JP2013055856A - Non-contact electric power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact electric power supply device which sends a large amount of electric power to a power receiving coil while preventing the power receiving coil from generating heat.SOLUTION: The non-contact electric power supply device comprises: a power transmission coil 12 connected to an inverter 13 which generates high-frequency power of frequency f1; a power receiving coil 16 which is arranged to movable moving objects 14, 15 and generates electric power by an alternating magnetic field generated by the power transmission coil 12; and a charge control part 30 which is connected to the power receiving coil 16 and converts electric power generated to the power receiving coil 16 into a direct current to charge a battery 31. A resonant circuit which resonates at frequency f2 and a temperature sensor 33 are provided in the power receiving coil 16. The frequency f2 of the resonant circuit is changed in accordance with the temperature detected by the temperature sensor 33 and a difference between the frequency f1 and the resonant frequency f2 is expanded, thereby preventing an excessive temperature rise in the power receiving coil 16.

Description

The present invention relates to an apparatus for supplying electric power in a contactless manner without using a connection cord for a moving object (for example, an automobile, a carriage, a moving robot, etc.) on which a battery is mounted.

In Patent Document 1, a high-frequency power source is connected to a primary coil, electric power is sent from a primary coil to a secondary coil mounted on an automobile or the like and away from the primary coil by electromagnetic induction, and mounted on an automobile or the like. An apparatus for charging the battery has been proposed.
In Patent Document 2, a power transmission device is provided below each parked vehicle in the power supply area, and power is transmitted from the power transmission device (primary coil) to the power receiving device (secondary coil) provided in each vehicle. However, a technique for charging a battery has been proposed.

Japanese Patent No. 4318742 JP 2010-273441 A

However, the techniques described in Patent Documents 1 and 2 have a problem that the secondary side resonance coil is provided on the power receiving side, and a resonance current flows through the resonance coil, so that heat is generated. Therefore, it is disclosed that the resonance frequency of the secondary side resonance coil is separated from the frequency of the primary side inverter (distant), but if the resonance frequency is separated, the resonance current decreases, and the secondary side There was a problem that large electric power could not be generated.

Further, when charging of the battery finally connected to the secondary coil is completed, the charging current to the battery does not flow, but there is a problem that the resonance current still flows through the resonance circuit and causes power loss. These problems have occurred remarkably when power is supplied to a plurality of automobiles (that is, moving objects).

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a non-contact power supply apparatus that prevents heat generation of a power receiving coil mounted on a moving object and efficiently receives maximum power. And

The non-contact power supply apparatus according to the first aspect of the invention that meets the above-described object is a power transmission coil connected to an inverter that generates high-frequency power having a frequency f1 and an alternating power that is provided in a movable moving object and is generated by the power transmission coil. Non-contact power having a power receiving coil that generates power by a magnetic field, and a charging control unit that is mounted on the moving object and that is connected to the power receiving coil and converts the power generated in the power receiving coil to direct current to charge the battery In the supply device,
The power receiving coil is provided with a resonance circuit that resonates at a frequency f2 and a temperature sensor. When the temperature detected by the temperature sensor becomes higher than a predetermined value a, the frequency f2 of the resonance circuit is moved away from the frequency f1. And a resonance frequency adjusting circuit is provided for increasing the power received by the power receiving coil by bringing the frequency f2 of the resonance circuit close to the frequency f1 when the temperature detected by the temperature sensor is lower than a predetermined value b. Yes.

Further, the non-contact power supply device according to the second aspect of the present invention is provided by a power transmission coil connected to an inverter that generates high-frequency power having a frequency f1 and an alternating magnetic field generated by the movable coil and generated by the power transmission coil. A non-contact power supply device comprising a power receiving coil that generates power, and a charging control unit that is mounted on the moving object and that is connected to the power receiving coil and converts the power generated in the power receiving coil into direct current to charge the battery. In
The power receiving coil is provided with a resonance circuit that resonates at a frequency f2 and is provided with a temperature sensor, and the frequency f2 of the resonance circuit is changed according to the detected temperature of the temperature sensor, and the frequency f1 and the frequency f2 are changed. A resonance frequency adjusting circuit is provided to enlarge the difference and prevent an excessive temperature rise of the power receiving coil.

The contactless power supply device according to a third aspect of the present invention is the contactless power supply device according to the first and second aspects of the invention, wherein the resonance frequency adjustment circuit includes a charge completion sensor that detects completion of charging of the battery. Regardless of the output of the temperature sensor, the difference between the frequency f1 and the frequency f2 is increased by the output of the charge completion sensor to reduce the current of the resonance circuit.

A contactless power supply apparatus according to a fourth aspect of the present invention is the contactless power supply apparatus according to the first to third aspects of the invention, wherein the resonance frequency adjusting circuit switches the capacitance of capacitors connected in parallel by switching means. Yes.

A contactless power supply apparatus according to a fifth aspect of the present invention is the contactless power supply apparatus according to any of the first to fourth aspects of the invention, wherein the power receiving coil is magnetically coupled to a secondary coil that generates power and the secondary coil. And a resonance coil that resonates at the frequency f2.

The contactless power supply apparatus according to a sixth aspect of the present invention is the contactless power supply apparatus according to the first to fifth aspects of the invention, wherein the power transmission coil is a long coil having a parallel region of a certain width, and the moving body There are a plurality of objects, and each moving object can be supplied with electric power from the power transmission coil.

A contactless power supply apparatus according to a seventh aspect of the present invention is the contactless power supply apparatus according to the sixth aspect of the present invention, wherein the power transmission coil is provided with a core that reduces magnetic flux leakage generated by the power transmission coil.

And the non-contact electric power supply apparatus which concerns on 8th invention is the non-contact electric power supply apparatus which concerns on 6th, 7th invention. WHEREIN: The said moving body is moving from the said power transmission coil while moving along the said power transmission coil. The power of can be received.
In the above invention, as a method of moving the frequency (resonance frequency) f2 of the resonance circuit of the power receiving coil away from the frequency f1 of the inverter, there are a case where the resonance frequency is raised and a case where it is lowered. The

In the contactless power supply devices according to the first to eighth aspects of the invention, a temperature sensor is provided in the power receiving coil, and the frequency f1 of the resonance circuit is changed by changing the frequency f2 of the resonance circuit depending on the temperature detected by the temperature sensor. ) Since the difference from f2 is enlarged and a resonance frequency adjusting circuit for preventing an excessive temperature rise of the power receiving coil is provided, a temperature rise of the power receiving coil can be prevented thereby.
In this case, when the temperature of the power receiving coil decreases, the resonance frequency f2 can be brought close to the frequency f1, thereby increasing the power supply.

In the non-contact power supply apparatus according to the third aspect of the invention, the resonance frequency adjustment circuit is provided with a charge completion sensor for detecting the completion of battery charging, regardless of the output of the temperature sensor, Since the current of the resonance circuit is reduced by increasing the difference between the oscillation frequency f1 and the resonance frequency f2, the resonance current flowing through the power receiving coil can be reduced.

In the non-contact power supply apparatus according to the fourth aspect of the invention, the resonance frequency adjustment circuit switches the capacitance of the capacitors connected in parallel by the switching means. Thereby, the capacitor can be easily switched, and the resonance frequency f2 can be changed.

In the non-contact power supply device according to the fifth aspect of the invention, the power receiving coil individually includes a secondary coil that generates power and a resonance coil that is magnetically coupled to the secondary coil and resonates at a frequency f2. It is sufficient to control only the current generated in the resonant coil.

In the non-contact power supply apparatus according to the sixth aspect of the invention, the power transmission coil is a long coil having a parallel region with a constant width, and there are a plurality of moving objects, and power can be supplied to each moving object from the power transmission coil. It is. Thereby, electric power can be supplied to a plurality of moving objects simultaneously or individually.

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In the non-contact power supply apparatus according to the seventh aspect of the invention, the power transmission coil is provided with a core that reduces magnetic flux leakage generated by the power transmission coil, so that the leakage magnetic flux is reduced and useless energy can be saved.

In the contactless power supply device according to the eighth aspect of the present invention, the moving object can receive power from the power transmission coil while moving along the power transmission coil, and the power cable can be largely omitted. The signal cable can be completely wireless by using radio (radio wave or light).

It is explanatory drawing of the non-contact electric power supply apparatus which concerns on the 1st Embodiment of this invention. It is a front view of the non-contact power supply device. It is explanatory drawing of the surroundings of the receiving coil mounted in the moving body. (A), (B) is a graph which shows the relationship between a resonant frequency and an electric current, respectively. It is a flowchart which shows a part of control apparatus of the non-contact electric power supply apparatus. (A) is explanatory drawing at the time of providing a core in a primary coil, (B) is AA arrow sectional drawing of (A), (C) is explanatory drawing of the core which concerns on another example.

Next, embodiments of the present invention will be described with reference to the accompanying drawings.
As shown in FIGS. 1 and 2, the non-contact power supply apparatus 10 according to one embodiment of the present invention includes a power transmission coil 12 embedded in the ground 11 (or a floor surface) and high-frequency power to the power transmission coil 12. It has the inverter 13 to supply and the receiving coil 16 each mounted in the some vehicles 14 and 15 which are examples of the movable body. These will be described in detail below.

The power transmission coil 12 (i.e., the primary coil) has a parallel region with a constant width, an inner width a of, for example, 150 to 400 mm, an inner length b of 3 to 10 m, and a length of 3 to 12 turns. As the conducting wire (conductor), for example, a litz wire or a normal insulated copper wire having excellent high frequency characteristics is used. In addition, if necessary, a lead wire using a copper pipe or an aluminum pipe can be used, and water can be flowed inside to be water-cooled. Since the conducting wire is covered with an insulating film, and the current that flows is usually about 5 to 20 A, an electric wire that can withstand this current is used.

The power transmission coil 12 is embedded in the ground (floor surface) 11 shallowly, and no conductor is provided on the surface. That is, the power transmission coil 12 may be exposed from the ground 11, and when embedded in the ground 11, an insulator may be disposed on the upper surface of the power transmission coil 12.
Further, as shown in FIGS. 6A and 6B, a core 17 having an E-shaped cross section and a core 17a having a U-shaped cross section as shown in FIG. A plurality of coils 12 may be disposed so as to cover the bottom and sides of the coil 12 to reduce magnetic flux leakage and improve magnetic characteristics. The cores 17 and 17a may be divided into appropriate lengths (for example, 5 to 30 cm).

A capacitor 20a is connected in series (or in parallel) to the power transmission coil 12, and the power transmission coil viewed from the inverter 13 side is brought close to the oscillation frequency f1 of the inverter 13 with the resonance frequency fp formed by the power transmission coil 12 and the capacitor 20a. The impedance of 12 is decreased so that more current flows in the power transmission coil 12. The relationship between f1 and fp is preferably 0.05 · f1 <| f1−fp | <0.3 · f1. Moreover, it is good to select f1 in the range of 10 kHz-1000 kHz (preferably 20-50 kHz).

As shown in FIG. 3, power receiving coils 16 are provided at the bottoms of the vehicles 14 and 15 with a gap from the ground 11. The power receiving coil 16 includes a secondary coil 18 that generates electric power by an alternating magnetic field generated by the long power transmitting coil 12, and a resonance coil 19 that is magnetically coupled in parallel (that is, overlapped) to the secondary coil 18. Individually. A resonance frequency adjusting circuit 20 is connected to the resonance coil 19 in series (or in parallel). In this embodiment, there are two vehicles, but one or three or more vehicles may be used.
The resonance frequency adjusting circuit 20 includes capacitors 21 to 24 having capacities C1 to C4 and switching means 25 to 27 connected in series to these capacitors 22 to 24, and the switching means 25 to 27 are turned on / off. This is performed by a signal from the switch element control unit 28.
In addition, as shown in FIG. 3, in order to reduce leakage magnetic flux, it is preferable to provide the receiving coil 16 with a downwardly open core (ferrite core) 16a.

Here, although a contact switch can be used as the switching means 25 to 27, for example, it is preferable from the viewpoint of durability to use a semiconductor element such as a transistor, FET, or MOS-FET.
Since the resonance coil 19 has a certain inductance L, if the capacitors 21 to 24 are connected in parallel, it is determined by the capacitance C and the inductance (including the induction from the secondary coil 18) of the capacitors 21 to 24. A resonance circuit having a resonance frequency f2 is formed.
The resonance frequency f2 varies as shown in FIG. 4A or B depending on the connection status of the capacitors 21 to 24.

4A shows that the resonance frequency f2 is higher than the oscillation frequency f1 of the inverter 13, and the resonance frequency f2 is gradually increased depending on the connection state of the capacitors 21 to 24 (that is, when the capacitance C of the capacitor is gradually decreased). Is away from the oscillation frequency f1 of the inverter 13.
On the other hand, the power receiving coil 16 is provided with a temperature sensor 33 so that the temperature of the power receiving coil 16 (specifically, the resonance coil 19) can be constantly measured.

The output of the temperature sensor 33 is input to the resonance frequency adjusting circuit 20, and when the temperature of the resonance coil 19 becomes higher than a certain value (for example, a predetermined value a), the resonance frequency f2 is moved away from the frequency f1, and the resonance coil 19 is moved. The flowing current is reduced to prevent the temperature from rising. Further, when the temperature of the resonance coil 19 is measured and the temperature of the resonance coil 19 is lower than a certain value (for example, a predetermined value b), the resonance frequency f2 is brought close to the frequency f1, and the battery 31 is charged with more current. The battery is charged to shorten the charging time.

This will be described with reference to FIG. The detection temperature of the temperature sensor 33 is Tth, and the allowable maximum temperature of the resonance coil 19 is Tmax. To reduce the capacitor capacity by one step means that the capacitors 24, 23, and 22 are sequentially disconnected from the capacitors 21 to 24 that are connected in parallel by operating the switching elements 27, 26, and 25. The capacitor 21 is always connected. Further, increasing the capacitor capacity by one step means, for example, sequentially connecting the capacitor 22, the capacitor 23, and the capacitor 24 in parallel from the state where one capacitor 21 is connected to the resonance coil 19.

In this embodiment, the capacitance of the minimum capacitor is C1, and the capacitance of the maximum capacitor is C1 + C2 + C3 + C4. As shown in FIG. 4A, the capacitances of the capacitors 21 to 24 connected to the resonance coil 19 Is reduced, the resonance frequency f2 is increased and is moved away from the frequency f1 of the inverter 13.

Therefore, as shown in FIG. 5, it is confirmed that the detected temperature Tth of the temperature sensor 33 is lower than the allowable maximum temperature Tmax (for example, 220 ° C.) (step S1). If the detected temperature Tth is equal to or higher than the maximum allowable temperature Tmax, it is dangerous. Therefore, a signal is sent to the resonance frequency adjusting circuit 20 to turn off all the switching means 25 to 27 and set the resonance frequency f2 to the frequency. Either greatly deviate from f1, or disconnect the connection between the resonant coil 19 and the capacitor. By this treatment 1 (step S2), the current flowing through the resonance coil 19 is greatly reduced, so that the heat generation is reduced and the temperature of the resonance coil 19 is lowered.

Next, when the detected temperature Tth of the temperature sensor 33 is T1 <Tth <Tmax (for example, T1 (predetermined value a) = 180 ° C.) (step S3), the capacitor capacity is decreased by one step (step S4). Assuming that all of the capacitors 21 to 24 are connected in parallel, the state of C1 + C2 + C3 + C4 in FIG. Move away from the frequency f1. As a result, the temperature of the secondary coil 18 decreases, but it takes time to change the temperature, so the timer counts for about 20 to 60 seconds (step S5).

Thereafter, when the detected temperature Tth of the temperature sensor 33 is lower than a predetermined temperature T2 (= predetermined value b, for example, 130 ° C.) (step S6), the reduced capacitance is increased by one step (step S7). As a result, the resonance frequency f2 of the resonance circuit approaches the frequency f1, and more resonance current flows. Since the resonance current and the secondary current are approximately linearly proportional, the maximum current flowing through the secondary coil 18 also increases.

In this embodiment, the resonance circuit current is controlled in a range where the resonance frequency f2 is larger than the frequency f1 of the inverter. However, as shown in FIG. 4B, the resonance frequency f2 is a range smaller than the frequency f1 of the inverter 13. Thus, the capacitance of the capacitor can be changed.

Since the electric power induced by the secondary coil 18 is high-frequency electric power, it is converted into direct current by the charging control unit 30 that is mounted on the vehicles 14 and 15 and includes the rectifier circuit, and the battery 31 is charged. In this embodiment, if the battery 31 is overcharged, the battery 31 is damaged. Therefore, when the charging of the battery 31 is completed by adjusting the charging voltage to the output voltage of the charging control unit 30, the charging completion sensor is used. Detect the battery 31 so that the battery 31 is not charged. Even in this state, the resonance current flows through the resonance coil 19, so that a signal is given to the resonance frequency adjustment circuit 20 so that the resonance frequency f 2 is kept away from the oscillation frequency f 1 of the inverter 13, thereby reducing the current in the resonance circuit. .

The present invention is not limited to the above-described embodiment, and the configuration thereof can be changed without changing the gist of the present invention. Furthermore, although this invention demonstrated embodiment based on the specific number, it is not limited to this number.
In the embodiment, the temperature of the power receiving coil is measured by the temperature sensor, but the temperature of the resonance coil may be directly measured.
In the above embodiment, the power receiving coil is separated into the secondary coil and the resonant coil. However, the secondary coil and the resonant coil are integrated, and a capacitor is connected in parallel to this. However, the present invention is applied.
And in the said embodiment, although the vehicle is arrange | positioned on the power transmission coil in the fixed state, even when a vehicle (for example, trolley | bogie) moves along a power transmission coil, it can receive the electric power from a power transmission coil.

10: Non-contact power supply device, 11: Ground, 12: Power transmission coil, 13: Inverter, 14, 15: Vehicle, 16: Power reception coil, 16a: Core, 17, 17a: Core, 18: Secondary coil, 19: Resonant coil, 20: Resonant frequency adjustment circuit, 20a: Capacitor, 21-24: Capacitor, 25-27: Switching means, 28: Switch element control unit, 30: Charge control unit, 31: Battery, 33: Temperature sensor

Claims (8)

A power transmission coil connected to an inverter that generates high-frequency power of frequency f1, a movable moving object, and a power receiving coil that generates power by an alternating magnetic field generated by the power transmission coil; and mounted on the moving object; In the non-contact power supply device having a charging control unit that is connected to the power receiving coil and converts the power generated in the power receiving coil into direct current and charges the battery,
The power receiving coil is provided with a resonance circuit that resonates at a frequency f2 and a temperature sensor. When the temperature detected by the temperature sensor becomes higher than a predetermined value a, the frequency f2 of the resonance circuit is moved away from the frequency f1. And a resonance frequency adjusting circuit is provided for increasing the power received by the power receiving coil by bringing the frequency f2 of the resonance circuit close to the frequency f1 when the temperature detected by the temperature sensor is lower than a predetermined value b. A non-contact power supply device. A power transmission coil connected to an inverter that generates high-frequency power of frequency f1, a movable moving object, and a power receiving coil that generates power by an alternating magnetic field generated by the power transmission coil; and mounted on the moving object; In the non-contact power supply device having a charging control unit that is connected to the power receiving coil and converts the power generated in the power receiving coil into direct current and charges the battery,
The power receiving coil is provided with a resonance circuit that resonates at a frequency f2 and is provided with a temperature sensor, and the frequency f2 of the resonance circuit is changed according to the detected temperature of the temperature sensor, and the frequency f1 and the frequency f2 are changed. A non-contact power supply apparatus, wherein a resonance frequency adjusting circuit is provided to enlarge the difference and prevent an excessive temperature rise of the power receiving coil. 3. The non-contact power supply apparatus according to claim 1, wherein the resonance frequency adjustment circuit is provided with a charge completion sensor that detects completion of charging of the battery, and the charge completion is performed regardless of an output of the temperature sensor. A non-contact power supply apparatus that reduces a current of the resonance circuit by enlarging a difference between the frequency f1 and the frequency f2 according to an output of a sensor. The contactless power supply device according to any one of claims 1 to 3, wherein the resonance frequency adjusting circuit switches the capacitance of capacitors connected in parallel by switching means. Feeding device. 5. The contactless power supply device according to claim 1, wherein the power receiving coil is a secondary coil that generates power, and a resonance coil that is magnetically coupled to the secondary coil and resonates at the frequency f <b> 2. And a non-contact power supply device. The contactless power supply device according to any one of claims 1 to 5, wherein the power transmission coil is a long coil having a parallel region with a constant width, and there are a plurality of moving objects, and each of the moving objects. A non-contact power supply apparatus capable of supplying power to a moving object from the power transmission coil. The contactless power supply apparatus according to claim 6, wherein the power transmission coil is provided with a core that reduces magnetic flux leakage generated by the power transmission coil. 8. The non-contact power supply apparatus according to claim 6 or 7, wherein the moving object can receive power from the power transmission coil while moving along the power transmission coil. .

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