JP2010141976A - Non-contact power transmission apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-contact power transmission apparatus capable of efficiently supplying power from an AC power supply to a load without changing a frequency of an AC output voltage of the AC power supply even if at least either the distance between two resonant coils or the load changes. <P>SOLUTION: The non-contact power transmission apparatus 10 includes: an AC power supply 11; a primary coil 12 connected to the AC power supply 11; a primary side resonant coil 13; a secondary side resonant coil 14; a secondary coil 15 having a load 16 connected thereto; and an impedance variable circuit 17 provided between the AC power supply 11 and the primary coil 12. A resonant system 20 is configured by the primary coil 12, the primary side resonant coil 13, the secondary side resonant coil 14, the secondary coil 15, the load 16 and capacitors 18, 19. In the impedance variable circuit 17, an impedance is adjusted so that an input impedance Zin in the resonant frequency of the resonant system 20 may match the impedance of the AC power supply 11 side close to the primary coil 12. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a contactless power transmission device, and more particularly to a resonance type contactless power transmission device.

As a non-contact power transmission device, for example, those described in Non-Patent Literature 1 and Patent Literature 1 are known. As shown in FIG. 5, this non-contact power transmission device is arranged with two copper wire coils 51, 52 separated from each other, and power is transferred from one copper wire coil 51 to the other copper wire coil 52 by resonance of an electromagnetic field. Has been introduced. Specifically, the magnetic field generated by the primary coil 54 connected to the AC power source 53 is enhanced by magnetic field resonance by the copper wire coils 51 and 52, and the magnetic field near the copper wire coil 52 enhanced by the secondary coil 55 is used. Electric power is extracted using electromagnetic induction and supplied to the load 56. And when the copper wire coils 51 and 52 of radius 30cm are arrange | positioned 2 m apart, it has been confirmed that the 60W electric lamp as the load 56 can be lighted.
NIKKEI ELECTRONICS 2007.12.3 pages 117-128 International Patent Publication WO / 2007/008646 A2

  In this resonance type non-contact power transmission device, in order to efficiently supply the power of the AC power source to the load, it is necessary to efficiently supply the power from the AC power source to the resonance system. However, in Non-Patent Document 1 and Patent Document 1, when designing (manufacturing) this non-contact power transmission device, a copper wire coil 51 on the transmission side (power transmission side) and a copper wire coil 52 on the reception side (power reception side). The relationship between the resonance frequency of the AC and the output AC frequency of the AC power supply is not specified.

  In the case of a non-contact power transmission device that is used in a state where the distance between the power transmission side and the power reception side is constant and the resistance of the load connected to the power reception side is constant, the AC power source that first becomes the resonance frequency of the resonance system What is necessary is just to obtain | require the output frequency of 53 by experiment, and to output an alternating voltage from the alternating current power supply 53 to the primary coil 54 with the frequency. However, when the distance between the resonance coils, that is, the distance between the two copper wire coils 51 and 52 and the resistance value of the load 56 change, the input impedance of the resonance system at the resonance frequency of the resonance system changes. Therefore, matching between the AC power supply 53 and the input impedance of the resonance system cannot be achieved, and the reflected power to the AC power supply 53 increases, so that the power cannot be efficiently supplied to the load 56. Here, the “resonance frequency of the resonance system” means a frequency at which the power transmission efficiency η is maximized.

  The object of the present invention is to efficiently use power from an AC power source without changing the frequency of the AC output voltage of the AC power source even if at least one of the distance between the two resonance coils and the load in the resonance system changes. An object of the present invention is to provide a non-contact power transmission device that can supply a load well.

  In order to achieve the above object, an invention according to claim 1 is an AC power supply, a primary coil connected to the AC power supply, a primary resonance coil, a secondary resonance coil, and a secondary coil. And a load connected to the secondary coil, and an impedance variable circuit provided between the AC power source and the primary coil. The primary coil, the primary resonance coil, the secondary resonance coil, the secondary coil, and the load constitute a resonance system. State detection means for detecting the state of the resonance system, and the impedance variable circuit includes an input impedance at a resonance frequency of the resonance system based on a detection result of the state detection means, and the AC power supply side from the primary coil. The impedance is adjusted so as to match the impedance.

  Here, the “AC power supply” means a power supply that outputs an AC voltage, and includes an output that converts a DC input from a DC power supply into an AC. The “resonance system input impedance” refers to the impedance of the entire resonance system measured at both ends of the primary coil. The “resonance system state” means the resonance system at the resonance frequency of the resonance system, such as the positional relationship between the primary resonance coil and the secondary resonance coil (for example, the distance between them) and the magnitude of the load. It means something that affects the input impedance. Further, “the input impedance matches the impedance on the AC power supply side from the primary coil” not only means that both impedances are perfectly matched, but also, for example, the power transmission efficiency 80 of the non-contact power transmission device. Difference within a range that achieves desired performance, such as at least% or reflected power to an AC power source of 5% or less, is allowed. For example, it also means that the difference between both impedances is within a range of ± 10%, preferably within a range of ± 5%.

  According to the present invention, the state of the resonance system, for example, the distance or load between the two resonance coils is detected by the state detection means, and when the state of the resonance system changes from the reference state when setting the resonance frequency, The impedance of the variable impedance circuit is adjusted so that the input impedance at the resonance frequency of the resonance system matches the impedance on the AC power supply side from the primary coil. Therefore, if the distance or load between the two resonance coils changes from the reference value when setting the resonance frequency, the reflected power to the AC power supply can be reduced without changing the frequency of the AC output voltage of the AC power supply. The power can be efficiently supplied from the AC power source to the load.

  According to a second aspect of the present invention, in the first aspect of the invention, the state detection unit is a distance measurement unit that measures a distance between the primary resonance coil and the secondary resonance coil. The impedance variable circuit adjusts the impedance based on the measurement result of the distance measuring means.

  According to the present invention, when it is confirmed that the distance between the two resonance coils has changed based on the measurement result of the distance measuring means, the impedance of the impedance variable circuit is adjusted, and the impedance on the AC power supply side from the primary coil is adjusted. And the input impedance at the resonance frequency of the resonance system are maintained in a matched state.

  The invention according to claim 3 is the invention according to claim 1, wherein the state detecting means is load detecting means for detecting the magnitude of the load, and the variable impedance circuit is detected by the load detecting means. The impedance is adjusted based on the result. According to this invention, when a change in the load is confirmed based on the detection result of the load detection means, the impedance of the impedance variable circuit is adjusted, and the impedance on the AC power supply side from the primary coil and the resonance frequency of the resonance system Is maintained in a state that matches the input impedance.

  According to the present invention, even if at least one of the distance between the two resonance coils and the load that are in the resonance system changes, the power from the AC power source is efficiently changed without changing the frequency of the AC output voltage of the AC power source. It can supply the load well.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 schematically shows the configuration of the non-contact power transmission apparatus 10. As shown in FIG. 1, the non-contact power transmission device 10 includes an AC power supply 11, a primary coil 12 connected to the AC power supply 11, a primary resonance coil 13, a secondary resonance coil 14, 2 A secondary coil 15, a load 16 connected to the secondary coil 15, and an impedance variable circuit 17 provided between the AC power supply 11 and the primary coil 12 are provided. Capacitors 18 and 19 are connected in parallel to the primary resonance coil 13 and the secondary resonance coil 14, respectively. The primary coil 12, the primary resonance coil 13, the secondary resonance coil 14, the secondary coil 15, the load 16 and the capacitors 18 and 19 constitute a resonance system 20.

The AC power supply 11 is a power supply that outputs an AC voltage. The frequency of the output AC voltage of the AC power supply 11 is set to the resonance frequency of the resonance system 20.
The primary coil 12, the primary side resonance coil 13, the secondary side resonance coil 14, and the secondary coil 15 are formed of electric wires. For the electric wire constituting the coil, for example, an insulated vinyl-coated wire is used. The winding diameter and the number of turns of the coil are appropriately set according to the magnitude of power to be transmitted. In this embodiment, the primary coil 12, the primary side resonance coil 13, the secondary side resonance coil 14, and the secondary coil 15 are formed in the same winding diameter. The primary resonance coil 13 and the secondary resonance coil 14 are formed in the same manner, and the same capacitors are used as the capacitors 18 and 19.

  The impedance variable circuit 17 is composed of two variable capacitors 21 and 22 and an inductor 23. One variable capacitor 21 is connected to the AC power supply 11 in parallel, and the other variable capacitor 22 is connected to the primary coil 12 in parallel. The inductor 23 is connected between the variable capacitors 21 and 22. The impedance variable circuit 17 is changed in impedance by changing the capacitance of the variable capacitors 21 and 22. The impedance variable circuit 17 adjusts the impedance so that the input impedance Zin at the resonance frequency of the resonance system 20 matches the impedance on the AC power supply 11 side from the primary coil 12. The variable capacitors 21 and 22 have a known configuration in which, for example, a rotation shaft (not shown) is driven by a motor, and the motor is driven by a drive signal from the control device 24.

  FIG. 2 illustrates a charging device 32 and a moving body 30 when the non-contact power transmission device 10 is applied to a system that performs non-contact charging with respect to a secondary battery 31 mounted on a moving body (for example, a vehicle) 30. This is shown schematically. The secondary resonance coil 14, the secondary coil 15, the rectifier circuit 34, and the secondary battery 31 as the load 16 are mounted on the moving body 30. The AC power source 11, the primary coil 12, the primary side resonance coil 13, the impedance variable circuit 17, and the control device 24 are provided in a charging device 32 that charges the secondary battery 31 in a non-contact state. The charging device 32 is provided in the charging station.

  The charging device 32 includes a distance sensor 33 as a distance measuring unit that functions as a state detecting unit that detects the state of the resonance system 20. The distance sensor 33 measures the distance from the moving body 30 while the moving body 30 is stopped at the charging position, and indirectly measures the distance between the primary side resonance coil 13 and the secondary side resonance coil 14.

  The control device 24 includes a CPU 35 and a memory 36. The memory 36 stores data indicating the relationship between the distance between the primary resonance coil 13 and the secondary resonance coil 14 and the input impedance Zin at the resonance frequency of the resonance system 20 as a map or a relational expression. This data is obtained in advance by testing. The memory 36 adjusts the impedance of the impedance variable circuit 17 so that the input impedance Zin matches the impedance on the AC power supply 11 side from the primary coil 12 without changing the output frequency of the AC power supply 11. Data indicating the relationship between the capacitance of the variable capacitors 21 and 22 and the input impedance Zin is stored. “The input impedance Zin matches the impedance on the AC power supply 11 side from the primary coil 12” not only means that both impedances are perfectly matched, but also, for example, power transmission of the non-contact power transmission device 10 Differences within a range that achieves desired performance, such as efficiency of 80% or more, or reflected power to the AC power supply 11 of 5% or less, are allowed. For example, it also means that the difference between both impedances is within a range of ± 10%, preferably within a range of ± 5%.

Next, the operation of the non-contact power transmission apparatus 10 configured as described above will be described.
When charging the secondary battery 31, charging is performed in a state where the moving body 30 is stopped at the charging position near the charging device 32. When the moving body 30 stops at the charging position, the distance sensor 33 measures the distance from the moving body 30. The control device 24 inputs the output signal of the distance sensor 33 and calculates the distance between the primary resonance coil 13 and the secondary resonance coil 14 from the measurement result of the distance sensor 33. The control device 24 determines the capacity of the variable capacitors 21 and 22 suitable for the calculated distance from the data stored in the memory 36. Next, the control device 24 outputs a drive signal to the variable capacitors 21 and 22 so as to change the capacity of the variable capacitors 21 and 22 to an appropriate capacity at the time of charging. And the capacity | capacitance of the variable capacitors 21 and 22 is changed into the value suitable for the distance between resonance coils.

  Next, an AC voltage is output from the AC power source 11 to the primary coil 12 at the resonance frequency of the resonance system 20, and a magnetic field is generated in the primary coil 12. This magnetic field is enhanced by magnetic field resonance by the primary side resonance coil 13 and the secondary side resonance coil 14. Electric power is extracted from the magnetic field in the vicinity of the enhanced secondary resonance coil 14 by the secondary coil 15 using electromagnetic induction, and is supplied to the secondary battery 31 through the rectifier circuit 34.

  FIG. 3 shows a relationship between the frequency and the input impedance Zin of the resonance system when the distance between the resonance coils, that is, the distance between the primary resonance coil 13 and the secondary resonance coil 14 is changed. When the distance between the primary resonance coil 13 and the secondary resonance coil 14 changes, the value of the input impedance Zin at the resonance frequency of the resonance system 20 also changes. 3 shows that the primary coil 12, the primary side resonance coil 13, the secondary side resonance coil 14, and the secondary coil 15 have a winding diameter of about 300 mm, the output impedance of the AC power supply 11 is 50Ω, and the resistance value of the load 16. The relationship between the input impedance Zin and the frequency in the case where is set to 50Ω is shown. The value of the input impedance Zin at a resonance frequency of approximately 2.2 MHz increased as the distance between the primary resonance coil 13 and the secondary resonance coil 14 increased.

  When the distance between the primary side resonance coil 13 and the secondary side resonance coil 14 changes, the value of the input impedance Zin at the resonance frequency of the resonance system 20 also changes, so that the stop position of the moving body 30 during charging changes. The value of the input impedance Zin at the resonance frequency of the resonance system 20 changes. Therefore, in the configuration without the impedance variable circuit 17, depending on the stop position of the moving body 30 at the time of charging, the output impedance of the AC power supply 11 and the input impedance Zin of the resonance system 20 cannot be matched, Reflected power is generated.

  The contactless power transmission device 10 of this embodiment includes an impedance variable circuit 17 and indirectly measures the distance between the primary resonance coil 13 and the secondary resonance coil 14 by the distance sensor 33 during charging. Then, the impedance of the variable impedance circuit 17 is adjusted so that the impedance on the AC power supply 11 side of the primary coil 12 matches the input impedance Zin of the resonance system 20 at that distance. Therefore, even if the frequency of the AC output voltage of the AC power supply 11 is not changed, the reflected power to the AC power supply 11 is reduced and the power is efficiently supplied from the AC power supply 11 to the secondary battery 31.

According to this embodiment, the following effects can be obtained.
(1) The non-contact power transmission apparatus 10 includes an AC power source 11, a primary coil 12 connected to the AC power source 11, a primary side resonance coil 13, a secondary side resonance coil 14, and a secondary coil 15. A load 16 connected to the secondary coil 15 and an impedance variable circuit 17 provided between the AC power supply 11 and the primary coil 12 are provided. The primary coil 12, the primary side resonance coil 13, the secondary side resonance coil 14, the secondary coil 15, and the load 16 constitute a resonance system 20. Further, the non-contact power transmission apparatus 10 includes a state detection unit (distance sensor 33) that detects the state of the resonance system 20, and the impedance variable circuit 17 is based on the detection result of the state detection unit at the resonance frequency of the resonance system 20. The impedance is adjusted so that the input impedance Zin matches the impedance on the AC power supply 11 side from the primary coil 12. Therefore, when at least one of the distance between the two resonance coils 13 and 14 and the load 16 is changed from a reference value when setting the resonance frequency, the frequency of the AC output voltage of the AC power supply 11 does not need to be changed. The reflected power to the AC power supply can be reduced, and the power can be efficiently supplied from the AC power supply 11 to the load 16.

  (2) The non-contact power transmission device 10 includes distance measuring means (distance sensor 33) that measures the distance between the primary resonance coil 13 and the secondary resonance coil 14 as state detection means, and the impedance variable circuit 17 includes: The impedance is adjusted based on the measurement result of the distance measuring means. Therefore, even if the distance between the primary side resonance coil 13 and the secondary side resonance coil 14 changes and the input impedance Zin changes, the impedance of the impedance variable circuit 17 is adjusted, and the AC power supply 11 from the primary coil 12 is adjusted. The impedance on the side and the input impedance Zin at the resonance frequency of the resonance system are maintained in a matched state.

  (3) The non-contact power transmission device 10 is applied to a system that performs non-contact charging on the secondary battery 31 mounted on the moving body 30, and the charging device 32 provided in the charging station includes the distance sensor 33. ing. Therefore, in a state where the moving body 30 is stopped at the time of charging, even if the distance between the moving body 30 and the charging device 32 is different for each charging time, the input impedance Zin of the resonance system 20 and the primary coil without changing the resonance frequency. 12 can match the impedance on the AC power supply 11 side, and the secondary battery 31 can be charged efficiently. Further, it is not necessary to provide the distance sensor 33 in each moving body 30, and the system becomes simpler than the case where the distance sensor 33 is provided in each moving body 30. In addition, since it is not necessary to stop the moving body 30 at a predetermined position where the distance from the charging device 32 is a predetermined value, the steering wheel operation, the accelerator operation, and the brake operation are facilitated when stopping at the charging position.

  (4) Capacitors 18 and 19 are connected to the primary resonance coil 13 and the secondary resonance coil 14. Therefore, the resonance frequency of the resonance system 20 can be lowered without increasing the number of turns of the primary resonance coil 13 and the secondary resonance coil 14. Further, if the resonance frequency is the same, the primary resonance coil 13 and the secondary resonance coil 14 can be reduced in size as compared with the case where the capacitors 18 and 19 are not connected.

(Second Embodiment)
Next, a second embodiment will be described with reference to FIG. In this embodiment, during charging, the moving body 30 stops at a position where the distance from the charging device 32 is determined, and the distance between the primary side resonance coil 13 and the secondary side resonance coil 14 is constant and the load 16 is large. This is different from the first embodiment in that it is configured to cope with a case where the input impedance Zin of the resonance system 20 changes due to the change in the length. In other words, the distance measuring means is not provided as the state detecting means, but the load detecting means for detecting the load magnitude is provided. The same parts as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted.

  The moving body 30 stops at a predetermined position where the distance from the charging device 32 is a determined value. The moving body 30 is provided with a charge amount sensor 37 as load detecting means for detecting the charge amount of the secondary battery 31. The charge amount data of the secondary battery 31 detected by the charge amount sensor 37 is sent to the charging device 32 via a wireless communication device (not shown).

  In the memory 36, data indicating the relationship between the charge amount of the secondary battery 31 and the input impedance Zin of the resonance system 20 at the charge amount is stored as a map or a relational expression. This data is obtained in advance by testing. The memory 36 adjusts the impedance of the impedance variable circuit 17 so that the input impedance Zin matches the impedance on the AC power supply 11 side from the primary coil 12 without changing the output frequency of the AC power supply 11. Data indicating the relationship between the capacitance of the variable capacitors 21 and 22 and the input impedance Zin is stored.

  When charging the secondary battery 31, charging is performed in a state where the moving body 30 is stopped at a predetermined charging position where the distance from the charging device 32 is constant. When the moving body 30 stops at the charging position, the charge amount sensor 37 starts detecting the charge amount of the secondary battery 31. The detected charge amount data is sent to the charging device 32 via the wireless communication device. The control device 24 inputs the charge amount data, obtains the input impedance Zin of the resonance system 20 corresponding to the charge amount from the data stored in the memory 36, and the variable capacitor 21 suitable for the value of the input impedance Zin. , 22 is determined from the data stored in the memory 36. Next, the control device 24 outputs a drive signal to the variable capacitors 21 and 22 so as to change the capacity of the variable capacitors 21 and 22 to the determined capacity. And the capacity | capacitance of the variable capacitors 21 and 22 is changed into the value suitable for charge amount.

  Then, an AC voltage is output from the AC power source 11 to the primary coil 12 at the resonance frequency of the resonance system 20, and charging is started. During charging, the charge amount sensor 37 detects the charge amount of the secondary battery 31 and sends the detection data to the charging device 32. Further, the control device 24 determines the capacity of the variable capacitors 21 and 22 suitable for the charge amount from the charge amount data, and sets the capacity of the variable capacitors 21 and 22 so that the capacity of the variable capacitors 21 and 22 becomes the value. adjust. Therefore, even if the input impedance Zin of the resonance system 20 changes with the change in the charge amount of the secondary battery 31 during charging, the impedance on the AC power supply 11 side from the primary coil 12 becomes the input impedance Zin of the resonance system 20. The impedance of the variable impedance circuit 17 is adjusted so as to match.

According to the second embodiment, the following effects can be obtained in addition to the effects (1) and (4) of the first embodiment.
(5) Load detecting means (charge amount sensor 37) for detecting the size of the load 16 is provided as state detecting means, and the impedance variable circuit 17 adjusts the impedance based on the detection result of the load detecting means. Therefore, even when the input impedance Zin of the resonance system 20 changes due to the change of the load 16 during non-contact power transmission, the reflected power to the AC power supply 11 can be obtained without changing the frequency of the AC output voltage of the AC power supply 11. The power can be efficiently supplied from the AC power supply 11 to the load 16.

  (6) The non-contact power transmission device 10 is applied to a system that performs non-contact charging on the secondary battery 31 mounted on the moving body 30, and the moving body 30 is at a certain distance from the charging device 32 during charging. A charge amount sensor 37 that stops at the stop position and detects the charge amount of the secondary battery 31 is provided on the moving body 30. The control device 24 is based on the detection data of the charge amount sensor 37 so that even if the input impedance Zin of the resonance system 20 changes, the input impedance Zin matches the impedance on the AC power supply 11 side from the primary coil 12. Then, the impedance variable circuit 17 is adjusted. Therefore, the secondary battery 31 can be charged more efficiently.

The embodiment is not limited to the above, and may be embodied as follows, for example.
In the second embodiment, the distance sensor 33 is provided in the charging device 32, and the impedance variable circuit 17 takes into account the stop position of the moving body 30 during charging and the change in the load of the secondary battery 31 during charging. It is good also as a structure which adjusts an impedance. In this configuration, unlike the second embodiment, the input impedance Zin of the resonance system 20 changes during charging without stopping the mobile body 30 at a predetermined position where the distance from the charging device 32 is constant during charging. In this case, the impedance of the variable impedance circuit 17 is adjusted so that charging is performed under appropriate conditions.

  The variable impedance circuit 17 is not limited to one composed of two variable capacitors 21 and 22 and one inductor 23. For example, either one of the variable capacitors 21 and 22 constituting the impedance variable circuit 17 may be omitted, and the impedance variable circuit 17 may be configured by one variable capacitor and one inductor 23. The impedance variable circuit 17 may be configured with a fixed capacitor and a variable inductor.

  When the non-contact power transmission device 10 is applied to a charging system for the secondary battery 31 mounted on the moving body 30, the rated capacity is different from the configuration in which only the secondary battery 31 having the same rated capacity is charged. It is good also as a structure which charges also with respect to the secondary battery 31 of the moving body 30 carrying the secondary battery 31. FIG. For example, in the memory 36 of the control device 24, the relationship between the distance between the resonance coils and the value of the input impedance Zin at the resonance frequency of the resonance system 20 at the distance or the secondary battery 31 for each secondary battery 31 having a different rated capacity. Data indicating the relationship between the charge amount of the battery 31 and the input impedance Zin of the resonance system 20 at the charge amount is stored. And the control apparatus 24 calculates the capacity | capacitance of the suitable variable capacitor | condenser 21 and 22 corresponding to the input impedance Zin of the resonance system 20 at the time of charge with the rated capacity of the secondary battery 31 mounted in the mobile body 30, The impedance of the impedance variable circuit 17 is adjusted.

  O Instead of indirectly detecting the change in the load of the secondary battery 31 during charging from the change in the charge amount, a sensor configured to directly detect the load may be used as the load detection means. For example, a current sensor that detects the amount of current supplied to the secondary battery 31 may be used as the load detection means.

  The non-contact power transmission device 10 supplies power to not only the charging device 32 but also an electric device whose load changes stepwise during use as a load or a plurality of electric devices having different load values. You may apply to an apparatus.

  ○ When the non-contact power transmission device 10 uses an electric device whose load changes stepwise during use as the load 16, when the load change time is determined in advance, when the load 16 starts driving (non-contact power The impedance of the variable impedance circuit 17 may be adjusted based on the elapsed time from when the power transmission of the transmission apparatus 10 is started.

  The capacitors 18 and 19 connected to the primary resonance coil 13 and the secondary resonance coil 14 may be omitted. However, the configuration in which the capacitors 18 and 19 are connected can lower the resonance frequency compared to the case where the capacitors 18 and 19 are omitted. Further, if the resonance frequency is the same, the primary side resonance coil 13 and the secondary side resonance coil 14 can be downsized as compared with the case where the capacitors 18 and 19 are omitted.

The AC power supply 11 may be capable of changing or not changing the frequency of the output AC voltage.
The outer shape of the primary coil 12, the primary side resonance coil 13, the secondary side resonance coil 14, and the secondary coil 15 is not limited to a circle, but may be, for example, a polygon such as a rectangle, a hexagon, or a triangle, or an ellipse. It may be shaped.

The outer shape of the primary coil 12, the primary side resonance coil 13, the secondary side resonance coil 14, and the secondary coil 15 is not limited to a substantially symmetric shape, but may be an asymmetric shape.
The electric wire is not limited to a general copper wire having a circular cross section, and may be a plate-like copper wire having a rectangular cross section.

○ The material of the electric wire is not limited to copper, and for example, aluminum or silver may be used.
(Circle) the primary side resonance coil 13 and the secondary side resonance coil 14 are good not only as the coil by which the electric wire was wound cylindrically but in the shape where the electric wire was wound on one plane.

  The primary coil 12, the primary side resonance coil 13, the secondary side resonance coil 14, and the secondary coil 15 do not have to be formed with the same diameter. For example, the primary resonance coil 13 and the secondary resonance coil 14 may have the same diameter, and the primary coil 12 and the secondary coil 15 may have different diameters.

The primary coil 12, the primary side resonance coil 13, the secondary side resonance coil 14, and the secondary coil 15 may be formed with a wiring pattern provided on the substrate instead of being formed with electric wires.
The following technical idea (invention) can be understood from the embodiment.

  (1) In the invention according to any one of claims 1 to 3, the impedance variable circuit includes a variable capacitor and an inductor, and the variable capacitor includes an input impedance at a resonance frequency of a resonance system; The capacity is adjusted to an appropriate capacity by a drive signal from a control device having a memory in which data indicating the relationship with the capacity of the variable capacitor that matches the impedance on the AC power supply side with respect to the primary coil is stored. .

  (2) A non-contact power transmission device according to a second aspect of the invention is applied to a system for charging a secondary battery mounted on a moving body, and the moving body includes the secondary resonance coil, the 2 A secondary battery as a load and a secondary battery as a load are mounted, and a charging device provided in a charging station includes the AC power source, the primary coil, the primary side resonance coil, the impedance variable circuit, the distance measuring means, and a control And the control device matches the measurement result of the distance measuring means, the input impedance at the resonance frequency of the resonance system stored in the memory, and the impedance on the AC power supply side from the primary coil. The capacitance of the variable capacitor is adjusted based on data indicating the relationship with the capacitance of the variable capacitor.

  (3) A non-contact power transmission device according to a third aspect of the present invention is applied to a system for charging a secondary battery mounted on a moving body, and the moving body includes the secondary resonance coil, the 2 A secondary coil, a secondary battery as a load, and load detection means are mounted, and the charging device provided in the charging station includes the AC power source, the primary coil, the primary resonance coil, the impedance variable circuit, and the control device. The control device matches the detection result of the load detection means, the input impedance at the resonance frequency of the resonance system stored in the memory, and the impedance on the AC power supply side from the primary coil. The capacity of the variable capacitor is adjusted based on data indicating the relationship with the capacity of the variable capacitor.

The block diagram of the non-contact electric power transmission apparatus which concerns on 1st Embodiment. The schematic diagram which shows a charging device and a moving body. The graph which shows the relationship between the input impedance of a resonance system at the time of changing the distance between resonance coils, and a frequency. The schematic diagram which shows the charging device and moving body of 2nd Embodiment. The block diagram of the non-contact electric power transmission apparatus of a prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... AC power source, 12 ... Primary coil, 13 ... Primary side resonance coil, 14 ... Secondary side resonance coil, 15 ... Secondary coil, 16 ... Load, 17 ... Impedance variable circuit, 20 ... Resonance system, 33 ... Distance sensor as distance measuring means, 37... Charge amount sensor as load detecting means.

Claims (3)

AC power supply,
A primary coil connected to the AC power source;
A primary resonance coil;
A secondary resonance coil;
A secondary coil;
A load connected to the secondary coil;
An impedance variable circuit provided between the AC power source and the primary coil;
The primary coil, the primary resonance coil, the secondary resonance coil, the secondary coil, and the load constitute a resonance system,
State detection means for detecting the state of the resonance system, and the impedance variable circuit includes an input impedance at a resonance frequency of the resonance system based on a detection result of the state detection means, and the AC power supply side from the primary coil. A non-contact power transmission device, wherein the impedance is adjusted so as to match the impedance of the contactless power transmission device.   The state detection means is a distance measurement means for measuring a distance between the primary resonance coil and the secondary resonance coil, and the impedance variable circuit adjusts an impedance based on a measurement result of the distance measurement means. The contactless power transmission device according to claim 1.   2. The non-contact power according to claim 1, wherein the state detection unit is a load detection unit that detects a size of the load, and the impedance variable circuit adjusts an impedance based on a detection result of the load detection unit. Transmission equipment.

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