WO2015121977A1

WO2015121977A1 - Non-contact power supply apparatus

Info

Publication number: WO2015121977A1
Application number: PCT/JP2014/053495
Authority: WO
Inventors: 有二成瀬; クライソントロンナムチャイ
Original assignee: 日産自動車株式会社
Priority date: 2014-02-14
Filing date: 2014-02-14
Publication date: 2015-08-20
Also published as: JP6149209B2; JPWO2015121977A1

Abstract

This non-contact power supply apparatus, which supplies power to a power reception coil (21) in a non-contact manner by means of at least magnetic operations, is provided with: a plurality of power transmission coils (11a-11c), which have different coil surface areas, while having coil surfaces thereof disposed at positions parallel to each other; a power reception coil detection means that detects the power reception coil (21); and a control means, which, on the basis of detection results obtained from the power reception coil detection means, controls power to be outputted to a magnetizing coil from the power supply. The control means selects, as the magnetizing coil, a coil to be magnetized, from among the power transmission coils (11a-11c) corresponding to a coil surface area of the power reception coil (21), and distances between the power reception coil (21) and the power transmission coils (11a-11c).

Description

Non-contact power feeding device

The present invention relates to a non-contact power feeding device.

Regarding a wireless power supply system that transmits power from a power supply resonance coil to a power reception resonance coil as magnetic field energy by resonating the power supply resonance coil and the power reception resonance coil, the power supply resonance coil uses a copper wire having a wire diameter of 1 mm as a power supply resonance coil diameter. The coil diameter E of the power reception resonance coil is made smaller than the coil diameter D of the power supply resonance coil, and the ratio of the coil diameter of the power supply resonance coil to the coil diameter of the power reception resonance coil is 100: A wireless power supply system in the range of 7 to 100: 15 is disclosed (Patent Document 1).

JP 2012-2222989 A

However, in the above wireless power supply system, when the shape of the coil surface of the power reception resonance coil or the distance between the power reception resonance coil and the power transmission resonance coil differs depending on the device that receives power, the power transmission coil There was a problem of lowering.

The problem to be solved by the present invention is to reduce the power transmission efficiency even when the area of the coil surface of the power receiving coil or the distance between the power receiving coil and the power transmitting coil is different depending on the device that receives power. Provided is a non-contact power feeding device that can be suppressed.

In the present invention, a plurality of power transmission coils having different coil surface areas are arranged so that the coil surfaces are parallel to each other, and the area of the coil surface of the power reception coil and the distance between the power reception coil and the power transmission coil Accordingly, the above-mentioned problem is solved by selecting a coil to be excited among a plurality of power transmission coils as an excitation coil and controlling the power output from the power source to the excitation coil.

In the present invention, since a coil is selected from a plurality of power transmission coils so that the coil surface of the coil on the power transmission side becomes an optimum coil surface with respect to the coil surface of the power reception coil, the power transmission coil and the power reception are selected. Coupling with the coil is increased, and a decrease in power transmission efficiency can be suppressed.

It is a block diagram of the non-contact electric power feeding system concerning this embodiment. It is a perspective view of the power transmission coil and power receiving coil of FIG. It is a graph which shows the characteristic of the coupling coefficient with respect to the magnitude | size (size) of the power transmission coil of FIG. It is a graph which shows the characteristic of the magnitude | size of the power transmission coil with respect to the distance between coils of FIG. 3 is a graph showing a characteristic of a ratio (D1 / D2) of a size of a power receiving coil and a size of a power transmitting coil with respect to a ratio (G / D2) of a size of the power receiving coil and a distance (G) between the coils in FIG. It is a perspective view of the power transmission coil of FIG. (A) It is a graph which shows the characteristic of the component of the Z direction component of magnetic flux density when the electric current of 1A (ampere) is supplied to one power transmission coil. (B) It is a graph which shows the characteristic of the component of the Z direction of magnetic flux density when the electric current of 1A and 2A is each supplied to the power transmission coil 11a and the power transmission coil 11b. It is sectional drawing of the power transmission coil and power receiving coil of FIG. It is a graph which shows the characteristic of the current amplitude ratio with respect to the size of the receiving coil of FIG. It is a figure for demonstrating the map recorded on the memory of FIG. It is a flowchart which shows the control flow of the controller of FIG. 1, and a receiving coil detection part. 1A and 1B are diagrams for explaining coil areas of a power transmission coil and a power reception coil, in which FIG. 1A is a perspective view of a loop-shaped coil, and FIG. 1B is a perspective view of a solenoid-shaped coil. In the non-contact electric power feeding system which concerns on other embodiment of this invention, it is a top view of a power transmission coil and a receiving coil. It is a side view of the power transmission coil and power receiving coil of FIG. In the non-contact electric power feeding system which concerns on other embodiment of this invention, it is a top view of a power transmission coil and a receiving coil. It is a side view of the power transmission coil and power receiving coil of FIG. It is a perspective view of the power transmission coil of FIG. It is a graph which shows the characteristic of the coupling coefficient with respect to the pitch length of the power transmission coil of FIG. 1 is a diagram for explaining the coil area of the power transmission coil and the power reception coil, is a perspective view of the power transmission coil of FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

<< First Embodiment >>
FIG. 1 is a block diagram of a contactless power feeding system according to an embodiment of the present invention. The non-contact power feeding system of this example is a system that supplies power in a non-contact manner between a non-contact power feeding device provided on the ground and a vehicle that is a moving body. The non-contact power supply system includes a power transmission side unit provided on the ground and a power reception side unit provided on the vehicle.

First, the ground unit will be explained. The unit on the ground side includes a power feeding device 10 and an AC power supply 30. The power feeding device 10 is provided in a parking space for parking a vehicle, for example. The AC power supply 30 is a 100V or 200V household power supply.

The power feeding device 10 includes power transmission coils 11a to 11c, resonance capacitors 12a to 12c, amplitude adjustment circuits 13a to 13c, an inverter 14, a controller 15, a memory 16, a power receiving coil detector 17, and a communication device 18. And.

The power transmission coils 11a to 11c are coils that transmit power to the power reception coil 21 in a non-contact manner at least by a magnetic action. In this example, electric power is transmitted using magnetic resonance. The power transmission coils 11a to 11c are a plurality of coils configured such that the coil surfaces are different from each other while the coil surfaces are arranged in parallel to each other. The power transmission coils 11a to 11c are coils each having a circular coil surface. The coil surface indicates a surface acting as a coil, and is a circular surface in the example of FIG. The diameters (D _1a , D _1b , D _1c ) of the coil surfaces of the power transmission coils 11a to 11c are different from each other, the diameter (D _1a ) of the power transmission coil 11a is the shortest, and the diameter (D _1c ) of the power transmission coil 11c. ) Is the longest diameter. When viewed from the normal direction of the coil surface, the coil surfaces of the power transmission coils 11a to 11c overlap each other. In this example, the coil surfaces of the power transmission coils 11a to 11c are arranged in the same plane. The power transmission coils 11a to 11c are configured by winding a conducting wire once or a plurality of times.

When a vehicle including the power receiving coil 21 is parked in a predetermined parking space, the power transmitting coils 11a to 11c are positioned below the power receiving coil 21 (side closer to the ground) while maintaining a predetermined distance from the power receiving coil 21. . The power transmission coils 11a to 11c are independent coils. The power transmission coils 11a to 11c are installed along the ground surface of the parking space.

The resonance capacitors 12a to 12c are connected to the power transmission coils 11a to 11c, respectively. The resonance coils 12a to 12c are capacitors for forming a resonance circuit together with the power transmission coils 11a to 11c.

The amplitude adjustment circuits 13a to 13c are circuits for adjusting the amplitude of the alternating current output from the inverter 14 to the coils 11a to 11c, and are connected between the resonance capacitors 12a to 12c and the inverter 14. The amplitude adjustment circuits 13a to 13c are controlled by the controller 15. The amplitude adjustment circuits 13a to 13c are also circuits that select and supply the output power of the inverter 14 to the power transmission coils 11a to 11c under the control of the controller 15. For example, when the amplitude adjustment circuits 13a and 13b are operating and the amplitude adjustment circuit 13c is stopped, the power of the inverter 14 is supplied to the

power transmission coils

11a and 11b, and the current flows to the

power transmission coils

11a and 11b. Does not flow into the power transmission coil 11c. As a result, among the plurality of power transmission coils 11a to 11c, a coil that allows current to flow and a coil that does not allow current to flow are selectively switched.

The inverter 14 is a conversion circuit for converting AC power input from the AC power supply 30 and outputting the AC power to the power transmission coils 11a to 11c via the amplitude adjustment circuits 13a to 13c and the resonance capacitors 12a to 12c. .

The controller 15 is a controller that controls the amplitude adjustment circuits 13a to 13c and the inverter 14 in accordance with the detection result of the power receiving coil detection unit 17. The memory 16 records a map showing the relationship between the distance between the power transmission coils 11a to 11c and the power reception coil 21, the size of the power reception coil 21, and the current amplitude flowing through the power transmission coils 11a to 11c. The map of the memory 16 will be described later.

The power receiving coil detector 17 uses the communication device 18 to determine the position of the power receiving coil 21, the size of the power receiving coil 21, and the distance between the power transmitting coils 11a to 11c and the power receiving coil 21 (hereinafter also referred to as the inter-coil distance). ) And the detection result is output to the controller 15. When detecting the position of the receiving coil 21, the receiving coil detection part 17 transmits an infrared signal, an ultrasonic signal, etc. by the communication device 18, for example, and detects the position of the receiving coil 21 from the reflected wave of the signal. . The power receiving coil detection unit 17 may detect the distance between the coils from the position of the power receiving coil 21.

The power receiving coil detection unit 17 detects the size of the power receiving coil 21 by using the communication device 18 to receive information indicating the size of the power receiving coil 21 from the vehicle side. Information on the size of the power receiving coil 21 is recorded in the memory 26 on the vehicle side. When the vehicle height information is recorded in the memory 26, the power receiving coil detection unit 17 receives the vehicle height information using the communicator 18, and from the vehicle height information, the information between the coils is received. The distance may be detected. The communication device 18 has an antenna and communicates with the communication device 28 on the vehicle side by radio.

Next, the vehicle unit will be explained. The vehicle-side unit includes a power receiving coil 21, a resonance capacitor 22, a load 23, a memory 26, and a communication device 28. These configurations are provided in the vehicle.

The power receiving coil 21 is a coil that receives power supplied from the power transmitting coils 11a to 11-11. The power receiving coil 21 is a circular coil having a coil surface parallel to the coil surfaces of the power transmitting coils 11a to 11c. The power receiving coil 21 is a single loop coil. The diameter (D ₂ ) of the coil surface of the power receiving coil 21 is smaller than the diameter of the coil surface of the power transmission coil 11c. The power receiving coil 21 is provided along the chassis of the vehicle.

The resonant capacitor 22 is connected to the power receiving coil 21 and is a capacitor for forming a resonant circuit together with the power receiving coil 21. The load 23 is a battery or a motor. In addition, when the battery included in the load 23 is charged with the power received by the power receiving coil 21, an inverter or the like for converting alternating current into direct current is connected between the battery and the power receiving coil 21.

The memory 26 records information on the size of the power receiving coil 21, position information on the power receiving coil 21, vehicle height information, battery information on the load 23, and the like. The communicator 28 has an antenna and communicates with the vehicle-side communicator 28 wirelessly. The communication device 28 transmits information recorded in the memory 26 to the ground side unit.

Next, the relationship among the sizes of the power transmission coils 11a to 11c and the power reception coil 21, the distance between the coils, and the coupling coefficient (κ) will be described. In addition, although the power transmission coils 11a to 11c in this example are a plurality of coils, only one power transmission coil 11 is used here for the sake of explanation. FIG. 2 is a perspective view of the power transmission coil 11 and the power reception coil 21. D ₁ indicates the diameter of the power transmission coil 11, D ₂ indicates the diameter of the power receiving coil 21, and G indicates the inter-coil distance (gap).

The coupling coefficient when the size (diameter) of the power transmission coil 11 is changed for each gap (50 mm, 100 mm, 150 mm, 200 mm, 250 mm, 300 mm) while the size (diameter) of the power receiving coil 21 is fixed at 500 mm. The characteristic is as shown in FIG. FIG. 3 is a graph showing the characteristics of the coupling coefficient with respect to the size (size) of the power transmission coil 11. As shown in FIG. 3, the coupling coefficient has a peak at one point of the diameter of the power transmission coil 11. For example, when the gap is 50 mm, the coupling coefficient takes a peak value (0.36) when the diameter of the power transmission coil 11 is 50 mm.

Also, the coupling coefficient decreases as the gap increases, but the diameter of the power transmission coil 11 that takes the peak value of the coupling coefficient increases as the gap increases (see the circle in FIG. 3).

The coupling coefficient (κ) represents the ratio between the generated magnetic flux and the magnetic flux interlinking the counterpart coil. When the size of the power transmission coil 11 and the size of the power reception coil 21 are the same (corresponding to D ₁ = D ₂ = 500 mm in FIG. 3) and the gap is small, the magnetic flux generated in the power transmission coil 11 is reduced. Since most of them are linked to the power receiving coil 21, the coupling coefficient increases. On the other hand, when the sizes of the power transmission coil 11 and the power reception coil 21 are the same and the gap is large, the magnetic flux generated in the power transmission coil 11 is short-circuited without interlinking with the power reception coil 21, so that the coupling coefficient is It gets smaller.

That is, as shown in FIG. 3, when the size of the power transmission coil 11 and the size (diameter) of the power reception coil 21 are set to the same size of 500 mm and the gap (G) is increased from 50 mm to 100 mm, the coupling coefficient decreases. (G: corresponds to a graph of 100 mm and D ₁ = 500 mm). From this state, when the size of the power transmission coil 11 is increased to an appropriate size (D ₁ = about 550 mm), the coupling coefficient increases and takes the maximum value (G: corresponding to the peak value of the graph of 100 mm).

Further, when the size (D ₂ ) of the power receiving coil 21 is 500 mm, the size (D ₁ ) of the power transmitting coil 11 is 550 mm, and the gap (G) is reduced from 100 mm, the coupling coefficient becomes smaller than the peak value. In this state, when viewed in the Z direction in FIG. 2, the power receiving coil 21 can receive the interlinkage magnetic flux in the overlapping portion of the power transmission coil 11 and the power receiving coil 21, but the magnetic flux in the non-overlapping portion is the power receiving coil 21. The coupling coefficient is lowered because the chain is not linked.

As described above, in order to increase the coupling coefficient (κ), there is an appropriate size of the power transmission coil 11 with respect to the size of the power receiving coil 21 and the distance (gap) between the coils.

Furthermore, the relationship among the coupling coefficient (κ), the sizes of the power transmission coils 11a to 11c and the power reception coil 21, and the distance between the coils is generalized with reference to FIGS. FIG. 4 shows the distance (G) between the coils as the horizontal axis and the size (D ₁ ) of the power transmission coil that maximizes the coupling coefficient (κ) as the vertical axis, for each size of the power receiving coil 21 (D ₂ = It is a graph which shows the characteristic of 400, 500, 600 (mm)). FIG. 5 shows the size of the power receiving coil and the size of the power transmitting coil with the ratio (G / D ₂ ) between the size of the power receiving coil 21 and the inter-coil distance (G) being the horizontal axis and maximizing the coupling coefficient (κ). 6 is a graph showing characteristics for each size (D ₂ = 400, 500, 600 (mm)) of the power receiving coil 21 with the ratio (D ₁ / D ₂ ) of the vertical axis as the vertical axis.

As shown in FIG. 4, if the size of the power receiving coil 21 is the same, the size (D ₁ ) of the power transmission coil for maximizing the coupling coefficient increases as the gap increases. Further, if the size of the gap is the same, the size (D ₁ ) of the power transmission coil for maximizing the coupling coefficient decreases as the size of the power receiving coil 21 increases.

In addition, as shown in FIG. 4, even if the size of the power receiving coil 21 is changed, it can be seen that the relationship between the distance between the coils and the size of the power transmitting coil 11 for maximizing the coupling coefficient is similar. Therefore, as shown in FIG. 5, when the characteristics shown in FIG. 4 are normalized by the size (D ₂ ) of the power receiving coil 21, the inter-coil distance and the coupling coefficient are maximized regardless of the size of the power receiving coil 21. It can be seen that the relationship with the size of the power transmission coil 11 to be matched is the same.

Furthermore, the characteristics shown in FIG. 5 are expressed by the following equations.

However, when the coupling coefficient takes a peak value, θ = 23 °, and when the coupling coefficient is in a range from the peak value to 10% reduction, 21 ° ≦ θ ≦ 25 °.

Further, assuming that the coil area of the power transmission coil 11 is S ₁ and the coil surface area S _{2 of} the power receiving coil 21 is the coil area (S ₁ , S ₂ ) using the coil diameters (D ₁ , D ₂ ), respectively. It is represented by the following formula (2).

When the above relational expression is expressed by the coil area (S ₁ ) while substituting Expression (2) into Expression (1), Expression (3) is obtained.

That is, if the size (D ₂ or S ₂ ) of the coil surface of the power receiving coil 21 and the distance (G) between the coils are determined, the size (D ₁ or S ₁ ) of the power transmission coil 11 that increases the coupling coefficient is determined. It will be. Therefore, if the size of the coil surface of the power transmission coil 11 is changed to an appropriate size according to the area of the coil surface of the power receiving coil 21 and the distance between the coils, the coupling coefficient becomes high.

Unlike this example, when the power transmission coil 11 is formed of a single loop coil, it is sufficient if the size of the loop can be changed according to the size of the power reception coil 21, etc. Becomes complicated.

Therefore, the system of the present invention is configured by composing a plurality of coils by configuring the power transmission coil 11 with a plurality of coils and adjusting a current amplitude flowing through the coil while selecting a coil through which a current flows from the plurality of coils. A pseudo coil that can freely change the area of the coil surface is formed.

Hereinafter, selection of the power transmission coils 11a to 11c and current amplitude of the power transmission coils 11a to 11c will be described. FIG. 6 is a perspective view of the power transmission coils 11a and 11b. The diameter (φ ₁ ) of the coil surface of the power transmission coil 11a is 400 mm, and the diameter (φ ₂ ) of the coil surface of the power transmission coil 11b is 800 mm. And the component of the Z direction of the magnetic flux density when the electric current of 1A (ampere) is each supplied to the power transmission coil 11a and the power transmission coil 11b is shown to Fig.7 (a). The component in the Z direction of the magnetic flux density is a component having a height (200 mm) in the Z direction (positive direction) from the center point O of the power transmission coils 11a and 11b. The characteristic when the horizontal axis is the diameter (R _O ) and the vertical axis is the Z direction component of the magnetic flux density while taking the diameter (R _O ) along the X direction from the height (200 mm) is shown in FIG. ). However, the two graphs shown in FIG. 7A respectively show the characteristics when a current of 1A flows through only the power transmission coil 11a and the characteristics when a current of 1A flows through only the power transmission coil 11b.

Since the power transmission coils 11a and 11b are loop coils, the magnetic flux passes through the coil wire so as to loop. Therefore, when the diameter (R ₀ ) is gradually increased from zero, the magnetic field in the Z direction is reversed from upward to downward with a certain diameter as a boundary. As shown in FIG. 7A, when a current of 1 A is supplied only to the power transmission coil 11a, the magnetic field density in the Z direction is reversed from upward to downward when the diameter (R ₀ ) is 340 mm. Further, when a current of 1 A is supplied only to the power transmission coil 11b, the magnetic field density in the Z direction is reversed from upward to downward when the diameter (R ₀ ) is 480 mm.

Next, characteristics when a current of 1 A is passed through the power transmission coil 11 b while a current of 2 A is passed through the power transmission coil 11 a will be described with reference to FIG. The measurement conditions for the magnetic flux density are the same as described above. As shown in FIG. 7B, when the diameter (R ₀ ) is 450 mm, the magnetic field density in the Z direction is reversed from upward to downward. When compared with FIG. 7A, an intermediate magnetic flux characteristic between the magnetic flux characteristic of the power transmission coil 11a and the magnetic flux characteristic of the power transmission coil 11b is obtained by passing a current through the plurality of power transmission coils 11a and 11b. It is done. That is, by passing a current having an amplitude of a predetermined ratio to the two power transmission coils 11a and 11b, a magnetic flux characteristic in which one power transmission coil is pseudo can be obtained, and further, one pseudo power transmission A coil can be made into the size (area of a coil surface) different from the two power transmission coils 11a and 11b.

In the non-contact power feeding system of this example, the power transmission coils 11a to 11c selected to flow current and the magnitude of the current amplitude to flow through the selected coil are determined by the map. The map shows the correspondence between the selection coil and current amplitude with respect to the area of the coil surface of the power receiving coil 21 and the distance between the coils, and is recorded in the memory 16.

The map of the memory 16 is created by the following method. FIG. 8 is a cross-sectional view of the power transmission coils 11 a and 11 b and the power reception coil 21, and FIG. 9 is a graph showing the characteristics of the current amplitude ratio of the power transmission coils 11 a and 11 b with respect to the size of the power reception coil 21.

As shown in FIG. 8, it is assumed that the center point of the coil surface of the power transmission coils 11a and 11b is the origin, the coordinates are taken, and the center point of the power reception coil 21 and the middle start point of the power transmission coils 11a and 11b are on the Z axis. . FIG. 8 shows the power receiving coil 21 with coordinates (x, z) and coordinates (−x, z) in the cross section of the XZ plane (see FIG. 2). The distance (G) between the coils is 100 mm. The diameter (D _1a ) of the power transmission coil 11a is 400 mm, and the diameter (D _1b ) of the power transmission coil 11b is 800 mm.

Then, at the coordinates (x, z) and the coordinates (−x, z), the current ratio of the power transmission coils 11a and 11b such that the magnetic flux density of the Z direction component becomes zero is set to the diameter of the coil surface of the power reception coil 21 (power reception). When it is determined according to the coil size, the characteristics shown in FIG. 9 are obtained. However, Ia shows the current amplitude of the power transmission coil 11a, and Ib shows the current amplitude of the power transmission coil 11b.

When the magnetic flux density of the Z direction component is zero at the coordinates (x, z) and the coordinates (−x, z), Z is within the range from the coordinates (−x, z) to the coordinates (−x, z). The magnetic flux density in the direction is positive, and outside this range, the magnetic flux density in the Z direction is negative. For example, when the size of the power receiving coil 21 is 840 mm, if the ratio (Ib / Ia) of the current amplitudes of the power transmitting coils 11a and 11b is set to 1/1, the most efficient with respect to the coil surface of the power receiving coil 21. The magnetic flux can be interlinked well. Thus, the relationship between the power transmission coils 11a to 11c to be selected and the current amplitude ratio can be obtained according to the size of the power receiving coil 21 while fixing the distance between the coils to a certain value. If the distance between the coils is changed while the size of the power receiving coil 21 is fixed, the relationship between the power transmission coils 11a to 11c to be selected and the current amplitude ratio can be obtained according to the distance between the coils.

When the relationship between the power transmission coils 11a to 11c to be selected and the current amplitude ratio according to the size of the power receiving coil 21 and the distance between the coils and the current amplitude ratio is represented by a map by the above-described creation method, the map is represented as shown in FIG. .

FIG. 10 is a graph for explaining the map. The horizontal axis indicates the size of the power receiving coil 21, and the vertical axis indicates the distance between the coils. The size of the power receiving coil 21 is indicated by the size of the diameter of the coil surface or the size of the area of the coil surface. “Coil 1” indicates the power transmission coil 11a, “Coil 2” indicates the power transmission coil 11b, and “Coil 3” indicates the power transmission coil 11c. I ₁ indicates the current amplitude flowing through the power transmission coil 11a, I ₂ indicates the current amplitude flowing through the power transmission coil 11b, and I ₃ indicates the current amplitude flowing through the power transmission coil 11c.

For example, when the size (area) of the power receiving coil 21 is Sa and the distance between the coils is Ga, a current is passed through the power transmitting coil 11a and the power transmitting coil 11b, and the current amplitude ratio (I ₁ : I ₂ ) is One to one. Further, for example, when the size (area) of the power receiving coil 21 is Sb and the distance between the coils is Gb, a current is passed through the power transmission coil 11b and the power transmission coil 11c, and the current amplitude ratio (I ₂ : I ₃ ) Is 2 to 1.

When a current flows through the plurality of power transmission coils 11a to 11c selected based on the map with the set current amplitude, the selected plurality of power transmission coils 11a to 11c are excited. Furthermore, between the synthetic coil and the receiving coil 21 of the exciter coils, for formula (3) is satisfied, the coil area of the composite coils of the exciting coils is represented by S _1.

The controller 15 detects the size of the power receiving coil 21 and the distance between the coils using the power receiving coil detector 17 and refers to the map to select a coil corresponding to the detection result (the size of the power receiving coil 21 and the distance between the coils). And the current amplitude is calculated. The controller 15 operates the amplitude adjustment circuits 13a to 13c corresponding to the selected coil, and stops the amplitude adjustment circuits 13a to 13c corresponding to the coils not selected. Then, the controller 15 controls the amplitude adjustment circuits 13a to 13c and the inverter 14 so as to obtain the calculated amplitude ratio, and causes the current having the calculated current amplitude ratio to flow through the selected power transmission coils 11a to 11c. . Thereby, the controller 15 selects a coil to be excited as the exciting coil among the plurality of power transmitting coils 11 a to 11 c according to the area of the coil surface of the power receiving coil 21 and the distance between the power transmitting coils, and from the power source 30. The power output to the exciting coil is controlled.

Next, the control flow of the controller 15 and the receiving coil detection unit 17 will be described with reference to FIG. FIG. 11 is a flowchart showing a control flow of the controller 15 and the receiving coil detector 17. Note that the control flow in FIG. 11 is a control flow from the detection of vehicle entry to the start of power supply.

In step S <b> 1, the power receiving coil detection unit 17 detects the position of the power receiving coil 21 using the communication device 18 to determine whether or not a vehicle has entered the parking space provided with the ground side unit. When the vehicle enters, the power receiving coil detection unit 17 transmits an activation signal to the controller 15, and the controller 15 activates the main system by receiving the activation signal.

In step S <b> 3, the controller 15 detects the size of the power receiving coil 21 using the power receiving coil detection unit 17. In step S <b> 4, the controller 15 detects the inter-coil distance using the receiving coil detection unit 17. In step S5, the controller 15 selects a coil to be excited according to the detected size of the power receiving coil 21 and the distance between the coils while referring to the map recorded in the memory 16. The coil to be excited is a coil that actually flows current. In step S6, the controller 15 sets the current amplitude ratio of the coil to be excited according to the detected size of the power receiving coil 21 and the distance between the coils while referring to the map recorded in the memory 16. In step S8, the controller 15 starts the power supply by controlling the amplitude adjusting circuits 13a to 13c and the inverter 14 so that the current having the set current amplitude ratio flows through the coil (selection coil) to be excited. Then, the control flow shown in FIG. 11 ends.

As described above, in this example, while detecting the power receiving coil 21, the coil to be excited among the plurality of power transmitting coils 11a to 11c is excited according to the area of the coil surface of the power receiving coil 21 and the distance between the coils. It is selected as a coil, and the power output from the power supply 30 to the exciting coil is controlled. Accordingly, the optimum transmission coil area can be set with respect to the area of the coil surface of the power receiving coil 21 in consideration of the spread of the magnetic flux generated from the power transmission coils 11a to 11c, thereby increasing the coupling coefficient between the power transmitting and receiving coils. be able to.

Generally, when a non-contact power supply system is used for applications such as electronic equipment, the power supply is several watts or less, and output performance that is more stable than loss is required for fluctuations in the gap between coils. Therefore, even if the efficiency between the coils is about 40 to 50%, it is sufficiently established. On the other hand, when a non-contact power supply system is applied to a moving body such as an electric vehicle, a power supply of several kW or more is required. For example, when the battery capacity of the battery included in the load 23 is 24 kWh, 8 hours are required for power supply of 3 kW. For this reason, when the loss is large, the output when power is supplied is increased, and the temperature of the coil becomes high, which may affect continuous power supply for a long time. Further, since a cooling facility for lowering the coil temperature is required, the cost of the system increases and the size of the apparatus increases.

Furthermore, when power is supplied to an electric vehicle or the like, the unit on the ground side is required to support various vehicle types. In other words, since the position of the power receiving coil 21 and the distance between the coils differ depending on the vehicle type, the position or size has changed when the power transmission side unit is designed assuming only the position and size of one charger coil. In this case, the power transmission efficiency decreases.

Further, in order to deal with any power receiving coil 21, the number of power transmitting coils is increased so that only one coil having an appropriate size can be selected according to the size of the coil surface of the power receiving coil and the distance between the coils. Configuration is also conceivable. However, in order to cope with many vehicle types, the number of power transmission coils becomes enormous.

In this example, a plurality of power transmission coils 11a to 11c are configured in a small number, and the power transmission coil having an appropriate coil surface size is synthesized according to the size of the coil surface of the power receiving coil and the distance between the coils. A coil is formed. Therefore, even when the size of the power receiving coil 21 is different, the power transmission efficiency can be kept high. As a result, an increase in coil temperature can also be suppressed. Furthermore, since the number of power transmission coils is small, it is possible to reduce the size and cost of the ground unit.

In the present invention, the currents flowing through the power transmission coils 11a to 11c are controlled so as to satisfy the relational expression (3) between the power transmission coils 11a to 11c to be excited and the power reception coil. As a result, the area of the coil surfaces of the power transmission coils 11a to 11c becomes an optimal area with respect to the coil surface of the power receiving coil 21, so that the coupling coefficient between the coils can be increased.

In this example, power is simultaneously supplied to a plurality of coils selected among the power transmission coils 11a to 11c. As a result, magnetic fluxes generated by the plurality of power transmission coils 11a to 11c can be combined to bring the magnetic flux distribution closer to a coil having an optimal coil area, so that the coupling coefficient between the coils can be increased.

Also, in this example, the amplitude of the current flowing through the plurality of power transmission coils 11a to 11c is set according to the area of the coil surface of the power receiving coil 21 and the distance between the coils. As a result, magnetic fluxes generated by the plurality of power transmission coils 11a to 11c can be combined to bring the magnetic flux distribution closer to a coil having an optimal coil area, so that the coupling coefficient between the coils can be increased.

Further, the power transmission coils 11a to 11c of the present example are arranged at positions where the coil surfaces overlap each other when viewed from the normal direction of the coil surfaces. As a result, when the power transmission coils 11a to 11c and the power reception coil 21 face each other, the magnetic flux can be sent to the power reception coil 21 regardless of the current transmission coil 11a to 11c. The coupling coefficient can be increased.

In this example, information on the power receiving coil 21 is transmitted using the

communication devices

18 and 28 for transmitting battery information (SOC: State of Charge, etc.). Therefore, it is not necessary to separately provide a dedicated communication device for transmitting the coil information of the power receiving coil 21.

In this example, the current amplitude ratio is set according to the area of the coil surface of the power receiving coil 21 and the distance between the coils, but the current phase may be set instead of the current amplitude.

As for the area of the coil surface of the power transmission coils 11a to 11c or the power reception coil 21c, as shown in FIG. 12A, when the power transmission coils 11a to 11c or the power reception coil 21c are loop-shaped coils, FIG. The area surrounded by the circle P in (a) is the area of the coil surface. On the other hand, when the power transmission coils 11a to 11c or the power reception coil 21c are solenoid type, the area surrounded by the rectangle Q in FIG. 12A is the area of the coil surface.

The power receiving coil detector 17 corresponds to the “power receiving coil detector” of the present invention, and the controller 15 corresponds to the “controller” of the present invention.

<< Second Embodiment >>
13 and 14 are diagrams for explaining the coil shape of the non-contact power feeding system according to another embodiment of the invention. In this example, the shapes of the power transmission coils 11a to 11c are different from the first embodiment described above. Other configurations are the same as those in the first embodiment described above, and the description thereof is incorporated.

FIG. 13 is a plan view of the power transmission coils 11a to 11c and the power reception coil 21, and FIG. 14 is a side view of the power transmission coils 11a to 11c and the power reception coil 21. In addition, the arrow of FIG. 13 has shown the advancing direction of the vehicle.

The power transmission coils 11a to 11c are rectangular coils. The length of the power transmission coils 11a to 11c in the Y direction is slightly longer than the diameter (500 mm) of the power reception coil 21, the length of the power transmission coil 11a (D _1a ) is 550 mm, and the length of the power transmission coil 11b (D _1b ) is 600 mm, and the length (D _1c ) of the power transmission coil 11c is 700 mm. On the other hand, the length of the power transmission coils 11a to 11c in the Y direction is considerably longer than the diameter (500 mm) of the power reception coil 21. The distance (G) between the coils is 200 mm. The coil surfaces of the power transmission coils 11a to 11c are portions surrounded by a rectangular shape.

As in the first embodiment, the controller 15 detects the power receiving coil 21 and excites the power transmitting coils 11a to 11c according to the area of the coil surface of the power receiving coil 21 and the distance between the coils. The coil to be operated is selected as the exciting coil, and the power output from the power supply 30 to the exciting coil is controlled.

In order to supply electric power to a running vehicle in a non-contact manner, a configuration in which a plurality of loop-shaped power transmission coils 1 are arranged along the traveling direction of the vehicle is also conceivable. At this time, the power receiving coil moves at a speed of several tens to hundreds of kilometers per hour from the speed of the vehicle. For this reason, the time for the power receiving coil to pass through the coils arranged in the traveling direction of the vehicle is several tens of milliseconds to one hundred and several tens of milliseconds. If the energizing coil is not switched at this time, the power receiving coil receives a continuous magnetic field. I can't. Therefore, in such a system configuration, the infrastructure cost becomes enormous.

In the system according to the second embodiment, the coil length in the traveling direction of the vehicle is sufficiently longer than the coil length in the width direction of the vehicle, so that the balance between cost and power feeding performance can be achieved. The widths (D _1a , D _1b , D _1c ) of the power transmission coils 11a to 11c are the same as the diameters (D _1a , D _1b , D _1c ) of the coil surfaces of the power transmission coils 11a to 11c according to the first embodiment. While deciding, the coil to be excited is switched to selection according to the area of the coil surface of the power receiving coil and the distance between the coils, and the current amplitude is set. Thereby, also in the system which supplies electric power to the moving mobile body, the coupling coefficient between the power transmitting and receiving coils can be increased.

<< Third Embodiment >>
15 and 16 are diagrams for explaining the coil shape of the non-contact power feeding system according to another embodiment of the invention. In this example, the shapes of the power transmission coils 11a to 11c are different from the first embodiment described above. Other configurations are the same as those in the first embodiment described above, and the description thereof is incorporated.

The power transmission coils 11a to 11c are provided on the traveling road surface so that the coil surfaces are parallel to the XY plane. The power transmission coils 11a to 11c are arranged so as to overlap in the Z direction. Regarding the size of the power transmission coils 11a to 11c, the length in the X direction which is the traveling direction of the vehicle is sufficiently longer than the length (D ₂ ) of the power receiving coil 21 in the X direction, and the length in the Y direction. Is slightly longer than the length (D ₂ ) of the power receiving coil 21 in the Y direction.

The power transmission coils 11a to 11c have a plurality of loop-shaped coils by bending a conducting wire. The area of the loop-shaped coil is formed to be different for each of the power transmission coils 11a to 11c, and the area of the coil surface of the power transmission coil 11c is the largest.

In addition, the power transmission coils 11a to 11c intersect the conductive wires in the XY plane, and form a plurality of loop-shaped coils with the intersected portions as boundaries. The pitch lengths (D _1a , D _1c , D _1c ) of the power transmission coils 11a to 11c are different, and the pitch length (D _1a ) of the power transmission coil 11a is the shortest. Further, the pitch lengths (D _1a , D _1c , D _1c ) of the power transmission coils 11a to 11c also correspond to the interval between the intersecting portions (intersection points) of the conducting wires. The lengths of the power transmission coils 11a to 11c in the Y direction are equal to the corresponding pitch lengths (D _1a , D _1c , D _1c ).

When an alternating current flows through a coil selected by the controller 15 among the power transmission coils 11a to 11c in adjacent loop-shaped coils, the alternating current is clockwise in one of the adjacent loop-shaped coils. AC current flows counterclockwise through the other coil. In other words, in the loop-shaped coils adjacent in the x direction, the conduction directions of the alternating current flowing in the loop shape are opposite to each other at the intersecting portion.

Similar to the second embodiment, in the system of this example, the coil length in the traveling direction of the vehicle is sufficiently longer than the coil length in the width direction of the vehicle, thereby achieving a balance between cost and power supply performance. Can do.

In a coil (ladder coil) that crosses coil wires as shown in FIG. 15, the magnetic field is reversed between adjacent crossing loops, so that the leakage magnetic field can also be reduced. And if pitch length is shortened, it will become easier to cancel a magnetic field adjacent and a leakage magnetic field can be reduced. However, it must be considered that when the pitch length is less than or equal to the predetermined length, the coupling coefficient also decreases.

Hereinafter, the relationship between the pitch length and the coupling coefficient will be described with reference to FIGS. 17 and 18. FIG. 17 is a perspective view of the power transmission coil 11c and the power reception coil 21, and FIG. 18 is a graph showing the characteristics of the coupling coefficient with respect to the pitch length for each inter-coil distance (G). The length of the power transmission coil 11c in the X direction is 5 m, the length in the Y direction is 0.7 m, and the power receiving coil 21 is a rectangular coil of 0.5 m square.

As shown in FIG. 18, the coupling coefficient takes a peak value at a certain point with respect to the pitch length, and when the pitch length becomes smaller than the peak pitch length, the coupling coefficient decreases rapidly. That is, as can be seen from the characteristics shown in FIG. 18, the pitch length of the ladder coil shown in FIG. 17 requires a certain length even if the area of the coil surface exceeds a certain value.

The pitch lengths (D _1a , D _1b , D _1c ) of the power transmission coils 11a to 11c are the same as the diameters (D _1a , D _1b , D _1c ) of the coil surfaces of the power transmission coils 11a to 11c according to the first embodiment. In accordance with the area of the coil surface of the power receiving coil and the distance between the coils, the coil to be excited is switched to selection and the current amplitude is set. Thereby, also in the system which supplies electric power to the moving mobile body, the coupling coefficient between the power transmitting and receiving coils can be increased.

As shown in FIG. 19, regarding the areas of the coil surfaces of the power transmission coils 11a to 11c, when the power transmission coils 11a to 11c are ladder coils, the portion surrounded by the rectangle R in FIG. Become.

DESCRIPTION OF SYMBOLS 10 ... Power feeder 11a-11c ... Power transmission coil 12a-12c ... Resonance capacitor 13a-13c ... Amplitude adjustment circuit 14 ... Inverter 15 ... Controller 16 ... Memory 17 ... Power receiving coil detection part 18 ... Communication device 21 ... Power receiving coil

Claims

In the non-contact power feeding device that supplies power to the power receiving coil in a non-contact manner by at least magnetic action,
A plurality of power transmission coils having different areas of the coil surface while arranging the coil surfaces in parallel to each other;
A receiving coil detecting means for detecting the receiving coil;
Control means for controlling the power output from the power source to the exciting coil based on the detection result of the power receiving coil detecting means;
The control means includes
The non-excited coil is selected as the exciting coil among the plurality of power transmitting coils according to the area of the coil surface of the power receiving coil and the distance between the power receiving coil and the power transmitting coil. Contact power supply device.
In the non-contact electric power feeder of Claim 1,
Between the exciting coil and the receiving coil

The non-contact electric power feeder characterized by satisfy | filling the relational expression.
However,
S 1 indicates the area of the coil surface of the combined coil obtained by combining the exciting coils,
S 2 represents the area of the coil surface of the power receiving coil,
G indicates a distance between the power transmission coil and the power reception coil;
θ is between 21 ° and 25 °.
In the non-contact electric power feeder of Claim 1 or 2,
The control means includes
A non-contact power feeding apparatus that outputs power from the power source to the plurality of exciting coils simultaneously.
The contactless power feeding device according to any one of claims 1 to 3,
The control means includes
The amplitude or phase of the current flowing from the power source to the plurality of exciting coils is set according to the area of the coil surface of the power receiving coil and the distance between the power receiving coil and the power transmitting coil. Non-contact power feeding device.
The contactless power feeding device according to any one of claims 1 to 4,
The plurality of power transmission coils are:
The non-contact power feeding device, wherein the coil surfaces are arranged at positions where the coil surfaces overlap each other when viewed from the normal direction of the coil surface.