Noncontact power feed system, noncontact relay apparatus, noncontract power reception apparatus, and noncontact power feed method

A noncontact power feed system includes: a noncontact power feed apparatus including a power feed resonance device to supply alternate-current power to an electronic apparatus by resonance in a noncontact manner, and an alternate-current power source section to generate the alternate-current power and supply it to the power feed resonance device; a noncontact relay apparatus including a relay resonance device to receive the alternate-current power and relay it to another electronic apparatus by resonance in a noncontact manner, a relay-side rectifier circuit to form direct-current power for output, and a movement means for moving the noncontact relay apparatus by the direct-current power; and at least one noncontact power reception apparatus including a power reception resonance device to receive the alternate-current power by magnetic field resonance in a noncontact manner, a power-reception-side rectifier circuit to form direct-current power for output, and a load means driven by the direct-current power.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a noncontact power feed system that feeds power by using resonance phenomena such as magnetic field resonance and electric field rescnance, an apparatus used in the system, and a noncontact power feed method used for the system and the apparatus.

2. Description of the Related Art

As techniques of enabling electric energy to be transmitted in a noncontact manner, there are an electromagnetic induction system and a magnetic field resonance system. The electromagnetic induction system and the magnetic field resonance system are different from each other in various points as described below, and in recent years, an energy transmission using the magnetic field resonance system has attracted attention.

FIG. 11is a block diagram showing a structural example of a magnetic-field-resonance-type noncontact power feed system in which a power feed source and a power feed destination have a one-to-one relationship. The magnetic-field-resonance-type noncontact power feed system shown inFIG. 11includes a power feed source100and a power feed destination200.

As shown inFIG. 11, the power feed source100such as a charging base includes an AC power source101, an excitation device (coupling device)102, and a resonance device103. Further, the power feed destination200such as a cellular phone terminal includes a resonance device201, an excitation device (coupling device)202, and a rectifier circuit203.

The excitation device102and the resonance device103of the power feed source100, and the resonance device201and the excitation device202of the power feed destination200are each constituted of an air-cored coil. Inside the power feed source100, the excitation device102and the resonance device103are strongly coupled to each other by electromagnetic induction. Similarly, inside the power feed destination200, the resonance device201and the excitation device202are strongly coupled to each other by electromagnetic induction.

When a self-resonant frequency of the resonance device (air-cored coil)103of the power feed source100coincides with that of the resonance device (air-cored coil)201of the power feed destination200, a magnetic field resonance relationship is obtained, in which a coupling amount becomes a maximum and a loss becomes a minimum.

Specifically, in the noncontact power feed system shown inFIG. 11, AC power (energy such as alternating current) having a predetermined frequency from the AC power source101is first supplied to the excitation device102, which induces AC power in the resonance device103by electromagnetic induction in the power feed source100. In this case, a frequency of the AC power that is generated in the AC power source101is set to be the same as the self-resonant frequencies of the resonance device103of the power feed source100and the resonance device201of the power feed destination200.

As described above, the resonance device103of the power feed source100and the resonance device201of the power feed destination200are provided in the magnetic field resonance relationship. Therefore, the AC power (energy such as alternating current) is supplied from the resonance device103to the resonance device201in a noncontact manner at the self-resonant frequency.

In the power feed destination200, the AC power supplied from the resonance device103of the power feed source100is received by the resonance device201. The AC power from the resonance device201is supplied to the rectifier circuit203via the excitation device202by electromagnetic induction, and converted into DC power and output from the rectifier circuit203.

Thus, the AC power is supplied from the power feed source100to the power feed destination200in a noncontact manner. It should be noted that the DC power output from the rectifier circuit203is supplied to a charging circuit connected with a battery, and used for charging the battery.

In the noncontact power feed system in which the power feed source100and the power feed destination200that are structured as shown inFIG. 11have a one-to-one correspondence, the following features are found.

The noncontact power feed system has a relationship as shown inFIG. 12A, between a frequency of an AC power source and a coupling amount. As is found fromFIG. 12A, the coupling amount is not increased even when the frequency of the AC power source is low or high, but the coupling amount becomes a maximum only at a specific frequency at which a magnetic field resonance phenomenon is caused. In other words, frequency selectivity is shown by magnetic field resonance.

Moreover, the noncontact power feed system has a relationship as shown inFIG. 12B, between a distance from the resonance device103to the resonance device201, and a coupling amount. As is found fromFIG. 12B, the coupling amount is smaller as the distance between the resonance devices is larger.

However, a shorter distance between the resonance devices does not increase the coupling mount, and a distance at which the coupling mount becomes a maximum exists at a certain frequency. Further, it is found fromFIG. 12Bthat if the distance between the resonance devices has a certain range, a coupling mount above a certain level can be ensured.

In addition, the noncontact power feed system has a relationship as shown inFIG. 12C, between a resonant frequency and a distance between the resonance devices at which a maximum coupling mount is obtained. Specifically, it is found that when the resonant frequency is low, the distance between the resonance devices is large. Further, it is found that when the resonant frequency is high, a maximum coupling mount is obtained by narrowing the interval between the resonance devices.

In an electromagnetic-induction-type noncontact power feed system that has been widely used in recent years, it is necessary to share a magnetic flux between a power feed source and a power feed destination and to arrange the power feed source and the power feed destination very close to each other in order to efficiently transmit power, in which alignment of coupling axes is also important.

On the other hand, in the noncontact power feed system using the magnetic field resonance phenomenon, it is possible to transmit power with the resonance devices being more away from each other than in the electromagnetic induction system by the principle of the magnetic field resonance phenomenon, as described above. In addition, this noncontact power feed system has an advantage that transmission efficiency is not decreased so much even if the alignment of axes is not favorable.

In summary, as shown inFIG. 13, there are differences between the magnetic-field-resonance-type noncontact power feed system and the electromagnetic-induction-type noncontact power feed system. As shown inFIG. 13, the magnetic-field-resonance-type noncontact power feed system has an advantage in a deviation between transmission/reception coils (resonance devices), with the result that a transmission distance can be made longer.

Accordingly, in the case of the magnetic-field-resonance-type noncontact power feed system, it is possible to charge a plurality of power feed destinations (cellular phone terminals) by placing them on one power feed source (charging base) as shown inFIG. 14.

It should be noted that US Patent Application No. 2007/0222542 discloses a technique regarding a power transmission system using the magnetic field resonance system as described above.

SUMMARY OF THE INVENTION

Incidentally, in a case of a magnetic-field-resonance-type power supply technique, for example, a transmission distance is longer and a deviation between transmission/reception coils causes less influence than in an electromagnetic-induction-type power supply technique that has been used from the past, as described above. In addition, the magnetic-field-resonance-type power supply technique allows a repeater to intervene and accordingly has high flexibility.

Therefore, in the case of the magnetic-field-resonance-type power supply technique, it is highly possible to enable new power-supply mode and a new power-use mode in the new power-supply mode to be created, not merely to supply power from a power feed source to a power feed destination. This applies to not only the magnetic-field-resonance-type noncontact power feed system but also a noncontact power feed system of another resonance type other than an electromagnetic resonance type, for example.

In view of the points described above, it is desirable to provide a new power-supply mode that uses a resonance-type power supply technique, and a new power-use mode in the new power-supply mode.

According to an embodiment of the present invention, there is provided a noncontact power feed system including: a noncontact power feed apparatus including a power feed resonance device to supply alternate-current power to an electronic apparatus by resonance in a noncontact manner, and an alternate-current power source section to generate the alternate-current power having a frequency corresponding to a resonant frequency of the power feed resonance device and supply the alternate-current power to the power feed resonance device; a noncontact relay apparatus including a relay resonance device to receive supply of the alternate-current power from the power feed resonance device of the noncontact power feed apparatus by resonance in a noncontact manner and relay the alternate-current power to another electronic apparatus by resonance in a noncontact manner, a relay-side rectifier circuit to form direct-current power based on the alternate-current power supplied from the relay resonance device and output the direct-current power, and a movement means for moving the noncontact relay apparatus by being driven by the direct-current power from the relay-side rectifier circuit; and at least one noncontact power reception apparatus including a power reception resonance device to receive supply of the alternate-current power from the relay resonance device of the noncontact relay apparatus by magnetic field resonance in a noncontact manner, a power-reception-side rectifier circuit to form direct-current power based on the alternate-current power supplied from the power reception resonance device and output the direct-current power, and a load means driven by the direct-current power from the power-reception-side rectifier circuit.

By the noncontact power feed system according to the embodiment of the present invention, in the noncontact power feed apparatus, the alternate-current power from the alternate-current power source is transmitted via the power feed resonance device in the noncontact manner.

In the noncontact relay apparatus, the alternate-current power from the noncontact power feed apparatus is received via the relay resonance device and supplied to the movement means via the relay-side rectifier circuit, with the result that the noncontact relay apparatus is moved. Simultaneously, the alternate-current power received via the relay resonance device is transmitted to another electronic apparatus (noncontact power reception apparatus) via the relay resonance device.

Specifically, the noncontact relay apparatus has a function of relaying the alternate-current power from the noncontact power feed apparatus to another electronic apparatus (noncontact power reception apparatus) while moving by the alternate-current power from the noncontact power feed apparatus.

Further, in the at least one noncontact power reception apparatus, the alternate-current power from the movable noncontact relay apparatus is received via the power reception resonance device and supplied to a load circuit via the power-reception-side rectifier circuit, with the result that the load circuit is driven.

With this structure, the alternate-current power (energy such as alternating current) from the noncontact power feed apparatus can be supplied to the noncontact relay apparatus in the noncontact manner and can move the noncontact relay apparatus. Then, the alternate-current power (energy such as alternating current) can be relayed and supplied to the at least one noncontact power reception apparatus via the movable noncontact relay apparatus.

As described above, it is possible to supply the alternate-current power to the at least one noncontact power reception apparatus as a target via the movable noncontact relay apparatus, and operate the load means in the at least one noncontact power reception apparatus.

Accordingly, it is possible to drive the load means in the at least one noncontact power reception apparatus by supplying power to the at least one noncontact power reception apparatus not only in the noncontact manner but also using the moving noncontact relay apparatus as a relay.

Specifically, through the mediation of a moving noncontact power reception/relay apparatus, it is possible to provide a new power-supply mode that uses a power supply technique of a so-called resonance type such as a magnetic field resonance type and a new power-use mode in the new power-supply mode.

According to the embodiment of the present invention, it is possible to realize a new power-supply mode that uses a resonance-type power supply technique and a new power-use mode in the new power-supply mode.

DESCRIPTION OF PREFERRED EMBODIMENTS

Hereinafter, embodiments of an apparatus and a method according to the present invention will be described with reference to the drawings. Though the present invention is applicable to various resonance systems such as a magnetic field resonance system, an electric field resonance system, and an electromagnetic resonance system, an example in which the magnetic field resonance system is used will be described below.

(Outline of Noncontact Power Feed System of First Embodiment)

FIG. 1is a diagram for explaining a structural example of a magnetic-field-resonance-type noncontact power feed system according to a first embodiment of the present invention. As shown inFIG. 1, the noncontact power feed system of this embodiment includes a power feed source1, a moving body2, and a power feed destination3. It should be noted that a plurality of power feed destinations that are similarly structured can be used, which will be described later in detail.

The power feed source1uses a magnetic field resonance system to supply power to another electronic apparatus in a noncontact manner, thus realizing a function as a noncontact power feed apparatus.

The moving body2receives power from the power feed source1and has a function as a relay apparatus that supplies the power to another electronic apparatus and a function of using the power to drive a drive motor thereof, thus realizing a function as a noncontact relay apparatus.

The power feed destination3receives supply of power from the power feed source1via the moving body2and uses the power to drive a load circuit thereof, thus realizing a function as a noncontact power reception apparatus in this embodiment.

As shown inFIG. 1, the power feed source1includes an AC power source11, a coupling coil (coupling device (excitation device))12, and a transmission resonance coil (resonance device)13.

As shown inFIG. 1, the moving body2includes a relay resonance coil (resonance device)21that receives power (AC power) from the power feed source1and transmits the power to the power feed destination3. It should be noted that though not shown inFIG. 1, the moving body2includes a coupling coil (coupling device (excitation device)), a rectifier circuit, a drive motor, and the like and also has a structure in which part of the power supplied from the power feed source1is used for driving a drive motor thereof.

As shown inFIG. 1, the power feed destination3includes a reception resonance coil (resonance device)31, a coupling coil (coupling device (excitation device))32, a rectifier circuit33, and a load circuit34. It should be noted that the load circuit34of the power feed destination3is constituted of an LED (Light Emitting Diode), an LED driver, and the like.

The coupling coil12and the transmission resonance coil13of the power feed source1, the relay resonance coil21and the not-shown coupling coil of the moving body2, and the reception resonance coil31and the coupling coil32of the power feed destination3each have a structure of an air-cored coil.

The AC power source11of the power feed source1generates AC power (energy such as alternating current) having a frequency that is the same or substantially the same as a self-resonant frequency of the transmission resonance coil13of the power feed source1, and supplies it to the excitation device12.

It should be noted that each of the relay resonance coil21of the moving body2and the reception resonance coil31of the power feed destination3also has a self-resonant frequency that is the same or substantially the same as that of the transmission resonance coil13of the power feed source1.

In other words, in the magnetic-field-resonance-type noncontact power feed system shown inFIG. 1, the transmission resonance coil13of the power feed source1, the relay resonance coil21of the moving body2, and the reception resonance coil31of the power feed destination3each have the same or substantially the same resonant frequency.

Further, in order to generate AC power having a target frequency, the AC power source11of the power feed source1includes a Colpitts oscillator or a Hartley oscillator, for example.

The coupling coil12is a device that supplies AC power to the transmission resonance coil13by being oscillated by the AC power from the AC power source11. The coupling coil12that receives supply of the AC power from the AC power source11and the transmission resonance coil13are strongly coupled to each other by electromagnetic induction. Accordingly, the AC power from the AC power source11is supplied to the transmission resonance coil13via the coupling coil12.

It should be noted that the coupling coil12also plays a role in preventing reflection of an electric signal by matching impedance of the AC power source11to that of the transmission resonance coil13. That is, in the magnetic-field-resonance-type noncontact power feed system, an unmodulated sine wave having a center frequency of f0is normally used. Since the unmodulated sine wave is unmodulated, an occupied frequency band is narrow (0 Hz is ideal).

Accordingly, a frequency band necessary for a resonance coil that transmits the unmodulated sine wave may also be narrow, e.g., several Hz, but in order to improve transmission efficiency, a low loss (high “Q” factor) is needed. It should be noted that here, the value “Q” represents a sharpness of a resonant peak of a resonator circuit. If a resonant peak becomes sharp, the transmission efficiency of power (AC power) can be improved.

In other words, in order to obtain high transmission efficiency in a magnetic-field-resonance-type noncontact power transmission, it is desirable to obtain as high Q factor as possible in the transmission resonance coil13of the power feed source1or the reception resonance coil31of the power feed destination3.

However, when the transmission resonance coil13is directly connected to the AC power source11in the power feed source1or the reception resonance coil31is directly connected to the rectifier circuit33in the power feed destination3, a Q factor of the transmission resonance coil13or reception resonance coil31is lowered due to the influence of circuit impedance.

To avoid the above situation, direct connection of the transmission resonance coil13to the AC power source11is avoided in the power feed source1by using the coupling coil12, with the result that impedance of the transmission resonance coil13is kept high and a Q factor thereof is also kept high.

Moreover, the transmission resonance coil13is a coil that generates a magnetic field by the AC power supplied from the coupling coil12. The transmission resonance coil13has inductance and capacitance. The transmission resonance coil13has a maximum strength of the magnetic field at a resonant frequency.

FIG. 10is a diagram showing an expression used for calculating a resonant frequency fr of the transmission resonance coil13. In Expression (1) shown inFIG. 10, a letter L represents inductance of the transmission resonance coil13and a letter C represents capacitance thereof.

Accordingly, a resonant frequency of the transmission resonance coil13is determined by inductance L and capacitance C of the transmission resonance coil13. As described above, since the transmission resonance coil13is constituted of an air-cored coil, line-to-line capacitance of the transmission resonance coil13serves as capacitance. Then, the transmission resonance coil13generates a magnetic field in an axial direction of the coil.

The relay resonance coil21of the moving body2is a device for receiving supply of the AC power from the power feed source1by magnetic field coupling due to magnetic field resonance. The relay resonance coil21of the moving body2has inductance L and capacitance C as in the case of those of the transmission resonance coil13of the power feed source1that are described using Expression (1) ofFIG. 10, and has a resonant frequency that is the same or substantially the same as that of the transmission resonance coil13of the power feed source1.

As described above, since the relay resonance coil21of the moving body2has a structure of an air-cored coil, line-to-line capacitance thereof serves as capacitance. Then, the relay resonance coil21of the moving body2is connected to the transmission resonance coil13of the power feed source1by magnetic field resonance, as shown inFIG. 1.

Accordingly, the AC power (energy such as alternating current) at a resonant frequency is supplied from the transmission resonance coil13of the power feed source1to the relay resonance coil21of the moving body2in a noncontact manner by magnetic field resonance.

The relay resonance coil21of the moving body2is also connected to the reception resonance coil31of the power feed destination3by the magnetic field coupling due to the magnetic field resonance.

Specifically, the reception resonance coil31of the power feed destination3is a device for receiving supply of the AC power from the power feed source1, the AC power being relayed via the moving body2, by the magnetic field coupling due to the magnetic field resonance. The reception resonance coil31of the power feed destination3has inductance L and capacitance C as in the case of those of the transmission resonance coil13of the power feed source1that are described using Expression (1) ofFIG. 10, and has a resonant frequency that is the same or substantially the same as that of the transmission resonance coil13of the power feed source1.

As described above, since the reception resonance coil31of the power feed destination3has a structure of an air-cored coil, line-to-line capacitance thereof serves as capacitance. Then, as shown inFIG. 1, the reception resonance coil31of the power feed destination3is connected to the relay resonance coil21of the moving body2by the magnetic field resonance.

Accordingly, the AC power (energy such as alternating current) at a resonant frequency is supplied from the relay resonance coil21of the moving body2to the reception resonance coil31of the power feed destination3in a noncontact manner by the magnetic field resonance.

Then, as described above, the reception resonance coil31and the coupling coil32are coupled to each other by electromagnetic induction in the power feed destination3, and the AC power is supplied from the reception resonance coil31to the rectifier circuit33via the coupling coil32.

It should be noted that the coupling coil32of the power feed destination3also plays a role in preventing reflection of an electric signal by matching impedance of the reception resonance coil31to that of the rectifier circuit33, as in the case of the coupling coil12of the power feed source1.

Specifically, as in the case of the coupling coil12of the power feed source1, direct connection of the reception resonance coil31to the rectifier circuit33is avoided in the power feed destination3by using the coupling coil32, with the result that impedance of the reception resonance coil31is kept high and a Q factor thereof is also kept high.

The rectifier circuit33forms DC power to be supplied to the load circuit34as a subsequent stage, based on the AC power supplied via the coupling coil32, and then supplies the DC power to the load circuit34. The load circuit34is constituted of an LED, an LED driver, and the like as described above and also to be described later in detail, and receives supply of the AC power to cause the LED to emit light.

It should be noted that though described later in detail, the moving body2also includes a coupling coil, a rectifier circuit, a drive motor as a load circuit, and the like. Accordingly, the moving body2uses the power supplied from the power feed source1to drive a drive motor thereof, as well as relaying the power to the power feed destination3.

(Outer Appearance of Noncontact Power Feed System of First Embodiment)

FIG. 2is a diagram for explaining an outer appearance of the noncontact power feed system according to the first embodiment. In a case of the first embodiment, for example, the moving body (circulating car)2, a circular guide plate5that is formed to guide travel of the moving body2, and the power feed destinations (decorative illumination bodies)3(1) to3(8) are provided on a placement base4having about several tens of centimeters on each side. On a lower side of the placement base4, the power feed source1that supplies power to the moving body2is provided.

A size of the transmission resonance coil13of the power feed source1and a positional relationship between the transmission resonance coil13and the moving body2, or between the transmission resonance coil13and each power feed destination3are set (determined) such that the power feed source1can supply power to only the moving body2.

Further, the moving body2receives supply of power from the power feed source1and uses the power to drive a drive motor thereof, thus moving the moving body2. Then, the moving body2relays the power supplied from the power feed source1to, out of the power feed destinations3(1) to3(8), a power feed destination3that is located close to the moving body2after the moving body2is moved.

In this case, the moving body2may be incapable of relaying the power to all the power feed destinations3(1) to3(8) at the same time, but is capable of relaying the power supplied from the power feed source1to only one or two adjacent power feed destinations3that are to be more strongly coupled to the moving body2as the magnetic field resonance becomes stronger.

Accordingly, the moving body2drives the drive motor by the power supplied from the power feed source1in a noncontact manner, and circularly moves on the placement base4along the circular guide plate5. Simultaneously, the moving body2relays the power supplied from the power feed source1in a noncontact manner and supplies the power to, out of the power feed destinations3(1) to3(8), only a power feed destination3located close thereto, and causes an LED of the power feed destination3to emit light.

Specifically, a large amount of power is supplied to only a power feed destination3(decorative illumination body) to which the moving body2comes close. As a result, the LEDs of the power feed destinations3(1) to3(8) arranged along the circular guide plate5sequentially emit light with the circular movement of the moving body2along the circular guide plate5.

(Structural Example of Moving Body (Circulating Car)2)

Next, a structural example of the moving body (circulating car)2of the noncontact power feed system according to the first embodiment will be described.FIG. 3is a diagram for explaining a structural example of the moving body2of the noncontact power feed system according to the first embodiment.

As shown inFIG. 3, the moving body2is in an automobile shape. The moving body2includes the relay resonance coil21, a coupling coil22, a rectifier circuit23, and a drive motor section24and has a structure in which a rotation of a drive motor of the drive motor section24is transmitted to drive wheels of the moving body2.

Then, though described above, the relay resonance coil21receives supply of the AC power (energy such as alternating current) from the transmission resonance coil13of the power feed source1, to which the relay resonance coil21is coupled by magnetic field resonance, and supplies part of the AC power to the rectifier circuit23via the coupling coil22.

The rectifier circuit23forms DC power from the AC power supplied thereto, and supplies the DC power to the drive motor section24. The drive motor section24drives the drive motor to rotate by the DC power supplied thereto and transmits the rotation to the drive wheels.

Accordingly, the drive wheels of the moving body2rotate and the moving body2circularly moves (circularly travels) along the circular guide plate5on the placement base4as described with reference toFIG. 2.

Further, the relay resonance coil21of the moving body2is also coupled to the reception resonance coil31of the power feed destination3by magnetic field resonance, and sequentially relays (supplies) part of the power from the power feed source1to each of the power feed destinations3(1) to3(8) to which the moving body2comes close.

In this manner, the moving body2functions as a moving relay (moving repeater) that relays power from the power feed source1to an adjacent power feed destination3, as well as using the power to move the moving body2.

(Structural Example of Power Feed Destination (Decorative Illumination Body)3)

Next, a structural example of the power feed destination (decorative illumination body)3of the noncontact power feed system according to the first embodiment will be described. It should be noted that as described with reference toFIG. 2, the plurality of power feed destinations3(1) to3(8) each having the same structure are used. Accordingly, each structure of the plurality of power feed destinations3(1) to3(8) will be described as a structure of the power feed destination3hereinafter.

FIG. 4is a diagram for explaining the structural example of the power feed destination (decorative illumination body)3of the first embodiment. As shown inFIG. 4, the power feed destination3is constituted of a circuit accommodation portion30A and a decorative illumination arrangement portion (tree portion)30B.

As shown inFIG. 4, the circuit accommodation portion30A includes the reception resonance coil31, the coupling coil32, the rectifier circuit33, and an LED driver circuit341as a part of the load circuit34. Further, the decorative illumination arrangement portion30B includes a plurality of LEDs342(1),342(2),342(3), . . . , as a part of the load circuit34.

As described above, the reception resonance coil31receives supply of power (AC power) from the power feed source1via the relay resonance coil21of the moving body2that is coupled thereto by magnetic field resonance, and supplies the power to the rectifier circuit33via the coupling coil32.

The rectifier circuit33forms DC power from the AC power supplied thereto and supplies the DC power to the LED driver circuit341. The LED driver circuit341forms a drive current for the LEDs342(1),342(2),342(3), . . . , from the DC power supplied thereto, and supplies the drive current to each of the LEDs342(1),342(2),342(3), . . . .

Accordingly, the power feed destination (decorative illumination body)3can cause the LEDs342(1),342(2),342(3), . . . , which are arranged in the decorative illumination arrangement portion30B, to emit light when receiving the power supplied from the power feed source1via the moving body2.

As described above, though the noncontact power feed system according to the first embodiment is constituted of the power feed source1, the moving body2, and the power feed destination3, they are not connected to one another with wires and the power feed source1can supply power to the moving body2and each of the plurality of power feed destinations3.

(Effects of First Embodiment)

As described above, it is unnecessary to connect the power feed source1, the moving body2, and the plurality of power feed destinations3(1) to3(8) to one another with wires in the noncontact power feed system of the first embodiment, with the result that the apparatuses constituting the system can be flexibly arranged.

For example, when the placement base4shown inFIG. 2is constituted of a transparent acrylic plate or the like, it is possible to arrange the moving body2and each of the power feed destinations3(1) to3(8) in a floating state in which the moving body2and the power feed destinations3(1) to3(8) are away from the power feed source1.

Further, in a case where the decorative illumination bodies are used as the power feed destinations as described above, it is possible to cause the decorative illumination bodies to emit light with an extremely simple structure. In other words, complicated microcomputer control or the like is completely unnecessary and it is possible to control the decorative illumination bodies to emit light sequentially.

Further, though the decorative illumination bodies are used as the power feed destinations3in the noncontact power feed system of the first embodiment described above, if members that mechanically operate by power are arranged instead of the decorative illumination bodies, it is possible to cause the members to mechanically operate in a wireless manner in sequence.

Members having various structures can be used as the load circuit34, for example, in which the motor is driven and rotated to lift an object each time the moving body2comes close, or a shutter is released to take a picture each time the moving body2comes close.

Further, in the case of the noncontact power feed system of the first embodiment described above, the power feed destination3is constituted of the decorative illumination body and has one purpose to attract attention of people, with the result that the effect thereof can be increased with the moving body2being circularly moved.

Further, the power can be transmitted/received among the apparatuses in a noncontact manner, with the result that it is possible to enjoy advantages that wiring as in the related art is not carried out, the apparatuses can be arranged easily, a failure due to wrong wiring or the like is not caused, and the like.

As described above, in the case of the noncontact power feed system of the first embodiment, by using the moving body2as a relay apparatus of power, it is possible to form a noncontact power feed system that is pleasant to the eye without carrying out complicated wiring or the like.

Moreover, the noncontact power feed system of the first embodiment can be used as, for example, a display in various shops in addition to a toy for kids.

(Outline of Noncontact Power Feed System of Second Embodiment)

The noncontact power feed system according to the first embodiment described above has a relatively small size such that the noncontact power feed system can be provided on a table, for example. On the other hand, a noncontact power feed system according to a second embodiment is formed as one of amusement attractions in a theme park, in which a moving body can be moved while taking humans thereon.

FIG. 5is a diagram for explaining the noncontact power feed system according to the second embodiment. As shown inFIG. 5, the noncontact power feed system according to the second embodiment includes a plurality of power feed sources1(1),1(2),1(3), . . . , a moving body2A having a structure of an automobile, and a plurality of power feed destinations3(1),3(2),3(3), . . . .

Each of the plurality of power feed sources1(1),1(2),1(3), . . . realizes a function as a noncontact power feed apparatus. Further, the moving body2A realizes a function as a noncontact relay apparatus. Furthermore, each of the plurality of power feed destinations3(1),3(2),3(3), . . . realizes a function as a noncontact power reception apparatus.

The plurality of power feed sources1(1),1(2),1(3), . . . are arranged with intervals therebetween on a traveling road on which the moving body2A travels so that the moving body2A can be supplied with power. Each of the plurality of power feed sources1(1),1(2),1(3), . . . is arranged at a position from which enough power to reach a next power feed source is supplied to the moving body2A but from which power is difficult to be directly supplied to each of the power feed destinations3(1),3(2),3(3), . . . .

Conversely, each of the plurality of power feed sources1(1),1(2),1(3), . . . is arranged for a distance in which the moving body2A can reach a next power feed source by the power supplied from each of the power feed sources1(1),1(2),1(3), . . . and at a position where the power is difficult to be directly supplied to each of the plurality of power feed destinations3(1),3(2),3(3), . . . .

Each of the power feed sources1(1),1(2),1(3), . . . basically has the same structure as the power feed source1of the first embodiment shown inFIG. 1. For example, the power feed source1(1) includes an AC power source11(1), a coupling coil12(1), and a transmission resonance coil13(1). Each of the power feed sources1(2),1(3), . . . , also includes an AC power source11, a coupling coil12, and a transmission resonance coil13.

Further, the moving body2A basically has the same structure as the moving body2shown inFIG. 2. Specifically, the moving body2A includes a relay resonance coil21, a coupling coil22, a rectifier circuit23, and a drive motor section24to be described later.

Further, each of the power feed destinations3(1),3(2),3(3), . . . basically has the same structure as the power feed destination3of the first embodiment shown inFIG. 3. Specifically, each of the power feed destinations3(1),3(2),3(3), . . . includes a reception resonance coil31, a coupling coil32, a rectifier circuit33, and a load circuit34.

It should be noted that as described above, the power feed sources1(1),1(2),1(3), . . . are arranged at positions from which the power is difficult to be directly supplied to the power feed destinations3(1),3(2),3(3), . . . , respectively.

Conversely, the power feed destinations3(1),3(2),3(3), . . . are arranged at positions from which the power is difficult to be received from the power feed sources1(1),1(2),1(3), . . . , respectively, but can be received via the moving body2A.

The load circuit34of the power feed destination3of tae first embodiment is constituted of the LED driver circuit341and the plurality of LEDs342, whereas the load circuit34of each power feed destination3of the second embodiment is constituted of an electronic billboard and a driver circuit thereof.

Moreover, the moving body2A takes two or several humans thereon, and by receiving power sequentially from the power feed sources1(1),1(2),1(3), . . . , drives a drive motor thereof and travels on the traveling road along which the power feed sources1(1),1(2),1(3), . . . are arranged.

At this time, the moving body2A sequentially supplies power supplied from the power feed sources1(1),1(2),1(3), . . . to adjacent power feed destinations3(1),3(2),3(3), . . . respectively, and displays a message on an electronic billboard of each of the power feed destinations3(1),3(2),3(3), . . . .

In this case, a message displayed on an electronic billboard of each of the power feed destinations3(1),3(2),3(3), . . . includes various types of advertising information and the like.

(Use Mode of Noncontact Power Feed System of Second Embodiment)

FIG. 6is a diagram for explaining a use mode of the noncontact power feed system according to the second embodiment.

As shown inFIG. 6, the moving body2A picks up a user (human) and sequentially receives power from the power feed sources1(1),1(2), . . . provided on the traveling road. Then, the moving body2A supplies the power from the power feed sources1to the power feed destinations3(1),3(2),3(3), . . . to which the moving body2A comes close in turns while traveling on the traveling road.

Each of the power feed destinations3(1),3(2),3(3), . . . that receives supply of the power from the moving body2A displays a predetermined message on the electronic billboard thereof.

In a case of an example shown inFIG. 6, the moving body2A that has received power from the power feed source1(1) relays the power to the adjacent power feed destination3(1). Accordingly, an advertising message indicating “Character goods on sale in xx shop” is displayed on the electronic billboard of the power feed destination3(1).

Then, when the moving body2A travels by the power from the power feed source1(1) and reaches the power feed source1(2), the moving body2A receives power from the power feed source1(2), and uses the power to drive the moving body2A and also relays the power to the adjacent power feed destination3(2) from the power feed source1(2). Accordingly, an advertising message indicating “No waiting time in xx attraction” is displayed on the electronic billboard of the power feed destination3(2).

It should be noted that a message displayed on the electronic billboard of each of the power feed destinations3(1),3(2),3(3), . . . can be delivered in advance from a center side in a wired or wireless manner, for example.

In such a manner, the moving body2A as an automobile carrying humans moves by being supplied with power from the power feed sources1(1),1(2),1(3), . . . , and relays and supplies the power from the power feed sources1(1),1(2),1(3), . . . to the power feed destinations3(1),3(2),3(3), . . . sequentially.

Then, it is possible to provide the user on the moving body2A with a display message that is timely displayed on an adjacent electronic billboard. Accordingly, it is possible for the user to obtain latest information and use it as a reference for a next behavior, and for an information provider to guide the user to a shop or another amusement attraction.

It should be noted that in the second embodiment described above, the case where the display message displayed on the electronic billboard of each of the power feed destinations3(1),3(2),3(3), . . . is delivered in advance from, for example, a predetermined center or the like has been described, but the present invention is not limited thereto.

For example, in the case of the noncontact power feed system of the second embodiment, it is also possible to supply a display message to be displayed on the electronic billboard of the power feed destination3from the power feed source1to the power feed destination3via the moving body2A by using a noncontact power supply path.

Hereinafter, there will be described structural examples of the power feed source1, the moving body2A, and the power feed destination3in a case where a display message to be displayed on an electronic billboard of the power feed destination3is supplied from the power feed source1to the power feed destination3via the moving body2A by using a noncontact power supply path.

It should be noted that as described above, since each of the power feed sources1(1),1(2),1(3), . . . has the same structure, each structure of the power feed sources1(1),1(2),1(3), . . . will be hereinafter described as a structure of a power feed source1.

Similarly, since each of the power feed destinations3(1),3(2),3(3), . . . has the same structure, each structure of the power feed destinations3(1),3(2),3(3), . . . will be hereinafter described as a structure of a power feed destination3.

(Structural Example of Power Feed Source1)

First, a structural example of the power feed source1will be described.FIG. 7is a diagram for explaining the structural example of the power feed source1of the second embodiment. The power feed source1of the second embodiment transmits a display message as well as supplying power.

As shown inFIG. 7, the power feed source1of this example includes a communication section14in addition to the AC power source11, the coupling coil12, and the transmission resonance coil13. The communication section14is connected to the transmission resonance coil13so that the transmission resonance coil13can also be used as a communication antenna.

If the communication section14and the transmission resonance coil13are unconditionally connected to each other, impedance of the transmission resonance coil13is lowered and a Q factor thereof is also lowered, which causes power feeding efficiency to be lowered.

In this regard, in the power feed source1of the second embodiment, a filter circuit15ais provided between the AC power source11and the coupling coil12, and a filter circuit15bis provided between the communication section14and the transmission resonance coil13.

Specifically, as also described above, a frequency band necessary for power transmission is low, for example, in a range from several Hz to several tens of Hz. In contrast to this, a frequency band necessary for information transmission is wider as information is transmitted at higher speed. In such a case, at least several kHz is necessary, or several MHz to several GHz may be necessary in some cases.

In the second embodiment, it is assumed that a frequency f1of AC power generated in the AC power source11is a value around 10 Hz and a frequency of an information transmission signal that is generated in the communication section14is more than several MHz, for example.

In this case, the filter circuit15bof the power feed source1is designed to have sufficiently high impedance that does not lower a Q factor of the transmission resonance coil13at a frequency f1. Further, the filter circuit15aof the power feed source1is designed to have appropriate impedance at which the coupling coil12does not adversely affect wireless communication at a frequency f2. Here, the appropriate impedance differs depending on the frequency f2or a structure of the coupling coil12.

Accordingly, in a case where power is fed from the AC power source11, impedance of the transmission resonance coil13is kept high and a Q factor thereof is also kept high due to the function of the filter circuit15b, with the result that power can be fed without lowering the power feeding efficiency.

On the other hand, in a case where information from the communication section14is transmitted, a frequency band of a signal of the information is set as a high-frequency band of several MHz or more and impedance is lowered due to the function of the filter circuit15bat a time other than at the frequency f1.

In other words, the filter circuit15bkeeps impedance high at the frequency f1, and lowers the impedance other than at the frequency f1. In this case, a Q factor of the transmission resonance coil13can be lowered and the information signal from the communication section14can be desirably transmitted.

Accordingly, first, the power feed source1can desirably transmit a high-frequency information signal (display message) via the communication section14, the filter circuit15b, and the transmission resonance coil13. After that, the power feed source1can transmit (feed) AC power from the AC power source11via the filter circuit15a, the coupling coil12, and the transmission resonance coil13without lowering the power feeding efficiency.

(Structural Example of Moving Body2A)

Next, a structural example of the moving body2A will be described.FIG. 8is a diagram for explaining a structural example of the moving body2A of the second embodiment. The moving body2A of the second embodiment relays not only power but also an information signal (display message).

As shown inFIG. 8, the moving body2A of this example includes a communication section25and an operation section26in addition to the relay resonance coil21, the coupling coil22, the rectifier circuit23, and the drive motor section24. The communication section25is connected to the relay resonance coil21so that the relay resonance coil21can also be used as a communication antenna.

Similar to the case of the power feed source1described above, if the communication section25and the relay resonance coil21are unconditionally connected to each other, impedance of the relay resonance coil21is lowered and a Q factor thereof is also lowered, which causes power feeding efficiency to be lowered as in the case of the power feed source1described above.

In this regard, also in the moving body2A of the second embodiment, a filter circuit27ais provided between the coupling coil22and the rectifier circuit23, and a filter circuit27bis provided between the communication section25and the relay resonance coil21.

Then, as in the case of the power feed source1described above, the filter circuit27bof the moving body2A is designed to have sufficiently high impedance that does not lower a Q factor of the relay resonance coil21at a frequency f1. Further, the filter circuit27aof the moving body2A is designed to have appropriate impedance at which the coupling coil22does not adversely affect the wireless communication at a frequency f2. Here, the appropriate impedance differs depending on the frequency f2or a structure of the coupling coil22.

Accordingly, in a case where power is fed from the power feed source1and relayed to a power feed destination, impedance of the relay resonance coil21is kept high and a Q factor thereof is also kept high due to the function of the filter circuit27b, with the result that power can be fed and relayed (transmitted) without lowering power receiving efficiency or power feeding efficiency.

On the other hand, in a case where information from the power feed source1is received or information from the communication section25is transmitted, a frequency band of a signal of the information is set as a high-frequency band of several MHz or more, and impedance is lowered due to the function of the filter circuit27bat a time other than at the frequency f1.

In other words, the filter circuit27bkeeps impedance high at the frequency f1, and lowers the impedance other than at the frequency f1. Accordingly, in this case, a Q factor of the relay resonance coil21can be lowered and the information signal can be desirably transmitted and received.

Accordingly, first, the moving body2A receives an information signal (display message) from the power feed source1via the relay resonance coil21, the filter circuit27b, and the communication section25. Then, the communication section25adds information that is input via the operation section26to the received information signal as necessary, with the result that a high-frequency information signal can be desirably transmitted to the power feed destination3via the filter circuit27band the relay resonance coil21.

After that, the AC power from the power feed source1can be received via the relay resonance coil21, supplied to the rectifier circuit23via the coupling coil22and the filter circuit27a, converted into DC power, and then supplied to the drive motor section24. At the same time, the AC power from the power feed source1is relayed to the power feed destination3via the relay resonance coil21without lowering the power feeding efficiency.

It should be noted that the information that is input via the operation section26is, for example, information of a name or nickname of a user, with which a display message such as “Mr. XX, xx shop is on sale.” that is beneficial for only the user riding on the moving body2A can be displayed.

Further, in a case where the display message has been set in a power feed destination in advance, the moving body2A can transmit the information of the user name or the like that has been received via the operation section26, as information that constitutes part of the display message, to the power feed destination.

In other words, the moving body2A does not only relay the information signal from the power feed source1. For example, the moving body2A can independently transmit, for example, only an information signal generated in the moving body2A based on information or the like received via the operation section26to the power feed destination3via the communication section25, the filter circuit27b, and the relay resonance coil21.

(Structural Example of Power Feed Destination3)

Next, a structural example of the power feed destination3will be described.FIG. 9is a diagram for explaining a structural example of the power feed destination3of the second embodiment. The power feed destination3of the second embodiment receives not only power but also relay of a display message via the moving body2A.

As shown inFIG. 9, the power feed destination3of this example includes a communication section35in addition to the reception resonance coil31, the coupling coil32, the rectifier circuit33, and an electronic billboard34as a load circuit. The communication section35is connected to the reception resonance coil31so that the reception resonance coil31can also be used as a communication antenna.

Also in the case of the power feed destination3, if the communication section35and the reception resonance coil31are unconditionally connected to each other, impedance of the reception resonance coil31is lowered and a Q factor thereof is also lowered, which causes power receiving efficiency to be lowered as in the case of the power feed source1and moving body2A described above.

In this regard, also in the power feed destination3of the second embodiment, a filter circuit36ais provided between the coupling coil32and the rectifier circuit33, and a filter circuit36bis provided between the communication section35and the reception resonance coil31.

Then, as in the case of the power feed source1and moving body2A described above, the filter circuit36bof the power feed destination3is designed to have sufficiently high impedance that does not lower a Q factor of the reception resonance coil31at a frequency f1. Further, the filter circuit36aof the power feed destination3is designed to have appropriate impedance at which the coupling coil32does not adversely affect the wireless communication at a frequency f2. Here, the appropriate impedance differs depending on the frequency f2or a structure of the coupling coil32.

Accordingly, in a case where power is fed from the moving body2A, impedance of the reception resonance coil31is kept high and a Q factor thereof is also kept high due to the function of the filter circuit36b, with the result that power can be received without lowering the power receiving efficiency.

On the other hand, in a case where information from the moving body2A is received, a frequency band of a signal of the information is set as a high-frequency band of several MHz or more and impedance is lowered due to the function of the filter circuit36bat a time other than at the frequency f1.

In other words, the filter circuit36bkeeps impedance high at the frequency f1, and lowers the impedance other than at the frequency f1. Accordingly, in this case, a Q factor of the reception resonance coil31can be lowered and the information signal can be desirably transmitted and received.

Accordingly, first, the power feed destination3can smoothly receive an information signal (display message) from the power feed source1that is relayed by the moving body2A via the reception resonance coil31, the filter circuit36b, and the communication section35.

The communication section35extracts a display message from the received information signal, converts the display message into an information signal to be supplied to the electronic billboard34, and then supplies the information signal to the electronic billboard34, with the result that the display message can be displayed on the electronic billboard34.

After that, the AC power supplied from the power feed source1via the moving body2A is received via the reception resonance coil31, supplied to the rectifier circuit33via the coupling coil32and the filter circuit36a, and converted into DC power, with the result that the DC power can be supplied to the electronic billboard34.

Accordingly, the display message from the power feed source1that is relayed and supplied by the moving body2A is supplied to the electronic billboard34, and the electronic billboard34is driven by the power from the power feed source1that is relayed and supplied by the moving body2A, with the result that the display message can be displayed.

(Effects of Second Embodiment)

The magnetic-field-resonance-type noncontact power feed system can be applied to a system in which an automobile that moves while taking humans thereon is used as a moving relay apparatus.

Further, the magnetic-field-resonance-type noncontact power feed system can provide necessary information to users who ride on the moving body2A as an automobile at an appropriate timing or guide the users to a shop or another amusement attraction.

(Modified Example of Second Embodiment)

It should be noted that though impedance is adjusted using the filter circuits in the apparatuses described with reference toFIGS. 7 to 9, the present invention is not limited thereto. For example, switching circuits may be provided instead of the filter circuits.

For example, in the case of the power feed source1shown inFIG. 7, a switching circuit16bis provided at the position of the filter circuit15b, i.e., between the communication section14and the transmission resonance coil13. Further, a switching circuit16ais provided at the position of the filter circuit15a, i.e., between the AC power source11and the coupling coil12.

Then, the switching circuit16ais turned on and the switching circuit16bis turned off when power is fed. Accordingly, impedance of the transmission resonance coil13can be kept high and power from the AC power source can be fed efficiently.

In addition, the switching circuit16ais turned off and the switching circuit16bis turned on when communication is performed. Accordingly, the information signal from the communication section14can be appropriately transmitted via the transmission resonance coil13.

As described above, the switching circuits may be provided instead of the filter circuits and switched when power is fed and communication is performed. It should be noted that also in the moving body2A and the power feed destination3, switching circuits may be similarly provided to a communication system and a power feed system and switched when communication is performed and power is fed (received).

Further, in the examples described with reference toFIGS. 7 to 9, the transmission resonance coil13, the relay resonance coil21, and the reception resonance coil31are also used as the communication antenna, and the supply of the power and the supply of the information signal are performed using the same path as much as possible.

However, the present invention is not limited to the above case. Since the information signal can be transmitted with a relatively small amount of power and a large amount of information can be transmitted at high-speed, an antenna designated for communication may of course be provided.

Specifically, in the case of the power feed source1shown inFIG. 7, the communication section14is connected to not the transmission resonance coil13but a communication antenna that is newly provided. Further, in the case of the moving body2A shown inFIG. 8, the communication section25is connected to not the relay resonance coil21but a communication antenna that is newly provided. Furthermore, in the case of the power feed destination3shown inFIG. 9, the communication section35is connected to not the reception resonance coil31but a communication antenna that is newly provided.

With this structure, the communication system and the power feed system may be separated and independently transmit/receive information signals and power, respectively. In this case, since the transmission/reception of information signals and the transmission/reception of power can be performed at the same time, the effect that the transmission/reception of information signals is easily controlled, or the like can be produced.

Further, in the case of the noncontact power feed system of the second embodiment, the moving body2A also receives supply of power from the power feed source1, but the present invention is not limited thereto. For example, the moving body2A may be equipped with a drive battery and travel by power from the drive battery.

In addition, the moving body2A may include an AC power source and feed the power generated in the moving body2A (AC power) to a power feed destination. That is, the moving body2A can be given a function as the power feed source1.

(Application to Method of the Present Invention)

The noncontact power feed method in the noncontact power feed system described with reference toFIGS. 1 to 9is one of noncontact power feed methods of the present invention. Further, the noncontact power feed method for the moving bodies2and2A descried with reference toFIGS. 3 and 8is one of the noncontact power feed methods of the present invention. Moreover, the noncontact power feed method for the power feed destination descried with reference toFIGS. 4 and 9is one of the noncontact power feed methods of the present invention.

It should be noted that though the moving bodies2and2A have been described as one having an automobile shape or as an automobile in the embodiments described above, but the present invention is not limited thereto. Moving bodies of various modes such as a hull-type moving body that moves on the water, an airplane-type moving body that flies in the air, and an elevator-type moving body that vertically moves can be structured and used.

Further, the power feed destination has been described as one using a light-emitting device and a display device, such as an LED and an electronic billboard in the embodiment described above, but the present invention is not limited thereto. As the load circuit of the power feed destination that receives supply of the power from a moving body, various circuits such as a circuit for generating/releasing sound, an oscillation circuit, and a photographing circuit can be used.

Moreover, the case where power is supplied in a noncontact manner by a magnetic field resonance system has been described in the embodiments described above, but the present invention can be similarly applied to a case where power is supplied in a noncontact manner by using not only the magnetic field resonance system but also an electric field resonance system and an electromagnetic resonance system.

In addition, the power feed source is provided with the coupling coil (coupling device) between the AC power source and the transmission resonance coil in the embodiments described above. Further, the moving body is provided with the coupling coil (coupling device) between the relay resonance coil and the rectifier circuit. Furthermore, the power feed destination is provided with the coupling coil (coupling device) between the reception resonance coil and the rectifier circuit.

However, the present invention is not limited to the above case, and can be structured without using the above coupling coils (coupling devices) as long as the reflection of power or the problems of impedance can be suppressed.

The present application contains subject matter related to that disclosed in Japanese Priority Patent Application JP 2009-171797 filed in the Japan Patent Office on Jul. 23, 2009, the entire content of which is hereby incorporated by reference.