JP6375750B2 - Non-contact power transmission / reception system - Google Patents

Description

  The present invention relates to a non-contact power transmission / reception system, and more particularly to a non-contact power transmission / reception system capable of detecting foreign matters such as metal.

  Conventionally, power transmission / reception systems that transmit power in a non-contact manner have been proposed. For example, Japanese Patent Laying-Open No. 2014-039369 (Patent Document 1) discloses a configuration in which a detection coil for detecting a foreign object such as metal is arranged in a power transmission device or a power reception device.

JP 2014-039369 A US Patent Specification 2013/0069441 JP2013-154815A JP2013-146154A JP2013-146148A JP 2013-110822 A JP 2013-126327 A

  The foreign matter detection device disclosed in Japanese Patent Application Laid-Open No. 2014-039369 is a detection coil that detects that the electromagnetic field used for power transmission / reception changes due to the presence of foreign matter while power is being transmitted / received by an electromagnetic field. By detecting with, foreign objects such as metal are detected.

  However, the above foreign matter detection device can detect with high sensitivity when foreign matter is present near the detection coil, but foreign matter is present on the resin cover when the detection coil is covered with the resin cover. When the distance between the detection coil and the foreign object is long, the sensitivity becomes worse. In addition, when the foreign object is in the form of a thin metal foil, even if there is a foreign object on the power transmission device, the direction of the magnetic field for power transmission is parallel to the metal foil, so a change in the magnetic field appears in the detection coil. Hateful.

  The present invention has been made to solve the above-described problems, and an object thereof is to provide a non-contact power transmission / reception system with improved foreign object detection accuracy.

  In summary, the present invention is a non-contact power transmission / reception system, which is a power transmission device, a power reception device that receives power from a power transmission device in a contactless manner, and a transmission antenna provided in one of the power transmission device and the power reception device And a receiving antenna provided on the other of the power transmitting device and the power receiving device, and a foreign object around the power transmitting device and the power receiving device based on the reception intensity at which the electromagnetic wave from the transmitting antenna is received by the receiving antenna. A detection unit for detecting.

  With the above configuration, electromagnetic waves can be transmitted from the transmitting antenna to the receiving antenna at a frequency and direction suitable for foreign object detection, separately from the direction and frequency of the electromagnetic field used for power transmission and reception. Therefore, the accuracy and sensitivity of foreign object detection can be improved.

  Preferably, power transmission is performed between the power transmitting device and the power receiving device by an electromagnetic field having a first frequency, and an electromagnetic wave transmitted from the transmitting antenna is an electromagnetic wave having a second frequency higher than the first frequency. is there.

  The higher the frequency, the stronger the straightness of the electromagnetic wave. When there is an obstacle, the electromagnetic wave is blocked and cannot reach the destination. However, when the frequency is low, the obstacle can go around the obstacle to some extent. While it is preferable that the electromagnetic field for power transmission reaches the power receiving device from the power transmission device even if there are some obstacles, the electromagnetic wave for foreign material detection is interrupted by the foreign material when it is present, and changes to the received intensity. The detection sensitivity is better when this occurs. Therefore, by setting the second frequency (for foreign object detection) higher than the first frequency (for power transmission), it is possible to appropriately achieve both power transmission and foreign object detection.

  Preferably, the power receiving device includes a power transmission coil arranged so that the winding axis is along the horizontal direction, and electromagnetic waves are radiated radially from the transmitting antenna toward the receiving antenna.

  If electromagnetic waves for foreign object detection are transmitted from a transmission antenna provided separately from the power transmission coil, even if there are foreign objects in the region where the direction of the magnetic field next to the power transmission coil is horizontal, When there is a foreign object in the vicinity of the receiving antenna that receives radio waves from a transmitting antenna provided separately from the power transmission coil, the detection sensitivity of the foreign object can be increased.

  Preferably, the detection unit obtains information for alignment between the power reception device and the power transmission device based on the reception intensity at which the electromagnetic wave from the transmission antenna is received by the reception antenna, and the power transmission device and the power reception device. Detect surrounding foreign objects.

  When the transmitting antenna and the receiving antenna are used not only for detecting a foreign substance but also for positioning the power transmitting device and the power receiving device, it is not necessary to provide a separate positioning device.

  In another aspect, the present invention provides a power reception system for a vehicle, including a power reception device that receives power in a non-contact manner from a power transmission device outside the vehicle, a transmission antenna provided in the power reception device, and a transmission antenna. And a detection unit that detects foreign matter around the power transmission device and the power reception device based on the reception intensity of the electromagnetic waves received by the reception antenna provided in the power transmission device.

  ADVANTAGE OF THE INVENTION According to this invention, the detection precision and sensitivity of a foreign material can be improved in a non-contact power transmission / reception system.

It is a figure for demonstrating the structure of the non-contact power transmission / reception system which concerns on Embodiment 1. FIG. It is a figure for demonstrating in detail the structure regarding the foreign material detection of FIG. It is the figure which looked up the power receiving part 100 arrange | positioned at the bottom face of a vehicle from the bottom. It is the figure which looked down at the power transmission part 700 of the power transmission apparatus arrange | positioned on the ground from the top. It is a figure for demonstrating the state in which the power transmission part and the power receiving part are performing electric power transmission. It is the figure which showed the intensity distribution of the received signal when there is no foreign material. It is the figure which showed the intensity distribution of the received signal when there exists a foreign material. 6 is a diagram for describing a configuration related to foreign object detection in the non-contact power transmission and reception system according to Embodiment 2. FIG. It is the figure which looked up 100A of power receiving parts arrange | positioned at the bottom face of a vehicle from the bottom. It is the figure which looked down at the power transmission part 700A of the power transmission apparatus arrange | positioned on the ground from the top. It is the figure which showed the detectable range when the antenna for transmission is provided in the power receiving part independently. It is the figure which showed the detectable range in case the some antenna for transmission is provided in the power receiving part. FIG. 13 is a diagram showing a detectable range when a plurality of transmission antennas are also provided in the power transmission unit in addition to FIG. 12. It is the figure which showed the case where the position of a call | power receiving part is changing to 3 types with respect to the power transmission part. It is the figure which showed intensity distribution of the receiving antenna in the position P1. It is the figure which showed intensity distribution of the receiving antenna in the position P2. It is the figure which showed intensity distribution of the receiving antenna in the position P3.

  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.

[Basic configuration of contactless power transmission and reception system]
FIG. 1 is a diagram for explaining a basic configuration of a contactless power transmission and reception system according to the first embodiment.

  Referring to FIG. 1, the non-contact power transmission / reception system 1 includes a vehicle 10 and a power transmission device 90. In the non-contact power transmission / reception system 1, non-contact power transmission is performed from the power transmission device 90 to the vehicle 10. Non-contact power transmission is performed via a power transmission unit 700 included in the power transmission device 90 and a power reception unit 100 mounted on the vehicle 10.

  First, the vehicle 10 in the non-contact power transmission / reception system 1 will be described. Vehicle 10 includes a power receiving device 120, a relay 210, a battery 300, a system main relay (SMR) 310, and a power generation device 400.

  Power reception device 120 includes power reception unit 100, filter circuit 150, and rectifier 200. The power receiving unit 100 includes a power receiving coil 142 for receiving AC power output from the power transmitting unit 700 in a non-contact manner. The power received by the power receiving unit 100 is output to the filter circuit 150. The filter circuit 150 suppresses harmonic noise.

  The AC power whose harmonic noise is suppressed by the filter circuit 150 is output to the rectifier 200. The rectifier 200 rectifies AC power. The power rectified by the rectifier 200 is output as charging power for the battery 300.

  A relay 210 is provided between the rectifier 200 and the battery 300. Relay 210 is turned on (ON) when battery 300 is charged with power from power transmission device 90.

  Battery 300 is formed of a secondary battery such as a lithium ion battery or a nickel metal hydride battery. The voltage of the battery 300 is about 200V, for example.

  The power generation device 400 uses the electric power stored in the battery 300 to generate the driving force for driving the vehicle 10.

  The vehicle 10 further includes a vehicle ECU (Electronic Control Unit) 500 that is a control unit, a communication unit 510, and a notification device 520. As an example, the vehicle ECU 500 executes traveling control of the vehicle 10 and charging control of the battery 300.

  Next, the power transmission device 90 in the non-contact power transmission / reception system 1 will be described. Power transmission device 90 includes an external power supply 900, a communication unit 810, a power supply unit 600, a filter circuit 610, and a power transmission unit 700. The power transmission unit 700 is accommodated in the accommodation case 703. The power transmission unit 700 includes a power transmission coil 702.

  Power is transmitted from the external power supply 900 to the power transmission coil 702 via the filter circuit 610, and the power reception coil 142 of the vehicle 10 receives the power.

  The power receiving unit 100 and the power transmitting unit 700 include a capacitor in addition to the coil. The coil and the capacitor constitute a resonance circuit. The Q value indicating the strength of resonance is preferably 100 or more.

[Configuration for foreign object detection]
The non-contact power transmission / reception system having the configuration described above preferably performs foreign object detection even during power transmission / reception. The notification device 520 is a user interface, and is used, for example, to notify the vehicle user that there is a foreign object on the power transmission unit 700. The vehicle user can see the image or video output from the notification device 520 to know the presence of a foreign object and remove the foreign object in order to start charging. In addition to or instead of images and videos, sound and sound may be output to the notification device 520.

  When foreign matter detection is performed during power transmission / reception, it is conceivable that the foreign matter detection coil detects that the magnetic field generated by the power transmission coil 702 has changed due to the influence of the foreign matter. However, a current having a frequency of several kHz may be used as the alternating current of the power transmission coil 702. When the frequency is low, the magnetic field generated in the power transmission coil 702 detects the foreign matter because the foreign matter wraps around the foreign matter without being blocked by the foreign matter and reaches the foreign matter detection coil when the foreign matter is located away from the foreign matter detection coil. Sensitivity is lowered.

  Therefore, in this embodiment, a foreign object detection antenna 130 that transmits an electromagnetic wave having a frequency higher than the electromagnetic field generated by the power transmission coil 702 is provided in the power receiving unit 100 of the vehicle, and the electromagnetic wave transmitted from the foreign object detection antenna 130 is received. A plurality of foreign object detection antennas 704 are provided in the power transmission unit 700 of the power transmission device 90. Hereinafter, in order to make transmission and reception easy to understand, the foreign object detection antenna 130 is also referred to as a transmission antenna 130, and the foreign object detection antenna 704 is also referred to as a reception antenna 704.

  FIG. 2 is a diagram for explaining the configuration related to foreign object detection in FIG. 1 in more detail. Referring to FIG. 2, vehicle power receiving unit 100 includes an oscillator 110, an RF amplifier 115, and a transmission antenna 130.

  The power transmission unit 700 of the power transmission device includes a plurality of reception antennas 704 and a multiplexer 750. FIG. 2 shows that a foreign object 550 has entered between the power transmission unit 700 and the power reception unit 100.

  The high frequency signal output from the oscillator 110 is amplified by the RF amplifier 115 and radiated from the transmitting antenna 130. The radiated electromagnetic wave is received by each of the plurality of receiving antennas 704. The control unit 800 transmits a reception antenna selection signal to the multiplexer 750 and sequentially receives signals received by the individual reception antennas 704 via the multiplexer 750. Control unit 800 determines whether or not a foreign object exists at a position corresponding to each antenna according to the received signal strength.

  FIG. 3 is a view of the power receiving unit 100 arranged on the bottom surface of the vehicle as viewed from below. FIG. 4 is a view of the power transmission unit 700 of the power transmission device arranged on the ground surface or the floor surface of the garage as viewed from above. FIG. 5 is a diagram for explaining a state where the power transmission unit and the power reception unit perform power transmission. A plurality of reception antennas 704 are arranged in the power transmission unit 700, and a transmission antenna 130 is arranged in the power reception unit 100. The plurality of receiving antennas 704 are arranged in a 5 × 5 matrix, for example. In FIG. 3, a state where the power receiving unit 100 is looked up from below is illustrated for the sake of explanation, but in reality, the power receiving unit 100 is disposed on the bottom surface of the vehicle. The power receiving unit 100 faces each other. Assume that the foreign object 550 is placed above the power transmission unit 700 as shown in FIGS.

  Although the shape of the power transmission coil is not particularly limited, as an example, as shown in FIG. 5, a magnetic flat plate core 701 housed in a case of the power transmission unit 700 and a power transmission coil 702 wound around the core 701. And can be adopted. Further, a flat plate core 141 made of a magnetic material and housed in the case of the power receiving unit 100 and a power receiving coil 142 wound around the core 141 can be employed. The winding axis of power transmission coil 702 and power reception coil 142 is the horizontal direction, and the direction of the magnetic field is the direction indicated by the arrow.

  As shown in FIG. 5, when the foreign object 550 is, for example, a thin metal foil, the direction of the magnetic field for power transmission is parallel to the metal foil even if the foreign object exists on the power transmission unit 700. Change is difficult to appear in the magnetic field. However, it is desirable to detect the foreign matter even in such a case because the foreign matter may be moved by wind or the like to change the magnetic field.

Therefore, an electromagnetic wave having high linearity from the transmitting antenna 130 radiates toward the entire upper surface of the power transmission unit 700, received by the receiving antenna 704 disposed on the upper surface of the power transmission unit 700 in a matrix, the foreign matter by the reception intensity The presence or absence of 550 is detected. If there is a foreign object 550, the electromagnetic wave radiated from the transmitting antenna 130 is blocked as shown in FIG. Detection of a foreign substance in such a case will be described with reference to FIGS.

  FIG. 6 is a diagram showing the intensity distribution of the received signal when there is no foreign object. FIG. 7 is a diagram showing the intensity distribution of the received signal when there is a foreign object. As can be understood from FIG. 5, since the distance between the receiving antenna and the transmitting antenna in the central portion is the shortest, the reception intensity is strongest in the central portion as shown in FIG. The strength gradually decreases as you move away. In the case of FIG. 7 where the foreign object 550 exists, the intensity of the place where the foreign object exists is one step lower than the intensity distribution of FIG. Therefore, the location of the foreign substance can be specified by recording the normal intensity distribution in advance and comparing it with the detected intensity as shown in FIG.

  In the example of FIG. 4, the foreign object 550 is placed on the case of the power transmission unit. However, even if the foreign object 550 is in the air as shown in FIG. As the relationship between the flash and the image sensor that receives the light from the flash, the shadow of the foreign matter is generated in the receiving antenna arranged in a matrix, so that the foreign matter can be detected.

[Embodiment 2]
In the first embodiment, the receiving antenna 704 is arranged in the power transmission unit 700, and only the transmission antenna 130 is arranged in the power receiving unit 100. However, with this configuration, there is a case where a foreign object near the power receiving unit 100 cannot be detected.

  Therefore, in the second embodiment, in addition to the configuration of the first embodiment, a transmission antenna is further arranged in the power transmission unit of the power transmission device, and a reception antenna is also arranged in the power reception unit of the vehicle.

  FIG. 8 is a diagram for describing a configuration related to foreign object detection in the non-contact power transmission and reception system according to the second embodiment. Referring to FIG. 8, vehicle power reception unit 100 </ b> A includes an oscillator 110, an RF amplifier 115, a multiplexer 151, a plurality of transmission antennas 130, a plurality of reception antennas 541, and a multiplexer 552.

  The power transmission unit 700A of the power transmission apparatus includes a plurality of reception antennas 704, a multiplexer 750, an oscillator 711, an RF amplifier 721, and a plurality of transmission antennas 731.

  ECU 500 and ECU 800 communicate with each other through communication units 510 and 810 to adjust the transmission timing of each transmission antenna and the timing of antenna selection by a multiplexer.

  By adopting such a configuration, foreign matter existing on the power receiving side can also be detected. In addition, the detection range can be expanded by providing a plurality of transmitting antennas on each of the power receiving side and the power transmitting side.

  FIG. 9 is a view of the power receiving unit 100A disposed on the bottom surface of the vehicle as viewed from below. FIG. 10 is a view of a power transmission unit 700A of the power transmission device arranged on the ground as viewed from above.

  A plurality of reception antennas 541 and a plurality of transmission antennas 130 are arranged in the power receiving unit 100A. The plurality of receiving antennas 541 are arranged in a 5 × 5 matrix, for example. The plurality of transmitting antennas 130 are arranged at four locations so as to surround an area where the plurality of receiving antennas 541 are arranged.

  A plurality of reception antennas 704 and a plurality of transmission antennas 731 are arranged in power transmission unit 700A. The plurality of receiving antennas 704 are arranged in a 5 × 5 matrix, for example. The plurality of transmitting antennas 731 are arranged at four locations so as to surround an area where the plurality of receiving antennas 704 are arranged. FIG. 10 shows a state in which foreign object 550 is placed on power transmission unit 700A.

  FIG. 11 is a diagram illustrating a detectable range when a transmission antenna is provided alone in the power receiving unit. FIG. 12 is a diagram illustrating a detectable range when a plurality of transmitting antennas are provided in the power receiving unit. FIG. 13 is a diagram showing a detectable range when a plurality of transmitting antennas are also provided in the power transmission unit in addition to FIG. 12.

  The detectable range shown in FIG. 11 corresponds to the detectable range of the configuration of the first embodiment, but a blind spot where a foreign object cannot be detected is formed near the surface of the power receiving unit 100. On the other hand, when a plurality of transmitting antennas 130 are provided around the power receiving unit 100B as shown in FIG. 12, the blind spots where foreign objects cannot be detected are reduced as compared with the case shown in FIG. In Embodiment 2, the transmitting antenna 731 is also provided in the power transmission unit 700A as shown in FIG. 13, so the blind spot near the surface of the power reception unit 100A can be further reduced.

  Since transmission antennas are provided in both the power transmission unit and the power reception unit, in order to prevent crosstalk and multipath, the ECU 500 and the ECU 800 communicate with each other through the communication units 510 and 810 to determine the transmission timing of each transmission antenna and the multiplexer. The timing of antenna selection is adjusted. Further, in order to avoid crosstalk in the transmission / reception circuit, the transmission frequency may be changed for each transmission / reception pair.

  As shown in FIGS. 9 and 10, when a plurality of transmitting antennas are provided, it is preferable to provide them at the end portions (peripheral portions) of the power receiving unit and the power transmitting unit because the detection range is enlarged. The frequency of the transmitting / receiving antenna is preferably a high frequency of GHz or higher. This contributes to miniaturization of the antenna.

[Other uses of foreign object detection antenna]
In non-contact charging, charging cannot be performed if the positions of the power transmission coil and the charging coil are shifted. For this reason, positioning of the charging coil is important. The transmission / reception antenna for detecting foreign matter introduced in the first and second embodiments can also be used for coil positioning.

  FIG. 14 is a diagram illustrating a case where the position of the power receiving unit is changed in three ways with respect to the power transmitting unit. Referring to FIG. 14, one transmitting antenna 731 is arranged in the center of power transmission unit 700C. Reception antennas 541 are arranged in a 5 × 5 matrix in power reception unit 100C. The positions P1, P2, and P3 of the power receiving unit 100C are illustrated. The position P1 is a position where the power reception unit directly faces the power transmission unit.

  FIG. 15 is a diagram showing the intensity distribution of the receiving antenna at the position P1. FIG. 16 is a diagram showing the intensity distribution of the receiving antenna at the position P2. FIG. 17 is a diagram showing the intensity distribution of the receiving antenna at the position P3.

  As can be seen from FIGS. 15 to 17, the positional deviation between the power reception unit and the power transmission unit corresponds to the reception intensity distribution. For example, when a signal whose reception intensity exceeds a certain threshold is in the power receiving range 950, it can be determined that the power can be received and the driver can be notified. For example, in the case shown in FIG. 15, if the reception intensity is set in three stages of 2, 1 and 0, one area where the reception intensity is 2 and eight areas where the reception intensity is 1 enter the power receiving range 950. Yes. At this time, the entire strength of the power receiving range 950 becomes the strongest at 2 × 1 + 1 × 8 = 10. When calculated in the same manner, the overall strength of the power receiving range 950 shown in FIG. 16 is 1, and the overall strength of the power receiving range 950 shown in FIG. Therefore, before starting the transmission / reception of electric power, it is possible to perform alignment while obtaining information used for alignment using the antenna for foreign object detection.

  In the configuration illustrated in FIG. 14, the power transmission unit 700C is provided with a transmission antenna and the power reception unit 100C is provided with a plurality of reception antennas. However, the opposite configuration, that is, the power transmission unit 700C is provided with a plurality of reception antennas and the power reception unit 100C is provided. A transmission antenna may be provided.

  Although not particularly shown in FIG. 1, power generation device 400 includes, for example, an inverter that receives electric power from battery 300, a motor driven by the inverter, a drive wheel driven by the motor, and the like. Power generation device 400 may include a generator for charging battery 300 and an engine capable of driving the generator.

  In FIG. 1, vehicle ECU 500 performs charge control and vehicle travel control. However, a plurality of ECUs are provided, and charge control and vehicle travel control (motor control, engine control) and the like are performed by separate ECUs. You may comprise so that it may carry out.

  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 1 Contactless power transmission / reception system, 10 vehicles, 90 power transmission apparatus, 100,100A, 100B, 100C Power reception part, 110,711 Oscillator, 115,721 RF amplifier, 120 Power reception apparatus, 130,731 Foreign object detection antenna (for transmission), 141,701 core, 142 power receiving coil, 150,610 filter circuit, 151,552,750 multiplexer, 200 rectifier, 210 relay, 300 battery, 400 power generation device, 500,800 control unit, 510,810 communication unit, 520 notification Device, 541, 704 Foreign object detection antenna (for reception), 600 power supply unit, 700, 700A, 700B, 700C power transmission unit, 702 power transmission coil, 703 housing case, 900 external power source.

Claims (1)

A power transmission device;
A power receiving device that receives power from the power transmitting device in a contactless manner;
A plurality of first transmitting antennas provided in the power transmission device;
A plurality of first receiving antennas provided in the power receiving device;
A plurality of second transmitting antennas provided in the power receiving device;
A plurality of second receiving antennas provided in the power transmission device;
The reception intensity at which the electromagnetic waves from each of the plurality of first transmission antennas are received by the plurality of first reception antennas, and the electromagnetic waves from each of the plurality of second transmission antennas are the plurality of A non-contact power transmission / reception system comprising: a detection unit configured to detect a foreign object around the power transmission device and the power reception device based on reception intensity received by the second reception antenna.

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