JP2001238349A - Current limiter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a current limiter, which is high in current limiting efficiency, does not need a direct-current power supply, and enables to reduce its price and makes it maintenance-free. SOLUTION: The current limiter is provided with magnetic circuits 10a and 10b, that are at least partially formed of soft magnetic cores 3a and 3b and magnetically saturated by permanent magnets 1a and 1b and a coil 4 wound on the magnetic saturation regions of the magnetic circuits 10a and 10b. The magnetic circuits 10a and 10b comprises the permanent magnets 1a and 1b, yokes 2a, 2b, 2c, and 2d, and the soft magnetic cores 3a and 3b with the coil 4 wound thereon.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a current limiter for efficiently suppressing an overcurrent generated due to a short circuit accident in an electric circuit and the like, and more particularly, to a current limiter comprising a permanent magnet, a soft magnetic core and a coil having high reliability. The present invention also relates to a current limiter that can be made maintenance-free.

[0002]

2. Description of the Related Art For example, in order to limit a short-circuit current only by impedance, an air-core reactor whose reactance is determined by the number of turns and the shape is described in page 304 of "Transformer Design and Construction" edited by Hisao Kimura, published by Denki Shoin in 1960. (Solenoid coil) is disclosed. Also, at pages 309 to 310 of the same book, a saturable reactor capable of controlling a load current by adjusting a DC current of a control winding is disclosed.

Further, three types of superconducting current limiters are disclosed on page 614 of "Electrical Engineering Handbook" published by Ohmsha. One method is to connect a superconducting wire and a resistor in parallel.In normal conditions, current flows through the superconducting wire, and in the event of a system fault, the superconducting wire undergoes normal conduction transition, resulting in high resistance. It is stated that the flow is limited. Although other methods are omitted, all methods require a low-temperature cooling device as an auxiliary device. Examples of current limiters using permanent magnets include, for example, the 20th Annual Meeting of the Japan Society of Applied Magnetics (1996), page 22, B-4, and the 23rd Annual Meeting of the Japan Society of Applied Magnetics, 7aD-6. An inner magnet type structure is disclosed.

[0004]

In the method using the air-core reactor described in the above-mentioned conventional example, the impedance is low due to the air-core structure, and the current limiting efficiency is poor because the impedance is constant without depending on the current. There is a disadvantage that the physique becomes large.

Further, the DC excitation saturable reactor has a disadvantage that a secondary winding for magnetically saturating the reactor core is required, and a DC power supply for supplying DC to the secondary winding is required.

Further, the superconducting current limiter requires a low-temperature cooling device, so that there is a problem that a large amount of maintenance is required.

[0007] In the current limiter of the inner-magnet type structure described in the 20th Annual Meeting of the Japan Society of Applied Magnetics, the permanent magnet is disposed inside the coil. However, there is a problem that the magnet is directly exposed to a large magnetic field, and the magnet is demagnetized.

In the current limiter having the inner magnetic structure described in the 23rd Annual Meeting of the Japan Society of Applied Magnetics, the permanent magnet is disposed inside a flat annular magnet, so that the ferrite having a low residual magnetic flux density is used. When a system magnet is used, there is a problem that the core window height (C) is increased.

Further, in the case of a current limiting device for a large current in a transmission and distribution system, the cost of manufacturing the coil is high. Is required.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a high current limiting efficiency, does not require a DC power supply, can be inexpensive, and can be made maintenance-free. It is intended to provide a current limiter.

[0011]

According to the present invention, there is provided a current limiter comprising a magnetic circuit which is at least partially made of a soft magnetic core and is magnetically saturated by a permanent magnet, and a coil wound around a magnetic saturation region of the magnetic circuit. Wherein the magnetic circuit is constituted by a soft magnetic core on which a permanent magnet, a yoke, and a coil are wound.

The coil is formed by connecting a first coil and a second coil wound in the opposite polarity to the first coil in series.

[0013] The first coil and the second coil are connected to a bar-shaped permanent magnet, two yokes respectively connected to both ends of the permanent magnet, and connected between the other ends of the two yokes. A first magnetic circuit comprising a soft magnetic core, and a second magnetic circuit having substantially the same material and the same shape as the first magnetic circuit, wherein the first magnetic circuit and the soft magnetic core are opposed to each other via a gap. In the circuit, it is one coil wound so as to be bundled with two soft magnetic cores facing each other.

The first coil and the second coil are composed of a bar-shaped permanent magnet, two first yokes respectively joined to both ends of the permanent magnet, and other ends of the two first yokes. The soft magnetic core joined between the portions, the yokes at both ends of the soft magnetic core and the inside or outside of the yoke are respectively joined to form a substantially L-shape, and the ends opposite to the soft magnetic core are opposed to each other with a gap therebetween. A first magnetic circuit consisting of two second yokes to be driven,
The two soft magnetic cores which are substantially the same material and the same shape as the first magnetic circuit, and are opposed to each other in the first magnetic circuit and the second magnetic circuit in which the soft magnetic cores are opposed to each other via a gap. It is one coil wound so as to be bundled.

The first coil comprises a bar-shaped permanent magnet, two yokes joined to both ends of the permanent magnet, and a soft magnetic core joined between the other ends of the two yokes. The second coil is wound around the soft magnetic core of the first magnetic circuit, and the second coil is made of the same material and the same shape as the first magnetic circuit. The same number of turns are wound with the opposite polarity to the coil.

Further, the first coil includes two rod-shaped permanent magnets arranged at a predetermined interval, two yokes for joining between the extreme ends of the two permanent magnets, and two Is wound around a soft magnetic core of a first magnetic circuit composed of a soft magnetic core joined between central portions of the yokes, and the second coil is
The second magnetic circuit is formed by winding the same number of turns with the opposite polarity to the first coil on the soft magnetic core of the second magnetic circuit having substantially the same material and shape as the first magnetic circuit.

Further, the first coil comprises a rod-shaped permanent magnet, two first yokes joined to both ends of the permanent magnet, and a soft magnet joined between the other ends of the two yokes. Core and
A first magnetic field comprising two second yokes joined to opposite ends of the soft magnetic core and opposite to the yokes to form a substantially L-shape, with the soft magnetic core and the opposite end facing each other with a gap therebetween. The second coil is wound around the soft magnetic core of the circuit, and the second coil is made of the same material and the same shape as the first magnetic circuit. It is the same number of turns with opposite polarity.

The first coil includes a rod-shaped permanent magnet, two first yokes joined to both ends of the permanent magnet, and a soft magnet joined between the other ends of the two yokes. Core and
A soft magnetic core is wound around a soft magnetic core of a first magnetic circuit composed of a substantially U-shaped second yoke joined between both ends on the opposite side of the yoke, and the second coil is The second magnetic circuit is formed by winding the same number of turns with the opposite polarity to the first coil on the soft magnetic core of the second magnetic circuit having substantially the same material and shape as the first magnetic circuit.

The first coil has a rod-shaped permanent magnet and a substantially U-shape joined to both ends of the permanent magnet.
Wound around the soft magnetic core of the first magnetic circuit consisting of a soft magnetic core whose cross-sectional area of the first side joined to the permanent magnet is larger than the cross-sectional area of the second side substantially parallel to the permanent magnet The second coil is made of a soft magnetic core of a second magnetic circuit having substantially the same material and the same shape as the first magnetic circuit, the same number of turns being wound with the opposite polarity to the first coil. It is.

The soft magnetic core is a laminated soft magnetic core manufactured by joint wrap bonding.

The soft magnetic core is made of directional silicon steel, 50%
It is a square hysteresis material of any of a Ni—Fe alloy and a Co-based amorphous alloy.

Further, the length of the soft magnetic core in the direction of magnetization is extended so as to extend further outward from the joint with the two yokes joined to the soft magnetic core.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a schematic diagram illustrating a configuration of a current limiter according to Embodiment 1 of the present invention. In FIG. 1, reference numeral 10a denotes a rare-earth magnet (Sm-Co based, Nd-
Fe-B system), ferrite magnet (Ba system, Sr system), bond magnet (ferrite system, Nd-Fe-B system), cast magnet (Al-Ni-Co system), rolled magnet (Fe-Mn system,
A prismatic permanent magnet 1a such as Fe-Cr-Co), pure iron, silicon steel, iron-cobalt alloy (49Co-2V-F)
e) The yokes 2a and 2b composed of a soft magnetic core having a high saturation magnetic flux density and having a prismatic block shape or a prismatic laminated shape, such as directional silicon steel, permalloy (50Ni-Fe), an amorphous alloy, and finemet (nanocrystalline magnetic material) Laminated soft magnetic core 3 having high permeability and rectangular hysteresis characteristics
a is a first magnetic circuit composed of a.

The first magnetic circuit 10a includes a rod-shaped permanent magnet 1a, two yokes 2a and 2b joined to both ends of the permanent magnet 1a, respectively, and another end between the other ends of the two yokes 2a and 2b. And a soft magnetic core 3a to be joined.

On the other hand, 10b has substantially the same configuration as the first magnetic circuit 10a, and includes a permanent magnet 1b of the same material as the above-described permanent magnet 1a, and yokes 2c and 2d of the same material as the above-mentioned yokes 2a and 2b. This is a second magnetic circuit comprising a soft magnetic core 3b having the same material as described above and having a square hysteresis characteristic. The first magnetic circuit 10a and the second magnetic circuit 10b are disposed so that the soft magnetic cores 3a and 3b face each other with a gap therebetween.

4 is wound around the center of the soft magnetic core 3a forming a part of the first magnetic circuit 10a and the soft magnetic core 3b forming a part of the second magnetic circuit 10b so as to bundle them. Coil. 5 is a load resistance connected to one end of the coil 4. Reference numeral 6 denotes a power transformer connected between the load resistor 5 and the other end of the coil 4.

Here, when the saturation magnetic flux densities inherent to the materials of the yokes 2a, 2b, 2c, 2d and the soft magnetic cores 3a, 3b do not change, the yokes 2a, 2b, 2b, 2c, 2d are magnetically saturated only from the soft magnetic cores 3a, 3b. It is necessary to make the core sectional area of 2b, 2c, 2d larger than that of the soft magnetic cores 3a, 3b.

Next, the operation will be described. In FIG. 1, a coil 4 and a load resistor 5 are connected in series, and an AC alternating input is applied to the series circuit via a power transformer 6. The soft magnetic core 3a of the first magnetic circuit 10a is magnetized by the permanent magnet 1a from the upper side to the lower side in FIG. On the other hand, the soft magnetic core 3b of the second magnetic circuit 10b is magnetized by the permanent magnet 1b from the bottom to the top in FIG. 1 to the saturation region.

FIG. 2 schematically shows a hysteresis curve of the soft magnetic cores 3a and 3b. The hysteresis curve shown by the solid line in FIG. 2 is obtained when the magnetic circuit has no demagnetizing field.
In the magnetic circuit as shown in FIG. 1, since it is a demagnetizing field, it has an inclined curve as shown by a broken line in FIG. In FIG. 2, it is assumed that the soft magnetic core 3a is magnetized at the magnetization operating point A in the figure, while the soft magnetic core 3b is magnetized at the magnetization operating point B in the figure.

When a normal current is flowing through the load 5, the current is small, so that the soft magnetic cores 3a, 3b
Does not deviate from the region of magnetic saturation, the inductance of the coil 4 is small, and the larger the saturation point H in the drawing, the closer to the air-core coil, and the applied voltage is almost applied to the load resistance 5.

When the load resistor 5 is short-circuited and a large fault current flows through the coil 4, a half cycle of the soft magnetic core 3a in which a magnetic field is generated from the bottom to the top in FIG.
The magnetization is reversed in the direction from A to B. On the other hand, the soft magnetic core 3b
In another half period in which a magnetic field is generated from the upper side to the lower side in FIG. 1, the magnetization is reversed from B to A. That is, when a large current is supplied, the inductance of the coil increases over the entire period, and most of the input voltage is applied to the coil 4 to limit the current.

As described above, the current limiting device according to the present embodiment has the magnetic circuit 1 at least partially composed of the soft magnetic cores 3a and 3b.
A part (central part) of the permanent magnets 1a, 1b
And the coil 4 in this magnetic saturation region.
Is used.

In the current limiter having such a configuration, the impedance of the coil 4 is low with respect to a steady AC current, while the fault current, that is, a large current is reduced with respect to a half wave of the saturable reactor according to the principle of a saturable reactor. As a result, magnetization reversal occurs in the magnetically saturated portion, and the impedance becomes high. And if it is connected in series with one having the reverse characteristic, the impedance becomes high with respect to the full wave of the fault current, and a current limiting device with high current limiting efficiency can be realized.

Further, as described above, the current limiting device having such a configuration mainly includes the permanent magnets 1a and 1b and the soft magnetic cores 3a and 3a.
Since it is composed of the coil 3b and the coil 4, it has a feature that it can be made maintenance-free and can be realized at low cost.

In this embodiment, the coil 4
Is wound directly around the soft magnetic cores 3a, 3b, but a bobbin coil may be used. In this case, the soft magnetic cores 3a and 3b are inserted into the bobbin coil.

Embodiment 2 FIG. 3 is a schematic diagram illustrating a configuration of a current limiter according to Embodiment 2 of the present invention. In FIG. 3, reference numeral 16a denotes a permanent magnet 1a, yokes 2a, 2b, 2c, 2d, and a soft magnetic core 3 of the same material as those described in the first embodiment.
a and a first magnetic circuit comprising newly added yokes 2e and 2f. Then, the first magnetic circuit 16a
Is a rod-shaped permanent magnet 1a, two yokes 2a and 2b joined to both ends of the permanent magnet 1a, and two yoke 2
a, 2b, a soft magnetic core 3a joined between both ends, the permanent magnet 1a, two yokes 2a, 2b, and a soft magnetic core 3a.
And two substantially L-shaped yokes 2e, 2f, one end of which is opposed to each other with a gap therebetween, and the other end of which is joined to the soft magnetic core 3a.

Reference numeral 16b denotes a second magnetic circuit comprising a permanent magnet 1b, yokes 3c, 3d, 3g, 3h and a soft magnetic core 3b of the same material as described in 16a. The second magnetic circuit 16b has substantially the same structure as the first magnetic circuit. The first magnetic circuit 16a and the second magnetic circuit 16b are arranged so that the soft magnetic cores 3a and 3b face each other with a gap therebetween.

Reference numeral 4 denotes a soft magnetic core 3a constituting a part of the second magnetic circuit 16a and a second magnetic circuit wound around a central portion of the soft magnetic core 3b constituting a part of the 16b so as to bundle them. It is a coil that is turned. Here, the yokes 2a, 2b, 2
From the viewpoint of suppressing demagnetization of the permanent magnet, for example, c and 2d are desirably materials having good DC characteristics and poor AC characteristics, such as massive pure iron. When a short-circuit large current is applied, the return magnetic flux to the permanent magnet is reduced, and the magnet is easily demagnetized and has a relatively small coercive force. For example, an iron-manganese permanent magnet can be used.

The yokes 2e, 2f, 2g, and 2h are desirably made of a material having excellent AC magnetic characteristics, such as a ferrite or a silicon copper plate. This is because the current limiting characteristics when a short-circuit large current flows are improved. The current limiting device having such a configuration is described in the first embodiment.
Has the effect that the inductance when a large current is applied is higher than that of the current limiter having the configuration described in (1) and the current limiting characteristics are excellent. In the second embodiment, the yokes 2e and 2f and the yokes 2g and 2h are
Although the permanent magnet 1a, the soft magnetic core 3a, and the permanent magnet 1b are arranged inside the soft magnetic core 3b, the yokes 2e, 2f
The yokes 2g and 2h may be disposed outside the permanent magnet 1a, the soft magnetic core 3a, the permanent magnet 1b, and the soft magnetic core 3b (not shown). In this case, among the components of the current limiter, there is an effect that a relatively expensive permanent magnet can be made compact. The yokes 2e and 2f and the yokes 2g,
2h may be arranged in a space perpendicular to the plane of FIG. This has the effect that a compact current limiting device with high current limiting efficiency can be realized.

Embodiment 3 FIG. 4 is a schematic diagram showing a configuration of a current limiter according to Embodiment 3 of the present invention. In FIG. 4, reference numeral 11a denotes a first magnetic circuit including a permanent magnet 1a, yokes 2a and 2b, and a soft magnetic core 3a of the same material as described in the first embodiment.

The first magnetic circuit 11a includes a rod-shaped permanent magnet 1a, two yokes 2a and 2b joined to both ends of the permanent magnet 1a, and the other end of the two yokes 2a and 2b. It consists of a soft magnetic core 3a joined between them.

The length of the soft magnetic core 3a in the direction of magnetization is extended so as to extend further outward from the junction between the two yokes 2a and 2b joined to the soft magnetic core 3a. A first coil 4a is wound around the center of the soft magnetic core 3a.

Reference numeral 11b designates a second magnet comprising a permanent magnet 1b, yokes 2c and 2d, a soft magnetic core 3b, and a coil 4b wound around the soft magnetic core 3b, which are also made of the same material as described in the first embodiment. Magnetic circuit.

The second magnetic circuit 11b has substantially the same structure as the first magnetic circuit 11b. A second coil 4b is wound around the center of the soft magnetic core 3b. The second coil 4b is formed by winding the same number of turns with the opposite polarity to the first coil 4a. The first coil 4a and the second coil 4b are connected in series.

The present embodiment is different from the first embodiment in that the first magnetic circuit 11a and the second magnetic circuit 11b can be separately manufactured, and the ease of manufacturing the current limiter is improved. I do.

In the present embodiment, the first magnetic circuit 11a, the second magnetic circuit 11b, the first coil 4
a and the second coil 4b, the impedance becomes high with respect to the full wave, and the current limiting device can have a high current limiting efficiency. And the current limiting efficiency is reduced, but the current limiting device can be made compact and more inexpensive. In addition, the same effect can be obtained as the effect that can be made maintenance-free.

Embodiment 4 FIG. 5 is a schematic diagram showing a configuration of a first magnetic circuit of the current limiter according to Embodiment 4 of the present invention. In FIG. 5, 1a and 1b are permanent magnets of the same material as described above, 2a, 2b, 2c and 2d are yokes, 3 is a soft magnetic core, and 4 is wound around the center of the soft magnetic core 3. This is the first coil.

The first magnetic circuit 12 comprises two rod-shaped permanent magnets 1a, 1b arranged at a predetermined interval.
And two divided yokes 2a, 2c and 2b, 2d joining the same extreme portions of the two permanent magnets 1a, 1b.
And the soft magnetic core 3 whose both ends are held between the divided portions of the divided yokes 2a, 2c and 2b, 2d.

In the present embodiment, a second magnetic circuit (not shown) having substantially the same material and shape as the first magnetic circuit 12 is provided. A second coil (not shown) is wound around the center of the soft magnetic core of the second magnetic circuit. The second coil is formed by winding the same number of turns with the opposite polarity to the first coil 4. The first coil 4 and the second coil are connected in series.

In the current limiting device having such a configuration, the magnetic circuit 12 magnetizes the soft magnetic core 3 by the two permanent magnets 1a and 1b from both side surfaces, so that the soft magnetic core 3 is strongly magnetically saturated. Therefore, there is an effect that the inductance of the coil during normal operation can be reduced, so that the voltage drop of the coil during normal operation can be reduced.

Embodiment 5 FIG. FIG. 6 is a schematic diagram showing a configuration of a first magnetic circuit of the current limiter according to Embodiment 5 of the present invention. In FIG. 6, 1 is a permanent magnet of the same material as described above,
2a, 2b, 2c, 2d are yokes, 3 is a soft magnetic core,
Reference numeral 4 denotes a coil wound around the soft magnetic core 3.

The first magnetic circuit 13 includes a rod-shaped permanent magnet 1, two first yokes 2a and 2b joined to both ends of the permanent magnet 1, and the two yokes 2a and 2b.
A soft magnetic core 3 joined between the other ends of the
And two second yokes 2c and 2d, which are joined to opposite ends of the yokes 2a and 2b at both ends to form a substantially L-shape, and the soft magnetic core 3 and opposite ends are opposed to each other with a gap therebetween. .

In the present embodiment, a second magnetic circuit (not shown) having substantially the same material and the same shape as the first magnetic circuit 13 is provided. A second coil (not shown) is wound around the center of the soft magnetic core of the second magnetic circuit. The second coil is formed by winding the same number of turns with the opposite polarity to the first coil 4. The first coil 4 and the second coil are connected in series.

In the current limiting device having such a structure, the yokes 2c and 2d are further added to the current limiting device of the second embodiment, so that the demagnetizing field of the coil winding portion can be reduced, Since the reversal becomes sharp and the time derivative dΦ / dt of the total reversal magnetic flux, which is the coil induced voltage, becomes large,
This has the effect of improving the current limiting efficiency.

Embodiment 6 FIG. FIG. 7 is a schematic diagram showing a configuration of a first magnetic circuit of a current limiter according to Embodiment 6 of the present invention. In FIG. 7, 1 is a permanent magnet of the same material as described above,
2a, 2b, 2c are yokes, 3 is a soft magnetic core, 4 is
The coil is wound around the center of the soft magnetic core 3.

The first magnetic circuit 14 comprises a rod-shaped permanent magnet 1, two first yokes 2a and 2b joined to both ends of the permanent magnet 1, and two yokes 2a and 2b.
A soft magnetic core 3 is joined between the other ends of the soft magnetic core 2b, and a substantially U-shaped second yoke 2c is joined between both ends of the soft magnetic core opposite to the yokes 2a and 2b.

In the present embodiment, a second magnetic circuit (not shown) having substantially the same material and shape as the first magnetic circuit 14 is provided. A second coil (not shown) is wound around the center of the soft magnetic core of the second magnetic circuit. The second coil is formed by winding the same number of turns with the opposite polarity to the first coil 4. The first coil 4 and the second coil are connected in series.

In the current limiter having such a configuration, the magnetic circuit of the first to fifth embodiments is an open magnetic circuit, whereas the magnetic circuit of the present embodiment has a closed magnetic circuit formed by the yoke 2c and the soft magnetic core 3a. The difference is in the configuration. Therefore, there is a problem that the magnetic saturation of the soft magnetic core is shallow because the DC magnetic flux generated by the permanent magnet 1 is diverted to 2c, but there is no demagnetizing field due to the closed magnetic path, and there is no reduction in the squareness of the soft magnetic core. Has advantages.

Embodiment 7 FIG. FIG. 8 is a schematic diagram showing a configuration of a first magnetic circuit of a current limiter according to Embodiment 7 of the present invention. In FIG. 8, reference numeral 1 denotes a permanent magnet made of the same material as described above, and reference numeral 3 denotes a laminated soft magnetic core joined by a joint wrap which also serves as a yoke. Reference numeral 4 denotes a coil wound around a side of the soft magnetic core 3 facing the permanent magnet 1.

The first magnetic circuit 15 is a rod-shaped permanent magnet 1
And a second side 3B having a substantially U-shape joined to both ends of the permanent magnet and having a cross-sectional area of a first side 3A joined to the permanent magnet 1 substantially parallel to the permanent magnet 1. It is composed of a laminated soft magnetic core 3 having a larger area.

In the present embodiment, a second magnetic circuit (not shown) having substantially the same material and shape as the first magnetic circuit 15 is provided. A second coil (not shown) is wound around the center of the laminated soft magnetic core of the second magnetic circuit.
The second coil is formed by winding the same number of turns with the opposite polarity to the first coil 4. The first coil 4 and the second coil are connected in series.

In the current limiting device having such a configuration, in order to sufficiently magnetically saturate the side 3A around which the coil is wound, the cross-sectional area of the side 3B joined to the permanent magnet 1 is set to the side where the coil is wound. It is important to make the cross section larger than 3A.

The laminated soft magnetic core 3 of the present embodiment is joined by joint lap joining. As shown in FIG. 9, joint lap joining refers to a roughly L-shaped thin plate 30 a
And the substantially I-shaped thin plates 30b are joined so as to be stacked alternately so that the contact positions do not overlap. With such a joint lap joint, there is no problem that a slight gap is formed between the yoke and the soft magnetic core as occurs in the first to sixth embodiments, so that the magnetic efficiency is deteriorated.

[0064]

According to the present invention, there is provided a current limiter including a magnetic circuit at least partially composed of a soft magnetic core and magnetically saturated by a permanent magnet, and a coil wound around a magnetic saturation region of the magnetic circuit. The magnetic circuit is composed of a soft magnetic core around which a permanent magnet, a yoke, and a coil are wound. Therefore, it is possible to provide a current limiting device that has high current limiting efficiency, does not require a DC power supply, can be inexpensive, and can be maintenance-free.

The coil is formed by connecting a first coil and a second coil wound in the opposite polarity to the first coil in series. Therefore, by connecting in series with one having the reverse characteristic, high impedance can be obtained for all waves, and a current limiting device having high current limiting efficiency can be obtained.

The first coil and the second coil are connected to a bar-shaped permanent magnet, two yokes respectively joined to both ends of the permanent magnet, and a joint between the other ends of the two yokes. A first magnetic circuit comprising a soft magnetic core, and a second magnetic circuit having substantially the same material and the same shape as the first magnetic circuit, wherein the first magnetic circuit and the soft magnetic core are opposed to each other via a gap. In the circuit, it is one coil wound so as to be bundled with two soft magnetic cores facing each other. Therefore, the first coil and the second coil can be realized by one coil, and an inexpensive and compact current limiter can be obtained.

The first coil and the second coil are composed of a rod-shaped permanent magnet, two first yokes joined to both ends of the permanent magnet, and the other end of the two first yokes, respectively. The soft magnetic core joined between the portions, the yokes at both ends of the soft magnetic core and the inside or outside of the yoke are respectively joined to form a substantially L-shape, and the ends opposite to the soft magnetic core are opposed to each other with a gap therebetween. A first magnetic circuit consisting of two second yokes to be driven,
The two soft magnetic cores which are substantially the same material and the same shape as the first magnetic circuit, and are opposed to each other in the first magnetic circuit and the second magnetic circuit in which the soft magnetic cores are opposed to each other via a gap. It is one coil wound so as to be bundled. Therefore, there is an effect that the inductance when a large current flows is high and the current limiting characteristics are excellent.

The first coil comprises a bar-shaped permanent magnet, two yokes joined to both ends of the permanent magnet, and a soft magnetic core joined between the other ends of the two yokes. The second coil is wound around the soft magnetic core of the first magnetic circuit, and the second coil is made of the same material and the same shape as the first magnetic circuit. The same number of turns are wound with the opposite polarity to the coil. Therefore, the first magnetic circuit and the second magnetic circuit 11 can be separately manufactured, and the ease of manufacturing the current limiter is improved.

The first coil is composed of two rod-shaped permanent magnets arranged at a predetermined interval, two yokes for joining between the extreme parts of the two permanent magnets, and two Is wound around a soft magnetic core of a first magnetic circuit composed of a soft magnetic core joined between central portions of the yokes, and the second coil is
The second magnetic circuit is formed by winding the same number of turns with the opposite polarity to the first coil on the soft magnetic core of the second magnetic circuit having substantially the same material and shape as the first magnetic circuit. Therefore, since the first and second magnetic circuits magnetize the soft magnetic core by two permanent magnets from both sides, the soft magnetic core can be strongly magnetically saturated,
This has the effect that the inductance of the coil during normal operation can be reduced, and therefore the voltage drop of the coil during normal operation can be reduced.

The first coil comprises a rod-shaped permanent magnet, two first yokes joined to both ends of the permanent magnet, and a soft magnet joined between the other ends of the two yokes. Core and
A first magnetic field comprising two second yokes joined to opposite ends of the soft magnetic core and opposite to the yokes to form a substantially L-shape, with the soft magnetic core and the opposite end facing each other with a gap therebetween. The second coil is wound around the soft magnetic core of the circuit, and the second coil is made of the same material and the same shape as the first magnetic circuit. It is the same number of turns with opposite polarity. Therefore, the demagnetizing field of the coil winding part can be reduced, the magnetization reversal becomes sharp,
Time derivative dΦ / of the total amount of reversal magnetic flux, which is the coil induced voltage
Since dt becomes large, there is an effect that current limiting efficiency is improved.

The first coil is composed of a rod-shaped permanent magnet, two first yokes joined to both ends of the permanent magnet, and a soft magnet joined between the other ends of the two yokes. Core and
A soft magnetic core is wound around a soft magnetic core of a first magnetic circuit composed of a substantially U-shaped second yoke joined between both ends on the opposite side of the yoke, and the second coil is The second magnetic circuit is formed by winding the same number of turns with the opposite polarity to the first coil on the soft magnetic core of the second magnetic circuit having substantially the same material and shape as the first magnetic circuit. Therefore, the magnetic circuit forms a closed magnetic circuit with the yoke and the soft magnetic core. As a result, there is a problem that the magnetic flux of the soft magnetic core is shallow due to the shunting of the DC magnetic flux by the permanent magnet, but there is no demagnetizing field due to the closed magnetic path, and there is no reduction in the squareness ratio of the soft magnetic core. Have.

The first coil has a rod-shaped permanent magnet and a substantially U-shape joined to both ends of the permanent magnet.
Wound around the soft magnetic core of the first magnetic circuit consisting of a soft magnetic core whose cross-sectional area of the first side joined to the permanent magnet is larger than the cross-sectional area of the second side substantially parallel to the permanent magnet The second coil is made of a soft magnetic core of a second magnetic circuit having substantially the same material and the same shape as the first magnetic circuit, the same number of turns being wound with the opposite polarity to the first coil. It is. Therefore, the number of members can be reduced, and an inexpensive current limiter can be obtained.

The soft magnetic core is a laminated soft magnetic core manufactured by joint lap joining. Therefore, a slight gap is not formed between the yoke and the soft magnetic core, and the magnetic efficiency can be improved.

The soft magnetic core is made of directional silicon steel, 50%
It is a square hysteresis material of any of a Ni—Fe alloy and a Co-based amorphous alloy. Therefore, the characteristics can be improved, and the current limiting efficiency can be improved.

Further, the length of the soft magnetic core in the direction of magnetization is extended so as to extend further outward from the joint with the two yokes joined to the soft magnetic core. Therefore, the characteristics can be improved, and the current limiting efficiency can be further improved.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a configuration of a current limiter according to Embodiment 1 of the present invention.

FIG. 2 is a schematic diagram of a square hysteresis curve of a soft magnetic core used in the current limiter of the present invention.

FIG. 3 is a schematic diagram showing a configuration of a current limiter according to Embodiment 2 of the present invention.

FIG. 4 is a schematic diagram showing a configuration of a current limiter according to Embodiment 3 of the present invention.

FIG. 5 is a schematic diagram showing a configuration of a first magnetic circuit of a current limiter according to Embodiment 4 of the present invention.

FIG. 6 is a schematic diagram showing a configuration of a first magnetic circuit of a current limiter according to Embodiment 5 of the present invention.

FIG. 7 is a schematic diagram showing a configuration of a first magnetic circuit of a current limiter according to Embodiment 6 of the present invention.

FIG. 8 is a schematic diagram showing a configuration of a first magnetic circuit of a current limiter according to a seventh embodiment of the present invention.

FIG. 9 is a perspective view showing a state of joint lap joining of the laminated soft magnetic core.

[Explanation of symbols]

1, 1a, 1b permanent magnet, 2a, 2b, 2c, 2d
Yoke, 3, 3a, 3b Soft magnetic core, 4, 4a First coil (coil), 4b Second coil (coil), 1
0a, 11a, 12, 13, 14, 15 First magnetic circuit (magnetic circuit), 10b, 11b Second magnetic circuit (magnetic circuit).

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01F 27/24 K

Claims (12)

[Claims] 1. A current limiter comprising: a magnetic circuit which is at least partially made of a soft magnetic core and is magnetically saturated by a permanent magnet; and a coil wound around a magnetic saturation region of the magnetic circuit. Is a current limiter comprising the permanent magnet, the yoke, and the soft magnetic core wound with the coil. 2. The coil according to claim 1, wherein the first coil and a second coil wound in the opposite polarity to the first coil are connected in series. 2. The current limiter according to 1. 3. The first coil and the second coil include a rod-shaped permanent magnet, two yokes respectively joined to both ends of the permanent magnet, and the other end of the two yokes. A first magnetic circuit made of the soft magnetic core joined between the portions, a material and a shape substantially the same as the first magnetic circuit, the gap between the first magnetic circuit and the soft magnetic core 3. The current limiting device according to claim 2, wherein the current limiting device is a single coil wound so as to be bundled with the two opposed soft magnetic cores in a second magnetic circuit opposed to the second magnetic circuit. 4. The first coil and the second coil comprise a rod-shaped permanent magnet, two first yokes respectively joined to both ends of the permanent magnet, and the two first yokes. The soft magnetic core joined between the other ends of one yoke, the yoke at both ends of the soft magnetic core and the inside or outside of the yoke are respectively joined to form a substantially L-shape, A first magnetic circuit composed of two second yokes whose opposite ends are opposed to each other with a gap therebetween, and have substantially the same material and shape as the first magnetic circuit, and The second magnetic circuit in which the soft magnetic cores are opposed to each other with a gap therebetween, wherein one coil is wound so as to be bundled with the two opposed soft magnetic cores. 2
Current limiter as described. 5. The first coil, wherein the bar-shaped permanent magnet, two yokes joined to both ends of the permanent magnet, and the first coil joined between the other ends of the two yokes. A first magnetic circuit made of a soft magnetic core is wound around the soft magnetic core, and the second coil is formed of a second magnetic circuit having substantially the same material and shape as the first magnetic circuit. 3. The current limiter according to claim 2, wherein the soft magnetic core is wound around the first coil in the same number of turns with the opposite polarity to the first coil. 6. The first coil includes: two rod-shaped permanent magnets arranged at a predetermined interval; and two yokes that join between the same extreme portions of the two permanent magnets. Wound around the soft magnetic core of a first magnetic circuit composed of the soft magnetic core joined between the center portions of the two yokes, and the second coil is provided with the first magnetic circuit. The soft magnetic core of a second magnetic circuit having substantially the same material and the same shape as the circuit, the same number of turns having the opposite polarity to the first coil being wound around the soft magnetic core. Current limiter. 7. The first coil includes a rod-shaped permanent magnet, two first yokes joined to both ends of the permanent magnet, and a joint between the other ends of the two yokes. Two soft cores, each of which is joined to opposite ends of the soft magnetic core on opposite sides of the yoke to form a substantially L-shape, and whose ends opposite to the soft magnetic core face each other with a gap therebetween. The second coil is wound around the soft magnetic core of the first magnetic circuit comprising the second yoke, and the second coil has a second magnetic material having substantially the same material and the same shape as the first magnetic circuit. 3. The current limiting device according to claim 2, wherein the soft magnetic core of the circuit is wound with the same number of turns of opposite polarity to the first coil. 8. The first coil includes a rod-shaped permanent magnet, two first yokes joined to both ends of the permanent magnet, and a joint between the other ends of the two yokes. Wound around the soft magnetic core of a first magnetic circuit including the soft magnetic core to be formed and a substantially U-shaped second yoke joined between both ends of the soft magnetic core opposite to the yoke. The second coil has the same polarity and the same polarity as the first coil in the soft magnetic core of the second magnetic circuit having the same material and shape as the first magnetic circuit. 3. The current limiting device according to claim 2, wherein the current limiting device has a number of turns. 9. The first coil has a rod-shaped permanent magnet and a substantially U-shape joined to both ends of the permanent magnet, and has a cross-sectional area of a first side joined to the permanent magnet. Is wound around the soft magnetic core of the first magnetic circuit including the soft magnetic core having a larger cross-sectional area of a second side substantially parallel to the permanent magnet, and the second coil is The material is substantially the same as the first magnetic circuit, the soft magnetic core of the second magnetic circuit of the same shape, the same number of turns with the opposite polarity to the first coil, characterized in that The current limiter according to claim 2, wherein 10. The current limiter according to claim 9, wherein the soft magnetic core is a laminated soft magnetic core manufactured by joint lap joining. 11. The soft magnetic core is made of directional silicon steel, 50
The current limiting device according to any one of claims 1 and 3 to 10, wherein the current limiting device is a square hysteresis material of any one of a Ni-Fe alloy and a Co-based amorphous alloy. 12. The soft magnetic core according to claim 1, wherein a length of the soft magnetic core in a magnetization direction is extended so as to extend further outward from a joint between the soft magnetic core and the two yokes. The current limiter according to any one of claims 3 to 8.