JP3532050B2 - Linear variable reactor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a quadrature core type and a tripod core type variable reactor in which the inductance of a main winding can be changed by the value of an exciting current of a control winding, and more particularly to a variable reactor having a reduced harmonic current. , Reactor that can make current non-distorted by using it in three phases.

[0002]

2. Description of the Related Art As a conventional technique of a rectangular magnetic core type variable reactor, Japanese Patent Laid-Open No. 6-364 previously proposed by the applicant of the present application.
There is a linear variable reactor disclosed in Japanese Patent Laid-Open No. 03.
FIG. 14 is a perspective view for explaining an example of a linear variable reactor proposed by the present applicant, and this reactor has a first winding 12 around which a main winding 12 is wound, as shown in FIG.
The U-shaped cut core 11 and the control winding 14 are wound, and a gap 15 having a substantially V shape is formed inward at the center of the cut end face.
The second U-shaped cut core 13 formed with is cut and the cut surfaces thereof are rotated by 90 ° to face each other. The four contact surfaces 16 of the cut surfaces are the main winding 12,
This is a common magnetic path through which all the magnetic fluxes φ ₁ and φ ₂ generated by applying the voltages e ₁ and e ₂ to each of the control windings 14 pass. Therefore, by magnetically saturating the common magnetic path with the current i ₂ of the control winding 14, the magnetic path of the magnetic flux by the main winding 12 is changed from φ _1-1 to φ.
_As shown in _1-4, it moves to a V-shaped gap.

However, what is magnetically saturated by the current of the control winding 14 is the common magnetic path corresponding to the contact surfaces of the cut surfaces at the portion where the magnetic circuit cross-sectional area is minimum and the magnetic flux density is maximum, and leakage occurs at this location. Magnetic flux is generated. Since the location where this magnetic saturation occurs is the common magnetic path on the side of the main winding 12 rather than the V-shaped gap, the magnetic flux of the main winding 12 that moves to the V-shaped gap is small. Therefore, of the main winding magnetic flux φ ₁ , the control winding current i ₂
The amount of magnetic flux that can be controlled by is small, and a wide range of linear inductance cannot be obtained. When the inductance is made variable, the current of the main winding 12 contains many harmonics in addition to the third harmonic, and even if it is used in a three-phase circuit, the current waveform shows the fifth harmonic as shown in FIG. It becomes a distorted waveform including harmonics.

[0004]

As described above, in the conventional linear variable reactor, the gap for improving the magnetic saturation characteristic is cut by the cut core for the control winding, which is outside the common magnetic path when viewed from the main winding. Since it was provided on the magnetic circuit in the center part of the end face, it was not possible to control the passage of the main winding magnetic flux to the gap sufficiently by the control winding current.

The present invention has been made in view of the above-mentioned circumstances, and has been made with the object of providing a three-phase linear variable reactor capable of controlling a wide range and improving harmonic distortion. .

[0006]

According to a first aspect of the present invention, there is provided a first U-shaped cut core around which a main winding is wound and a second U-shaped cut core around which a control winding is wound. The cut surfaces of the two cut cores face each other, and the other cut core is twisted in the twist direction with respect to the one cut core.
A contact is made in a rotated state, a part of the contact portion of the first U-shaped cut core and the second U-shaped cut core is cut to create a wedge-shaped gap, and the value of the exciting current of the control winding is Change
It is characterized in that the inductance of the main winding is changed.

According to a second aspect of the present invention, two tripod cores each having an outer leg around which a main winding is wound and a central leg around which a control winding is wound are brought into contact with each other, and one of the outer legs is The portion is cut to form a wedge-shaped gap, the value of the exciting current of the control winding is changed, and the inductance of the main winding is changed.

The invention of claim 3 has a compact core structure for application to a three-phase power system, and includes a first E-shaped cut core around which a three-phase main winding is wound, and a control. A second U-shaped cut core around which a winding is wound, the cut surfaces of the cut cores are opposed to each other, and one cut core is twisted in the other cut core in a twisting direction. The control coil is excited by exciting the control winding by contacting the first E-shaped cut core and the second U-shaped cut core by cutting a part of the contact portion between the first E-shaped cut core and the second U-shaped cut core. It is characterized in that the current value is changed to change the inductance of the main winding.

[0009]

DETAILED DESCRIPTION OF THE INVENTION

(Invention of Claim 1) In the present invention, a gap for improving the magnetic saturation characteristic is a common magnetic path for the magnetic flux of the main winding and the control winding,
And, it is closest to the main winding and has the smallest magnetic path cross-sectional area.
It is formed on the contact surfaces of the cut surfaces of the first and second cut cores where the magnetic flux density is maximum, and specifically, the first U-shaped cut core around which the main winding is wound. And a second U-shaped cut core around which the control winding is wound, with their cut surfaces facing each other, and the other cut core rotated 90 ° in the twisting direction with respect to one cut core. In contact with each other, and the facing contact portion between the first U-shaped cut core and the second U-shaped cut core is used as a common magnetic path for the magnetic flux of the main winding and the magnetic flux of the control winding. A part of the contact portion to be formed is cut to form a wedge-shaped gap, and thus the first portion is formed.
In the U-shaped cut core and the second U-shaped cut core, a composite magnetic path including a magnetic core contact surface and a wedge-shaped gap is formed at the facing contact portions of the magnetic cores.

According to the above configuration, first, a voltage is applied to the main winding to form a magnetic circuit via the common magnetic path of the first and second U-shaped cut cores. By applying a voltage to the control winding, a magnetic circuit is formed even through the common magnetic path of the first and second U-shaped cut cores. Therefore, when there is no control winding current, the inductance of the main winding has a large value when the main winding magnetic flux passes through the magnetic core contact surface of the common magnetic path portion where the magnetic resistance is small. On the other hand, when a current flows through the control winding, the magnetic permeability of the magnetic core contact portion of the common magnetic path portion decreases, and the inductance of the main winding decreases. When the control winding current is further increased and a magnetic potential difference occurs in the magnetic core contact portion, part of the main winding magnetic flux passes through the cut wedge-shaped gap in the common magnetic path portion, and the main winding magnetic circuit is common. In the magnetic path portion, a parallel circuit of the magnetic core contact portion and the wedge-shaped gap portion is formed. By controlling the magnetic flux of the parallel circuit, the non-linear characteristic of the magnetic circuit is improved, and the main winding inductance is linearly changed. Therefore, the inductance of the main winding can be linearly changed by changing the value of the exciting current of the control winding by external control.

FIG. 1 is a perspective view for explaining an embodiment of a linear variable reactor according to the present invention. In the drawing, 11 is a first U-shaped cut core, around which a main winding 12 is wound. .
Reference numeral 13 is a second U-shaped cut core around which a control winding 14 is wound. These first and second U-shaped cut cores 11 and 13 have their cut surfaces opposed to each other and twist the second U-shaped cut core 13 with respect to the first U-shaped cut core 11. They are in contact with each other while being rotated 90 ° in the direction. The four surfaces of this contact portion are the first and second U
It becomes a common magnetic circuit of the shape cut cores 11 and 13. A part of this common magnetic circuit is cut to form a triangular wedge-shaped gap 15. In this way, when the triangular wedge-shaped gap 15 is formed in the common magnetic circuit, the common magnetic path is a parallel magnetic path of the contact portions 16 of the first and second U-shaped cut cores 11 and 13 and the triangular wedge-shaped gap 15. Becomes

FIG. 2 is an equivalent circuit diagram of the magnetic core circuit element in the structure shown in FIG. 1, and the mark "x" indicates that the two magnetic cores are in contact with each other in a state of being rotated by 90 °, and the windings 12, 14 are
Is a symbol that does not mutually intersect with the magnetic flux generated by the winding on the other side. FIG. 3 shows an example of a connection circuit of three-phase reactors connected in three phases.

In FIG. 1, an alternating voltage e1 is applied to the main winding 12.
Is applied and the current i1 flows in the direction of the arrow in the figure,
A magnetic flux φ1 is generated by the common magnetic paths at both ends of the first U-shaped cut core 11 and both ends of the second U-shaped cut core 13, as indicated by a dotted arrow in FIG. In this case, magnetic flux φ1
Of the control winding 14, the second U-shaped cut core 13 is wound around the control winding 14, and the second U-shaped cut core 13 is twisted with respect to the first U-shaped cut core 11. Since it is rotated by 90 °, no induced voltage is generated in the control winding 14. Then, by applying the alternating voltage e1 to the main winding 12, a reactive alternating current delayed by 90 ° from the alternating voltage e1 flows through the main winding 12. If a constant voltage e2 is applied to the control winding 14 and a current i2 flows in the direction of the arrow in the figure, both ends of the second U-shaped cut core 13 and both ends of the first U-shaped cut core 11 will have the same magnetic field. Depending on the path, a magnetic flux φ2 is generated as shown by a dotted arrow in FIG. Also in this case,
Although a part of φ2 is applied to the first U-shaped cut core 11 around which the main winding 12 is wound, the second U-shaped cut core 13 is
Since the U-shaped cut core 11 is rotated by 90 ° in the twisting direction, no induced voltage is generated in the main winding 12.

The magnetic circuit of the magnetic flux φ1 formed by applying the alternating voltage e1 to the main winding 12 is formed through a common magnetic path, and is formed by applying a constant voltage e2 to the control winding 14. The magnetic circuit of the magnetic flux φ2 is also configured through the common magnetic path. At this time, in the common magnetic path φ1 and φ
Two of the U-shaped cut cores 11 and 13 contact each other, and the magnetic permeability of the contact portions 16 of the first and second U-shaped cut cores 11 and 13 changes. Therefore, the magnetic flux φ2 is changed according to the value of the exciting current flowing through the control winding 14, and the magnetic permeability of the contact portion 16 of the first and second U-shaped cut cores 11 and 13 is changed.
By controlling the magnetic flux of the common magnetic path including the triangular wedge-shaped gap by generating the difference in magnetic potential, it is possible to improve the magnetic saturation characteristics and variably control the inductance of the main winding 12.

Therefore, as shown in FIG. 4, the control winding 1
The inductance of the main winding 12 can be changed by changing the excitation current of No. 4 by external control.

As described above, according to the present invention, by cutting a part of the contact portions of the cut surfaces of the first and second U-shaped cut cores 11 and 13, the common magnetic path is formed into the first and second common magnetic paths. Two
Contact portion 16 of the cut surface of the U-shaped cut cores 11 and 13
And a triangular wedge-shaped gap 15 are formed in parallel magnetic paths,
The magnetic characteristics are improved, and the main winding current becomes current distortion of only the fundamental wave current and the third harmonic component. Therefore, in the three-phase reactance in which the three-phase variable inductance is connected, the three-phase line current is
It can operate as a linear three-phase variable reactor with extremely low distortion. The current waveform used in the three-phase circuit is a sine wave AC waveform that does not include harmonics as shown in FIG.

FIGS. 5 and 6 are views showing other embodiments of the present invention, respectively, and both are wedge-shaped at the contact portions of the cut surfaces of the first U-shaped cut core 11 and the second U-shaped cut core 13. The shape of the gap 15 is changed so that the contact surface 16 between the cut cores 11 and 13 is changed. The operation is
Since the operation is the same as that described with reference to FIG. 1, parts having the same operations as those of the embodiment shown in FIG. 1 are designated by the same reference numerals as those in the case of FIG. 1, and detailed description thereof will be omitted.

(Invention of Claim 2) FIG. 7 is an overall perspective view for explaining an embodiment of the invention of Claim 2. In this invention, a variable reactor is constructed by using two tripod cores. The outer leg around which the main winding 12 is wound and the control winding 14
The tripod cores 11 and 13 each having a central leg wound with are opposed to each other, and a wedge-shaped gap 15 is created by cutting a part of both outer legs, and the value of the exciting current of the control winding 14 is changed. hand,
The inductance of the main winding 12 is changed. In this way, the minimum cross-section in the common magnetic path of the multiple magnetic circuits of the main winding magnetic flux φ ₁ and the control winding magnetic flux φ ₂ ,
That is, a wedge-shaped gap may be formed in a part of the portion where the magnetic flux density is maximum, and a common magnetic path may be formed by synthesizing the contact portions of the cores and the wedge-shaped gap in parallel. Note that, also in the present invention, the shape of the wedge-shaped gap 15 is not limited to the illustrated example, and it can be easily understood that various changes may be made as described above.

(Invention of Claim 3) FIG. 8 is an overall perspective view for explaining one embodiment of the invention of Claim 3, 11 in the figure.
Is a first E-shaped cut core, around which the three-phase main winding 12 is wound. Further, in the figure, 13 is a second U-shaped cut core around which a control winding 14 is wound. The first E-shaped cut core 11 and the second U-shaped cut core 13 have their cut surfaces opposed to each other, and the second U-shaped cut core 13 is opposed to the first E-shaped cut core 11. Are contacted while being rotated 90 ° in the twisting direction. Six surfaces of this contact portion form a common magnetic circuit for the first E-shaped cut core 11 and the second U-shaped cut core 13. A part of this common magnetic circuit is cut to form a triangular wedge-shaped gap 15. When the triangular wedge-shaped gap 15 is formed in the common magnetic circuit, the common magnetic path is formed by the first E-shaped cut core 11 and the second U-shaped cut core 11.
The cut-shaped core 13 is a magnetic path in which the contact portions 16 of the same shape and the triangular wedge-shaped gap 15 are combined in parallel. Here, the contact portion 16 of the cut surface has the same contact area for all three phases.

FIG. 9 is an equivalent circuit diagram of the magnetic core circuit element in the structure shown in FIG. 8, and the crosses indicate that the two magnetic cores are in contact with each other while being rotated by 90 °. Is a symbol. In FIG. 8, a three-phase Δ-connected three-phase main winding 1 wound around the tripod of the first E-shaped cut core 11
The three-phase alternating voltage e1 is applied to 2 and the currents ia, ib, ic
However, if it flows in the direction of the arrow shown in the figure, the magnetic flux φ is applied to each leg of the first E-shaped cut core 11 as shown by the dotted arrow.
a, φb, and φc are generated. The passage route of each magnetic flux is a magnetic circuit that passes through the end portion of the first E-shaped cut core 11 and passes through the leg portion of the second U-shaped cut core 13.

Here, a part of the magnetic fluxes φa, φb, and φc are
The control winding 14 is applied to the leg portion of the second U-shaped cut core 13 around which the second U-shaped cut core 13 is wound.
Since it is rotated by 90 ° in the torsional direction with respect to the cut core 11, no induced voltage is generated in the control winding 14.
Then, by applying the three-phase alternating voltage e1 to the three-phase main winding 12, the alternating voltage e1 is 90 ° to the three-phase main winding 12.
The delayed reactive alternating current flows. If a constant voltage e2 is applied to the control winding 14 and a current i ₂ flows in the direction of the arrow in the figure, the first U-shaped cut core 13 moves from the leg portion to the first portion.
By the common magnetic path of the tripod end of the E-shaped cut core 11 of
A magnetic flux φ ₂ is generated as shown by a dotted arrow in FIG. Also in this case, a part of the magnetic flux φ ₂ is applied to the first E-shaped cut core 11 on which the three-phase main winding 12 is wound, but the second U-shaped cut core 13 is cut to the first E-shaped cut core 13. Since the core 11 is rotated by 90 ° in the twisting direction, no induced voltage is generated in the three-phase main winding 12.

The magnetic circuit of the magnetic fluxes φa, φb, and φc formed by applying the three-phase alternating voltage e1 to the three-phase main winding 12 is constructed through a common magnetic path, and the control winding 1
A magnetic circuit of the magnetic flux φ ₂ formed by applying a constant voltage e2 to 4 is also configured through the common magnetic path. At this time, on the common magnetic path .phi.a, .phi.b, .phi.c and phi ₂ are as mixed, mutually influence each other, the first E-shaped cut core 11 and the contact portion 16 of the cut surface comrades second U-shaped cut core 13
Changes the magnetic permeability of. Therefore, the magnetic flux φ ₂ is changed according to the value of the exciting current i ₂ flowing in the control winding 14, and the magnetic permeability of the contact portion 16 between the cut surfaces of the first E-shaped cut core 11 and the second U-shaped cut core 13 is changed. By changing the magnetic field of the three-phase main winding 12 to control the magnetic flux of the common magnetic path including the triangular wedge-shaped gap by changing the magnetic field. In order to keep each of the three phases in equilibrium, the contact area of the cut surface of each phase and the gap may be formed uniformly.

Next, an application example of the variable reactor according to the present invention to a power system will be described. FIG. 11 shows that the three-phase linear variable reactor and the power capacitor C are connected in parallel, and the three-phase linear variable reactor is changed by the current i ₂ of the control winding 14, and the reactive power from the lagging phase to the leading phase is changed. Is a diagram showing an example of a circuit applied to a reactive power compensator that continuously controls at high speed to contribute to stabilizing the voltage of an AC system, and FIG. 12 is a diagram showing each phase of the present three-phase linear variable reactor and a power capacitor. It is a figure which shows the example of an application circuit to the phase shifter which connects C in parallel, isolate | separates each phase, and inserts in series in an alternating current system. In the phase shift control, the reactor of each phase is changed by the current i ₂ of the control winding, the impedance of the phase shifter inserted in series in the AC system is adjusted, and the phase shift control is performed to stabilize the AC system. .

FIG. 13 is a diagram showing an example of an application circuit to a current limiting device in which the present three-phase linear variable reactor is separated into each phase and is inserted in series in an AC system. i
Keep ₂ flowing to reduce the inductance of the reactor separated into each phase and facilitate the flow of load current. In the event of a short-circuit accident, the load current differential circuit detects the current and cuts off the control winding current i ₂ . Then, the inductance of the reactor increases and the short-circuit current is suppressed.

[0025]

As described above in detail, according to the present invention, the inductance of the main winding serving as a reactor can be changed by the value of the exciting current of the control winding.
It is possible to construct a good three-phase linear variable reactor with extremely low distortion, and it can be effectively used in the field of AC system stabilizing equipment.

[Brief description of drawings]

FIG. 1 is a perspective view for explaining an embodiment of a linear variable reactor according to the invention of claim 1. FIG.

FIG. 2 is a circuit configuration diagram showing an electrically equivalent circuit of the variable reactor shown in FIG.

FIG. 3 is a diagram showing a circuit example when three-phase wiring is performed using the variable reactor shown in FIG.

FIG. 4 is a diagram showing the inductance of the main winding with respect to the control winding current of the variable reactor shown in FIG.

FIG. 5 is a perspective view showing a modified example of the variable reactor shown in FIG.

FIG. 6 is a perspective view showing another modification of the variable reactor shown in FIG.

FIG. 7 is a perspective view for explaining an embodiment of the invention of claim 2;

FIG. 8 is a perspective view for explaining an embodiment of a three-phase variable linear reactor according to the invention of claim 3;

9 is a circuit configuration diagram showing an equivalent circuit of the three-phase variable linear reactor of FIG.

FIG. 10 is a current waveform diagram of the main winding when the variable reactor according to the present invention is used.

FIG. 11 is a circuit configuration diagram showing an example of application of reactive power compensation of the present invention to a device.

FIG. 12 is a circuit configuration diagram showing an application example of the present invention to a phase shifter.

FIG. 13 is a circuit configuration diagram showing an application example of the present invention to a current limiting device.

FIG. 14 is a perspective view for explaining an example of a variable reactor previously proposed by the applicant.

FIG. 15 is a current waveform diagram of the main winding when a conventional variable reactor is used.

[Explanation of symbols]

11 ... 1st cut core, 12 ... Main winding, 13 ... 2nd cut core, 14 ... Control winding, 15 ... Wedge gap, 16 ...
Cut core surface The contact surface of each other.

Front page continued (72) Inventor Masaaki Sakamoto 7-2-1, Nakayama, Aoba-ku, Sendai-shi, Miyagi, Tohoku Electric Power Co., Inc. Research and Development Center (56) Reference JP-A-7-335456 (JP, A) (58) ) Fields surveyed (Int.Cl. ⁷ , DB name) H01F 29/14

Claims (3)

(57) [Claims] 1. A first U-shaped cut core around which a main winding is wound, and a second U-shaped cut core around which a control winding is wound. Are made to face each other, and one cut core is brought into contact with the other cut core while being rotated by 90 ° in the twisting direction.
Part of the contact portion between the U-shaped cut core and the second U-shaped cut core is cut to form a wedge-shaped gap, and the value of the exciting current of the control winding is changed to change the inductance of the main winding. A linear variable reactor characterized by being changed. 2. Two tripod cores each having an outer leg on which a main winding is wound and a central leg on which a control winding is wound are opposed to each other, and a part of both outer legs is cut. A linear variable reactor characterized in that a wedge-shaped gap is created and the value of the exciting current of the control winding is changed to change the inductance of the main winding. 3. A first E-shaped cut core around which a three-phase main winding is wound, and a second U-shaped cut core around which a control winding is wound. The cut surfaces are opposed to each other, and one cut core is brought into contact with the other cut core while being rotated by 90 ° in the twisting direction,
A part of the contact portion between the first E-shaped cut core and the second U-shaped cut core is cut to form a wedge-shaped gap, and the value of the exciting current of the control winding is changed to A three-phase linear variable reactor characterized in that the inductance of the winding is changed.