign object is detected during power transmission (YES in step S705), the power supply device is controlled to stop power supply to the power transmission coil (step S705).

  In addition, the power transmission system 10 according to the embodiment outputs the outputs of the non-contact power transmission device (power transmission device 200), the power reception device (power reception unit 120) mounted on the vehicle 100, and the metal detection coil (scan coil 221). The output of the metal detection coil (scan coil 221) is used as a reference when the detection unit (detection circuit 232) to be detected is aligned with the power reception device (power reception unit 120) and the power transmission device 200 (power transmission unit 210). A control unit (control unit 234, ECU 160) that controls the warning units 150 and 233 so as to perform a warning operation when the value is below the value is provided. The reference value is set lower when vehicle 100 is positioned inside the predetermined range from power transmission device 200 than when vehicle 100 is positioned outside the predetermined range from power transmission device 200.

  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 the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

  DESCRIPTION OF SYMBOLS 10 Electric power transmission system, 100 Vehicle, 110 Camera, 120 Power receiving part, 121 Power receiving coil, 122 Capacitor, 123 Power converter, 124 Power measuring part, 130 Battery, 132 Power split mechanism, 134 Drive wheel, 140,240 Communication unit, 150, 233 Warning unit, 200 Power transmission device, 210 Power transmission unit, 220 Metal detection coil unit, 221 Scan coil, 230 Power supply stand, 231 Power supply device, 232 Detection circuit, 234 Control unit, MG1, MG2 Motor generator.

Claims (6)

A non-contact power transmission device,
A detection unit for detecting the output of the metal detection coil;
A control unit that controls the warning unit to perform a warning operation when an output of the metal detection coil falls below a reference value when the power receiving device mounted on the vehicle and the contactless power transmission device are aligned; With
The reference value is set lower when the vehicle is located inside the predetermined range from the contactless power transmission device than when the vehicle is located outside the predetermined range from the contactless power transmission device. Power transmission device.   When the alignment is performed, the control unit controls the non-contact power transmission device so as to temporarily stop detection of a metallic foreign object when the vehicle enters the predetermined range, and after the alignment is completed, The contactless power transmission device according to claim 1, wherein the contactless power transmission device is controlled so as to resume detection of a metallic foreign object.   The control unit controls the non-contact power transmission device so that the metal foreign object detection is continued even when the vehicle enters the predetermined range, and performs the warning operation when the metal foreign object is detected. The non-contact power transmission device according to claim 1, wherein the warning unit is controlled. The contactless power transmission device is:
A power transmission coil;
A power supply for supplying power to the power transmission coil;
A communication unit that communicates with the vehicle;
The control unit controls the power supply device to supply weak power to the power transmission coil, and when a metal foreign object is detected before the alignment, the presence of the metal foreign object is detected when the communication is established. The non-contact power transmission apparatus according to claim 1, wherein the communication unit is controlled to notify the vehicle.   When the alignment is completed, the control unit controls the power supply device to supply electric power larger than the weak electric power to the power transmission coil to transmit power to the vehicle, and a metallic foreign object is detected during the power transmission. The contactless power transmission device according to claim 4, wherein the power supply device is controlled to stop power supply to the power transmission coil. A contactless power transmission device;
A power receiving device mounted on the vehicle;
A detection unit for detecting the output of the metal detection coil;
When positioning the power receiving device and the non-contact power transmission device, a control unit that controls the warning unit to perform a warning operation when the output of the metal detection coil falls below a reference value,
The reference value is set lower when the vehicle is located inside the predetermined range from the contactless power transmission device than when the vehicle is located outside the predetermined range from the contactless power transmission device. Power transmission system.

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