JP6204767B2 - Non-contact power transmission device - Google Patents

Description

The present invention, through the power receiving coil provided in the power transmission coil and the power receiving device provided in the power transmitting device, a non-contact (wireless) relates to the power non-contact power transmission equipment which transmits a.

  Non-contact power transmission methods include electromagnetic induction using electromagnetic induction (several hundreds of kHz), magnetic resonance using LC resonance transmission via magnetic resonance, microwave power transmission using radio waves (several GHz), or visible light region. A laser power transmission method using electromagnetic waves (light) is known. Among them, the electromagnetic induction method has already been put into practical use. This has the advantage that it can be realized with a simple circuit (transformer system), but there is also a problem that the transmission distance is short.

  Therefore, recently, magnetic resonance type power transmission has attracted attention. The magnetic field resonance method is attracting attention because the human body hardly absorbs energy and avoids dielectric loss and the long transmission distance.

  In recent years, it has been studied to mount a non-contact power transmission device on a small device such as a mobile phone, and there is a great demand for downsizing and thinning the non-contact power transmission device. Therefore, in the above-described non-contact power transmission device using the electromagnetic induction method or the magnetic field resonance method, a planar coil is adopted as the power receiving coil in the power receiving device. In many cases, the power receiving device includes a power receiving circuit and a rechargeable battery. From the viewpoint of reducing the thickness of the power receiving device, the power receiving coil is disposed so that the surface thereof is parallel to the surface of the rechargeable battery or the power receiving circuit. In this case, since the magnetic flux passing through the power receiving coil is linked to the power receiving circuit and the rechargeable battery of the power receiving device, an eddy current is generated due to electromagnetic induction. Eddy currents have a problem in that transmission efficiency is reduced, and circuit components generate heat or malfunction.

  In order to solve the problem, in Patent Document 1, a magnetic foil or a magnetic sheet is provided between the power receiving coil and the secondary battery or substrate. The magnetic foil or the magnetic sheet can shield the magnetic flux passing through the power receiving coil during charging. As a result, the magnetic flux interlinking with the circuit board is reduced, so that the generation of eddy current due to electromagnetic induction can be suppressed.

Japanese Patent No. 5231993

  In Patent Document 1, a magnetic foil or a magnetic sheet is used to prevent the generation of eddy current. However, when the received power is large, energy loss due to eddy current generated in the secondary battery or the substrate is large. It is necessary to increase the thickness of the magnetic foil or magnetic sheet. As a result, the power receiving device becomes large and heavy, which hinders the reduction in size and weight of the power receiving device. Furthermore, since the magnetic foil and the magnetic sheet are expensive, it has also hindered the price reduction of the power receiving apparatus. Although Patent Document 1 is based on an electromagnetic induction method, such a problem is the same in the magnetic field resonance method.

The present invention solves such problems in the prior art, and in the magnetic field resonance method, even if the magnetic sheet is made thinner than the conventional one, or even if the magnetic sheet is omitted, it is possible to reliably transmit power. together, it is not to occur heat generation and malfunctions in battery or circuit components, and to provide a non-contact power transmission equipment provides low cost and small size and weight.

  In order to solve the above-described problems, a contactless power transmission device according to the present invention includes a power transmission device including a power transmission resonator including a power transmission coil and a resonance capacitor, a power reception resonator including a power reception coil and a resonance capacitor, and a power reception device. A non-contact power transmission device comprising a power receiving device having a circuit and transmitting power from the power transmitting device to the power receiving device by magnetic field resonance between the power transmitting coil and the power receiving coil. Further comprising a power transmission auxiliary device having the power transmission device and the power transmission auxiliary device facing each other to form a power reception space for arranging the power reception coil between the power transmission coil and the auxiliary coil, In the power receiving space, the magnetic field in the region where the power receiving coil is disposed is strengthened, and the magnetic field in the region where the power receiving circuit is disposed is weakened. And sets the resonant frequency of the auxiliary resonator.

  According to the present invention, the intensity distribution of the magnetic field in the power receiving space can be controlled by adjusting the resonance frequency of the auxiliary resonator. As a result, the magnetic field in the region where the power receiving coil in the power receiving device is arranged can be strengthened, and the magnetic field in the region where the power receiving circuit, the rechargeable battery, etc. in the power receiving device are arranged can be weakened. As a result, power can be transmitted reliably, energy loss due to eddy current generated in a power receiving circuit or a rechargeable battery can be reduced, and conventional problems such as a decrease in transmission efficiency, heat generation in circuit components and circuit malfunction can be solved. Further, since the thickness of a magnetic sheet such as ferrite provided between the power receiving circuit and the power receiving circuit can be reduced or omitted, the power receiving device can be reduced in cost as compared with the prior art.

Schematic diagram showing the arrangement of each element device for power transmission in the first embodiment The graph which shows the power receiving power dependence with respect to the distance X between the power transmission coil in a coil center position, and a power receiving coil The graph which shows the magnetic field measurement result in the receiving space of FIG. The figure which shows the relationship between arrangement | positioning of each element apparatus for electric power transmission in Embodiment 2, and the magnetic field intensity in a receiving space Schematic diagram in the case where a radio control car is arranged in the housing used in Embodiment 2 to perform power transmission The figure which shows the relationship between arrangement | positioning of each element apparatus for electric power transmission in Embodiment 3, and the magnetic field intensity in a receiving space Schematic diagram in the case where a radio control car is arranged in the housing used in Embodiment 3 to perform power transmission Schematic diagram illustrating the shape of the housing and the direction in which the power receiving device is placed in the housing in Embodiment 4. Schematic diagram showing transmission efficiency when the distance between the power transmission coil and auxiliary coil is changed

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Each embodiment shows an example for embodying the present invention, and the present invention is not limited to this.

<Embodiment 1>
FIG. 1 is a schematic diagram illustrating a configuration of a magnetic field resonance type non-contact power transmission apparatus according to the first embodiment. The contactless power transmission device 20 of the present invention is characterized by including a power transmission auxiliary device 3 in addition to the power transmission device 1 and the power reception device 2.

  The power transmission device 1 includes a power transmission coil 4, an AC power source 5, and a high frequency power driver 6. The high-frequency power driver 6 converts the power of the AC power source 5 into high-frequency power that can be transmitted, and supplies the power transmission coil 4 with the high-frequency power. The high frequency power is transmitted to the power receiving coil 7 of the power receiving device 2 through the power transmitting coil 4.

  The power transmission device 1 may be provided with a power transmission loop coil. Although illustration is omitted, a resonance capacitor is connected to the power transmission coil 4, and the power transmission coil 4 and the resonance capacitor constitute a power transmission resonator. As the resonance capacitance, a variable capacitor (variable capacitor or trimmer capacitor) or a fixed capacitor may be connected, or a configuration using a stray capacitance may be used.

  The power receiving device 2 includes a power receiving coil 7 and a power receiving loop coil 8. The high frequency power transmitted from the power transmission coil 4 to the power reception coil 7 is transmitted to the power reception loop coil 8 by the action of electromagnetic induction. The electric power obtained by the power receiving loop coil 8 is stored in a load rechargeable battery 10 via a power receiving circuit 9 equipped with a rectifier circuit. In addition, although the example which accumulate | stored electric power in the rechargeable battery 10 is shown in the power receiving apparatus 2 of FIG. 1, you may make it the structure which transmits electric power directly to load without using the rechargeable battery 10. FIG. In some cases, the power receiving loop coil 8 may not be used.

  When a small battery such as a coin battery is used as the rechargeable battery 10, the magnetic sheet 11 may be disposed between the power receiving loop coil 8 and the power receiving circuit 9. The material of the magnetic sheet 11 is preferably ferrite having high permeability at the resonance frequency during transmission.

  The power transmission auxiliary device 3 includes an auxiliary resonator including an auxiliary coil 12 and an adjustment capacitor 13. The adjusting capacitor 13 may be configured by connecting a plurality of variable capacitors (variable capacitors or trimmer capacitors) or fixed capacitors. However, the method of adjusting the resonance frequency of the auxiliary resonator is not limited to the method of adjusting the capacitance of the adjustment capacitor 13.

  Next, the function of the power transmission auxiliary device 3 that is a feature of the present embodiment will be described. FIG. 9 is a diagram schematically showing the frequency dependence of the power transmission efficiency. When the distance between the power transmission coil 4 and the auxiliary coil 12 is sufficiently large, the mutual inductance between the power transmission resonator and the auxiliary resonator can be almost ignored (the coupling force is weak). In this case, as shown in FIG. 9A, the resonance frequency ft of the power transmission side resonance system has a single peak characteristic having the same peak as the resonance frequency f1 of the power transmission device 1 (loosely coupled state). The transmission-side resonance system is a resonance system configured by magnetic coupling of a power transmission resonator that is configured by the power transmission coil 4 and the resonant capacitor, and an auxiliary resonator that is configured by the auxiliary coil 12 and the resonant capacitor. . On the other hand, when the distance between the power transmission coil 4 and the auxiliary coil 12 is short, the mutual inductance between the power transmission resonator and the auxiliary resonator cannot be ignored (the coupling force is strong). In this case, as shown in FIG. 9B, the resonance frequency ft of the transmission-side resonance system has a bimodal characteristic having two peaks (ftL and ftH) (tightly coupled state).

  As described above, when the distance between the power transmission coil and the power reception coil is short and the frequency characteristic of the power transmission efficiency is a bimodal characteristic, the frequency at which the maximum transmission efficiency is obtained is not the resonance frequency ft. Since the transmission efficiency at the frequency ft in the bimodal characteristics changes depending on the distance between the power transmission coil and the power reception coil, there is a problem that high-efficiency power transmission cannot be performed if the frequency of the high-frequency power in the power transmission device remains constant. .

  In the present invention, an adjustment capacitor 13 having a variable capacity is used as a capacitor connected to the auxiliary coil 12, and the resonance frequency f3 of the power transmission auxiliary device 3 is changed by adjusting the capacity of the adjustment capacitor 13, thereby transmitting the transmission side. The resonance frequency ft of the resonance system can be changed. As a result, the strength of the magnetic field in the power receiving space formed by the power transmission coil 4 and the auxiliary coil 12 can be controlled. Note that a specific function of the power transmission auxiliary device 3 and a method for adjusting the resonance frequency and the like are described in Japanese Patent Application Laid-Open No. 2013-85436 filed earlier.

  In order to sufficiently obtain the function of controlling the magnetic field strength in the power receiving space by the power transmission auxiliary device 3, the auxiliary coil 12 constituting the power transmission auxiliary device 3 is substantially the same as the shape of the power transmission coil 4, and the central axis of both coils Also, it is desirable to arrange them almost coaxially.

  If the power transmission auxiliary device 3 is used, the transmission distance of power can be increased. For this purpose, when the diameter of the power transmission coil 4 is d1, the diameter of the power reception coil 7 is d2, and the diameter of the auxiliary coil 12 is d3, the relationship of d1> d2 and d2 <d3 may be satisfied. If the diameter d1 of the power transmission coil 4 is larger than the diameter d2 of the power receiving coil 7, the magnetic flux between the auxiliary coil 12 can be used effectively, and the diameter d3 of the auxiliary coil 12 is equal to the diameter d2 of the power receiving coil 7. This is because the magnetic flux between the power transmission coil 4 can be used as long as it is larger.

  FIG. 2 shows the relationship between the distance X from the power transmission coil 4 to the power reception coil 7 and the output power of the rectifier circuit in the power reception circuit 9 by actually performing power transmission using the non-contact power transmission device of FIG. It is a graph of the result. Note that the output power of the rectifier circuit corresponds to the received power. Here, the resonance frequency in each resonator is the same as f1 of the power transmission device 1, f2 of the power reception device 2, and the resonance frequency f0 of the high-frequency power driver 6, all at 13.6 MHz. The distance Z between the power transmission coil 4 and the auxiliary coil 12 was 50 mm. In order to examine a change in the received power according to the position of the power receiving coil 7, the power receiving coil 7 was moved in the distance Z direction within the power receiving space formed by the power transmitting coil 4 and the power transmission auxiliary coil 12. At this time, the distance from the power transmission coil 4 to the power reception coil 7 was set to X. Then, by changing the capacitance of the adjustment capacitor 13 connected to the auxiliary coil 12, the resonance frequency f3 of the power transmission auxiliary device 3 is set to 12 MHz, 13 MHz, 13.6 MHz, 14 MHz, and 15 MHz, respectively. The relationship between the distance X and the received power was measured.

  As shown in FIG. 2, when the resonance frequency f3 of the power transmission auxiliary device 3 is 12 MHz, it can be seen that the received power is almost zero in the region where the distance X = 35 mm or more. This is because the mutual inductance between the power transmission resonator and the auxiliary resonator is almost negligible, and the resonance frequency f1 of the power transmission device 1 is the resonance frequency ft of the power transmission side resonance system.

  When the resonance frequency f3 of the power transmission auxiliary device 3 is 13 MHz and is increased by 1 MHz, the mutual inductance between the power transmission resonator and the auxiliary resonator increases, and the received power becomes the lowest in the vicinity of the distance X = about 30 mm.

  When the resonance frequency f3 of the power transmission auxiliary device 3 is the same resonance frequency (13.6 MHz) as the resonance frequency f1 of the power transmission device 1, the received power is the smallest and the distance X is large in the region where the distance X close to the power transmission coil 4 is small. As the power increases, the received power increases and becomes the largest in the region close to the auxiliary coil 12.

  When the resonance frequency f3 of the power transmission auxiliary device 3 is 14 MHz, high power reception power can be obtained regardless of the position in the power reception space where the power reception coil 7 is formed by the power transmission coil 4 and the power transmission auxiliary coil 12. That is, when the distance Z between the power transmission coil 4 and the auxiliary coil 12 is constant, stable power reception can be achieved even if the position of the power reception coil 4 in the power reception space is changed by setting the resonance frequency f3 of the power transmission auxiliary device to an appropriate value. You can get power.

  It can be seen that when the resonance frequency f3 of the power transmission auxiliary device 3 is 15 MHz, the received power decreases as the distance X increases. This is considered because the mutual inductance of the power transmission resonator and the auxiliary resonator is reduced.

  Thus, it can be seen that by appropriately setting the resonance frequency f3 of the power transmission auxiliary device 3, it is possible to control the received power according to the position of the power receiving coil 4 in the power receiving space.

  FIG. 3 is a graph showing the relationship between the distance X from the power transmission coil 4 to the power reception coil 7 and the magnetic field strength in the power reception space by actually performing power transmission using the non-contact power transmission device of FIG. .

  The voltage value of the probe used for measuring the magnetic field strength was defined as the magnetic field strength. The resonance frequency f3 of the power transmission auxiliary device 3 was set to 12 MHz, 13 MHz, 13.6 MHz, 14 MHz, and 15 MHz, respectively, as in FIG. Comparing FIG. 2 and FIG. 3, it can be seen that the result of FIG. 3 shows almost the same tendency as the result of FIG. That is, it can be said that the magnitude of the received power is determined by the magnitude of the magnetic field strength at that position. In this way, by changing the resonance frequency f3 of the power transmission auxiliary device 3, the distribution of the magnetic field strength in the power receiving space can be controlled.

  The present invention finds that the distribution of the magnetic field strength in the receiving space can be controlled by using the power transmission auxiliary device, and weakens the magnetic field in a region where a power receiving circuit or a rechargeable battery that is easily affected by the magnetic field is disposed, thereby transmitting power. It is characterized in that the resonance frequency f3 of the power transmission auxiliary device 3 is set so that the magnetic field becomes stronger in the region where the power receiving coil for which efficiency is desired to be increased is arranged.

  The present invention is effective when the distance between the power transmission coil and the power reception coil is short and the mutual inductance cannot be ignored, and the frequency characteristic of the power transmission efficiency is a bimodal characteristic having two peaks (tightly coupled state). The frequency of the high frequency power output from the high frequency power driver 6 mounted on the power transmission device 1 is f0, the resonance frequency of the power transmission resonator is f1, the resonance frequency of the power reception resonator is f2, and the resonance frequency of the auxiliary resonator is f3. Then, if the condition of f3 ≦ f1 is satisfied, a region having a weak magnetic field can be created in the power receiving space (in FIG. 3, for example, f3 is between 12 MHz and 13.6 MHz). For example, a region having a weak magnetic field can be formed on the power transmission coil side, or a region having a weak magnetic field can be formed on the auxiliary coil side. In particular, it is preferable to satisfy the condition of f0 = f1 = f2 ≧ f3 because the transmission efficiency is increased.

  In this embodiment, the resonance frequency is in the MHz band, but the same effect can be obtained even in the KHz band (for example, f1 is 100 kHz).

  Although not shown, communication means, a circuit, and the like between the power transmission device 1, the power reception device 2, and the power transmission auxiliary device 3 are provided. Moreover, a means for monitoring the reflected power, resonance frequency, current value, voltage value, etc. of the power transmission coil 4 may be included as necessary.

<Embodiment 2>
FIG. 4 is a diagram illustrating a correspondence relationship between the configuration of the magnetic field resonance type non-contact power transmission apparatus according to the second embodiment and the magnetic field strength distribution in the power receiving space. The distance Z between the power transmission coil 4 and the auxiliary coil 12 was 50 mm.

  As shown in FIG. 4, in the power receiving device 2 according to the second embodiment, the power receiving coil 7 is disposed at a position close to the power transmitting coil 4, and the power receiving circuit 9 and the rechargeable battery 10 are substantially between the power transmitting coil 4 and the auxiliary coil 12. Placed in position. The frequency of the high frequency power output from the high frequency power driver 6 mounted on the power transmission device 1 is f0, the resonance frequency of the power transmission resonator is f1, the resonance frequency of the power reception resonator is f2, and the resonance frequency of the auxiliary resonator is f3. Then, f0 = f1 = f2 = 13.6 MHz and f3 = 13 MHz were set, respectively.

  As shown in the graph of the magnetic field strength distribution in FIG. 4, while strengthening the magnetic field in the region where the power receiving coil 7 is disposed (high magnetic field region A), the region in which the power receiving circuit 9 and the charging ground 10 are disposed. The magnetic field can be weakened (low magnetic field region A). Since the magnetic field in the region where the power receiving coil 7 is disposed is strong, power transmission can be reliably performed. In addition, since the magnetic field in the region where the power receiving circuit 9 and the charging ground 10 are arranged is weak, energy loss due to eddy current generated in the power receiving circuit 9 and the rechargeable battery 10 hardly occurs. As a result, conventional problems such as a decrease in transmission efficiency, heat generation in the power receiving circuit 9, and malfunction can be solved. Furthermore, since the magnetic field in the region where the power receiving circuit 9 and the charging ground 10 are disposed is weak, there is no problem even if the thickness of the magnetic sheet 11 provided between the power receiving coil 7 and the power receiving circuit 9 is reduced. Thereby, size reduction and cost reduction of the power receiving apparatus 2 are realizable.

  5, the non-contact power in which the power receiving coil 7 is disposed at a position close to the power transmitting coil 4 and the power receiving circuit 9 and the rechargeable battery 10 are disposed at an intermediate position between the power transmitting coil 4 and the auxiliary coil 12 as illustrated in FIG. A specific example of a transmission apparatus is shown. The case where the power receiving apparatus 2 is a radio control car is illustrated.

  The casing 14 holds the power transmission device 1 and the power transmission auxiliary device 3 so as to face each other so that a power reception space is formed. The housing 14 includes an openable / closable lid 15 at the top, and the power receiving device 2 can be inserted into and removed from the power receiving space from the top of the housing 14. A shield material (Cu plate) is provided inside the casing 14 and the lid 15. Power transmission from the power transmission coil 4 to the power reception coil 7 is performed in a state where the power transmission coil 4, the auxiliary coil 12, and the power reception coil 7 are electromagnetically shielded. Therefore, power transmission is started by closing the lid 15 in a state where the power receiving coil 7 is arranged in the power receiving space. If the lid 15 is opened during power transmission, the power transmission is stopped.

In addition, although the magnetic sheet 11 is provided between the receiving coil 7, the receiving circuit 9, and the charging place 10, since the magnetic field intensity of the area | region where the receiving circuit 9 and the charging place 10 is arrange | positioned is weak, the conventional magnetic sheet Thinner than. The power receiving circuit 9 and the charging ground 10 may be disposed at opposite positions.
<Embodiment 3>
FIG. 6 is a diagram illustrating a correspondence relationship between the configuration of the magnetic field resonance type non-contact power transmission apparatus according to the third embodiment and the magnetic field strength distribution in the power receiving space. The distance Z between the power transmission coil 4 and the auxiliary coil 12 was 50 mm.

  As shown in FIG. 6, in the power receiving device 2 according to the third embodiment, the power receiving coil 7 is disposed near the auxiliary coil 12, and the power receiving circuit 9 and the rechargeable battery 10 are disposed near the power transmitting coil 4. Yes. The frequency of the high frequency power output from the high frequency power driver 6 mounted on the power transmission device 1 is f0, the resonance frequency of the power transmission resonator is f1, the resonance frequency of the power reception resonator is f2, and the resonance frequency of the auxiliary resonator is f3. Then, f0 = f1 = f2 = f3 = 13.6 MHz was set.

  As shown in the graph of the magnetic field strength distribution in FIG. 6, while strengthening the magnetic field in the region where the power receiving coil 7 is disposed (high magnetic field region B), the region where the power receiving circuit 9 and the charging ground 10 are disposed. The magnetic field can be weakened (low magnetic field region B).

  The value of the resonance frequency f3 of the auxiliary resonator is different between FIG. 4 of the second embodiment and FIG. 6 of the third embodiment. As described above, if the resonance frequency f3 of the power transmission auxiliary device 3 is appropriately set, the magnetic field is weakened in the region where the power receiving circuit or the rechargeable battery that is easily affected by the set magnetic field is disposed, and the power transmission efficiency is increased. The magnetic field can be increased in the region where the power receiving coil is arranged.

  In the case shown in FIG. 6, the distance between the power receiving coil 7, the power receiving circuit 9, and the charging ground 10 is far away from that of the conventional case, and the magnetic field strength in the region where the power receiving circuit 9 and the charging ground 10 are further arranged. Is also weak. That is, if f3 = f1, the distance between the strong magnetic field region and the weak magnetic field region can be increased. Therefore, there is an advantage that the conventionally used magnetic sheet can be omitted, and the cost of the power receiving device 2 can be reduced.

  FIG. 7 shows a specific example of the non-contact power transmission apparatus in which the power receiving coil 7 is disposed near the auxiliary coil 12 and the power receiving circuit 9 and the rechargeable battery 10 are disposed near the power transmitting coil 4 as shown in FIG. Is shown. The other configuration is the same as that shown in FIG.

Since the power receiving device 2 is inserted into and removed from the power receiving space from the upper portion of the housing 14 via the housing lid 15, for example, a foreign material 16 such as metal may fall near the power transmission coil 4. However, in the case of FIG. 7, since the magnetic field closer to the power transmission coil 4 is set weak, there is an advantage that the possibility of heat generation by the foreign material 16 such as metal is reduced.
<Embodiment 4>
FIGS. 8A to 8D show an example of a method for putting the power receiving device 2 in and out of the housing 14 of the non-contact power transmission device according to the present invention. FIG. 8A is the same as FIG. 5 and FIG. 7 and shows the case where the lid 15 at the top of the housing 14 opens and closes. In FIG. 8B, the upper portion of the housing 14 is a shutter 17, and the shutter 17 is opened and closed when the power receiving device 2 is inserted into and removed from the power receiving space. In this case, the auxiliary coil 12 is an air-core coil type having no coil near the center, and is fixed to the upper portion of the housing 14. In FIG. 8C, there is a lid 15 on the side of the housing 14, and the lid 15 is opened and closed when the power receiving apparatus 2 is inserted into and removed from the power receiving space. In FIG. 8D, there is a shutter 17 on the side of the housing 14, and the shutter 17 is opened and closed when the power receiving device 2 is inserted into and removed from the power receiving space. By closing the lid 15 and the shutter 17, the inside of the casing 14 is electromagnetically shielded.

  8A to 8D, when the power receiving device 2 is inserted into the housing 14, positional information of the power receiving coil 7, the power receiving circuit 9, and the rechargeable battery 10 in the power receiving device 2 is obtained. The power receiving device 2 has a function of sending to the power transmission auxiliary device 3 and setting the resonance frequency of the power transmission auxiliary device 3 based on the information. Specifically, the adjustment is performed by adjusting the capacitance of the adjustment capacitor 13 connected to the auxiliary coil 12. As a result, the magnetic field in the region where the power receiving coil disposed in the power receiving device 2 is arranged is strengthened, and the magnetic field in the region where the rechargeable battery, the power receiving circuit, etc. is arranged is weakened, thereby reliably transmitting power. Can be done. That is, the strength of the magnetic field can be accurately controlled according to the positions of the power receiving coil 7, the power receiving circuit 9, and the rechargeable battery 10.

  Since the non-contact power transmission device of the present invention can control the strength of the magnetic field in the power receiving area, the invention is not limited to a radio control car, but an aircraft that requires weight reduction, and an electric vehicle such as an actual automobile, bus, or train. Etc. are also possible.

DESCRIPTION OF SYMBOLS 1 Power transmission device 2 Power reception device 3 Power transmission auxiliary device 4 Power transmission coil 5 AC power supply 6 High frequency power driver 7 Power reception coil 8 Power reception loop coil 9 Power reception circuit 10 Rechargeable battery 11 Magnetic sheet 12 Auxiliary coil 13 Adjustment capacitor 14 Housing 15 Cover 16 Metal Foreign object 17 Shutter 20 Non-contact power transmission device

Claims (8)

A power transmission device having a power transmission resonator composed of a power transmission coil and a resonance capacitor, a power reception device composed of a power reception coil and a resonance capacitor, and a power reception device having a power reception circuit, and a magnetic field between the power transmission coil and the power reception coil In a non-contact power transmission device that transmits power from a power transmission device to a power reception device by resonance,
A power transmission auxiliary device having an auxiliary resonator composed of an auxiliary coil and a resonant capacitor;
By arranging the power transmission device and the power transmission auxiliary device so as to face each other, a power reception space for arranging the power reception coil between the power transmission coil and the auxiliary coil is formed,
In the power receiving space, the resonance frequency of the auxiliary resonator is set so that the magnetic field in the region where the power receiving circuit is disposed is weaker than the magnetic field in the region where the power receiving coil is disposed. Non-contact power transmission device.   The non-contact power transmission apparatus according to claim 1, wherein a variable capacitor is provided as a resonance capacity of the power transmission auxiliary device, and the resonance frequency of the auxiliary resonator is set by adjusting a capacity of the variable capacitor.   After the position information of the power receiving coil and the power receiving circuit in the power receiving device is transmitted from the power receiving device to the power transmission auxiliary device, and the resonance frequency of the power transmission auxiliary device is set based on the position information, the power transmission device The non-contact power transmission apparatus according to claim 1, wherein power transmission is started from the power to the power receiving apparatus.   2. The resonance frequency f3 of the auxiliary resonator is set to satisfy f3 ≦ f1, where f1 is a resonance frequency of the power transmission resonator and f3 is a resonance frequency of the auxiliary resonator. Non-contact power transmission device. A housing for holding the power transmission auxiliary device and the power transmission device facing each other so that the power reception space for arranging the power reception coil is formed;
The housing includes an openable / closable lid or shutter,
The power receiving device can be inserted into and removed from the power receiving space in the housing through the lid or the shutter.
When power is transmitted from the power transmission coil to the power reception coil, the power transmission coil, the auxiliary coil, and the power reception coil are shielded electromagnetically with the lid or the shutter closed. The contactless power transmission device according to claim 1.   The power transmission coil is disposed below the housing, the auxiliary coil is disposed above the housing, and the resonance frequency of the auxiliary resonator is adjusted so that the magnetic field on the power transmission coil side rather than the auxiliary coil side. The non-contact power transmission device according to claim 5, wherein the strength of the non-contact power transmission device is weakened.   6. The resonance frequency f3 of the auxiliary resonator is set so as to satisfy f3 = f1, where f1 is a resonance frequency of the power transmission resonator and f3 is a resonance frequency of the auxiliary resonator. Non-contact power transmission device. The contactless power transmission device according to claim 5, wherein power transmission is performed in a state where the power reception circuit is disposed between the power transmission coil and the power reception coil .

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