WO2011099106A1 - Electric power feed device for vehicle and electric power reception device - Google Patents

Electric power feed device for vehicle and electric power reception device Download PDF

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Publication number
WO2011099106A1
WO2011099106A1 PCT/JP2010/007215 JP2010007215W WO2011099106A1 WO 2011099106 A1 WO2011099106 A1 WO 2011099106A1 JP 2010007215 W JP2010007215 W JP 2010007215W WO 2011099106 A1 WO2011099106 A1 WO 2011099106A1
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WIPO (PCT)
Prior art keywords
electric power
electromagnetic induction
coil
vehicle
induction coils
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PCT/JP2010/007215
Other languages
French (fr)
Inventor
Yukihiro Yamamoto
Shimpei Sakoda
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Toyota Jidosha Kabushiki Kaisha
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Publication of WO2011099106A1 publication Critical patent/WO2011099106A1/en

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L53/00—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
    • B60L53/10—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles characterised by the energy transfer between the charging station and the vehicle
    • B60L53/12—Inductive energy transfer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B60—VEHICLES IN GENERAL
    • B60L—PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES; SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL; MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES
    • B60L53/00—Methods of charging batteries, specially adapted for electric vehicles; Charging stations or on-board charging equipment therefor; Exchange of energy storage elements in electric vehicles
    • B60L53/60—Monitoring or controlling charging stations
    • B60L53/66—Data transfer between charging stations and vehicles
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/10—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling
    • H02J50/12—Circuit arrangements or systems for wireless supply or distribution of electric power using inductive coupling of the resonant type
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/20—Circuit arrangements or systems for wireless supply or distribution of electric power using microwaves or radio frequency waves
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J50/00—Circuit arrangements or systems for wireless supply or distribution of electric power
    • H02J50/80—Circuit arrangements or systems for wireless supply or distribution of electric power involving the exchange of data, concerning supply or distribution of electric power, between transmitting devices and receiving devices
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • H02J7/00032—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries characterised by data exchange
    • H02J7/00034—Charger exchanging data with an electronic device, i.e. telephone, whose internal battery is under charge
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/70—Energy storage systems for electromobility, e.g. batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T10/00—Road transport of goods or passengers
    • Y02T10/60—Other road transportation technologies with climate change mitigation effect
    • Y02T10/7072—Electromobility specific charging systems or methods for batteries, ultracapacitors, supercapacitors or double-layer capacitors
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02T90/10—Technologies relating to charging of electric vehicles
    • Y02T90/12—Electric charging stations
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02T90/10—Technologies relating to charging of electric vehicles
    • Y02T90/14—Plug-in electric vehicles
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
    • Y02T90/00—Enabling technologies or technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02T90/10—Technologies relating to charging of electric vehicles
    • Y02T90/16—Information or communication technologies improving the operation of electric vehicles

Definitions

  • the present invention relates to an electric power feed device for vehicle and an electric power reception device, and particularly to an electric power feed device for vehicle feeding electric power to a vehicle in a non-contact manner as a result of resonance of an electric power transmission coil provided in the electric power feed device outside the vehicle and an electric power reception coil mounted on the vehicle through electromagnetic field and an electric power reception device receiving electric power from the electric power feed device in a non-contact manner.
  • Electrically powered vehicles such as an electric vehicle or a hybrid vehicle have attracted much attention as environmentally friendly vehicles. These vehicles incorporate a motor generating driving force for running and a rechargeable power storage device storing electric power supplied to the motor.
  • the hybrid vehicle includes a vehicle incorporating not only a motor but also an internal combustion engine as an additional motive power source, a vehicle incorporating not only a power storage device but also a fuel cell as a DC power supply for driving a vehicle, and the like.
  • a vehicle in which a vehicle-mounted power storage device is chargeable by a power supply outside the vehicle has been known, as in the case of an electric vehicle.
  • a plug-in hybrid vehicle in which a power storage device is chargeable by a power supply in a general household by connecting a power outlet provided in a house and a charge port provided in the vehicle to each other through a charge cable, has been known.
  • wireless electric power transmission without using a power code or a power transmission cable has recently attracted attention as an electric power transmission method.
  • Three promising techniques of electric power transmission using electromagnetic induction, electric power transmission using microwaves, and electric power transmission using a resonance method have been known as such a wireless electric power transmission technique.
  • a resonance method is such a non-contact electric power transmission technique that a pair of resonators (for example, a pair of self-resonant coils) is caused to resonate in electromagnetic field (near field) so that electric power is transmitted through the electromagnetic field, and it even allows transmission of electric power as high as several kW over a relatively long distance (for example, several m).
  • a pair of resonators for example, a pair of self-resonant coils
  • an electrically powered vehicle and an electric power feed device for vehicle disclosed in Japanese Patent Laying-Open No. 2009-106136 have been known as an electric power feed device for vehicle and an electric power reception device using this resonance method.
  • Variation in positional relation between an electric power transmission coil in an electric power feed device and an electric power reception coil mounted on a vehicle leads to variation in electric power transmission efficiency from the electric power transmission coil to the electric power reception coil.
  • variation or the like in vehicle height due to a position where a car stops or loads carried thereon leads to variation in positional relation between the electric power transmission coil and the electric power reception coil for each occasion of electric power feed, it is aimed to enhance electric power transmission efficiency in consideration of such a change in condition.
  • measures that can be taken for that purpose should also be implemented with a configuration as simple as possible.
  • the electrically powered vehicle and the electric power feed device for vehicle disclosed in Japanese Patent Laying-Open No. 2009-106136 above do not particularly address such a problem.
  • an object of the present invention is to provide an electric power feed device for vehicle capable of enhancing efficiency in electric power transmission using a resonance method with a simplified configuration and an electric power reception device.
  • an electric power feed device for vehicle includes an electric power transmission coil, a power supply device, a plurality of electromagnetic induction coils, and a switching device.
  • the electric power transmission coil is configured to transmit electric power to an electric power reception coil mounted on a vehicle in a non-contact manner, as a result of resonance with the electric power reception coil through electromagnetic field.
  • the power supply device generates electric power having a prescribed frequency.
  • the plurality of electromagnetic induction coils are each configured to supply electric power output from the power supply device to the electric power transmission coil by electromagnetic induction.
  • the switching device is provided between the plurality of electromagnetic induction coils and the power supply device and configured to be able to switch an electromagnetic induction coil to electrically be connected to the power supply device.
  • a plurality of electromagnetic induction coils configured to supply electric power output from a power supply device to an electric power transmission coil by electromagnetic induction are provided, and an electromagnetic induction coil to electrically be connected to the power supply device can be switched by a switching device.
  • an electromagnetic induction coil relatively high in electric power transmission efficiency can readily be selected by the switching device for each occasion of electric power feed.
  • the switching device includes a plurality of relays.
  • the plurality of relays are provided in correspondence with the plurality of electromagnetic induction coils respectively, and each relay is connected between a corresponding electromagnetic induction coil and the power supply device.
  • the electromagnetic induction coils are different from one another in coil diameter.
  • the electromagnetic induction coils are disposed in an identical plane.
  • an electric power reception device is mounted on a vehicle, and it includes an electric power reception coil, a plurality of electromagnetic induction coils, and a switching device.
  • the electric power reception coil is configured to receive electric power from an electric power transmission coil included in an electric power feed device outside the vehicle in a non-contact manner, as a result of resonance with the electric power transmission coil through electromagnetic field.
  • the plurality of electromagnetic induction coils are each configured to extract electric power received by the electric power reception coil by electromagnetic induction.
  • the switching device is provided between the plurality of electromagnetic induction coils and a vehicle electric system and configured to be able to switch an electromagnetic induction coil to electrically be connected to the vehicle electric system.
  • a plurality of electromagnetic induction coils configured to extract electric power received by an electric power reception coil by electromagnetic induction are provided, and an electromagnetic induction coil to electrically be connected to a vehicle electric system can be switched by a switching device.
  • an electromagnetic induction coil relatively highest in received electric power can readily be selected by the switching device for each occasion of electric power reception.
  • the switching device includes a plurality of relays.
  • the plurality of relays are provided in correspondence with the plurality of electromagnetic induction coils respectively, and each relay is connected between a corresponding electromagnetic induction coil and the vehicle electric system.
  • the electromagnetic induction coils are different from one another in coil diameter.
  • the electromagnetic induction coils are disposed in an identical plane.
  • an electric power feed device for vehicle capable of enhancing efficiency in electric power transmission using a resonance method with a simplified configuration and an electric power reception device can be realized.
  • Fig. 1 is a functional block diagram showing an overall configuration of a vehicle electric power feed system according to a first embodiment of the present invention.
  • Fig. 2 is a diagram for illustrating principles of electric power transmission using a resonance method.
  • Fig. 3 is a diagram showing relation between a distance from a current source (magnetic current source) and electromagnetic field intensity.
  • Fig. 4 is a diagram showing variation in electric power transmission efficiency from an electric power feed device to a vehicle when a switching device shown in Fig. 1 is operated.
  • Fig. 5 is a functional block diagram showing an overall configuration of a vehicle electric power feed system according to a second embodiment.
  • Fig. 1 is a functional block diagram showing an overall configuration of a vehicle electric power feed system according to a first embodiment of the present invention.
  • this vehicle electric power feed system includes an electric power feed device 100 and a vehicle 200.
  • Electric power feed device 100 includes a high-frequency power supply device 110, a coaxial cable 120, a plurality of electromagnetic induction coils 130, a switching device 140, and a resonance coil 150.
  • electric power feed device 100 further includes a communication antenna 160, a communication device 170, and an ECU (Electronic Control Unit) 180.
  • ECU Electronic Control Unit
  • High-frequency power supply device 110 converts system electric power received from a power plug 350 connected, for example, to a system power supply into prescribed high-frequency electric power and outputs the high-frequency electric power to coaxial cable 120. It is noted that a frequency of high-frequency electric power generated by high-frequency power supply device 110 is set, for example, to a prescribed value within a range from 1 M to more than 10 MHz.
  • the plurality of electromagnetic induction coils 130 are disposed substantially coaxially with resonance coil 150 at a prescribed distance from resonance coil 150.
  • Each electromagnetic induction coil 130 can magnetically be coupled to resonance coil 150 by electromagnetic induction and it is configured to feed high-frequency electric power supplied from high-frequency power supply device 110 to resonance coil 150 by electromagnetic induction.
  • Switching device 140 is provided between the plurality of electromagnetic induction coils 130 and coaxial cable 120 and it includes a plurality of relays provided in correspondence with the plurality of electromagnetic induction coils 130 respectively. As any of the plurality of relays is turned on as appropriate in response to a control signal from ECU 180, switching device 140 switches an electromagnetic induction coil to electrically be connected to coaxial cable 120, in response to the control signal from ECU 180.
  • Resonance coil 150 is an LC resonant coil, and it receives supply of electric power by electromagnetic induction from an electromagnetic induction coil electrically connected to coaxial cable 120 by switching device 140.
  • Resonance coil 150 is configured to transmit electric power to vehicle 200 in a non-contact manner as a result of resonance with a resonance coil 210 for electric power reception mounted on vehicle 200, through electromagnetic field.
  • a coil diameter and the number of turns of resonance coil 150 are set as appropriate such that a Q value (for example, Q>100), a degree of coupling kappa, and the like increase, based on a distance from resonance coil 210 of vehicle 200, a resonance frequency, and the like.
  • Communication antenna 160 is connected to communication device 170.
  • Communication device 170 is a communication interface for establishing communication with a communication device 300 of vehicle 200, and it receives information transmitted from communication device 300 of vehicle 200 and outputs the information to ECU 180. It is noted that the information transmitted from communication device 300 of vehicle 200 to communication device 170 includes, for example, information on an electric power transmission request command and electric power received by vehicle 200 and the like.
  • ECU 180 controls an operation of high-frequency power supply device 110 and switching device 140. Specifically, when communication device 170 receives an electric power transmission request command, ECU 180 controls high-frequency power supply device 110 so as to generate prescribed high-frequency electric power. In addition, ECU 180 receives a detection value of electric power received by vehicle 200 from communication device 170 while electric power is being fed from electric power feed device 100 to vehicle 200, and controls switching device 140 such that electromagnetic induction coil 130 highest in electric power transmission efficiency among the plurality of electromagnetic induction coils 130 is electrically connected to coaxial cable 120.
  • vehicle 200 includes resonance coil 210, a plurality of electromagnetic induction coils 220, a switching device 230, a rectifier circuit 240, a charger 250, a power storage device 260, and a motive power output device 270.
  • vehicle 200 further includes an electric power sensor 280, an ECU 290, communication device 300, and a communication antenna 310.
  • Resonance coil 210 is an LC resonant coil, and it is configured to receive electric power from electric power feed device 100 in a non-contact manner as a result of resonance with resonance coil 150 for electric power transmission included in electric power feed device 100, through electromagnetic field. It is noted that a coil diameter and the number of turns of this resonance coil 210 are also set as appropriate such that a Q value (for example, Q>100), a degree of coupling kappa and the like increase, based on a distance from resonance coil 150 of electric power feed device 100, a resonance frequency, and the like.
  • the plurality of electromagnetic induction coils 220 are disposed substantially coaxially with resonance coil 210 at a prescribed distance from resonance coil 210.
  • Each electromagnetic induction coil 220 can magnetically be coupled to resonance coil 210 by electromagnetic induction and it is configured to extract electric power received by resonance coil 210 by electromagnetic induction and output the electric power to rectifier circuit 240.
  • Switching device 230 is provided between the plurality of electromagnetic induction coils 220 and rectifier circuit 240 and it includes a plurality of relays provided in correspondence with the plurality of electromagnetic induction coils 220 respectively. As any of the plurality of relays is turned on as appropriate in response to a control signal from ECU 290, switching device 230 switches an electromagnetic induction coil to electrically be connected to rectifier circuit 240, in response to the control signal from ECU 290.
  • Power storage device 260 is a rechargeable DC power supply, and it is implemented by a secondary battery such as a lithium ion battery or a nickel metal hydride battery. Power storage device 260 stores not only electric power supplied from charger 250 but also regenerative power generated by motive power output device 270. Then, power storage device 260 supplies the stored electric power to motive power output device 270. It is noted that a large-capacity capacitor can also be adopted as power storage device 260 and any electric power buffer capable of temporarily storing electric power supplied from electric power feed device 100 and regenerative power from motive power output device 270 and supplying the stored electric power to motive power output device 270 may be adopted.
  • Motive power output device 270 is configured to use electric power stored in power storage device 260 to generate driving force for running of vehicle 200.
  • motive power output device 270 includes, for example, an inverter receiving electric power output from power storage device 260, a motor driven by the inverter, a driving wheel receiving driving force from the motor, and the like. It is noted that motive power output device 270 may also include an engine capable of driving a generator for charging power storage device 260.
  • Electric power sensor 280 detects electric power received by vehicle 200, for example, by detecting electric power input to charger 250, and outputs the detection value to ECU 290. It is noted that an installation site of electric power sensor 280 is not limited to an input side of charger 250 but it may be installed on an output side of charger 250 or at other locations. Alternatively, a voltage sensor and a current sensor may be provided instead of electric power sensor 280 and received electric power may be calculated based on a detection value from each sensor.
  • ECU 290 outputs to communication device 300, an electric power transmission request command requesting electric power transmission from electric power feed device 100 to vehicle 200.
  • ECU 290 controls an operation of charger 250 and switching device 230.
  • ECU 290 controls charger 250 so as to convert electric power output from rectifier circuit 240 to a voltage level of power storage device 260.
  • receiving a detection value of electric power received by vehicle 200 ECU 290 controls switching device 230 so as to electrically connect electromagnetic induction coil 220 greatest in received electric power among the plurality of electromagnetic induction coils 220 to rectifier circuit 240.
  • ECU 290 outputs to communication device 300, the detection value of received electric power received from electric power sensor 280.
  • Communication device 300 is a communication interface for establishing communication with communication device 170 of electric power feed device 100, and it transmits an electric power transmission request command and such information as a detection value of received electric power received from ECU 290 to communication device 170 of electric power feed device 100.
  • Communication antenna 310 is connected to communication device 300.
  • resonance coil 150 of electric power feed device 100 and resonance coil 210 of vehicle 200 resonate through electromagnetic field, and energy is transmitted from resonance coil 150 to resonance coil 210.
  • Electric power received by resonance coil 210 in vehicle 200 is extracted from resonance coil 210 by electromagnetic induction coil 220 electrically connected to rectifier circuit 240 by switching device 230 and supplied to power storage device 260 through rectifier circuit 240 and charger 250.
  • a plurality of electromagnetic induction coils 130 are provided in electric power feed device 100. Then, electromagnetic induction coil 130 highest in electric power transmission efficiency among the plurality of electromagnetic induction coils 130 is selected as appropriate and that selected electromagnetic induction coil 130 is electrically connected to coaxial cable 120 by switching device 140.
  • a plurality of electromagnetic induction coils 220 are provided in vehicle 200 on the electric power reception side as well. Then, electromagnetic induction coil 220 greatest in received electric power among the plurality of electromagnetic induction coils 220 is selected as appropriate and that selected electromagnetic induction coil 220 is electrically connected to rectifier circuit 240 by switching device 230.
  • a plurality of electromagnetic induction coils are provided in electric power feed device 100 and vehicle 200 and an electromagnetic induction coil highest in electric power transmission efficiency (received electric power) from electric power feed device 100 to vehicle 200 is selected as appropriate.
  • Fig. 2 is a diagram for illustrating principles of electric power transmission using a resonance method.
  • two LC resonant coils (resonance coils) resonate in electromagnetic field (near field) as in resonance of two tuning forks, so that electric power is transmitted from one coil to the other coil through electromagnetic field.
  • electromagnetic induction coil 130 is connected to high-frequency power supply device 110 and high-frequency electric power is fed from electromagnetic induction coil 130 to resonance coil 150 magnetically coupled to electromagnetic induction coil 130 by electromagnetic induction.
  • Resonance coil 150 is an LC resonant coil and resonates with resonance coil 210 of vehicle 200 through electromagnetic field (near field). Then, energy (electric power) moves from resonance coil 150 to resonance coil 210 through electromagnetic field. Energy (electric power) that moved to resonance coil 210 is extracted from resonance coil 210 by electromagnetic induction coil 220 magnetically coupled to resonance coil 210 by electromagnetic induction and supplied to a load 320 (showing the entire electric system including rectifier circuit 240 and subsequent components).
  • Fig. 3 is a diagram showing relation between a distance from a current source (magnetic current source) and electromagnetic field intensity.
  • electromagnetic field includes three components.
  • a curve k1 represents a component inversely proportional to a distance from a wave source and it is referred to as a "radiation electromagnetic field.”
  • a curve k2 represents a component inversely proportional to a square of a distance from a wave source and it is referred to as an "induction electromagnetic field.”
  • a curve k3 represents a component inversely proportional to a cube of a distance from a wave source and it is referred to as a "static electromagnetic field.”
  • the resonance method energy (electric power) is transmitted by making use of this near field (evanescent field).
  • a pair of resonators for example, a pair of LC resonant coils
  • the resonance method can achieve electric power transmission with less energy loss than electromagnetic waves transmitting energy (electric power) by means of the "radiation electromagnetic field" propagating energy over a long distance.
  • Fig. 4 is a diagram showing variation in electric power transmission efficiency from electric power feed device 100 to vehicle 200 when switching device 140 shown in Fig. 1 is operated.
  • the ordinate shows electric power transmission efficiency
  • the abscissa shows a frequency of transmitted electric power.
  • f0 represents a resonance frequency and electric power transmission efficiency is maximized when the frequency of transmitted electric power matches with the resonance frequency.
  • resonance frequency f0 is determined by inductance L and capacitance C of the resonance coil, and therefore inductance L and capacitance C of the resonance coil are designed such that the resonance frequency matches with the frequency of transmitted electric power.
  • a solid line shows electric power transmission efficiency when electromagnetic induction coil 130 highest in electric power transmission efficiency among the plurality of electromagnetic induction coils 130 is selected, and other dotted lines show electric power transmission efficiency when other electromagnetic induction coils 130 are selected.
  • Electric power transmission efficiency varies as input impedance of a resonance system formed by resonance coils 150 and 210 varies.
  • the plurality of electromagnetic induction coils 130 are disposed substantially coaxially with resonance coil 150 at a prescribed distance from resonance coil 150.
  • a degree of coupling (kappa) between electromagnetic induction coil 130 and resonance coil 150 varies depending on a distance between electromagnetic induction coil 130 electrically connected to coaxial cable 120 and resonance coil 150. Therefore, switching of electromagnetic induction coil 130 by switching device 140 corresponds to variation in input impedance of resonance coil 150.
  • the present first embodiment allows adjustment of input impedance with a simplified configuration, by providing the plurality of electromagnetic induction coils 130 different in distance from resonance coil 150 and switching device 140 selectively connecting the plurality of electromagnetic induction coils 130 to high-frequency power supply device 110.
  • Fig. 5 is a functional block diagram showing an overall configuration of a vehicle electric power feed system according to a second embodiment.
  • electric power feed device 100 includes a plurality of electromagnetic induction coils 130A instead of the plurality of electromagnetic induction coils 130, in the configuration of the electric power feed device according to the first embodiment shown in Fig. 1.
  • vehicle 200 includes a plurality of electromagnetic induction coils 220A instead of the plurality of electromagnetic induction coils 220, in the configuration of the vehicle according to the first embodiment shown in Fig. 1.
  • the plurality of electromagnetic induction coils 130A are different from one another in coil diameter, and they are disposed, for example, substantially concentrically in substantially the same plane. Though the plurality of electromagnetic induction coils 130A do not have to be located in the substantially same plane, a space for arranging the plurality of electromagnetic induction coils 130A can be made smaller by disposing the coils in substantially the same plane.
  • electromagnetic induction coils 130A different in coil diameter By switching electromagnetic induction coils 130A different in coil diameter by means of switching device 140, a degree of coupling between electromagnetic induction coil 130A and resonance coil 150 varies, and hence input impedance of resonance coil 150 varies.
  • electric power transmission efficiency can be enhanced by preparing the plurality of electromagnetic induction coils 130A different in coil diameter in advance and selecting an electromagnetic induction coil highest in electric power transmission efficiency by means of switching device 140.
  • the plurality of electromagnetic induction coils 220A are also different from one another in coil diameter, and they are disposed, for example, substantially concentrically in substantially the same plane. Though the plurality of electromagnetic induction coils 220A do not have to be located in substantially the same plane either, a space for arranging the plurality of electromagnetic induction coils 220A can be made smaller by disposing the coils in substantially the same plane.
  • electromagnetic induction coils 220A different in coil diameter By switching electromagnetic induction coils 220A different in coil diameter by means of switching device 230, a degree of coupling between electromagnetic induction coil 220A and resonance coil 210 varies, and hence impedance varies.
  • electric power transmission efficiency can be enhanced by preparing the plurality of electromagnetic induction coils 220A different in coil diameter in advance and selecting an electromagnetic induction coil highest in electric power transmission efficiency (received electric power) by means of switching device 230.
  • an effect as in the first embodiment can be obtained and a space for arranging the plurality of electromagnetic induction coils 130A in electric power feed device 100 and a space for arranging the plurality of electromagnetic induction coils 220A in vehicle 200 can be made smaller.
  • the configuration may be such that a plurality of electromagnetic induction coils and a switching device are provided in any of electric power feed device 100 and vehicle 200. According to such a configuration as well, an effect of improvement in electric power transmission efficiency as shown in Fig. 4 can be obtained.
  • resonance coil 150 corresponds to one embodiment of the "electric power transmission coil” in the present invention
  • resonance coil 210 corresponds to one embodiment of the "electric power reception coil” in the present invention in the description above.

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  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Transportation (AREA)
  • Mechanical Engineering (AREA)
  • Computer Networks & Wireless Communication (AREA)
  • Electric Propulsion And Braking For Vehicles (AREA)
  • Charge And Discharge Circuits For Batteries Or The Like (AREA)

Abstract

Each of a plurality of electromagnetic induction coils (130) is configured to supply high-frequency electric power output from a high-frequency power supply device (110) to a resonance coil (150) by electromagnetic induction. The resonance coil (150) is an LC resonant coil, and it is configured to transmit electric power to a resonance coil (210) mounted on a vehicle (200) in a non-contact manner as a result of resonance with the resonance coil (210) through electromagnetic field. A switching device (140) is provided between the plurality of electromagnetic induction coils (130) and the high-frequency power supply device (110), and configured to be able to switch the electromagnetic induction coil (130) to electrically be connected to the high-frequency power supply device (110).

Description

ELECTRIC POWER FEED DEVICE FOR VEHICLE AND ELECTRIC POWER RECEPTION DEVICE
The present invention relates to an electric power feed device for vehicle and an electric power reception device, and particularly to an electric power feed device for vehicle feeding electric power to a vehicle in a non-contact manner as a result of resonance of an electric power transmission coil provided in the electric power feed device outside the vehicle and an electric power reception coil mounted on the vehicle through electromagnetic field and an electric power reception device receiving electric power from the electric power feed device in a non-contact manner.
Electrically powered vehicles such as an electric vehicle or a hybrid vehicle have attracted much attention as environmentally friendly vehicles. These vehicles incorporate a motor generating driving force for running and a rechargeable power storage device storing electric power supplied to the motor. The hybrid vehicle includes a vehicle incorporating not only a motor but also an internal combustion engine as an additional motive power source, a vehicle incorporating not only a power storage device but also a fuel cell as a DC power supply for driving a vehicle, and the like.
With regard to a hybrid vehicle as well, a vehicle in which a vehicle-mounted power storage device is chargeable by a power supply outside the vehicle has been known, as in the case of an electric vehicle. For example, what is called a "plug-in hybrid vehicle," in which a power storage device is chargeable by a power supply in a general household by connecting a power outlet provided in a house and a charge port provided in the vehicle to each other through a charge cable, has been known.
Meanwhile, wireless electric power transmission without using a power code or a power transmission cable has recently attracted attention as an electric power transmission method. Three promising techniques of electric power transmission using electromagnetic induction, electric power transmission using microwaves, and electric power transmission using a resonance method have been known as such a wireless electric power transmission technique.
Among these, a resonance method is such a non-contact electric power transmission technique that a pair of resonators (for example, a pair of self-resonant coils) is caused to resonate in electromagnetic field (near field) so that electric power is transmitted through the electromagnetic field, and it even allows transmission of electric power as high as several kW over a relatively long distance (for example, several m).
For example, an electrically powered vehicle and an electric power feed device for vehicle disclosed in Japanese Patent Laying-Open No. 2009-106136 (see PTL 1) have been known as an electric power feed device for vehicle and an electric power reception device using this resonance method.
Japanese Patent Laying-Open No. 2009-106136 Japanese National Patent Publication No. 2009-501510 Japanese Patent Laying-Open No. 2004-166384 WO98/34319
Variation in positional relation between an electric power transmission coil in an electric power feed device and an electric power reception coil mounted on a vehicle leads to variation in electric power transmission efficiency from the electric power transmission coil to the electric power reception coil. In the vehicle, since variation or the like in vehicle height due to a position where a car stops or loads carried thereon leads to variation in positional relation between the electric power transmission coil and the electric power reception coil for each occasion of electric power feed, it is aimed to enhance electric power transmission efficiency in consideration of such a change in condition. In addition, measures that can be taken for that purpose should also be implemented with a configuration as simple as possible. The electrically powered vehicle and the electric power feed device for vehicle disclosed in Japanese Patent Laying-Open No. 2009-106136 above do not particularly address such a problem.
Therefore, an object of the present invention is to provide an electric power feed device for vehicle capable of enhancing efficiency in electric power transmission using a resonance method with a simplified configuration and an electric power reception device.
According to the present invention, an electric power feed device for vehicle includes an electric power transmission coil, a power supply device, a plurality of electromagnetic induction coils, and a switching device. The electric power transmission coil is configured to transmit electric power to an electric power reception coil mounted on a vehicle in a non-contact manner, as a result of resonance with the electric power reception coil through electromagnetic field. The power supply device generates electric power having a prescribed frequency. The plurality of electromagnetic induction coils are each configured to supply electric power output from the power supply device to the electric power transmission coil by electromagnetic induction. The switching device is provided between the plurality of electromagnetic induction coils and the power supply device and configured to be able to switch an electromagnetic induction coil to electrically be connected to the power supply device.
In the present invention, a plurality of electromagnetic induction coils configured to supply electric power output from a power supply device to an electric power transmission coil by electromagnetic induction are provided, and an electromagnetic induction coil to electrically be connected to the power supply device can be switched by a switching device. Here, since variation or the like in vehicle height due to a position where the vehicle stops or loads carried thereon leads to variation in positional relation between the electric power transmission coil and the electric power reception coil for each occasion of electric power feed, efficiency in electric power transmission from the electric power feed device to the vehicle accordingly changes. According to the present invention, an electromagnetic induction coil relatively high in electric power transmission efficiency can readily be selected by the switching device for each occasion of electric power feed.
Preferably, the switching device includes a plurality of relays. The plurality of relays are provided in correspondence with the plurality of electromagnetic induction coils respectively, and each relay is connected between a corresponding electromagnetic induction coil and the power supply device.
Preferably, the electromagnetic induction coils are different from one another in coil diameter.
Further preferably, the electromagnetic induction coils are disposed in an identical plane.
In addition, according to the present invention, an electric power reception device is mounted on a vehicle, and it includes an electric power reception coil, a plurality of electromagnetic induction coils, and a switching device. The electric power reception coil is configured to receive electric power from an electric power transmission coil included in an electric power feed device outside the vehicle in a non-contact manner, as a result of resonance with the electric power transmission coil through electromagnetic field. The plurality of electromagnetic induction coils are each configured to extract electric power received by the electric power reception coil by electromagnetic induction. The switching device is provided between the plurality of electromagnetic induction coils and a vehicle electric system and configured to be able to switch an electromagnetic induction coil to electrically be connected to the vehicle electric system.
In the present invention, a plurality of electromagnetic induction coils configured to extract electric power received by an electric power reception coil by electromagnetic induction are provided, and an electromagnetic induction coil to electrically be connected to a vehicle electric system can be switched by a switching device. Here, since variation or the like in vehicle height due to a position where the vehicle stops or loads carried thereon leads to variation in positional relation between the electric power transmission coil and the electric power reception coil for each occasion of electric power feed, efficiency in electric power transmission from the electric power feed device to the vehicle accordingly changes. According to the present invention, an electromagnetic induction coil relatively highest in received electric power can readily be selected by the switching device for each occasion of electric power reception.
Preferably, the switching device includes a plurality of relays. The plurality of relays are provided in correspondence with the plurality of electromagnetic induction coils respectively, and each relay is connected between a corresponding electromagnetic induction coil and the vehicle electric system.
Preferably, the electromagnetic induction coils are different from one another in coil diameter.
Further preferably, the electromagnetic induction coils are disposed in an identical plane.
According to the present invention, an electric power feed device for vehicle capable of enhancing efficiency in electric power transmission using a resonance method with a simplified configuration and an electric power reception device can be realized.
Fig. 1 is a functional block diagram showing an overall configuration of a vehicle electric power feed system according to a first embodiment of the present invention. Fig. 2 is a diagram for illustrating principles of electric power transmission using a resonance method. Fig. 3 is a diagram showing relation between a distance from a current source (magnetic current source) and electromagnetic field intensity. Fig. 4 is a diagram showing variation in electric power transmission efficiency from an electric power feed device to a vehicle when a switching device shown in Fig. 1 is operated. Fig. 5 is a functional block diagram showing an overall configuration of a vehicle electric power feed system according to a second embodiment.
An embodiment of the present invention will be described hereinafter in detail with reference to the drawings. In the drawings, the same or corresponding elements have the same reference characters allotted and description thereof will not be repeated.
(First Embodiment)
Fig. 1 is a functional block diagram showing an overall configuration of a vehicle electric power feed system according to a first embodiment of the present invention. Referring to Fig. 1, this vehicle electric power feed system includes an electric power feed device 100 and a vehicle 200.
Electric power feed device 100 includes a high-frequency power supply device 110, a coaxial cable 120, a plurality of electromagnetic induction coils 130, a switching device 140, and a resonance coil 150. In addition, electric power feed device 100 further includes a communication antenna 160, a communication device 170, and an ECU (Electronic Control Unit) 180.
High-frequency power supply device 110 converts system electric power received from a power plug 350 connected, for example, to a system power supply into prescribed high-frequency electric power and outputs the high-frequency electric power to coaxial cable 120. It is noted that a frequency of high-frequency electric power generated by high-frequency power supply device 110 is set, for example, to a prescribed value within a range from 1 M to more than 10 MHz.
The plurality of electromagnetic induction coils 130 are disposed substantially coaxially with resonance coil 150 at a prescribed distance from resonance coil 150. Each electromagnetic induction coil 130 can magnetically be coupled to resonance coil 150 by electromagnetic induction and it is configured to feed high-frequency electric power supplied from high-frequency power supply device 110 to resonance coil 150 by electromagnetic induction.
Switching device 140 is provided between the plurality of electromagnetic induction coils 130 and coaxial cable 120 and it includes a plurality of relays provided in correspondence with the plurality of electromagnetic induction coils 130 respectively. As any of the plurality of relays is turned on as appropriate in response to a control signal from ECU 180, switching device 140 switches an electromagnetic induction coil to electrically be connected to coaxial cable 120, in response to the control signal from ECU 180.
Resonance coil 150 is an LC resonant coil, and it receives supply of electric power by electromagnetic induction from an electromagnetic induction coil electrically connected to coaxial cable 120 by switching device 140. Resonance coil 150 is configured to transmit electric power to vehicle 200 in a non-contact manner as a result of resonance with a resonance coil 210 for electric power reception mounted on vehicle 200, through electromagnetic field. It is noted that a coil diameter and the number of turns of resonance coil 150 are set as appropriate such that a Q value (for example, Q>100), a degree of coupling kappa, and the like increase, based on a distance from resonance coil 210 of vehicle 200, a resonance frequency, and the like.
Communication antenna 160 is connected to communication device 170. Communication device 170 is a communication interface for establishing communication with a communication device 300 of vehicle 200, and it receives information transmitted from communication device 300 of vehicle 200 and outputs the information to ECU 180. It is noted that the information transmitted from communication device 300 of vehicle 200 to communication device 170 includes, for example, information on an electric power transmission request command and electric power received by vehicle 200 and the like.
ECU 180 controls an operation of high-frequency power supply device 110 and switching device 140. Specifically, when communication device 170 receives an electric power transmission request command, ECU 180 controls high-frequency power supply device 110 so as to generate prescribed high-frequency electric power. In addition, ECU 180 receives a detection value of electric power received by vehicle 200 from communication device 170 while electric power is being fed from electric power feed device 100 to vehicle 200, and controls switching device 140 such that electromagnetic induction coil 130 highest in electric power transmission efficiency among the plurality of electromagnetic induction coils 130 is electrically connected to coaxial cable 120.
Meanwhile, vehicle 200 includes resonance coil 210, a plurality of electromagnetic induction coils 220, a switching device 230, a rectifier circuit 240, a charger 250, a power storage device 260, and a motive power output device 270. In addition, vehicle 200 further includes an electric power sensor 280, an ECU 290, communication device 300, and a communication antenna 310.
Resonance coil 210 is an LC resonant coil, and it is configured to receive electric power from electric power feed device 100 in a non-contact manner as a result of resonance with resonance coil 150 for electric power transmission included in electric power feed device 100, through electromagnetic field. It is noted that a coil diameter and the number of turns of this resonance coil 210 are also set as appropriate such that a Q value (for example, Q>100), a degree of coupling kappa and the like increase, based on a distance from resonance coil 150 of electric power feed device 100, a resonance frequency, and the like.
The plurality of electromagnetic induction coils 220 are disposed substantially coaxially with resonance coil 210 at a prescribed distance from resonance coil 210. Each electromagnetic induction coil 220 can magnetically be coupled to resonance coil 210 by electromagnetic induction and it is configured to extract electric power received by resonance coil 210 by electromagnetic induction and output the electric power to rectifier circuit 240.
Switching device 230 is provided between the plurality of electromagnetic induction coils 220 and rectifier circuit 240 and it includes a plurality of relays provided in correspondence with the plurality of electromagnetic induction coils 220 respectively. As any of the plurality of relays is turned on as appropriate in response to a control signal from ECU 290, switching device 230 switches an electromagnetic induction coil to electrically be connected to rectifier circuit 240, in response to the control signal from ECU 290.
Rectifier circuit 240 rectifies electric power (AC) extracted from resonance coil 210 by using electromagnetic induction coil 220 electrically connected by switching device 230, and outputs the resultant electric power to charger 250. Charger 250 converts electric power rectified by rectifier circuit 240 to a voltage level of power storage device 260 and outputs the electric power to power storage device 260, based on a control signal from ECU 290.
Power storage device 260 is a rechargeable DC power supply, and it is implemented by a secondary battery such as a lithium ion battery or a nickel metal hydride battery. Power storage device 260 stores not only electric power supplied from charger 250 but also regenerative power generated by motive power output device 270. Then, power storage device 260 supplies the stored electric power to motive power output device 270. It is noted that a large-capacity capacitor can also be adopted as power storage device 260 and any electric power buffer capable of temporarily storing electric power supplied from electric power feed device 100 and regenerative power from motive power output device 270 and supplying the stored electric power to motive power output device 270 may be adopted.
Motive power output device 270 is configured to use electric power stored in power storage device 260 to generate driving force for running of vehicle 200. Though not particularly illustrated, motive power output device 270 includes, for example, an inverter receiving electric power output from power storage device 260, a motor driven by the inverter, a driving wheel receiving driving force from the motor, and the like. It is noted that motive power output device 270 may also include an engine capable of driving a generator for charging power storage device 260.
Electric power sensor 280 detects electric power received by vehicle 200, for example, by detecting electric power input to charger 250, and outputs the detection value to ECU 290. It is noted that an installation site of electric power sensor 280 is not limited to an input side of charger 250 but it may be installed on an output side of charger 250 or at other locations. Alternatively, a voltage sensor and a current sensor may be provided instead of electric power sensor 280 and received electric power may be calculated based on a detection value from each sensor.
ECU 290 outputs to communication device 300, an electric power transmission request command requesting electric power transmission from electric power feed device 100 to vehicle 200. During electric power feed from electric power feed device 100 to vehicle 200, ECU 290 controls an operation of charger 250 and switching device 230. Specifically, ECU 290 controls charger 250 so as to convert electric power output from rectifier circuit 240 to a voltage level of power storage device 260. In addition, receiving a detection value of electric power received by vehicle 200, ECU 290 controls switching device 230 so as to electrically connect electromagnetic induction coil 220 greatest in received electric power among the plurality of electromagnetic induction coils 220 to rectifier circuit 240. Moreover, ECU 290 outputs to communication device 300, the detection value of received electric power received from electric power sensor 280.
Communication device 300 is a communication interface for establishing communication with communication device 170 of electric power feed device 100, and it transmits an electric power transmission request command and such information as a detection value of received electric power received from ECU 290 to communication device 170 of electric power feed device 100. Communication antenna 310 is connected to communication device 300.
In this vehicle electric power feed system, high-frequency electric power having a prescribed frequency is generated by high-frequency power supply device 110. Then, the high-frequency electric power is supplied from high-frequency power supply device 110 to electromagnetic induction coil 130 electrically connected to coaxial cable 120 by switching device 140, and electric power is supplied from that electromagnetic induction coil 130 to resonance coil 150 by electromagnetic induction.
Then, resonance coil 150 of electric power feed device 100 and resonance coil 210 of vehicle 200 resonate through electromagnetic field, and energy is transmitted from resonance coil 150 to resonance coil 210. Electric power received by resonance coil 210 in vehicle 200 is extracted from resonance coil 210 by electromagnetic induction coil 220 electrically connected to rectifier circuit 240 by switching device 230 and supplied to power storage device 260 through rectifier circuit 240 and charger 250.
Here, in this vehicle electric power feed system, a plurality of electromagnetic induction coils 130 are provided in electric power feed device 100. Then, electromagnetic induction coil 130 highest in electric power transmission efficiency among the plurality of electromagnetic induction coils 130 is selected as appropriate and that selected electromagnetic induction coil 130 is electrically connected to coaxial cable 120 by switching device 140.
Similarly, in vehicle 200 on the electric power reception side as well, a plurality of electromagnetic induction coils 220 are provided. Then, electromagnetic induction coil 220 greatest in received electric power among the plurality of electromagnetic induction coils 220 is selected as appropriate and that selected electromagnetic induction coil 220 is electrically connected to rectifier circuit 240 by switching device 230.
Thus, in this vehicle electric power feed system, a plurality of electromagnetic induction coils are provided in electric power feed device 100 and vehicle 200 and an electromagnetic induction coil highest in electric power transmission efficiency (received electric power) from electric power feed device 100 to vehicle 200 is selected as appropriate.
Fig. 2 is a diagram for illustrating principles of electric power transmission using a resonance method. Referring to Fig. 2, according to this resonance method, two LC resonant coils (resonance coils) resonate in electromagnetic field (near field) as in resonance of two tuning forks, so that electric power is transmitted from one coil to the other coil through electromagnetic field.
Specifically, electromagnetic induction coil 130 is connected to high-frequency power supply device 110 and high-frequency electric power is fed from electromagnetic induction coil 130 to resonance coil 150 magnetically coupled to electromagnetic induction coil 130 by electromagnetic induction. Resonance coil 150 is an LC resonant coil and resonates with resonance coil 210 of vehicle 200 through electromagnetic field (near field). Then, energy (electric power) moves from resonance coil 150 to resonance coil 210 through electromagnetic field. Energy (electric power) that moved to resonance coil 210 is extracted from resonance coil 210 by electromagnetic induction coil 220 magnetically coupled to resonance coil 210 by electromagnetic induction and supplied to a load 320 (showing the entire electric system including rectifier circuit 240 and subsequent components).
Fig. 3 is a diagram showing relation between a distance from a current source (magnetic current source) and electromagnetic field intensity. Referring to Fig. 3, electromagnetic field includes three components. A curve k1 represents a component inversely proportional to a distance from a wave source and it is referred to as a "radiation electromagnetic field." A curve k2 represents a component inversely proportional to a square of a distance from a wave source and it is referred to as an "induction electromagnetic field." In addition, a curve k3 represents a component inversely proportional to a cube of a distance from a wave source and it is referred to as a "static electromagnetic field."
Here, there is an area where intensity of electromagnetic waves sharply decreases with a distance from the wave source. According to the resonance method, however, energy (electric power) is transmitted by making use of this near field (evanescent field). Namely, a pair of resonators (for example, a pair of LC resonant coils) is caused to resonate by making use of the near field, so that energy (electric power) is transmitted from one resonator (resonance coil 150 of electric power feed device 100) to the other resonator (resonance coil 210 of vehicle 200). Since this near field does not propagate energy (electric power) over a long distance, the resonance method can achieve electric power transmission with less energy loss than electromagnetic waves transmitting energy (electric power) by means of the "radiation electromagnetic field" propagating energy over a long distance.
Fig. 4 is a diagram showing variation in electric power transmission efficiency from electric power feed device 100 to vehicle 200 when switching device 140 shown in Fig. 1 is operated. Referring to Fig. 4, the ordinate shows electric power transmission efficiency and the abscissa shows a frequency of transmitted electric power. Here, f0 represents a resonance frequency and electric power transmission efficiency is maximized when the frequency of transmitted electric power matches with the resonance frequency. In other words, resonance frequency f0 is determined by inductance L and capacitance C of the resonance coil, and therefore inductance L and capacitance C of the resonance coil are designed such that the resonance frequency matches with the frequency of transmitted electric power.
In Fig. 4, a solid line shows electric power transmission efficiency when electromagnetic induction coil 130 highest in electric power transmission efficiency among the plurality of electromagnetic induction coils 130 is selected, and other dotted lines show electric power transmission efficiency when other electromagnetic induction coils 130 are selected.
Electric power transmission efficiency varies as input impedance of a resonance system formed by resonance coils 150 and 210 varies. Here, as shown in Fig. 1, the plurality of electromagnetic induction coils 130 are disposed substantially coaxially with resonance coil 150 at a prescribed distance from resonance coil 150. A degree of coupling (kappa) between electromagnetic induction coil 130 and resonance coil 150 varies depending on a distance between electromagnetic induction coil 130 electrically connected to coaxial cable 120 and resonance coil 150. Therefore, switching of electromagnetic induction coil 130 by switching device 140 corresponds to variation in input impedance of resonance coil 150. The present first embodiment allows adjustment of input impedance with a simplified configuration, by providing the plurality of electromagnetic induction coils 130 different in distance from resonance coil 150 and switching device 140 selectively connecting the plurality of electromagnetic induction coils 130 to high-frequency power supply device 110.
Though not particularly illustrated, variation in electric power transmission efficiency caused when switching device 230 of vehicle 200 shown in Fig. 1 is operated is also shown as in Fig. 4, and electromagnetic induction coil 220 highest in electric power transmission efficiency (received electric power) among the plurality of electromagnetic induction coils 220 is selected by switching device 230.
As described above, according to the present first embodiment, since a plurality of electromagnetic induction coils 130 and switching device 140 are provided in electric power feed device 100, electric power transmission efficiency from electric power feed device 100 to vehicle 200 can be enhanced with a simplified configuration.
In addition, according to the present first embodiment, since a plurality of electromagnetic induction coils 220 and switching device 230 are provided in vehicle 200 on the electric power reception side, electric power transmission efficiency from electric power feed device 100 to vehicle 200 can be enhanced with a simplified configuration.
(Second Embodiment)
Fig. 5 is a functional block diagram showing an overall configuration of a vehicle electric power feed system according to a second embodiment. Referring to Fig. 5, in the present second embodiment, electric power feed device 100 includes a plurality of electromagnetic induction coils 130A instead of the plurality of electromagnetic induction coils 130, in the configuration of the electric power feed device according to the first embodiment shown in Fig. 1. In addition, in the present second embodiment, vehicle 200 includes a plurality of electromagnetic induction coils 220A instead of the plurality of electromagnetic induction coils 220, in the configuration of the vehicle according to the first embodiment shown in Fig. 1.
The plurality of electromagnetic induction coils 130A are different from one another in coil diameter, and they are disposed, for example, substantially concentrically in substantially the same plane. Though the plurality of electromagnetic induction coils 130A do not have to be located in the substantially same plane, a space for arranging the plurality of electromagnetic induction coils 130A can be made smaller by disposing the coils in substantially the same plane.
By switching electromagnetic induction coils 130A different in coil diameter by means of switching device 140, a degree of coupling between electromagnetic induction coil 130A and resonance coil 150 varies, and hence input impedance of resonance coil 150 varies. In the present second embodiment, electric power transmission efficiency can be enhanced by preparing the plurality of electromagnetic induction coils 130A different in coil diameter in advance and selecting an electromagnetic induction coil highest in electric power transmission efficiency by means of switching device 140.
Meanwhile, in vehicle 200, the plurality of electromagnetic induction coils 220A are also different from one another in coil diameter, and they are disposed, for example, substantially concentrically in substantially the same plane. Though the plurality of electromagnetic induction coils 220A do not have to be located in substantially the same plane either, a space for arranging the plurality of electromagnetic induction coils 220A can be made smaller by disposing the coils in substantially the same plane.
By switching electromagnetic induction coils 220A different in coil diameter by means of switching device 230, a degree of coupling between electromagnetic induction coil 220A and resonance coil 210 varies, and hence impedance varies. In the present second embodiment, electric power transmission efficiency can be enhanced by preparing the plurality of electromagnetic induction coils 220A different in coil diameter in advance and selecting an electromagnetic induction coil highest in electric power transmission efficiency (received electric power) by means of switching device 230.
As described above, according to the present second embodiment, an effect as in the first embodiment can be obtained and a space for arranging the plurality of electromagnetic induction coils 130A in electric power feed device 100 and a space for arranging the plurality of electromagnetic induction coils 220A in vehicle 200 can be made smaller.
Though a plurality of electromagnetic induction coils and a switching device are provided in each of electric power feed device 100 and vehicle 200 in each embodiment described above, the configuration may be such that a plurality of electromagnetic induction coils and a switching device are provided in any of electric power feed device 100 and vehicle 200. According to such a configuration as well, an effect of improvement in electric power transmission efficiency as shown in Fig. 4 can be obtained.
It is noted that resonance coil 150 corresponds to one embodiment of the "electric power transmission coil" in the present invention and resonance coil 210 corresponds to one embodiment of the "electric power reception coil" in the present invention in the description above.
It should be understood that the embodiments disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description of the embodiments above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.
100 electric power feed device; 110 high-frequency power supply device; 120 coaxial cable; 130, 220, 130A, 220A electromagnetic induction coil; 140, 230 switching device; 150, 210 resonance coil; 160, 310 communication antenna; 170, 300 communication device; 180, 290 ECU; 200 vehicle; 240 rectifier circuit; 250 charger; 260 power storage device; 270 motive power output device; 280 electric power sensor; 320 load; and 350 power plug.

Claims (8)

  1. An electric power feed device for vehicle, comprising:
    an electric power transmission coil (150) configured to transmit electric power to an electric power reception coil (210) mounted on a vehicle in a non-contact manner, as a result of resonance with the electric power reception coil through electromagnetic field;
    a power supply device (110) for generating electric power having a prescribed frequency;
    a plurality of electromagnetic induction coils (130, 130A) each configured to supply electric power output from said power supply device to said electric power transmission coil by electromagnetic induction; and
    a switching device (140) provided between said plurality of electromagnetic induction coils and said power supply device and configured to be able to switch an electromagnetic induction coil to electrically be connected to said power supply device.
  2. The electric power feed device for vehicle according to claim 1, wherein
    said switching device includes a plurality of relays provided in correspondence with said plurality of electromagnetic induction coils respectively, and
    each of said plurality of relays is connected between a corresponding electromagnetic induction coil and said power supply device.
  3. The electric power feed device for vehicle according to claim 1, wherein
    said plurality of electromagnetic induction coils (130A) are different from one another in coil diameter.
  4. The electric power feed device for vehicle according to claim 3, wherein
    said plurality of electromagnetic induction coils (130A) are disposed in an identical plane.
  5. An electric power reception device mounted on a vehicle, comprising:
    an electric power reception coil (210) configured to receive electric power from an electric power transmission coil (150) included in an electric power feed device (100) outside the vehicle in a non-contact manner, as a result of resonance with the electric power transmission coil through electromagnetic field;
    a plurality of electromagnetic induction coils (220, 220A) each configured to extract electric power received by said electric power reception coil by electromagnetic induction; and
    a switching device (230) provided between said plurality of electromagnetic induction coils and a vehicle electric system and configured to be able to switch an electromagnetic induction coil to electrically be connected to said vehicle electric system.
  6. The electric power reception device according to claim 5, wherein
    said switching device includes a plurality of relays provided in correspondence with said plurality of electromagnetic induction coils respectively, and
    each of said plurality of relays is connected between a corresponding electromagnetic induction coil and said vehicle electric system.
  7. The electric power reception device according to claim 5, wherein
    said plurality of electromagnetic induction coils (220A) are different from one another in coil diameter.
  8. The electric power reception device according to claim 7, wherein
    said plurality of electromagnetic induction coils (220A) are disposed in an identical plane.
PCT/JP2010/007215 2010-02-15 2010-12-13 Electric power feed device for vehicle and electric power reception device WO2011099106A1 (en)

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