JP2008177500A - Three-phase electromagnetic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide three-phase electromagnetic equipment with good three-phase balance which constitutes a variable reactor or variable transformer. <P>SOLUTION: A magnetic core is constituted which has six leg portions by putting together and joining one-end sides of six linear magnetic cores, coupling the other-end sides by coupling magnetic cores, and forming window portions. The magnetic cores of the six leg portions are wound with main windings connected to a three-phase AC power source. Control windings are wound around the coupling magnetic cores and connected in series or in parallel to cancel voltages induced with main magnetic flux produced by main windings, and a control circuit is connected to an open terminal thereof. A DC control current is supplied to the control windings to produce control magnetic flux which flows back in one direction and the magnetic resistance of a magnetic core as a common magnetic path of the main magnetic flux and control magnetic flux is controlled to continuously vary the reactance of the main windings. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an electromagnetic device capable of varying a three-phase reactance. Furthermore, the present invention relates to a three-phase electromagnetic device that has low harmonic distortion, does not require a gap in the butt surface of the iron core, and has an excellent three-phase balance.

  As conventional techniques capable of varying reactance, there are electromagnetic devices (Patent Document 1) and three-phase electromagnetic devices (Patent Document 2) previously proposed by the present applicant.

FIG. 9 is a connection diagram for explaining an example of a single-phase electromagnetic device previously proposed by the present applicant. In this electromagnetic device, a first main winding 31a, a second main winding 31b, and control windings 32a, 32b, 32c, and 32d are wound around a U-shaped magnetic core 33, and an open terminal of a control winding connected in series. The control circuit 34 is connected to the side.
When an AC power source is connected to the open end of the main winding and a DC control current Ic is passed through the control winding, the product of the number of turns of the control winding and the DC control current Ic in the control windings 32a, 32b, 32c, and 32d. When the magnetomotive force represented is generated, the magnetic flux density of the common magnetic path portion in which the control magnetic fluxes φc31 and φc32 and the main magnetic fluxes φ31a, φ31a ′, φ31b, and φ31b ′ are in the same direction increases, and the permeability changes. The main magnetic flux is controlled and the reactance is lowered.

FIG. 10 is a connection diagram for explaining an example of a three-phase electromagnetic device previously proposed by the present applicant. This three-phase electromagnetic device includes three H-shaped leg portions 44a to 44c that form a magnetic path with each end paired, and two frames that form a closed magnetic circuit by connecting the end sides of these H-shaped leg portions. The main windings 41aa to 41cb corresponding to the respective phases of the three-phase AC power source are wound around each magnetic path on one coupling end side of the H-shaped leg portion. On the other connecting end side, control windings 42aa to 42cb are wound around each magnetic path. The main winding is connected in series or in parallel so that the main magnetic flux generated in the pair of magnetic paths is in the same direction, and the control winding is connected in series so that the induced voltages generated by the main magnetic flux are canceled each other. The reactance of the main winding is continuously varied by controlling the magnetic resistance of the common magnetic path of the main magnetic flux and the control magnetic flux.
Japanese Patent No. 3789333 JP 2003-168612 A

However, although the electromagnetic device disclosed in Patent Document 1 can control the magnetic resistance of the common magnetic path of the main magnetic flux and the control magnetic flux and continuously vary the reactance of the main winding, it is a single-phase device. Therefore, in order to achieve a three-phase configuration that is generally used for power, it is necessary to configure a three-phase configuration with three units. From the viewpoint of weight and volume, a three-phase integrated electromagnetic device has been desired for miniaturization. .
The three-phase electromagnetic device disclosed in the above-mentioned document 2 can also control the magnetic resistance of the common magnetic path of the main magnetic flux and the control magnetic flux and continuously vary the reactance of the main winding. The magnetic resistance of the main magnetic path due to the main winding wound around the leg is different from the magnetic resistance of the main magnetic path due to the main winding wound around the outer leg, which causes an imbalance between the three phases during reactance control. was there.

  Therefore, in view of the above-mentioned problems, the present invention has no imbalance between the three phases, does not require a gap in the abutting surface of the iron core, has a simple magnetic circuit structure and winding structure of the winding, and constitutes a three-phase integrated structure. An object of the present invention is to provide a three-phase electromagnetic device capable of changing the reactance without providing a tap.

The technical means of the present invention includes a magnetic core in which the ends of six legs that are radially symmetrically branched in the same plane are connected to each other to form six windows, and three legs on each of the six legs of the magnetic core. The main winding connected to the phase AC power source is wound, the control winding is wound around the connecting portion connecting the leg portions of the magnetic core, and the voltage induced in the control winding by the AC main current flowing in the main winding is Connecting the control circuit to the open ends of the control windings so as to cancel each other, supplying a DC control current to generate a control magnetic flux that recirculates the connecting portion, and controlling the DC control current Three-phase electromagnetic device that controls the magnetic resistance of the magnetic core that forms a common magnetic path of the main magnetic flux generated by the AC main current flowing through the main winding and the control magnetic flux, and continuously varies the reactance of the main winding It is.
According to a second technical means, three pairs of magnetic cores are provided so that the main magnetic flux of the same phase is generated in the same direction in the magnetic cores of the leg portions that are paired in the extending direction of the six leg portions of the magnetic core. A three-phase electromagnetic device characterized by winding a main winding of each phase.
According to a third technical means, three pairs of magnetic cores are formed so that main magnetic fluxes of the same phase are generated in opposite magnetic cores in the magnetic cores of the leg portions adjacent to each other of the six leg portions of the magnetic cores. The three-phase electromagnetic device is characterized by winding a main winding of each phase.
A fourth technical means is a three-phase electromagnetic device characterized in that control windings are wound around the magnetic cores of each of the six connecting portions that connect the magnetic cores of the respective leg portions around which the main winding is wound. .
A fifth technical means is characterized in that three control windings are wound around every other magnetic core of each connecting portion for connecting the magnetic cores of the respective leg portions around which the main winding is wound. Equipment.
In the sixth technical means, one end of each of the six linear magnetic cores is assembled and joined, and the other end is connected with each of the six magnetic cores to form six windows, and each linear magnetic core is adjacent to the linear magnetic core. It is a three-phase electromagnetic device characterized by the configuration of a magnetic core arranged so that the angle between and the angle is 60 °.
In a seventh technical means, the secondary winding is wound around the magnetic core of the leg portion around which the main winding of each phase is wound, and the voltage induced in the secondary winding is continuously adjusted by adjusting the DC control current. This is a three-phase electromagnetic device characterized by being a variable transformer.

  According to the present invention, a three-phase electromagnetic device such as a variable reactor or a variable transformer with excellent three-phase balance that can vary reactance over a wide range without providing a tap and without requiring a gap in the abutting surface of the iron core is provided. With the recent increase in power demand and diversification of loads, flexible power facilities that can cope with diversification of loads such as fluctuations in system voltage can be provided. It can contribute to more appropriate control of rate and current.

  FIG. 1 is a connection diagram showing a basic configuration of the magnetic core and winding of a three-phase electromagnetic device according to the present invention, and FIG. 2 is a diagram showing a circuit configuration in which the three-phase electromagnetic device shown in FIG. FIG. 3 is a connection diagram showing the three-phase electromagnetic device shown in FIG. 1 together with a configuration example of a magnetic core. The basic configuration example of the present invention will be described below.

  As shown in FIG. 3, the magnetic cores constituting the three-phase electromagnetic device are assembled by joining one end of each of the six linear magnetic cores 3aa, 3ab, 3ba, 3bb, 3ca and 3cb, and having an angle with the adjacent linear magnetic core. It is arranged at 60 ° and six legs are formed. Further, the other end of the linear magnetic core forming the six legs is connected by a connecting magnetic core 3d so that six iron window portions are formed. In addition, each junction part of linear magnetic core 3aa, 3ab, 3ba, 3bb, 3ca, 3cb and junction part with the connection magnetic core 3d are faced | matched and comprised so that each laminated steel plate which comprises a magnetic core may be parallel.

  The main winding 1aa is wound around the first linear magnetic core 3aa, and the main winding 1ab is wound around the second linear magnetic core 3ab arranged on the same axis as the linear magnetic core 3aa. The main windings 1aa and 1ab are connected in series or in parallel so that the magnetic fluxes φa1 and φa2 generated from both main windings are in the same direction.

Similarly, the main winding 1ba is wound around the third linear magnetic core 3ba, the main winding 1bb is wound around the fourth linear magnetic core 3bb arranged on the same axis as the linear magnetic core 3ba, and the fifth linear magnetic core 3ca is wound. The main winding 1ca and the main winding 1cb are wound around the sixth linear magnetic core 3cb disposed on the same axis as the linear magnetic core 3ca.
The main windings 1ba and 1bb and the main windings 1ca and 1cb are connected in series or in parallel so that the magnetic fluxes φb1 and φb2 and the magnetic fluxes φc1 and φc2 generated from both main windings are in the same direction.

  Control windings 2a, 2b, 2c, 2d, 2e, and 2f are wound around the six connecting magnetic cores 3d that connect the linear magnetic cores, respectively. The main windings 1aa and 1ab, the main windings 1ba and 1bb, and the main windings The control windings are connected in series or in parallel so that the voltages induced in the control windings 2a, 2b, 2c, 2d, 2e, and 2f are canceled by the magnetic fluxes of the windings 1ca and 1cb, and the open terminal side thereof is connected. The control circuit 4 is connected. In the example shown in the figure, all six control windings wound in the same direction are connected in series. However, since a balanced three-phase alternating current flows in the main winding, the induced voltages of the control windings cancel each other. It is.

In FIG. 1, it is assumed that a three-phase AC power source is connected to an open terminal of a main winding that is wound and connected to a linear magnetic core, and currents ILu, ILv, and ILw in the directions indicated by the arrows flow through the respective main windings. When the current arrow direction shown in the figure is a positive cycle, a current in the reverse direction flows in the negative cycle.
In the three-phase electromagnetic device having the above configuration, when no DC control current is passed through the control winding, each of the phases generated from the main windings 1aa and 1ab, the main windings 1ba and 1bb, and the main windings 1ca and 1cb. The AC magnetic flux returns through the connecting magnetic core portion connecting the linear magnetic cores.

Hereinafter, the first linear magnetic core portion wound around the main winding 1aa and the second linear magnetic core portion wound around the main winding 1ab will be described.
When current ILu flows, main magnetic flux φa1 and main magnetic flux φa2 are generated in the magnetic path by main winding 1aa and main winding 1ab, respectively.
The generated main magnetic flux passes through the connecting magnetic core around which the control winding is wound when no DC control current is passed through the control winding, and reactance is generated in the main winding according to the number of turns and the magnetic resistance of the magnetic core. . The connecting magnetic core portion around which the control winding is wound serves as a common magnetic path for the control magnetic flux φdc and the main magnetic fluxes φa1 and φa2.

  When the DC control current Ic is supplied to the control winding while the main winding current ILu is supplied, in the control windings 2a, 2b, 2c, 2d, 2e and 2f, the product of the number of turns of the control winding and the control current Ic When the magnetomotive force expressed is generated, the magnetic flux density of the common magnetic path portion in which the control winding magnetic flux φdc and the main magnetic fluxes φa1 and φa2 are in the same direction increases, and the permeability changes, and the main magnetic flux is controlled. Reactance decreases.

  Since this also holds true for other linear magnetic cores, it can function as a three-phase electromagnetic device whose reactance can be varied by adjusting the DC control current Ic.

FIG. 4 shows an example of the configuration of this three-phase electromagnetic device. FIG. 4 (a) shows that the connecting magnetic cores connecting the linear magnetic cores form a circular shape as described above, and are used in an electric motor or the like. It can be easily constructed from a punched iron core. 4 (b) and 4 (c), the shape of the connecting magnetic cores connecting the linear magnetic cores is a straight line, and can be easily constituted by a stacked iron core in addition to the punched iron core. The connecting magnetic core can have various shapes as long as the six connecting magnetic cores have the same configuration. FIG. 4 (d) shows a connecting core between the linear magnetic cores in the central part of the magnetic core, and a trapezoidal window shape around which the winding is wound. The space factor can be improved and the weight of the electromagnetic device can be reduced.
Moreover, it can also be comprised with a cut core as shown in FIG.4 (e).

FIG. 5 is a connection diagram showing another winding configuration example of the three-phase electromagnetic device according to the present invention. The six linear magnetic cores 3aa, 3ab, 3ba, 3bb, 3ca and 3cb constituting the three-phase electromagnetic device are The main windings 1aa and 1ab, 1ba and 1bb, 1ca and 1cb are arranged so that the linear magnetic cores 3aa and 3ab, 3ba and 3bb, 3ca and 3cb constituting each phase pair form 60 °, respectively.
As before, the magnetic flux density of the common magnetic path part where the control winding magnetic flux and the main magnetic flux are in the same direction increases, the permeability changes, the main magnetic flux is controlled, and the reactance can be varied. Can function as.
In the example shown in FIGS. 3 and 5, the control winding is wound around each of the six connecting magnetic cores, but every other connecting core can be wound around three connecting cores. In this case, the three control windings are wound in the same direction and connected in series.

FIG. 6 shows an example of control characteristics when a three-phase AC voltage is applied to the three-phase electromagnetic device according to the present invention to increase the DC control current Ic.
FIG. 6A shows an example of control characteristics of the main winding current, and it can be seen that the reactance changes and the main winding current can be varied linearly by increasing the DC control current Ic.
FIG. 6B shows an example of the current distortion characteristic of the main winding current, and it can be seen that the main winding current distortion is good regardless of the DC control current Ic.

  As described above, according to the present invention, the reactance can be continuously varied at a high speed by adjusting the DC control current.

  FIG. 7 shows the configuration of the magnetic core winding shown in FIG. 1, in which the main winding portion constituting the electromagnetic device is a primary winding, and the secondary winding 6aa and the primary winding are wound around a linear magnetic core wound with the primary winding 5aa. The secondary winding 6ab is wound around the linear magnetic core wound around the wire 5ab, the secondary winding 6ba is wound around the linear magnetic core wound around the primary winding 5ba, and the secondary winding 6bb is wound around the linear magnetic core wound around the primary winding 5bb. A three-phase type constituted by connecting a secondary winding 6ca to a linear magnetic core wound with the winding 5ca and a secondary winding 6cb wound around a linear magnetic core wound with the primary winding 5cb in the same manner as the primary winding. It is an electromagnetic device.

In FIG. 7, it is assumed that a three-phase AC power source is connected to the primary winding and a three-phase load is connected to the secondary winding, and currents ILu2, ILv2, and ILw2 in the directions indicated by the arrows flow through the respective secondary windings. .
Hereinafter, the first linear magnetic core portion wound with the primary winding 5aa and the second linear magnetic core portion wound with the primary winding 5ab will be described.

  When the control current is not passed, the primary current ILu1 flows through the primary windings 5aa and 5ab so as to cancel the magnetic flux generated by the secondary current, and the transformer operation is shown as a whole.

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. For this reason, in accordance with the decrease in the main magnetic flux accompanying the control of the control current, the exciting current increases in order to generate the main magnetic flux necessary for maintaining the voltage between the terminals of the primary winding.
That is, in addition to the transformation function as a transformer, the reactive current flowing into the primary side can be adjusted by continuously adjusting the reactance of the main winding by adjusting the control current.
Since this also holds true for other linear magnetic cores, it can function as a three-phase electromagnetic device capable of varying reactance in addition to the transformer function as a transformer.

(Application example)
FIG. 8 shows an application example of the three-phase electromagnetic device of the present invention to a reactive power compensator.
In FIG. 8, the three-phase electromagnetic device according to the present invention and the power capacitor 7 are connected in parallel, inserted in parallel to the transmission line, and the reactive power from the slow phase to the fast phase generated in the system is continuously controlled by controlling the electromagnetic device. Is to compensate.

As described in detail above, according to the present invention, a three-phase electromagnetic device with excellent three-phase balance that can vary reactance over a wide range without providing a tap and without requiring a gap in the abutting surface of the iron core is realized. With the recent increase in power demand and diversification of loads, it is possible to provide flexible power facilities that can cope with diversification of loads such as fluctuations in system voltage. And contribute to more appropriate control of tidal currents.
In addition, various modifications can be made without departing from the scope of the invention.

It is a connection diagram showing a basic configuration example of an electromagnetic device according to the invention of claim 1 or 2 or 4 or 6. It is a circuit block diagram which shows the equivalent circuit of the electromagnetic device shown in FIG. It is a connection diagram which shows the electromagnetic device by invention of Claim 1 or 2 or 4 or 6 with the structural example of a magnetic core. It is a block diagram which shows the example of a magnetic core structure of the electromagnetic device by invention of Claim 1 or 2 or 3 or 4 or 6. It is a block diagram which shows the structural example of the electromagnetic device by invention of Claim 1 or 3 or 6. It is a figure which shows the example of control characteristics of an electromagnetic device. It is a connection diagram showing an example of the basic configuration of an electromagnetic device according to the invention of claim 7. It is a circuit block diagram which shows the example of application to the reactive power compensation apparatus of this invention. It is a connection diagram which shows one Example of the conventional electromagnetic device which the present applicant previously proposed. It is a connection diagram which shows one Example of the conventional three-phase type electromagnetic equipment which the present applicant previously proposed.

Explanation of symbols

1 (1aa, 1ab, 1ba, 1bb, 1ca, 1cb) ... main winding, 2 (2a, 2b, 2c, 2d, 2e, 2f) ... control winding, 3 (3aa, 3ab, 3ba, 3bb, 3ca, 3cb, 3d) ... magnetic core, 4 ... control circuit, 5 (5aa, 5ab, 5ba, 5bb, 5ca, 5cb) ... primary winding, 6 (6aa, 6ab, 6ba, 6bb, 6ca, 6cb) ... secondary winding 7 ... Power capacitors.

Claims (7)

A magnetic core in which the ends of six legs that are radially symmetrically branched in the same plane are connected to each other to form six windows;
A main winding connected to a three-phase AC power source is wound around each of the six legs of the magnetic core,
A control winding is wound around a connecting portion that connects the leg portions of the magnetic core, and the voltages induced in the control winding by the AC main current flowing through the main winding are connected to each other,
By connecting a control circuit to the open end of the control winding and supplying a DC control current to generate a control magnetic flux that circulates through the connecting portion,
By controlling the DC control current, the magnetic resistance of the magnetic core that forms a common magnetic path of the main magnetic flux generated by the AC main current flowing in the main winding and the control magnetic flux is controlled, and the reactance of the main winding is made continuous. Three-phase electromagnetic equipment characterized by being variable.   The main windings of each phase are arranged on each of the three pairs of magnetic cores so that the main windings of the same phase are generated in the same direction in the magnetic cores of the leg portions that are paired in the extension direction of the six leg portions of the magnetic core. The three-phase electromagnetic device according to claim 1, wherein the three-phase electromagnetic device is wound.   The main windings of the respective phases are arranged in three pairs of magnetic cores so that the main windings of the same phase are generated in the magnetic cores of the pair of leg portions adjacent to each other of the six leg portions of the magnetic cores. The three-phase electromagnetic device according to claim 1, wherein the three-phase electromagnetic device is wound.   4. The three-phase electromagnetic device according to claim 2, wherein the control winding is wound around the magnetic core of each connecting portion that connects the magnetic cores of the respective legs that wind the main winding. 5.   4. The three-phase electromagnetic according to claim 2, wherein every other control winding is wound around the magnetic core of each connecting portion that connects the magnetic cores of the respective legs that wind the main winding. 5. machine.   One end of each of the six linear magnetic cores is assembled and joined, and the other end is connected with each of the six magnetic cores to form six windows, and each linear magnetic core has an angle with an adjacent linear magnetic core. The three-phase electromagnetic device according to claim 1, wherein the three-phase electromagnetic device is arranged so as to form 60 °.   A secondary winding is wound around the magnetic core of the leg portion around which the main winding of each phase is wound, and the voltage induced in the secondary winding is continuously varied by adjusting the DC control current. The three-phase electromagnetic device according to any one of claims 1 to 6.

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