JP3789333B2 - Electromagnetic equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electromagnetic device that is not affected by the excitation current of a main winding, has less harmonic distortion, and can vary reactance without requiring an insulating film on a butt surface, and in particular, reactance that can be connected in series to a power system. It relates to variable electromagnetic equipment.
[0002]
[Prior art]
As conventional techniques for changing reactance, there are a linear variable reactor (Japanese Patent Laid-Open No. 09-330829) and an inductive element (Japanese Patent Laid-Open No. 09-129450) previously proposed by the present applicant.
[0003]
FIG. 7 is a perspective view showing an example of a linear variable reactor (Japanese Patent Laid-Open No. 09-330829) previously proposed by the present applicant. The linear variable reactor has a main winding 32 as shown in FIG. The first U-shaped cut core 31 wound around and the second U-shaped cut core 33 around which the control winding 34 is wound. The cut surfaces are opposed to each other, and the second U-shaped cut core 33 is in contact with the first U-shaped cut core 31 while being rotated 90 ° in the twisting direction. The four contact surfaces 36 between the cut surfaces serve as a common magnetic path through which all of the magnetic fluxes φ1 and φ2 generated by applying voltages e1 and e2 to the main winding 32 and the control winding 34, respectively. Therefore, by magnetically saturating the common magnetic path with the current i2 of the control winding 34, the magnetic path of the magnetic flux by the main winding 32 can be shifted to the wedge-shaped gap 35, and the excitation current of the control winding 34 is changed. As a result, the reactance of the main winding 32 can be varied linearly.
[0004]
FIG. 8 is a perspective view showing an example of an inductive element (Japanese Patent Laid-Open No. 09-129450). As shown in FIG. 8, the inductive element has an EI core 44 and a main winding 45 and a control winding. The wire 46 is wound, and by connecting an AC power source to the main winding 45, a magnetic flux φ1 by the winding portion 45a and a magnetic flux φ2 by the winding portion 45b are generated. Here, when a control current is passed through the control winding 46, a magnetic flux φ3 is generated. By making the outer frame 47 and the outer frame 48 have an equal cross-sectional area, the magnetic flux φ1 and the magnetic flux φ3 are equal to one in the outer frame 47. The magnetic flux obtained by adding / 2 passes, and the magnetic flux obtained by subtracting 1/2 of the magnetic flux φ3 from the magnetic flux φ2 passes through the outer frame 48. At this time, the added magnetic flux is concentrated on the end 47a of the outer frame 47, the tip is magnetically saturated, the magnetic permeability of the outer frame 47 is reduced, and the inductance is reduced.
[0005]
[Problems to be solved by the invention]
However, the linear variable reactor varies the reactance by magnetically saturating the common magnetic path of the first and second U-shaped cut cores with the excitation current of the control winding and controlling the permeability. The reactance of the inductive element is also varied by magnetically saturating the outer frame tip with the main magnetic flux and the control magnetic flux to control the magnetic permeability. For this reason, when the load current flowing through the main winding increases, a magnetic saturation phenomenon occurs due to the load current, and there is a problem that reactance control by the excitation current of the control winding becomes difficult.
[0006]
In addition, the linear variable reactor has an insulating film inserted on the joint surface to prevent short circuit between the laminated steel sheets at the core joint surface as a countermeasure against eddy current generation at the core joint surface of the U-shaped cut core orthogonal to each other. However, it is difficult to secure an insulating film material having sufficient durability, and if an insulating film is interposed, the magnetic resistance of the magnetic circuit increases and it becomes difficult to change a large reactance. there were.
[0007]
In view of the above-described problems, the present invention is an electromagnetic that has a simple magnetic circuit structure and winding winding structure, does not require an insulating film, can reduce harmonic current, and can vary reactance. The purpose is to provide equipment.
It is another object of the present invention to provide a variable reactance electromagnetic device that can be easily configured by applying a conventionally used main iron core structure.
[0008]
[Means for Solving the Problems]
The invention of claim 1 has a field-shaped magnetic core that symmetrically forms four closed magnetic paths, and forms a cross-shaped magnetic path by crossing the magnetic cores with each other. A pair of main windings are wound around a coaxial line opposite to the magnetic core of the core, and a control winding is wound around each of two pairs of magnetic cores parallel to the magnetic core around which the main winding is wound. The main windings are connected in series so that the magnetic fluxes of the main windings face each other at the intersection of the cruciform magnetic paths, and the control windings are connected so that the induced voltages generated by the magnetic fluxes of the main windings cancel each other, and their open terminals A control circuit is connected to the side to supply DC control current, and the reactance of the main winding is continuously varied by controlling the magnetic resistance of the common magnetic path of the magnetic flux generated by the main winding and the magnetic flux generated by the control winding. It is characterized by that.
[0009]
The invention of claim 2 is characterized in that, in the invention of claim 1, a pair of E-shaped magnetic cores are opposed to both sides of the long side of the I-shaped magnetic core to form the rice field-shaped magnetic core. .
[0010]
The invention of claim 3 is the invention of claim 1, wherein two pairs of tripod magnetic cores with the E-shaped cut cores facing up and down are in contact with the back sides of the E-shaped cut cores to form the rice field-shaped magnetic core. It is characterized by that.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a connection diagram showing a basic configuration example of an electromagnetic device according to the present invention, and FIG. 2 is a circuit configuration diagram equivalently displaying a circuit of the electromagnetic device shown in FIG. The basic configuration of the present invention will be described below.
[0012]
The U-shaped magnetic core has a first E-shaped magnetic core 3a and a second E-shaped magnetic core 3b which are symmetrically opposed to each other so that four core window portions are formed on the I-shaped magnetic core 4. The joining surface of the magnetic core 3a and the I-shaped magnetic core 4 and the joining surface of the second E-shaped magnetic core 3b and the I-shaped magnetic core 4 are configured by abutting each laminated steel plate constituting the magnetic core so as to be parallel.
[0013]
The first main winding 1a is wound around the central leg of the first E-shaped magnetic core 3a, and the second main winding 1b is wound around the central leg of the second E-shaped magnetic core 3b. The main windings 1 a and 1 b are connected in series so that the magnetic fluxes φ 1 a and φ 1 b generated from both main windings are in the same direction toward the I-shaped magnetic core 4. The control windings 2a and 2b are wound around the outer leg of the first E-shaped magnetic core 3a, and the control windings 2c and 2d are wound around the outer leg of the second E-shaped magnetic core 3b. All control windings are connected in series so that the induced voltages generated in the control windings 2a and 2b, 2c and 2d are canceled out, and the control circuit 5 is connected to the open terminal side.
The control winding is a set of two arbitrary windings of 2a, 2b, 2c, and 2d connected so that the induced voltage generated is canceled, and the remaining two windings connected in the same manner Can be connected in series or in parallel, and the control circuit 5 can be connected to the open terminal side.
[0014]
In FIG. 1, it is assumed that an AC power source is connected to the open end of the main winding and a current IL1 in the direction indicated by the arrow flows. When current IL1 is a positive cycle, current IL2 flows in a negative cycle. When the current IL1 flows, main magnetic flux φ1a and main magnetic flux φ1a ′ generated by the main winding 1a and main magnetic flux φ1b and main magnetic flux φ1b ′ generated by the main winding 1b are generated in the magnetic paths, respectively. On the contrary, when the current IL2 flows, a main magnetic flux in the opposite direction to that described above is generated. The generated main magnetic flux passes through four closed magnetic paths when no DC control current is passed through the control winding, and reactance according to the number of turns and the magnetic resistance of the iron core is generated in the main winding. The iron core portion and the I-shaped magnetic core portion around which the control winding is wound serve as a common magnetic path for the control magnetic flux φc and the main magnetic flux.
[0015]
When the DC control current Ic is supplied to the control winding while the currents IL1 and IL2 are supplied to the main winding, the control windings 2a, 2b, 2c and 2d are represented by the product of the number of turns of the control winding and the control current Ic. When the magnetomotive force is generated, the magnetic flux density of the common magnetic path portion in which the control winding magnetic fluxes φc1 and φc2 and the main magnetic fluxes φ1a, φ1a ′, φ1b, and φ1b ′ are in the same direction increases, and the permeability changes. Then, the main magnetic flux is controlled and the reactance is lowered.
[0016]
When the common magnetic path approaches a magnetic saturation state by increasing the main winding currents IL1 and IL2 or the DC control current Ic, the main magnetic flux generated from the main windings 1a and 1b is directed in the same direction toward the I-shaped magnetic core 4. Since the main windings are divided and connected so that the increasing main magnetic flux φ1a and main magnetic flux φ1a ′ and the increasing main magnetic flux φ1b and main magnetic flux φ1b ′ cancel each other, the magnetic path is in a completely magnetic saturation state. However, the magnetic flux density is kept constant. Since the increase in the main magnetic flux caused by the pair of main windings 1a and 1b does not circulate in the closed magnetic circuit, the magnetomotive force of the main windings cancels each other.
[0017]
Further, even if the main winding currents IL1 and IL2 increase, the main magnetic flux generated by the main winding 1a and the main magnetic flux generated by the main winding 1b cancel each other so that the common magnetic path is maintained at a constant magnetic flux density. Therefore, the main magnetic flux can be controlled by controlling the DC control current Ic, and the reactance can be varied.
That is, regardless of the main winding current, the reactance can be varied by passing the DC control current Ic through the control winding.
[0018]
FIG. 3A shows an example of reactance control characteristics according to the present invention. It can be seen that the reactance can be varied by increasing the DC control current Ic even when the main winding current is increased.
FIG. 3B shows the reactance magnetization characteristic according to the present invention. The vertical axis represents the magnetic flux of the main winding, and the horizontal axis represents the product of the number of turns of the main winding and the main winding current. Represents magnetic force.
When the DC control current Ic is small, non-linearity of the magnetization characteristic occurs, but by increasing the control current Ic, the main magnetic flux is canceled and the increase of the magnetic flux is suppressed, and the non-linearity of the magnetization characteristic is improved. This confirms that the harmonic distortion is reduced.
[0019]
The first E-shaped magnetic core 3a and the I-shaped magnetic core 4 and the second E-shaped magnetic core 3b and the I-shaped magnetic core 4 are joined to each other because the laminated steel plates are abutted in parallel. There is no short circuit between the steel plates. For this reason, it is not necessary to insert an insulating film in a magnetic core joining surface.
[0020]
As described above, according to the present invention, the main magnetic flux is controlled by adjusting the direct current control current, and the main magnetic flux between the main windings is canceled, so that the harmonics are not affected by the main winding current. The reactance can be varied at high speed continuously.
[0021]
In FIG. 4, the first E-shaped cut core 6a and the second E-shaped cut core 6b each having the main winding 1a wound around the central leg and the control windings 2a and 2b wound around the outer leg are opposed to the central leg. The magnetic path is composed of two sets of tripod cores in which the main winding 1b is opposed to the third E-shaped cut core 6c and the fourth E-shaped cut core 6d in which the control windings 2c and 2d are wound on the outer legs. It is made to face like a rice field.
[0022]
The main windings 1a and 1b are connected in series so that the magnetic fluxes φ1a and φ1b generated from both main windings are in the same direction in the E-shaped magnetic cores 6b and 6d. Further, all control windings were connected in series so that the induced voltages generated in the control windings 2a, 2b and 2c, 2d were canceled by the magnetic flux generated by the main winding, and the control circuit 5 was connected to the open terminal side. Is.
The control winding is a set of two arbitrary windings of 2a, 2b, 2c, and 2d connected so that the induced voltage generated is canceled, and the remaining two windings connected in the same manner Can be connected in series or in parallel, and the control circuit 5 can be connected to the open terminal side.
[0023]
According to this configuration, since an E-shaped cut core to which a high magnetic flux density steel plate is applied can be used, the design magnetic flux density of the core can be increased, the device can be made compact, and a low-cost electromagnetic device can be realized. be able to.
[0024]
(Application example)
FIG. 5 is a diagram showing an example in which the electromagnetic device of the present invention is applied to a reactive power compensator. In FIG. 5, the electromagnetic device 7 and the power capacitor 8 are connected in parallel and inserted in parallel to the transmission line. The electromagnetic device 7 is controlled by a control circuit so that the reactive power from the slow phase to the fast phase occurring in the system is continuously compensated.
[0025]
(Application examples)
FIG. 6 is a diagram for explaining an application example in which the electromagnetic device of the present invention shown in FIG. 1 is applied to a multi-function transformer. As shown in the figure, the main windings are primary windings 9a and 9b, and This is a multi-function transformer configured by winding secondary windings 10a and 10b on each leg around which primary windings 9a and 9b are wound and connecting them in the same manner as the primary winding.
[0026]
In FIG. 6, it is assumed that an AC power source is connected to the primary winding, a load is connected to the secondary winding, and a secondary current IL2 in the direction indicated by the arrow flows in the secondary winding. When the control current is not passed, the primary current IL1 flows through the primary windings 9a and 9b so as to cancel the magnetic flux generated by the secondary current, and the transformer operation is shown as a whole.
[0027]
When a DC control current Ic is passed through the control winding, a magnetic force is generated by generating a magnetomotive force represented by the product of the number of turns of the control winding and the control current Ic, thereby controlling the main magnetic flux. The main magnetic flux φ1a and main magnetic flux φ1a ′ generated by the main winding 1a and the main magnetic flux φ1b and main magnetic flux φ1b ′ generated by the main winding 1b are canceled because they are opposite to each other. Main magnetic flux to be reduced.
[0028]
For this reason, the excitation current, which is a delayed reactive current that generates the main magnetic flux required to maintain the voltage between the terminals of the primary winding, increases in the primary winding as the main magnetic flux decreases due to control current control. To do.
That is, in addition to the function as a transformer, it is possible to realize a multi-function transformer capable of adjusting the reactive current flowing into the primary side by adjusting the control current.
In addition, although the multi-function transformer was applied and demonstrated to the electromagnetic device shown in FIG. 1, it is clear that it can apply also to the other electromagnetic device described by this invention.
[0029]
【The invention's effect】
As described above in detail, according to the present invention, without providing a tap, it is possible to realize an electromagnetic device that suppresses a harmonic current regardless of the presence or absence of a load current and can vary a reactance over a wide range. The increase in power demand and the diversification of loads in recent years can contribute to the stabilization of the voltage of the power system that can provide flexible power equipment that can cope with the diversification of loads such as fluctuations in the system voltage.
[0030]
In addition, a magnetic path that circulates the four closed magnetic paths of the U-shaped magnetic core is formed with respect to the main magnetic flux generated by the main winding, and the main magnetic flux and control by the main winding are controlled except for the magnetic core around which the main winding is wound. It becomes a common magnetic path through which the control magnetic flux by the winding passes, and thereby the reactance of the main winding can be continuously varied by adjusting the control magnetic flux and controlling the magnetic resistance of the common magnetic path.
[0031]
Further, when the main winding current increases, the main magnetic fluxes facing each other toward the common magnetic path also increase, so that the magnetic flux density of the common magnetic path portion in the four closed magnetic paths increases, and the common magnetic path Accordingly, the main magnetic flux cancels each other and cancels the magnetomotive force of each pair of main windings. As a result, the main magnetic flux does not increase.
[0032]
As described above, since the common magnetic path does not reach the complete magnetic saturation, the reactance can be controlled even when the main winding current value is large, and in addition, the magnetic path is in the complete magnetic saturation state. Therefore, harmonic current distortion can be suppressed.
[0033]
Further, the formation of the U-shaped magnetic core can be easily configured by joining two E-shaped laminated cores on both sides of the I-shaped laminated magnetic core.
In the case of using cut cores, the back sides of two sets of tripod magnetic cores formed by facing E-shaped cut cores may be joined.
[0034]
In addition to the above, various modifications can be made without departing from the spirit of the present invention.
[Brief description of the drawings]
FIG. 1 is a connection diagram showing an example of a basic configuration of a single-phase electromagnetic device according to the present invention.
2 is a circuit configuration diagram showing an equivalent circuit of the electromagnetic device shown in FIG. 1. FIG.
FIG. 3 is a diagram illustrating an example of control characteristics of an electromagnetic device.
FIG. 4 is a connection diagram showing another basic configuration example of the electromagnetic device according to the invention.
FIG. 5 is a connection diagram showing an example in which the present invention is applied to a reactive power compensator.
FIG. 6 is a connection diagram showing an example in which the present invention is applied to a multi-function transformer.
FIG. 7 is a perspective view showing an example of a linear variable reactor previously proposed by the present applicant.
FIG. 8 is a perspective view showing an example of an inductive element.
[Explanation of symbols]
1 (1a, 1b) ... main winding, 2 (2a, 2b, 2c, 2d) ... control winding, 3 (3a, 3b) ... E type magnetic core, 4 ... I type magnetic core, 5 ... control circuit, 6 ( 6a, 6b, 6c, 6d) ... E-cut core, 7 ... electromagnetic device, 8 ... power capacitor, 9 (9a, 9b) ... primary winding, 10 (10a, 10b) ... secondary winding, 31 ... 1st U-shaped cut core, 32 ... main winding, 33 ... second U-shaped cut core, 34 ... control winding, 35 ... wedge-shaped gap, 36 ... contact surface between cut surfaces, 41 ... inductive element, 42 ... E-type core, 43 ... I-type core, 44 ... EI-type core, 45 ... main winding, 46 ... control winding, 47 ... outer frame, 48 ... outer frame, 49 ... inner frame.

Claims (3)

Symmetrically, it has a field-shaped magnetic core that forms four closed magnetic paths, and is opposed to the field-shaped magnetic core on the same axis as one magnetic core that crosses the cores to form a cross-shaped magnetic path. A pair of main windings are wound, and a control winding is wound around each of two pairs of magnetic cores parallel to the magnetic core around which the main winding is wound. Connected in series so as to face the intersection of the cross-shaped magnetic path, the control winding is connected so that the induced voltage caused by the magnetic flux by the main winding cancel each other, and the control circuit is connected to the open terminal side DC control current is supplied to control the magnetic resistance of the common magnetic path of the magnetic flux generated by the main winding and the magnetic flux generated by the control winding so that the reactance of the main winding is continuously variable. Electromagnetic equipment. 2. The electromagnetic device according to claim 1, wherein a pair of E-shaped magnetic cores are formed on opposite sides of a long side of the I-shaped magnetic core to form the rice field-shaped magnetic core. 2. The electromagnetic device according to claim 1, wherein two pairs of tripod magnetic cores each having an E-shaped cut core are vertically opposed to each other so that the back sides of the E-shaped cut core are in contact with each other to form the field-shaped magnetic core.

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