JP5928307B2 - Power receiving device and power transmitting device - Google Patents

Description

  The present invention relates to a power reception device and a power transmission device.

  2. Description of the Related Art Conventionally, a power transmission device that transmits power without contact and a power reception device that receives power are known. For example, a wireless power transmission device described in Japanese Patent Application Laid-Open No. 2010-252498 compares a predetermined parameter acquired from various sensors or a content of a predetermined parameter change with time with profile information, Alternatively, it is determined that an intrusion has occurred according to the comparison result between the content of the change and the profile information.

JP 2010-252498 A

  However, the wireless power transmission device described above does not detect foreign matter before power transmission. For this reason, the case where electric power transmission is started in the state with a foreign material is considered. Furthermore, the sensor has various characteristics, and foreign matter cannot be accurately detected depending on the sensor employed.

  The present invention has been made in view of the problems as described above, and an object of the present invention is to detect foreign matter with high accuracy and to suppress power transmission in the presence of foreign matter. It is providing the power receiving apparatus and power transmission apparatus which can do.

  A power receiving device according to the present invention detects a foreign object positioned between a power receiving unit that receives power in a non-contact manner from a power transmitting unit provided outside, a power transmitting unit, and a power receiving unit facing the power transmitting unit. A detection unit; a second detection unit that detects a foreign object that enters between the power transmission unit and the power reception unit; and a control unit that controls the first detection unit and the second detection unit. The first detection unit is a sensor that detects a physical quantity in a detection region detected by the first detection unit, and the second detection unit is a sensor that detects a change in physical quantity in the detection region detected by the second detection unit. It is. The control unit causes the first detection unit to detect a foreign object positioned between the power transmission unit and the power reception unit before power transmission from the power transmission unit to the power reception unit is started. During the power transmission from the power transmission unit to the power reception unit, the second detection unit is caused to detect foreign matter that enters between the power transmission unit and the power reception unit. Since the first sensor detects a stationary object before the start of charging, power transmission can be started in a state in which it is confirmed that there is no foreign object to be stationary. Moreover, since an intruding object is detected by the second sensor after the start of power transmission, the first sensor can be stopped.

  Preferably, the second detection unit is configured to be able to detect a foreign substance passing through a region located around a region located between the power transmission unit and the power reception unit.

  Preferably, the power receiving device further includes a notification unit. When the first detection unit detects a foreign object, the control unit uses a notification unit to notify the user that a foreign object has been detected.

  Preferably, the control unit stops power transmission by the power transmission unit when the second detection unit detects a foreign object.

  Preferably, the power reception unit is mounted on a vehicle. The control unit causes the first detection unit to detect a foreign object on the power transmission unit when the power reception unit and the power transmission unit are positioned to face each other.

  Preferably, a plurality of the first detection units are provided. The control unit stores temperature distribution data indicating detection results by the plurality of first detection units when the power transmission unit is at a high temperature. The said control part judges whether the some 1st detection part detected the foreign material based on the result of having compared the detection result detected by the some 1st detection part, and temperature distribution data.

  Preferably, the control unit stops the first detection unit during power transmission. Preferably, the difference between the natural frequency of the power transmission unit and the natural frequency of the power reception unit is 10% or less of the natural frequency of the power reception unit. Preferably, the coupling coefficient between the power reception unit and the power transmission unit is 0.3 or less.

  Preferably, the power reception unit is formed between the power reception unit and the power transmission unit, and is formed between the power reception unit and the power transmission unit, and is vibrated at a specific frequency. The power is received from the power transmission unit through at least one of the electric field to be transmitted.

  A power transmission device according to the present invention detects a foreign object positioned between a power transmission unit that transmits power in a non-contact manner to a power reception unit mounted on a vehicle, a power transmission unit, and a power reception unit facing the power transmission unit. A detection unit; a fourth detection unit that detects a foreign object that enters between the power transmission unit and the power reception unit; and a control unit that controls the third detection unit and the fourth detection unit. The third detection unit is a sensor that detects a physical quantity in a detection region detected by the third detection unit. A 4th detection part is a sensor which detects the change of the physical quantity in the detection area | region which a 4th detection part detects. The control unit causes the third detection unit to detect a foreign object positioned between the power transmission unit and the power reception unit before power transmission from the power transmission unit to the power reception unit is started. During the power transmission from the power transmission unit to the power reception unit, the fourth detection unit detects foreign matter that enters between the power transmission unit and the power reception unit.

  Preferably, the fourth detection unit is configured to be able to detect a foreign object passing through a region located around a region located between the power transmission unit and the power reception unit.

  Preferably, the vehicle further includes a notification unit. When the third detection unit detects a foreign object, the control unit uses a notification unit to notify the user that a foreign object has been detected.

  Preferably, the control unit stops power transmission by the power transmission unit when the fourth detection unit detects a foreign object.

  Preferably, a plurality of the third detection units are provided. The control unit stores temperature distribution data indicating detection results by the plurality of third detection units when the power transmission unit is at a high temperature. The said control part judges whether the some 3rd detection part detected the foreign material based on the result of having compared the detection result detected by the some 3rd detection part, and temperature distribution data.

  Preferably, the control unit stops the third detection unit during power transmission from the power transmission unit to the power reception unit. Preferably, the difference between the natural frequency of the power transmission unit and the natural frequency of the power reception unit is 10% or less of the natural frequency of the power reception unit. Preferably, the coupling coefficient between the power reception unit and the power transmission unit is 0.3 or less.

  Preferably, the power transmission unit includes a magnetic field that is formed between the power reception unit and the power transmission unit and vibrates at a specific frequency, and an electric field that is formed between the power reception unit and the power transmission unit and vibrates at a specific frequency. Power is received from the power transmission unit through at least one of them.

  According to the power reception device and the power transmission device according to the present invention, it is possible to detect foreign matter with high accuracy and to suppress power transmission in the presence of foreign matter.

It is a schematic diagram which shows typically the electric power transmission system, vehicle, power transmission apparatus, etc. which concern on Embodiment 1. FIG. It is an electric circuit diagram which implement | achieves non-contact electric power transmission in the electric power transmission system shown in FIG. 2 is a bottom view showing a bottom surface 25 of the vehicle 10. FIG. 2 is an exploded perspective view showing a power receiving device 11. FIG. 2 is a perspective view schematically showing a secondary coil 22. FIG. It is a schematic diagram which shows the detection part 80 etc. typically. 2 is a perspective view showing a power reception unit 20 and a power reception device 11. FIG. It is a perspective view which shows the state which the vehicle 10 stopped so that the power transmission part 56 and the power receiving part 20 might oppose. 2 is a side view showing a part of the vehicle 10 in a state where a power transmission unit 56 and a power reception unit 20 face each other. It is a flowchart which shows the control flow of vehicle ECU12 after stopping with the power receiving part 20 and the power transmission part 56 facing. It is a top view which shows typically a mode when the 1st detection unit 71 detects a foreign material. It is a top view showing typically the state where the 2nd detection units 72, 73, and 74 are performing foreign substance detection. It is a figure which shows the simulation model of an electric power transmission system. It is a graph which shows the relationship between the shift | offset | difference of the natural frequency of the power transmission part 193 and the power receiving part 196, and electric power transmission efficiency. It is a graph which shows the relationship between the power transmission efficiency when changing the air gap AG in the state which fixed the natural frequency f0, and the frequency f3 of the electric current supplied to a primary coil. It is the figure which showed the relationship between the distance from an electric current source or a magnetic current source, and the intensity | strength of an electromagnetic field. FIG. 6 is a schematic diagram showing an external power supply device 51 and the like according to Embodiment 2. It is a top view which shows the power transmission part 56 and the various detection units located in the circumference | surroundings. It is a top view which shows the state which 4th detection unit 91,92,93 driven. FIG. 5 is a flowchart showing a control flow of an external power feeding device 51.

  The power transmission system, the vehicle, the power receiving device, the power receiving coil unit, the power transmitting device, and the power transmitting coil unit according to the embodiment will be described with reference to FIGS. In addition, about the same or substantially the same structure, the same code | symbol may be attached | subjected and the description may be abbreviate | omitted.

(Embodiment 1)
FIG. 1 is a schematic diagram schematically showing the power transmission system, the vehicle, the power transmission device, and the like according to the first embodiment.

  The power transmission system according to the first embodiment includes an electric vehicle 10 including a power receiving device 11 and an external power feeding device 51 including a power transmission device 50. The power receiving device 11 of the electric vehicle 10 mainly receives power from the power transmitting device 50.

  The parking space 52 is provided with a line indicating a wheel stop, a parking position, and a parking range so that the electric vehicle 10 stops at a predetermined position.

  The external power feeding device 51 includes a high frequency power driver 54 connected to the AC power source 53, a control unit 55 that controls driving of the high frequency power driver 54, the power transmission device 50 connected to the high frequency power driver 54, and the vehicle 10. And an antenna 61 for exchanging information.

  The power transmission device 50 includes a power transmission unit 56, and the power transmission unit 56 includes a coil unit 60 and a capacitor 59 connected to the coil unit 60. The coil unit 60 includes a ferrite core 57 and a primary coil (first coil) 58 wound around the ferrite core 57. The primary coil 58 is connected to the high frequency power driver 54. The primary coil is the primary coil 58 in the first embodiment.

  In FIG. 1, an electric vehicle 10 includes a vehicle main body 10A, a power receiving device 11 provided in the vehicle main body 10A, a rectifier 13 connected to the power receiving device 11, and a DC / DC converter 14 connected to the rectifier 13. Is provided. The vehicle 10 includes a battery 15 connected to a DC / DC converter 14, a power control unit (PCU (Power Control Unit)) 16, a motor unit 17 connected to the power control unit 16, and a DC / DC converter 14. And a vehicle ECU (Electronic Control Unit) 12 that controls driving of the power control unit 16 and the like. The vehicle 10 includes a foreign object detection device 18, a notification unit 48 that notifies the user of the detection of the foreign material, and an antenna 49 that exchanges information with the external power supply device 51. The vehicle main body 10A includes a body in which an engine compartment and an occupant accommodation chamber are formed, and an exterior part such as a fender provided in the body. The vehicle 10 includes a front wheel 19F and a rear wheel 19B.

  In addition, in this Embodiment 1, although the hybrid vehicle provided with the engine 47 is demonstrated, it is not restricted to the said vehicle. For example, the present invention can be applied to an electric vehicle that does not include an engine, a fuel cell vehicle that includes a fuel cell instead of the engine, and the like.

  The rectifier 13 is connected to the power receiving device 11, converts an alternating current supplied from the power receiving device 11 into a direct current, and supplies the direct current to the DC / DC converter 14.

  The DC / DC converter 14 adjusts the voltage of the direct current supplied from the rectifier 13 and supplies it to the battery 15. The DC / DC converter 14 is not an essential component and may be omitted. In this case, the DC / DC converter 14 can be substituted by providing a matching unit for matching impedance with the external power feeding device 51 between the power transmission device 50 and the high frequency power driver 54.

  The power control unit 16 includes a converter connected to the battery 15 and an inverter connected to the converter, and the converter adjusts (boosts) a direct current supplied from the battery 15 and supplies it to the inverter. The inverter converts the direct current supplied from the converter into an alternating current and supplies it to the motor unit 17.

  The motor unit 17 employs, for example, a three-phase AC motor and is driven by an AC current supplied from an inverter of the power control unit 16.

  The power receiving device 11 includes a power receiving unit 20. The power receiving unit 20 includes a coil unit 24 and a capacitor 23 connected to the coil unit 24. The coil unit 24 includes a ferrite core 21 and a secondary coil (second coil) 22 wound around the ferrite core 21. In the power receiving unit 20 as well, the capacitor 23 is not an essential component. The secondary coil 22 is connected to the rectifier 13. The secondary coil is the secondary coil 22 in the present embodiment.

  FIG. 2 is an electric circuit diagram for realizing contactless power transmission in the power transmission system shown in FIG. The circuit configuration shown in FIG. 2 is an example, and the configuration for realizing non-contact power transmission is not limited to the configuration in FIG.

  The secondary coil 22 forms a resonance circuit together with the capacitor 23 and receives the electric power sent from the power transmission unit 56 of the external power feeding device 51 in a non-contact manner. Although not shown in particular, a closed loop is formed by the secondary coil 22 and the capacitor 23, and a coil for taking out AC power received by the secondary coil 22 from the secondary coil 22 by electromagnetic induction and outputting it to the rectifier 13 is separately provided. May be.

  On the other hand, the primary coil 58 forms a resonance circuit together with the capacitor 59, and transmits AC power supplied from the AC power supply 53 to the power receiving unit 20 in a contactless manner. Although not particularly illustrated, a closed loop may be formed by the primary coil 58 and the capacitor 59, and a coil for supplying the AC power output from the AC power supply 53 to the primary coil 58 by electromagnetic induction may be separately provided.

  The capacitors 23 and 59 are provided to adjust the natural frequency of the resonance circuit. When a desired natural frequency can be obtained by using the stray capacitances of the primary coil 58 and the secondary coil 22. The capacitors 23 and 59 may be omitted.

  FIG. 3 is a bottom view showing the bottom surface 25 of the vehicle 10. In FIG. 3, “D” indicates a downward direction D in the vertical direction. “L” indicates the left direction L of the vehicle. “R” indicates the vehicle right direction R. “F” indicates the vehicle front direction F. “B” indicates the vehicle rear direction B. The bottom surface 25 of the vehicle 10 (vehicle main body 10A) is a surface that can be seen when the vehicle 10 is viewed from a position vertically downward with respect to the vehicle 10 in a state where the tire of the vehicle 10 is in contact with the ground. . The power receiving device 11, the power receiving unit 20, and the secondary coil 22 are provided on the bottom surface 25.

  Here, the central portion of the bottom surface 25 is defined as a central portion P1. The central portion P <b> 1 is located at the center in the front-rear direction of the vehicle 10 and at the center in the width direction of the vehicle 10.

  The vehicle main body 10 </ b> A includes a floor panel 26 provided on the bottom surface of the vehicle 10. The floor panel 26 is a plate-like member that partitions the interior of the vehicle from the exterior of the vehicle.

  Note that the power receiving device 11 is provided on the bottom surface 25 includes a case where the power receiving device 11 is directly attached to the floor panel 26, a case where the power receiving device 11 is suspended from the floor panel 26, a side member, a cross member, or the like.

  That the power receiving unit 20 and the secondary coil 22 are provided on the bottom surface 25 means that the power receiving device 11 is accommodated in a casing of the power receiving device 11 described later in a state where the power receiving device 11 is provided on the bottom surface 25. To do.

  The front wheel 19F is provided on the vehicle front direction F side with respect to the center portion P1. Front wheel 19F includes a right front wheel 19FR and a left front wheel 19FL arranged in the width direction of vehicle 10. The rear wheel 19B includes a right rear wheel 19BR and a left rear wheel 19BL arranged in the width direction.

  The peripheral edge portion of the bottom surface 25 includes a front edge portion 30, a rear edge portion 31, a right edge portion 32, and a left edge portion 33. The front edge portion 30 is a portion of the peripheral portion of the bottom surface 25 that is located on the vehicle front direction F side with respect to the right front wheel 19FR and the left front wheel 19FL.

  The rear edge portion 31 is a portion of the outer peripheral edge portion of the bottom surface 25 that is located on the vehicle rear direction B side with respect to the right rear wheel 19BR and the left rear wheel 19BL.

  The rear edge portion 31 is connected to the rear side portion 65 extending in the width direction of the vehicle 10, the rear side portion 66 </ b> R connected to one end portion of the rear side portion 65, and the other end portion of the rear side portion 65. The rear side portion 66L. The rear side portion 66R extends from one end portion of the rear side portion 65 toward the right rear wheel 19BR, and the rear side portion 66L extends from the other end portion of the rear side portion 65 toward the left rear wheel 19BL. .

  The right edge 32 and the left edge 33 are arranged in the width direction of the vehicle 10. The right edge 32 and the left edge 33 are located between the front edge 30 and the rear edge 31 in the outer peripheral edge of the bottom surface 25.

  FIG. 4 is an exploded perspective view showing the power receiving device 11. The power receiving device 11 includes a power receiving unit 20 and a housing 27 that houses the power receiving unit 20 therein. The casing 27 includes a bottomed shield 28 having an opening, and a lid 29 arranged so as to close the opening of the shield 28. The shield 28 includes a top plate portion that faces the floor panel 26 and an annular peripheral wall portion that hangs downward in the vertical direction D from the top plate portion. The shield 28 is made of a metal material such as copper, for example.

  The lid portion 29 is formed so as to close the opening portion of the shield 28, and is formed of, for example, a resin material. The ferrite core 21 is formed in a plate shape. A secondary coil 22 is wound around the peripheral surface of the ferrite core 21. The ferrite core 21 may be accommodated in the resinous fixing member, and the secondary coil 22 may be attached to the ferrite core 21 by winding the secondary coil 22 around the peripheral surface of the fixing member.

  FIG. 5 is a perspective view schematically showing the secondary coil 22. As shown in FIG. 5, the secondary coil 22 includes a first end portion 34 and a second end portion 35. The secondary coil 22 is formed by winding a coil wire so as to surround the winding axis O1 and move in the direction in which the winding axis O1 extends as it goes from the first end 34 to the second end 35. Has been.

  The winding axis O1 is a virtual line approximated so as to pass through or near the center of curvature in each minute section when the coil wire is divided into minute sections.

  In the first embodiment, the central portion P2 of the secondary coil 22 is a virtual point located on the winding axis O1, and is located at the center of the secondary coil 22 in the direction in which the winding axis O1 extends.

  As shown in FIG. 3, the power receiving unit 20 (the power receiving device 11) configured as described above is disposed such that the winding axis O <b> 1 extends in the front-rear direction of the vehicle 10, and the winding axis O <b> 1 has a leading edge. It passes through the part 30 and the rear edge part 31.

  The power reception unit 20 (power reception device 11) is disposed on the vehicle rear direction B side with respect to the center portion P1. Specifically, it is provided at a position closer to the rear edge portion 31 than the central portion P1. The central portion P <b> 2 is disposed so as to be closest to the rear edge portion 31 among the front edge portion 30, the rear edge portion 31, the right edge portion 32, and the left edge portion 33.

  The foreign object detection device 18 includes a first detection unit 71 and second detection units 72, 73 and 74.

  The first detection unit 71 includes a plurality of detection units 75, 76, and 77. As each of the detection units 75, 76, and 77, for example, a temperature sensor or a sonar sensor can be employed.

  The detection units 75, 76, and 77 are sensors that measure physical quantities in the detection areas of the detection units 75, 76, and 77.

  For example, a temperature sensor such as an infrared sensor detects a physical quantity called infrared in the detection region. Further, when a sonar sensor is employed as the detection units 75, 76, 77, a physical quantity called sound reflection time is detected. And each detection part 75,76,77 sends the detected result to vehicle ECU12 (control part) shown in FIG.

  The vehicle ECU 12 calculates the temperature in the detection region detected by each detection unit 75, 76, 77 based on the input from each detection unit 75, 76, 77.

  The detection units 75, 76, and 77 are provided in the vicinity of the rear side portion 65 and at intervals in the extending direction of the rear side portion 65, and the detection units 75, 76, and 77 are mutually connected to the vehicle 10. Are arranged at intervals in the width direction. As described above, the detection units 75, 76, and 77 are arranged on the vehicle rear direction B side with respect to the power receiving device 11.

  In the example shown in FIG. 3, the detection unit 75 is disposed at the center in the width direction of the vehicle 10, and the detection unit 76 is disposed on the vehicle right direction R side with respect to the detection unit 75. . The detection unit 77 is arranged on the vehicle left direction L side with respect to the detection unit 75.

  The second detection unit 72 is disposed closer to the rear side portion 66R than the first detection unit 71 is. The second detection unit 72 includes a detection unit 80 and a detection unit 81.

  The second detection unit 73 is disposed closer to the rear side portion 66 </ b> L than the first detection unit 71. The second detection unit 73 includes a detection unit 82 and a detection unit 83.

  The second detection unit 74 is disposed on the vehicle front direction F side with respect to the power reception unit 20. The second detection unit 74 includes a detection unit 84 and a detection unit 85. The detection units 80, 81, 82, 83, 84, 85 detect a change in the physical quantity of the detection area detected by each detection unit 80, 81, 82, 83, 84, 85. For example, as the detection units 80, 81, 82, 83, 84, 85, pyroelectric sensors are employed. The pyroelectric sensor can detect the heat change in the detection region with high accuracy, and thus the detection units 80, 81, 82, 83, 84, and 85 detect the movement of the object having heat with high accuracy. can do. Detection units 80, 81, 82, 83, 84, 85 send detection results to vehicle ECU 12. The vehicle ECU 12 determines whether foreign matter has entered the detection areas of the detection units 80, 81, 82, 83, 84, 85 based on inputs from the detection units 80, 81, 82, 83, 84, 85. to decide.

  FIG. 6 is a schematic diagram schematically showing the detection unit 80 and the like. As shown in FIG. 6, the detection unit 80 includes a pyroelectric element 86, a resistor 87, and a voltage sensor 88. The pyroelectric element 86 is a sensor for detecting the presence or absence of an intruder by detecting infrared rays emitted from the intruder (not shown). The intruder is not originally present in the detection range of the pyroelectric sensor, and exists, for example, between a power transmission unit and a power reception unit of a power transmission system that performs non-contact power transmission at a predetermined interval. Small animals (cats and mice) are assumed.

  The pyroelectric element 86 has a surface charge due to spontaneous polarization even in a state where infrared rays are not irradiated, that is, a state where the temperature does not change. The pyroelectric element 86 is normally in a neutral state by attracting surrounding floating charges to the surface. When the state of spontaneous polarization changes with temperature change caused by irradiation with infrared rays, surface charge is generated. This change in surface charge is taken out from the surface electrode and the back electrode and used as an output signal.

  Also, when the infrared ray irradiated to the pyroelectric element 86 is cut off, the state of polarization charge changes to return to the original state, and the output of the pyroelectric element 86 changes accordingly. By detecting such an output change of the pyroelectric element 86, the presence or absence of an intruder can be detected.

  When an intruder enters the detection area, the change in state of polarization electrification based on the temperature change in the detection area is large, so that the intrusion of the intruder can be detected with high accuracy.

  The pyroelectric element 86 is provided with an infrared condensing lens, and the detection area of the pyroelectric element 86 can be changed as appropriate by changing the shape of the infrared condensing lens.

  In FIG. 1, for example, a notification unit 48 releases a sound source unit that emits a warning sound, a display unit that displays that a foreign object has been detected, and a user's operation to release the driving of the sound source unit and the warning display on the display unit. And an operation unit.

  FIG. 7 is a perspective view showing the power receiving unit 20 and the power receiving device 11. As illustrated in FIG. 7, the power receiving device 11 includes a power transmission unit 56 and a housing 62 that accommodates the power transmission unit 56 therein. The housing 62 includes a shield 63 in which an opening that opens upward in the vertical direction U is formed, and a lid (not shown) that is disposed so as to close the opening of the shield 63.

  The power transmission unit 56 includes a coil unit 60 and a capacitor 59 connected to the coil unit 60, and the coil unit 60 is wound around the plate-shaped ferrite core 57 and the peripheral surface of the ferrite core 57. Primary coil 58.

  The primary coil 58 is formed by winding a coil wire so as to surround the winding axis O10 and to be displaced in the extending direction of the winding axis O10 as it goes from one end to the other end.

  When power is transmitted between the power reception unit 20 and the power transmission unit 56, the power reception unit 20 and the power transmission unit 56 face each other in the vertical direction. In the present embodiment, the size of the power reception unit 20 and the size of the power transmission unit 56 are substantially the same, but the power transmission unit 56 may be formed larger than the power reception unit 20.

  FIG. 8 is a perspective view showing a state where the vehicle 10 is stopped so that the power transmission unit 56 and the power reception unit 20 face each other, and FIG. 9 shows the vehicle 10 in a state where the power transmission unit 56 and the power reception unit 20 face each other. It is a side view which shows a part.

  As shown in FIG. 9, the power reception unit 20 is disposed above the power transmission unit 56, and the power reception units 20 and 56 face each other.

  In the present embodiment, the approach direction D1 in which the vehicle 10 travels is the vehicle rearward direction B so that the power reception unit 20 is positioned above the power transmission unit 56.

  FIG. 10 is a flowchart showing a control flow of the vehicle ECU 12 after the vehicle is stopped with the power reception unit 20 and the power transmission unit 56 facing each other.

  When the vehicle 10 stops at a position where the power reception unit 20 can receive power from the power transmission unit 56, the vehicle ECU 12 activates the first detection unit 71. And vehicle ECU12 judges whether the 1st detection unit 71 detected the foreign material (STEP1).

  In STEP 1, the first detection unit 71 detects a physical quantity in a detection area located between the power receiving unit 20 and the power transmission unit 56, and the physical quantity detected by the first detection unit 71 is a foreign object detection device. 18 and a step in which the foreign matter detection device 18 determines the presence or absence of foreign matter based on the input from the first detection unit 71. Thus, in STEP 1, the foreign object detection device 18 uses the first detection unit 71 to determine whether there is a foreign object between the power receiving unit 20 and the power transmission unit 56.

  FIG. 11 is a plan view schematically showing a state when the first detection unit 71 performs foreign object detection. In FIG. 11, when an infrared sensor is employed as the detection unit 75, 76, 77, the detection unit 75, 76, 77 detects the amount of infrared radiation emitted from the detection regions R 1, R 2, R 3. The detection regions R1, R2, and R3 of the detection units 75, 76, and 77 are distributed so as to spread downward from the detection units 75, 76, and 77, and each detection region R1, R2, and R3 has a substantially conical shape. It is. And detection part 75,76,77 is arrange | positioned so that detection area | region R1, detection area | region R2, and detection area | region R3 may cover the whole upper surface of the power transmission part 56. FIG.

  For this reason, the detection units 75, 76, and 77 can detect a physical quantity such as infrared rays between the power reception unit 20 and the power transmission unit 56. The detection units 75, 76, 77 input the detected physical quantity to the foreign object detection device 18.

  And vehicle ECU12 calculates the temperature and temperature distribution in each detection area | region R1, R2, R3 based on the output from each detection part 75,76,77.

  Thus, before the start of power transmission from the power transmission unit 56 to the power reception unit 20, the detection unit 75, 76, 77 that detects the physical quantity in the detection region is used to be positioned between the power reception unit 20 and the power transmission unit 56. By detecting the foreign object to be detected, for example, even when the small animal is on the power transmission unit 56 from the beginning and the calligraphy animal does not move, the small animal can be detected.

  On the other hand, in a sensor that detects a change in a physical quantity in a detection area, such as a pyroelectric sensor, there is a foreign object such as a small animal between the power receiving unit 20 and the power transmission unit 56 from the beginning, and the foreign object does not move. It is difficult to detect such small animals.

  A step in which the vehicle ECU 12 determines whether or not there is a foreign substance in each of the detection areas R1, R2, and R3 based on the input value input from the first detection unit 71 will be described.

  The storage unit of the vehicle ECU 12 stores in advance temperature distribution data when the first detection unit 71 detects when the power transmission unit 56 is at a high temperature.

  Then, the vehicle ECU 12 determines whether or not there is a foreign object between the power receiving unit 20 and the power transmission unit 56 based on the result of comparing the stored temperature distribution data and the detection result detected by the first detection unit 71. Judging.

  For example, when the deviation of the temperature distribution of the temperature distribution data and the deviation of the temperature distribution detected by the first detection unit 71 exceed a predetermined threshold, the vehicle ECU 12 determines that the foreign object is the power receiving unit 20 and the power transmitting unit. 56.

  As a result, when the other vehicle has just been charged, it is assumed that the temperature of the power transmission unit 56 itself is normal and high, but even in such a case, the power receiving unit 20 It can be determined whether there is a foreign object between the power transmission unit 56 and the power transmission unit 56. The “normal temperature” is a temperature when the power transmission unit 56 is not used for several hours, for example. Further, when a sonar sensor is employed as each detection unit of the first detection unit 71, the foreign object detection device 18 stores a detection result in a state where there is no foreign object in advance. And the foreign material detection apparatus 18 actually compares the result of having driven the 1st detection unit 71 before electric power transmission with the stored detection result, and the foreign material between the power receiving part 20 and the power transmission part 56 is compared. Determine the presence or absence.

  When the vehicle ECU 12 determines that the first detection unit 71 has detected a foreign object based on the output from the first detection unit 71 (“YES” in STEP 1), the vehicle ECU 12 drives the notification unit 48 (STEP 9). ). Accordingly, it is possible to notify the user that there is a foreign object between the power receiving unit 20 and the power transmission unit 56.

  Next, the vehicle ECU 12 determines whether the warning has been canceled by the user (STEP 3). As a result of the user confirming between the power receiving unit 20 and the power transmitting unit 56, when a foreign object such as a small animal cannot be confirmed, or to eliminate a foreign object located between the power receiving unit 20 and the power transmitting unit 56, the user Can release the warning of the notification unit 48 by operating the operation unit provided in the notification unit 48.

  If the vehicle ECU 12 determines that the warning of the notification unit 48 has not been released (“NO” in STEP 3), the vehicle ECU 12 again causes the first detection unit 71 to remove foreign matter between the power reception unit 20 and the power transmission unit 56. It is determined whether or not it has been detected (STEP 1).

  When vehicle ECU 12 determines that there is no foreign object between power reception unit 20 and power transmission unit 56 (“NO” in STEP 1), vehicle ECU 12 stops warning of notification unit 48 (STEP 4).

  Next, the foreign object detection device 18 activates the second detection units 72, 73, 74 (STEP 5). In the above “STEP 3”, the vehicle ECU 12 also activates the second detection units 72, 73, 74 when the warning of the notification unit 48 is canceled by the user (“YES” in STEP 3) (STEP 5). ).

  Next, the vehicle ECU 12 stops the first detection unit 71 (STEP 6). Power consumption can be suppressed by stopping the driving of the first detection unit 71. In the flow shown in FIG. 11, the first detection unit 71 is stopped after starting the second detection units 72, 73, 74. However, the first detection unit 71 may be continuously driven. Good.

  Next, power transmission is started between the power reception unit 20 and the power transmission unit 56 (STEP 7). The transmission principle and the like when performing power transmission between the power reception unit 20 and the power transmission unit 56 will be described later.

  Next, the foreign object detection device 18 determines whether or not the second detection units 72, 73, and 74 have detected the foreign object (STEP 8). That is, STEP 8 is a step in which the foreign object detection device 18 uses the second detection units 72, 73, and 74 to determine whether or not a foreign object has entered between the power receiving unit 20 and the power transmission unit 56. . Specifically, the step in which the second detection units 72, 73, and 74 detect the change in the physical quantity of each detection region and the change in the physical quantity detected by the second detection unit 72, 73 and 74 are input to the foreign object detection device 18. And a step of determining whether or not a foreign substance has passed through the detection area based on an input value input by the foreign substance detection device 18.

  FIG. 12 is a plan view schematically showing a state in which the second detection units 72, 73, 74 are performing foreign object detection. As shown in FIG. 12, the detection unit 81 and the detection unit 82 cooperate to detect a change in the physical quantity in the detection region R4. The vehicle ECU 12 determines whether or not a foreign object such as a small animal has entered the detection region R4 based on the change in the physical quantity detected by the detection units 81 and 82.

  The detection unit 80 and the detection unit 84 cooperate to detect a change in the physical quantity in the detection region R5. The vehicle ECU 12 determines whether or not a foreign object such as a small animal has entered the detection region R5 based on the change in the physical quantity detected by the detection units 80 and 84.

  For example, when the small animal passes through the detection region R5, at least one of the detection units 80 and 84 detects a temperature change due to the entry of the small animal, and transmits the detection result to the vehicle ECU 12. The vehicle ECU 12 determines whether or not a foreign object such as a small animal has entered the detection region R5 based on the detection results input from the detection units 80 and 84.

  The detection unit 83 and the detection unit 85 cooperate to detect a change in the physical quantity in the detection region R6. The vehicle ECU 12 determines whether or not a foreign object such as a small animal has entered the detection region R6 based on the change in the physical quantity detected by the detection units 83 and 85.

Here, the detection units 80 to 85 that detect changes in the physical quantities of the detection region R4, the detection region R5, and the detection region R6 can detect changes in the physical amount more accurately than the detection units 75 to 77. .

  The detection region R4, the detection region R5, and the detection region R6 are arranged so as to surround the periphery of the region located between the power reception unit 20 and the power transmission unit 56. In the example illustrated in FIG. 12, the detection regions R4, R5, and R6 include a part of the region located between the power transmission unit 56 and the power reception unit 20, and between the power reception unit 20 and the power transmission unit 56. It is arrange | positioned so that the circumference | surroundings of the area | region located in may be surrounded.

  As a matter of course, the detection regions R4, R5, and R6 may include the entire region located between the power reception unit 20 and the power transmission unit 56.

  Here, when a small animal or the like enters the detection regions R5, R6, and R7, the foreign matter passes through the detection regions R5, R6, and R7 and enters between the power receiving unit 20 and the power transmission unit 56. It is conceivable that the detection area R5, R6, R7 is in the area away from the power transmission unit 56.

  Even if the small animal enters the detection region R5, R6, R7 and is located away from the power transmission unit 56, the foreign object is likely to enter between the power reception unit 20 and the power transmission unit 56.

  Therefore, when a small animal or the like enters the detection areas R5, R6, and R7 during power transmission from the power transmission unit 56 to the power reception unit 20, the foreign object detection device 18 indicates that “foreign matter is transmitted from the power transmission unit to the power reception unit. It is determined that it has entered between the power transmitting unit and the power receiving unit during power transmission.

  Therefore, when the vehicle ECU 12 determines that the second detection units 72, 73, and 74 have detected a foreign object (“YES” in STEP 7), the vehicle ECU 12 stops the power transmission of the power transmission unit 56 (STEP 9).

  Specifically, the vehicle ECU 12 transmits a signal for stopping the driving of the high-frequency power driver 54 from the antenna 49 functioning as the communication unit illustrated in FIG. 1 to the antenna 61 functioning as the communication unit.

  When the driving of the high-frequency power driver 54 is stopped, the power transmission from the power transmission unit 56 is stopped. Thereby, it is possible to suppress power transmission from the power transmission unit 56 to the power reception unit 20 in a state where there is a foreign object such as a small animal between the power reception unit 20 and the power transmission unit 56. Next, the vehicle ECU 12 stops the driving of the second detection units 72, 73, 74 (STEP 10).

  If no foreign object is detected in STEP 8, it is determined whether charging of the battery 15 is completed (STEP 11). When vehicle ECU 12 determines that battery 15 is not fully charged (“NO” in STEP 11), vehicle ECU 12 determines whether second detection units 72, 73, and 74 have detected a foreign object (STEP 8).

  And vehicle ECU12 repeats control of said STEP8 and STEP11, and if it detects that the battery 15 was fully charged (in STEP11, "YES"), it will stop the electric power transmission from the power transmission part 56 (STEP9). Next, the driving of the second detection units 72, 73, 74 is stopped (STEP 10).

  As described above, the vehicle ECU 12 uses the detection units 75, 76, and 77 that detect the physical quantities of the detection regions R1, R2, and R3 before power transmission from the power transmission unit 56 to the power reception unit 20 is performed. In addition, a foreign object such as a small animal located between the power reception unit 20 and the power transmission unit 56 is detected. During power transmission from the power transmission unit 56 to the power reception unit 20, the vehicle ECU 12 uses the detection units 80 to 85 that detect changes in physical quantities in the detection regions R4, R5, and R6, and the power reception unit 20 and the power transmission unit. 56, foreign objects such as small animals entering the space are detected.

  As described above, the vehicle ECU 12 controls each detection unit to suppress power transmission from the power transmission unit 56 to the power reception unit 20 in a state of being interposed between the power reception unit 20 and the power transmission unit 56. it can.

  In the first embodiment, detection by the first detection unit 71 shown in FIG. 11 is started in a state where the power reception unit 20 and the power transmission unit 56 face each other and the vehicle 10 stops. The timing at which one detection unit 71 is driven is not limited to the above timing.

  In FIG. 8, the first detection unit 71 passes above the power transmission unit 56 in the process in which the vehicle 10 moves in the vehicle rearward direction B so that the power reception unit 20 and the power transmission unit 56 face each other in the vertical direction. As described above, when the first detection unit 71 passes above the power transmission unit 56, it may be detected whether or not there is a foreign object on the power transmission unit 56.

  As described above, when the first detection unit 71 passes above the power transmission unit 56, the second detection units 72, 73, 74 are detected as soon as the vehicle 10 stops by detecting the foreign matter on the power transmission unit 56. The foreign object detection by can be started.

  The principle of power transmission between the power reception unit 20 and the power transmission unit 56 will be described with reference to FIGS. 13 to 16.

  In the power transmission system according to the present embodiment, the difference between the natural frequency of power transmission unit 56 and the natural frequency of power reception unit 20 is 10% or less of the natural frequency of power reception unit 20 or power transmission unit 56. By setting the natural frequency of each power transmission unit 56 and power reception unit 20 in such a range, the power transmission efficiency can be increased. On the other hand, when the difference between the natural frequencies becomes larger than 10% of the natural frequency of the power receiving unit 20 or the power transmitting unit 56, the power transmission efficiency becomes smaller than 10%, and the adverse effects such as the charging time of the battery 15 become longer. .

  Here, the natural frequency of the power transmission unit 56 is the vibration frequency when the electric circuit formed by the inductance of the primary coil 58 and the capacitance of the primary coil 58 freely vibrates when the capacitor 59 is not provided. Means. When the capacitor 59 is provided, the natural frequency of the power transmission unit 56 is the vibration frequency when the electric circuit formed by the capacitance of the primary coil 58 and the capacitor 59 and the inductance of the primary coil 58 freely vibrates. means. In the above electric circuit, the natural frequency when the braking force and the electric resistance are zero or substantially zero is also referred to as a resonance frequency of the power transmission unit 56.

  Similarly, the natural frequency of the power receiving unit 20 is that when the capacitor 23 is not provided, the electric circuit formed by the inductance of the secondary coil 22 and the capacitance of the secondary coil 22 freely vibrates. Means vibration frequency. In the case where the capacitor 23 is provided, the natural frequency of the power reception unit 20 is vibration when the electric circuit formed by the capacitance of the secondary coil 22 and the capacitor 23 and the inductance of the secondary coil 22 freely vibrates. Means frequency. In the electric circuit, the natural frequency when the braking force and the electric resistance are zero or substantially zero is also referred to as a resonance frequency of the power receiving unit 20.

  A simulation result obtained by analyzing the relationship between the natural frequency difference and the power transmission efficiency will be described with reference to FIGS. 13 and 14. FIG. 13 is a diagram illustrating a simulation model of the power transmission system. The power transmission system includes a power transmission device 190 and a power reception device 191, and the power transmission device 190 includes a coil 192 (electromagnetic induction coil) and a power transmission unit 193. The power transmission unit 193 includes a coil 194 (primary coil) and a capacitor 195 provided in the coil 194.

  The power receiving device 191 includes a power receiving unit 196 and a coil 197 (electromagnetic induction coil). Power receiving unit 196 includes a coil 199 and a capacitor 198 connected to this coil 199 (secondary coil).

  The inductance of the coil 194 is defined as an inductance Lt, and the capacitance of the capacitor 195 is defined as a capacitance C1. The inductance of the coil 199 is defined as an inductance Lr, and the capacitance of the capacitor 198 is defined as a capacitance C2. When each parameter is set in this way, the natural frequency f1 of the power transmission unit 193 is represented by the following equation (1), and the natural frequency f2 of the power reception unit 196 is represented by the following equation (2).

f1 = 1 / {2π (Lt × C1) ^1/2 } (1)
f2 = 1 / {2π (Lr × C2) ^1/2 } (2)
Here, when the inductance Lr and the capacitances C1 and C2 are fixed and only the inductance Lt is changed, the relationship between the deviation of the natural frequency of the power transmission unit 193 and the power reception unit 196 and the power transmission efficiency is shown in FIG. . In this simulation, the relative positional relationship between the coil 194 and the coil 199 is fixed, and the frequency of the current supplied to the power transmission unit 193 is constant.

  In the graph shown in FIG. 14, the horizontal axis indicates the deviation (%) of the natural frequency, and the vertical axis indicates the transmission efficiency (%) at a constant frequency. The deviation (%) in the natural frequency is expressed by the following equation (3).

(Deviation of natural frequency) = {(f1-f2) / f2} × 100 (%) (3)
As is clear from FIG. 14, when the deviation (%) in natural frequency is ± 0%, the power transmission efficiency is close to 100%. When the deviation (%) in natural frequency is ± 5%, the power transmission efficiency is 40%. When the deviation (%) of the natural frequency is ± 10%, the power transmission efficiency is 10%. When the deviation (%) in natural frequency is ± 15%, the power transmission efficiency is 5%. That is, by setting the natural frequency of each power transmission unit and the power reception unit so that the absolute value (difference in natural frequency) of the deviation (%) of the natural frequency is within a range of 10% or less of the natural frequency of the power reception unit 196. It can be seen that the power transmission efficiency can be increased. Furthermore, the power transmission efficiency can be further improved by setting the natural frequency of each power transmitting unit and the power receiving unit so that the absolute value of the deviation (%) of the natural frequency is 5% or less of the natural frequency of the power receiving unit 196. I understand that I can do it. As simulation software, electromagnetic field analysis software (JMAG (registered trademark): manufactured by JSOL Corporation) is employed.

Next, the operation of the power transmission system according to the present embodiment will be described.
In FIG. 1, AC power is supplied to the primary coil 58 from the high frequency power driver 54. At this time, electric power is supplied so that the frequency of the alternating current flowing through the primary coil 58 becomes a specific frequency.

  When a current having a specific frequency flows through the primary coil 58, an electromagnetic field that vibrates at a specific frequency is formed around the primary coil 58.

  The secondary coil 22 is disposed within a predetermined range from the primary coil 58, and the secondary coil 22 receives electric power from an electromagnetic field formed around the primary coil 58.

  In the present embodiment, so-called helical coils are employed for the secondary coil 22 and the primary coil 58. For this reason, a magnetic field and an electric field that vibrate at a specific frequency are formed around the primary coil 58, and the secondary coil 22 mainly receives electric power from the magnetic field.

  Here, a magnetic field having a specific frequency formed around the primary coil 58 will be described. The “specific frequency magnetic field” typically has a relationship with the power transfer efficiency and the frequency of the current supplied to the primary coil 58. First, the relationship between the power transmission efficiency and the frequency of the current supplied to the primary coil 58 will be described. The power transmission efficiency when power is transmitted from the primary coil 58 to the secondary coil 22 varies depending on various factors such as the distance between the primary coil 58 and the secondary coil 22. For example, the natural frequency (resonance frequency) of the power transmission unit 56 and the power reception unit 20 is the natural frequency f0, the frequency of the current supplied to the primary coil 58 is the frequency f3, and the air gap between the secondary coil 22 and the primary coil 58 Is an air gap AG.

  FIG. 15 is a graph showing the relationship between the power transmission efficiency and the frequency f3 of the current supplied to the primary coil 58 when the air gap AG is changed with the natural frequency f0 fixed.

  In the graph shown in FIG. 15, the horizontal axis indicates the frequency f3 of the current supplied to the primary coil 58, and the vertical axis indicates the power transmission efficiency (%). The efficiency curve L1 schematically shows the relationship between the power transmission efficiency when the air gap AG is small and the frequency f3 of the current supplied to the primary coil 58. As shown in the efficiency curve L1, when the air gap AG is small, the peak of power transmission efficiency occurs at frequencies f4 and f5 (f4 <f5). When the air gap AG is increased, the two peaks when the power transmission efficiency is increased change so as to approach each other. As shown in the efficiency curve L2, when the air gap AG is made larger than a predetermined distance, the peak of the power transmission efficiency is one, and the power transmission efficiency is increased when the frequency of the current supplied to the primary coil 58 is the frequency f6. It becomes a peak. When the air gap AG is further increased from the state of the efficiency curve L2, the peak of power transmission efficiency is reduced as shown by the efficiency curve L3.

  For example, the following first method can be considered as a method for improving the power transmission efficiency. As a first technique, the frequency of the current supplied to the primary coil 58 shown in FIG. 1 is constant, and the capacitances of the capacitor 59 and the capacitor 23 are changed according to the air gap AG. The method of changing the characteristic of the power transmission efficiency with 20 is mentioned. Specifically, the capacitances of the capacitor 59 and the capacitor 23 are adjusted so that the power transmission efficiency reaches a peak in a state where the frequency of the current supplied to the primary coil 58 is constant. In this method, the frequency of the current flowing through the primary coil 58 and the secondary coil 22 is constant regardless of the size of the air gap AG. As a method for changing the characteristics of the power transmission efficiency, a method using a matching device provided between the power transmission device 50 and the high-frequency power driver 54, a method using the converter 14, or the like can be adopted. .

  The second method is a method of adjusting the frequency of the current supplied to the primary coil 58 based on the size of the air gap AG. For example, in FIG. 15, when the power transmission characteristic is the efficiency curve L <b> 1, the primary coil 58 is supplied with a current having a frequency of f4 or f5 to the primary coil 58. When the frequency characteristic becomes the efficiency curves L2 and L3, a current having a frequency f6 is supplied to the primary coil 58. In this case, the frequency of the current flowing through the primary coil 58 and the secondary coil 22 is changed in accordance with the size of the air gap AG.

  In the first method, the frequency of the current flowing through the primary coil 58 is a fixed constant frequency, and in the second method, the frequency flowing through the primary coil 58 is a frequency that changes as appropriate depending on the air gap AG. A current having a specific frequency set so as to increase the power transmission efficiency is supplied to the primary coil 58 by the first method, the second method, or the like. When a current having a specific frequency flows through the primary coil 58, a magnetic field (electromagnetic field) that vibrates at a specific frequency is formed around the primary coil 58. The power reception unit 20 receives power from the power transmission unit 56 through a magnetic field that is formed between the power reception unit 20 and the power transmission unit 56 and vibrates at a specific frequency. Therefore, the “magnetic field oscillating at a specific frequency” is not necessarily a magnetic field having a fixed frequency. In the above example, focusing on the air gap AG, the frequency of the current supplied to the primary coil 58 is set. However, the power transmission efficiency depends on the horizontal direction of the primary coil 58 and the secondary coil 22. The frequency varies depending on other factors such as a deviation, and the frequency of the current supplied to the primary coil 58 may be adjusted based on the other factors.

  In addition, although the example which employ | adopted the helical coil as a resonance coil was demonstrated, when antennas, such as a meander line, are employ | adopted as a resonance coil, the electric current of a specific frequency flows into the primary coil 58, A specific frequency is flowed. An electric field is formed around the primary coil 58. And electric power transmission is performed between the power transmission part 56 and the power receiving part 20 through this electric field.

  In the power transmission system according to the present embodiment, the efficiency of power transmission and power reception is improved by using a near field (evanescent field) in which the “electrostatic magnetic field” of the electromagnetic field is dominant. FIG. 16 is a diagram showing the relationship between the distance from the current source or the magnetic current source and the strength of the electromagnetic field. Referring to FIG. 16, the electromagnetic field is composed of three components. The curve k1 is a component that is inversely proportional to the distance from the wave source, and is referred to as a “radiated electromagnetic field”. A curve k2 is a component inversely proportional to the square of the distance from the wave source, and is referred to as an “induction electromagnetic field”. The curve k3 is a component inversely proportional to the cube of the distance from the wave source, and is referred to as an “electrostatic magnetic field”. When the wavelength of the electromagnetic field is “λ”, the distance at which the strengths of the “radiant electromagnetic field”, the “induction electromagnetic field”, and the “electrostatic magnetic field” are approximately equal can be expressed as λ / 2π.

  The “electrostatic magnetic field” is a region where the intensity of electromagnetic waves suddenly decreases with the distance from the wave source. In the power transmission system according to the present embodiment, this “electrostatic magnetic field” is a dominant near field (evanescent field). ) Is used to transmit energy (electric power). That is, in the near field where the “electrostatic magnetic field” is dominant, by resonating the power transmitting unit 56 and the power receiving unit 20 (for example, a pair of LC resonance coils) having adjacent natural frequencies, the power receiving unit 56 and the other power receiving unit are resonated. Energy (electric power) is transmitted to 20. Since this "electrostatic magnetic field" does not propagate energy far away, the resonance method transmits power with less energy loss than electromagnetic waves that transmit energy (electric power) by "radiant electromagnetic field" that propagates energy far away. be able to.

  Thus, in this power transmission system, power is transmitted in a non-contact manner between the power transmission unit and the power reception unit by causing the power transmission unit and the power reception unit to resonate (resonate) with each other by an electromagnetic field. Such an electromagnetic field formed between the power reception unit and the power transmission unit may be referred to as a near-field resonance (resonance) coupling field, for example.

  For example, “magnetic resonance coupling”, “magnetic field (magnetic field) resonance coupling”, “magnetic field resonance (resonance) coupling”, “near-field resonance” may be used as the coupling between the power transmitting unit 56 and the power receiving unit 20 in the power transmission of the present embodiment. (Resonant) coupling "," Electromagnetic field (electromagnetic field) resonant coupling "or" Electric field (electric field) resonant coupling ".

  The “electromagnetic field (electromagnetic field) resonance coupling” means a coupling including any of “magnetic resonance coupling”, “magnetic field (magnetic field) resonance coupling”, and “electric field (electric field) resonance coupling”.

  Since the coil-shaped antenna is adopted for the primary coil 58 of the power transmission unit 56 and the secondary coil 22 of the power reception unit 20 described in this specification, the power transmission unit 56 and the power reception unit 20 are mainly magnetic fields. The power transmitting unit 56 and the power receiving unit 20 are “magnetic resonance coupled” or “magnetic field (magnetic field) resonant coupled”.

  For example, an antenna such as a meander line can be used as the primary coil 58 and the secondary coil 22, and in this case, the power transmitting unit 56 and the power receiving unit 20 are mainly coupled by an electric field. Yes. At this time, the power transmission unit 56 and the power reception unit 20 are “electric field (electric field) resonance coupled”. As described above, in the present embodiment, power is transmitted in a non-contact manner between the power receiving unit 20 and the power transmitting unit 56. As described above, when power is transmitted in a non-contact manner, a magnetic field is mainly formed between the power receiving unit 20 and the power transmitting unit 56.

(Embodiment 2)
The external power supply apparatus 51 according to the present embodiment will be described with reference to FIGS.

  The external power supply apparatus 51 according to the second embodiment includes a third detection unit that detects a foreign object positioned between the power reception unit 20 and the power transmission unit 56 in a state where the power transmission unit 56 and the power reception unit 20 are opposed to each other. 90, and a fourth detection unit 93 that detects foreign matter entering between the power reception unit 20 and the power transmission unit 56.

  FIG. 18 is a plan view showing the power transmission unit 56 and various detection units located around the power transmission unit 56. As shown in FIG. 18, the external power feeding device 51 includes a third detection unit 90 and fourth detection units 91, 92, 93.

  The third detection unit 90 is disposed on the front side in the approach direction D1 with respect to the power transmission unit 56. The third detection unit 90 includes detection units 94, 95, and 96.

  The detection unit 94 detects a physical quantity in the detection region R10. The detection unit 95 detects a physical quantity in the detection region R11. The detection unit 96 detects a physical quantity in the detection region R12. The detection areas R10, R11, and R12 cover the upper surface of the power transmission unit 56.

  For this reason, the third detection unit 90 can detect a foreign object positioned between the power reception unit 20 and the power transmission unit 56 in a state where the power reception unit 20 and the power transmission unit 56 face each other.

  The fourth detection unit 91 is disposed with an interval in the width direction of the vehicle 10 that stops with respect to the third detection unit 90. Further, the fourth detection unit 92 is disposed in the opposite direction to the fourth detection unit 91 with respect to the third detection unit 90. The fourth detection unit 93 is disposed on the rear side in the approach direction D1 with respect to the power transmission unit 56.

  The fourth detection unit 91 includes detection units 100 and 101. The fourth detection unit 92 includes detection units 103 and 104, and the fourth detection unit 93 includes detection units 104 and 105.

  The detection units 100 to 105 detect a change in the physical quantity of the detection area. As the detection units 100 to 105, for example, a pyroelectric sensor or the like is employed.

  As shown in FIG. 19, when the fourth detection units 91, 92, and 93 are driven, the fourth detection units 91, 92, and 93 are positioned around a region located between the power transmission unit 56 and the power reception unit 20. Changes in physical quantities in the detection regions R13, R14, and R15 arranged so as to surround the region located therebetween are detected.

  Specifically, the detection unit 101 and the detection unit 102 cooperate to detect a change in the physical quantity in the detection region R13. The detection region R13 is located on the front side in the approach direction D1 with respect to the power transmission unit 56.

  The detection unit 100 and the detection unit 104 cooperate to detect a change in the physical quantity in the detection region R14. The detection region R14 is shifted with respect to the power transmission unit 56 toward the width direction of the vehicle 10 to be stopped. The detection unit 103 and the detection unit 105 cooperate to detect a change in the physical quantity in the detection region R15. The detection region R14 is located on the opposite side of the detection region R14 with respect to the power transmission unit 56.

  The driving of the external power supply device 51 when power is transmitted to the power receiving unit 20 using the external power supply device 51 configured as described above will be described.

  FIG. 20 is a flowchart showing a control flow of the external power supply apparatus 51. First, when the vehicle 10 stops in a state where the power receiving unit 20 and the power transmission unit 56 face each other, the vehicle 10 transmits information indicating that the vehicle 10 has stopped to the antenna 61.

  When the external power supply device 51 receives from the vehicle 10 that the vehicle 10 has stopped, the external power supply device 51 starts control of the external power supply device 51.

  First, the control unit 55 determines whether or not the third detection unit 90 has detected a foreign object (STEP 1). Here, the storage unit of the control unit 55 stores in advance temperature distribution data indicating a detection result when the third detection unit 90 detects when the power transmission unit 56 is hot.

  Then, the control unit 55 determines whether or not there is a foreign object between the power reception unit 20 and the power transmission unit 56 based on the result of comparison between the detection result detected by the third detection unit 90 and the stored temperature distribution data. Determine whether.

  Note that the above-described determination method is an example, and other methods may be adopted to determine the presence or absence of a foreign object.

  For example, when a sonar sensor is employed as each detection unit of the third detection unit 90, the detection result detected by the third detection unit 90 in a state where there is no foreign object is stored in the storage unit of the foreign object detection device 18 in advance. Then, the result of driving the third detection unit 90 and the stored detection result may be compared, and the foreign object detection device 18 may determine the presence or absence of the foreign object.

  As described above, the control unit 55 uses the third detection unit 90 to detect whether there is a foreign object such as a small animal between the power receiving unit 20 and the power transmission unit 56. When determining that the third detection unit 90 has detected a foreign object (“YES” in STEP 21), the control unit 55 transmits a signal indicating that the foreign object has been detected from the antenna 61 to the vehicle 10 (STEP 22).

  In FIG. 17, when the vehicle ECU 12 receives a signal indicating that a foreign object has been detected, the vehicle ECU 12 drives the notification unit 48. After the notification unit 48 is driven, when the user operates the operation unit of the notification unit 48 and the warning state of the notification unit 48 is released, the vehicle ECU 12 releases the warning state from the antenna 49 to the antenna 61. Send a signal to that effect.

  On the other hand, if the control unit 55 has not received a signal indicating that the warning has been canceled from the vehicle 10, it determines that the warning has not been canceled by the user (STEP 23), and returns to the above STEP 21. .

  Then, when the control unit 55 receives a signal indicating that the warning is released from the vehicle 10, the fourth detection units 91, 92, and 93 assume that the warning is released by the user ("YES" in STEP 23). Is activated (STEP 24).

  Next, the third detection unit 90 is stopped (STEP 25). By stopping the driving of the third detection unit 90, power consumption can be reduced.

  Next, power transmission is started (STEP 26). Specifically, the control unit 55 drives the high frequency power driver 54 to transmit power from the power transmission unit 56 to the power reception unit 20.

  Next, the control unit 55 determines whether or not the fourth detection units 91, 92, and 93 have detected a foreign object (STEP 27). Here, when it is determined that at least one of the fourth detection units 91, 92, and 93 has detected the entry of a foreign object (“YES” in STEP 27), the control unit 55 stops power transmission (STEP 28). Specifically, the control unit 55 stops driving the high frequency power driver 54.

  Thereby, it is possible to prevent power from being transmitted from the power transmission unit 56 to the power reception unit 20 in a state where a foreign object has entered between the power reception unit 20 and the power transmission unit 56.

  Next, the control unit 55 stops driving the fourth detection units 91, 92, 93 (STEP 29). On the other hand, when the control unit 55 determines in STEP 27 that no foreign object has entered (NO in STEP 27), the control unit 55 receives a signal from the vehicle 10 that the charging of the battery 15 is completed. It is determined whether or not (STEP 30).

  Specifically, the vehicle ECU 12 of the vehicle 10 senses the state of charge of the battery 15 when power transmission from the power transmission unit 56 to the power reception unit 20 is started.

  When the vehicle ECU 12 determines that the charging of the battery 15 is completed, the vehicle ECU 12 transmits a signal indicating that the charging of the battery 15 is completed from the antenna 49 to the antenna 61.

  When the control unit 55 determines that the signal indicating that the charging of the battery 15 has been completed is received from the vehicle 10 or has already been received from the vehicle 10 in STEP 30 described above ("YES" in STEP 30), The power transmission to the unit 20 is stopped (STEP 28).

  And the control part 55 stops the 4th detection unit 91,92,93 (STEP29).

As described above, also in the external power feeding device 51 according to the second embodiment, the control unit 55 uses the third detection unit 90 in the detection regions R10, R11, and R12 before power transmission to the power reception unit 20. Detect foreign matter. Since the third detection unit 90 detects a physical quantity in the detection area, when the power reception unit 20 and the power transmission unit 56 face each other, a foreign object such as a small animal is already between the power reception unit 20 and the power transmission unit 56. In this case, the foreign object can be detected.

  During power transmission to the power receiving unit 20, the control unit 55 uses the fourth detection units 91, 92, and 93 to determine whether or not a foreign object has entered between the power receiving unit 20 and the power transmission unit 56. to decide. Since the fourth detection units 91, 92, and 93 can detect the fluctuation of the physical quantity in the detection area with high accuracy, the fourth detection units 91, 92, and 93 can accurately detect small animals that pass through the detection area.

  For this reason, according to the external power supply device 51 according to the second embodiment, power is transmitted from the power transmission unit 56 to the power reception unit 20 in a state where there is a foreign object such as a small animal between the power reception unit 20 and the power transmission unit 56. This can be suppressed.

  In the first and second embodiments, the case where power is transmitted from the power transmission unit 56 to the power reception unit 20 has been described. However, similarly, when power is transmitted from the power reception unit 20 to the power transmission unit 56, the power reception is performed similarly. It is possible to suppress power transmission in a state where there is a foreign object between the unit 20 and the power transmission unit 56.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims. Furthermore, the above numerical values are examples, and are not limited to the above numerical values and ranges.

  DESCRIPTION OF SYMBOLS 10 Vehicle, 10A Vehicle main body, 11,191 Power receiving device, 13 Rectifier, 14 Converter, 15 Battery, 16 Power control unit, 17 Motor unit, 18 Foreign object detection device, 20,196 Power receiving unit, 21,57 Ferrite core, 22 2 Next coil, 23, 59, 195, 198 Capacitor, 24, 60 Coil unit, 25 Bottom, 26 Floor panel, 27, 62 Housing, 28, 63 Shield, 29 Lid, 30 Front edge, 31 Rear edge, 32 Right edge portion, 33 Left edge portion, 34 First end portion, 35 Second end portion, 47 Engine, 48 Notification portion, 49, 61 Antenna, 50, 190 Power transmission device, 51 External power supply device, 52 Parking space, 53 AC power source, 54 high frequency power driver, 55 control unit, 56, 193 power transmission unit, 58 Next coil, 65 rear side, 66L rear side, 71 first detection unit, 72, 73, 74 second detection unit, 75-77, 80-85, 94-96, 100-105 detection unit, 86 focus Electrical element, 87 resistance, 88 voltage sensor, 90 third detection unit, 91, 92, 93 fourth detection unit.

Claims (17)

A power receiving unit that receives power in a non-contact manner from a power transmitting unit provided outside;
A plurality of first detection units for detecting foreign matter positioned between the power transmission unit and the power reception unit facing the power transmission unit;
A second detection unit for detecting a foreign substance entering between the power transmission unit and the power reception unit;
A control unit for controlling the first detection unit and the second detection unit;
The first detection unit is a sensor that detects a physical quantity in a detection region detected by the first detection unit, and the second detection unit detects a change in the physical quantity in a detection region detected by the second detection unit. A sensor to detect,
The control unit causes the first detection unit to detect a foreign object positioned between the power transmission unit and the power reception unit before power transmission from the power transmission unit to the power reception unit is started. During the power transmission from the power receiving unit to the power receiving unit, let the second detection unit detect foreign matter that enters between the power transmission unit and the power receiving unit ,
The control unit stores temperature distribution data indicating detection results by the plurality of first detection units when the power transmission unit is at a high temperature,
The control unit determines whether or not the plurality of first detection units have detected a foreign object based on a result of comparing the detection results detected by the plurality of first detection units and the temperature distribution data. The power receiving device.   2. The power receiving device according to claim 1, wherein the second detection unit is configured to be able to detect a foreign object passing through a region located around a region located between the power transmission unit and the power reception unit. Further comprising a notification unit,
3. The power receiving according to claim 1, wherein when the first detection unit detects a foreign object, the control unit notifies the user that the foreign object has been detected using the notification unit. apparatus.   The power receiving device according to any one of claims 1 to 3, wherein the control unit stops power transmission by the power transmission unit when the second detection unit detects a foreign object. The power receiving unit is mounted on a vehicle,
The control unit causes the first detection unit to detect a foreign object on the power transmission unit when the power reception unit and the power transmission unit are positioned to face each other. The power receiving apparatus described. The power reception device according to any one of claims 1 to 5 , wherein the control unit stops the first detection unit during the power transmission. The power receiving device according to any one of claims 1 to 6 , wherein a difference between the natural frequency of the power transmission unit and the natural frequency of the power reception unit is 10% or less of the natural frequency of the power reception unit. The power reception device according to any one of claims 1 to 6 , wherein a coupling coefficient between the power reception unit and the power transmission unit is 0.3 or less. The power receiving portion is formed between the power transmitting portion and the front Symbol power receiving unit, and a magnetic field that oscillates at a specific frequency, it is formed between the power transmission unit and the power receiving unit, and an electric field which oscillates at a particular frequency At least one through receiving power from the power transmission unit, the power receiving device according to any one of claims 1 to 8 with. A power transmission unit that transmits power in a contactless manner to a power reception unit mounted on the vehicle;
A plurality of third detection units for detecting foreign matter positioned between the power transmission unit and the power reception unit facing the power transmission unit;
A fourth detection unit for detecting a foreign substance entering between the power transmission unit and the power reception unit;
A control unit for controlling the third detection unit and the fourth detection unit;
The third detection unit is a sensor that detects a physical quantity in a detection region detected by the third detection unit, and the fourth detection unit detects a change in the physical quantity in a detection region detected by the fourth detection unit. A sensor to detect,
The control unit causes the third detection unit to detect a foreign object positioned between the power transmission unit and the power reception unit before power transmission from the power transmission unit to the power reception unit is started.
During the power transmission from the power transmission unit to the power reception unit, let the fourth detection unit detect foreign matter that enters between the power transmission unit and the power reception unit ,
The control unit stores temperature distribution data indicating detection results by the plurality of third detection units when the power transmission unit is at a high temperature,
The control unit determines whether the plurality of third detection units have detected a foreign object based on a result of comparison between the detection results detected by the plurality of third detection units and the temperature distribution data. A power transmission device. The power transmission device according to claim 10 , wherein the fourth detection unit is configured to be able to detect a foreign object passing through a region located around a region located between the power transmission unit and the power reception unit. The vehicle further includes a notification unit,
The power transmission according to claim 10 or 11 , wherein when the third detection unit detects a foreign object, the control unit notifies the user that the foreign object has been detected using the notification unit. apparatus. Wherein the control unit, the fourth when the detection unit detects the foreign matter, the power transmission unit by stopping the power transmission, the power transmission device of claim 12 Noise Re crab according to claims 10. The power transmission device according to any one of claims 10 to 13 , wherein the control unit stops the third detection unit during power transmission from the power transmission unit to the power reception unit. The power transmission device according to any one of claims 10 to 14 , wherein a difference between a natural frequency of the power transmission unit and a natural frequency of the power reception unit is 10% or less of a natural frequency of the power reception unit. The power transmission device according to any one of claims 10 to 15 , wherein a coupling coefficient between the power reception unit and the power transmission unit is 0.3 or less. The power transmission unit is formed between the power reception unit and the power transmission unit and vibrates at a specific frequency, and an electric field is formed between the power reception unit and the power transmission unit and vibrates at a specific frequency. The power transmission device according to any one of claims 10 to 16 , wherein power is transmitted to the power reception unit through at least one of the following.

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