JPH1132450A - Non-contact feeding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a non-contact feeding device which can reduce the voltage drop caused by a reactance, having its origin in the inductance of the primary- side conductor of the non-contact feeding device. SOLUTION: A non-contact feeding device is constituted for supplying electric power to a carrier side from its primary-side conductor 2, connected to a power source 1 in a non-contacting state by means of a secondary-side pickup coil 3 installed to the carrier by utilizing the electromagnetic conduction phenomenon. In order to compensate a reactance L2 of the coil 3, a capacitor 4 is connected in series with the coil 3, and both terminals of the capacitor 4 are connected to a load 5. Then, the reactance L2 of the coil 3 and the capacitance C2 of the capacitor 4 are set so as to satisfy a relation, ωL2 1>1/(ωC2 ), where ωrepresents the angular frequency of the power source 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-contact power supply device, and more particularly to a non-contact power supply device, in which a conductor connected to a power supply is used as a primary side and an electromagnetic induction phenomenon is used from the primary side wire to a carrier. The present invention relates to a non-contact power supply device in which electric power is supplied to a carrier in a non-contact manner by an installed secondary side pickup coil.

[0002]

2. Description of the Related Art For example, transport vehicles used in the manufacturing process of semiconductors, liquid crystals, etc. are transported in order to avoid contamination of a clean environment in these manufacturing processes by dust generated by contact between devices. Regarding the supply of power to the car, the conductor connected to the power
2. Description of the Related Art A non-contact power supply device that uses a secondary-side pickup coil installed in a carrier to supply electric power to the carrier in a non-contact manner using an electromagnetic induction phenomenon from a conductor on the next side is used.

[0003] In this contactless power supply device, power is efficiently obtained from the current flowing through the primary-side conductor, the size of the device is reduced, and the frequency of the power supply is reduced in order to suppress electromagnetic noise. A high frequency current of several kilohertz to several tens of kilohertz is supplied from a power supply to the primary conductor while suppressing the upper limit of the transfer number. Normally, the primary conductor is composed of a reciprocating conductor, and the going conductor from the power supply and the returning conductor to the power supply are spatially brought close to each other in order to reduce inductance due to magnetic flux linked to the primary conductor. This arrangement cancels the magnetic field created by the current flowing through the primary conductor.

However, in order to obtain electric power in a non-contact manner from the current flowing through the primary conductor by utilizing the electromagnetic induction phenomenon,
There is a part that utilizes the magnetic field generated by the current flowing through the primary conductor, and in principle, the magnetic flux linked to the primary conductor cannot be eliminated, and the inductance of the primary conductor remains. It will be. This inductance becomes a large reactance for a high-frequency current of several kilohertz to several tens of kilohertz used in the non-contact power feeding device. In order to flow a required current through the primary conductor against the voltage drop caused by this reactance, the terminal voltage of the power supply must be increased, which is a problem in terms of insulation equipment and safety. .

Since the voltage drop caused by the reactance increases in proportion to the length of the primary conductor, if the terminal voltage of the power supply is limited to, for example, several hundred volts or less from the viewpoint of safety, The length of the primary-side conductive wire that can be excited by one power supply is several tens of meters or less. Therefore, for a transport path that exceeds 100 meters per loop,
Excitation cannot be performed with a single power supply, so that it is necessary to divide the loop into a plurality of segments and prepare a high-frequency inverter power supply for each segment, which raises the problem of increasing equipment construction costs. I do. In some cases, it is difficult to supply power without interruption by a secondary-side pickup coil installed in the carrier when the carrier travels at the joint of each segment, and a battery is mounted on the carrier. There is a problem that additional equipment is required, such as the necessity arises.

[0006]

Conventionally, as a method of reducing the reactance caused by the inductance of the primary-side conductor, a negative reactance due to the capacitance of a series capacitor or a parallel capacitor is used.
A method of compensating reactance caused by the inductance of the secondary conductor and a method of using a zero-inductance cable for the primary conductor have been proposed. However,
Each of these methods has a problem that the construction cost of the equipment increases.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a contactless power supply device capable of reducing a voltage drop caused by a reactance caused by an inductance of a primary wire of the contactless power supply device.

[0008]

In order to achieve the above object, a contactless power supply device of the present invention uses a conductor connected to a power supply as a primary side and utilizes an electromagnetic induction phenomenon from the primary side conductor. In a non-contact power supply device for supplying electric power to the carrier in a non-contact manner by a secondary-side pickup coil installed in the carrier, a capacitor is connected in series with the pickup coil to compensate for reactance of the pickup coil. Both terminals of the capacitor are connected to the load, and the reactance of the pickup coil and the capacitance of the capacitor are set so as to satisfy the relationship of the following equation (1). ωL ₂ > 1 / (ωC ₂ ) (1) where L ₂ : reactance of the pickup coil C ₂ : capacitance of the capacitor ω: angular frequency of the power supply.

In this non-contact power supply device, both terminals of a capacitor connected in series to the pickup coil are connected to the load, and the reactance of the pickup coil and the capacitance of the capacitor are set so as to satisfy the relationship of the above equation (1). By setting, that is, making the combined reactance of the series circuit composed of the pickup coil and the capacitor inductive, the voltage drop caused by the reactance due to the inductance of the primary conductor can be reduced.

[0010]

Embodiments of the present invention will be described below with reference to the drawings. As shown in FIG. 1, this non-contact power supply apparatus uses a carrier I via a mutual inductance M by utilizing an electromagnetic induction phenomenon from a current I ₁ flowing through a primary conductor 2 connected to a power supply 1. in the power in a non-contact by the pickup coil 3 on the secondary side installed in (not shown) for supplying the transport vehicle side, in order to compensate for the reactance L ₂ of the pickup coil 3,
A capacitor 4 is connected in series with the pickup coil 3,
Both terminals of the capacitor 4 are connected to the load 5, respectively.

In this case, the reactance L ₂ of the pickup coil 3 is set so that the combined reactance X of the series circuit including the pickup coil 3 and the capacitor 4 represented by the following equation (2) is inductive, that is, a positive value.
And setting the capacitance C ₂ of the capacitor. X = ωL ₂ −1 / (ωC ₂ )> 0 (2) (ωL ₂ > 1 / (ωC ₂ ) (1))

In this case, when the combined reactant X of the series circuit is 0, it corresponds to a so-called series resonance. At this time, a large voltage can be applied to the terminal of the load 5 with a small input. In general, non-contact power supply is performed at a place where the combined reactance X remains slightly, although the resonance is close to the series resonance because of large fluctuations at the time of deviation. The fact that the synthetic reactance X is inductive, that is, a positive numerical value, is apparent from the above equation (1).
Can be easily realized by appropriately selecting the inductance L ₂ of the capacitor 4, the capacitance C _{2 of the} capacitor 4 and the magnitude of the angular frequency ω of the power supply.

Next, when the combined reactance X of the series circuit composed of the pickup coil 3 on the secondary side and the capacitor 4 is made inductive, that is, a positive value, the reactance caused by the inductance L ₁ of the primary conductor 2 is obtained. It is theoretically clarified that the resulting voltage drop can be canceled or reduced. For the sake of simplicity, the primary and secondary resistance components are ignored, and the case where there is no load 5 connected to both terminals of the series capacitor 4 is dealt with. There is essentially no difference in the mechanism from considering them.

Under the above conditions, in the circuit shown in FIG.
The AC circuit equations represented by the following equations (3) and (4) hold. V ₁ = jωL ₁ I ₁ + jωMI ₂ (3) jωMI ₁ + jXI ₂ = 0 (4) where X: synthetic reactance of a series circuit including a pickup coil and a capacitor (X = ωL ₂ −1 / (ω
C ₂ )). The AC circuit equation than _{V 1 = jωL 1 I 1 -j} (ω 2 M 2 / X) I 1 ····· is (5). In the equation (5), V ₁ indicates a terminal voltage of the power supply 1 necessary for flowing a current of I ₁ through the primary conductor 2. The first term of the right side of the expression (5) is a voltage drop caused by the reactance due to the inductance L ₁ of the conductors 2 of the primary side. The second term on the right side of the equation (5) is a voltage that a current flowing through a series circuit including the pickup coil 3 on the secondary side and the capacitor 4 induces on the conductor 2 on the primary side.
In the second term on the right side of the equation (5), the value of the combined reactance of the series circuit composed of the secondary-side pickup coil 3 and the capacitor 4 indicated by X is set to be inductive, ie, positive, as shown in the above embodiment. If a numerical value is obtained, the second term on the right side of the equation (5) becomes a negative value from the above equation (1) (ωL ₂ > 1 / (ωC ₂ )), and the second term on the right side of the equation (5) A power supply 1 necessary to cancel and reduce a voltage drop caused by a reactance caused by the inductance L ₁ of the primary-side conductor 2 of item _{1 and} to flow a required current I ₁ through the primary-side conductor 2.
It is possible to lower the terminal voltage V ₁ of the. Incidentally, assuming that the value of the combined reactance X of the series circuit is a negative value, that is, capacitive, the first term and the second term on the right side of the equation (5) are not canceled out and both are added. Next conductor 2
The terminal voltage V ₁ of the power source 1 which is required for passing the required current I ₁ in becomes possible to increase the reverse.

[0015]

According to the contactless power feeding device of the present invention, both terminals of the capacitor connected in series to the pickup coil are connected to the load, and the relationship between the reactance of the pickup coil and the capacitance of the capacitor is determined by the relationship between the pickup coil and the pickup coil. By setting the combined reactance of the series circuit composed of the capacitors to be inductive, it is possible to cancel and reduce the voltage drop caused by the reactance due to the inductance of the primary conductor. This eliminates the need for placing a series capacitor or a parallel capacitor on the primary conductor,
Or at least reduce its capacity,
Since it is not necessary to use an expensive zero-inductance cable, the construction cost of the non-contact power supply device can be reduced. In addition, since the voltage drop can be reduced, even if the terminal voltage of the power supply is limited to several hundred volts or less from the viewpoint of safety, the length of the primary-side conductive wire that can be excited by one power supply is reduced to one.
It is possible to provide a non-contact power supply device that is economical and simple, because the length can be set to 00 m or more, and the loop can be configured on a long transport path without dividing the loop into a plurality of segments.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing one embodiment of a non-contact power supply device of the present invention.

[Explanation of symbols]

1 power supply 2 primary conductor 3 pickup coil 4 capacitor 5 Load I 1 _primary conductor of the current M 1 primary flowing through the conductor and mutual inductance L 2 _secondary pickup coil between the secondary pickup coil Inductance C ₂ Capacitance of secondary side capacitor I ₂ Current of secondary side series circuit

Claims (1)

[Claims] 1. A conductor connected to a power supply is used as a primary side.
In a non-contact power supply device for supplying electric power to the carrier in a non-contact manner by a secondary pickup coil installed on the carrier using an electromagnetic induction phenomenon from a primary conductor, a reactance (L ₂₎ of the pickup coil ), A capacitor is connected in series with the pickup coil, and both terminals of the capacitor are connected to respective loads,
A non-contact power supply device, wherein the reactance (L ₂ ) of the pickup coil and the capacitance (C ₂ ) of the capacitor are set so as to satisfy the relationship of the following equation (1). ωL ₂ > 1 / (ωC ₂ ) (1) where ω is the angular frequency of the power supply.