JP2008004754A - Electromagnetic equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide electromagnetic equipment capable of decreasing an occurrence of a harmonic distortion in a broad current range from a small to a large current flowing a main winding, and capable of varying a reactance. <P>SOLUTION: A core has two by two matrix magnetic paths symmetrically formed by four closed magnetic paths. A main magnetic flux passes a first linear magnetic path of a crisscross magnetic path of the two by two matrix magnetic paths. An alternating winding is wound so as to symmetrically flow backward the four closed magnetic paths facing at the crisscross intersecting point. A direct-current control winding is wound so that control magnetic fluxes symmetrically flow backward two magnetic paths passing through the second linear magnetic path of the crisscross magnetic path in one direction. A magnetic resistance of a common magnetic path of the main magnetic flux and the control magnetic flux is adjusted by the control of the control magnetic flux. Interposing a non-magnetic part at a part of four each closed magnetic path with the main magnetic flux of the core forming the two by two matrix magnetic paths flowed backward improves a magnetization characteristic of the magnetic path with the main magnetic flux flowed backward to decrease an occurrence of the higher harmonic wave. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is an electromagnetic device with variable reactance in which the generation of harmonic distortion is reduced in a wide range of current flowing from a small current to a large current, and is particularly suitable for being inserted in series in a power system. Related to electromagnetic equipment.

  As a conventional technique that can reduce harmonic distortion, change reactance, and can be connected in series to the power system without being affected by the excitation current of the main winding, the electromagnetic device previously proposed by the applicant ( There exists patent document 1).

FIG. 10 is a connection diagram for explaining an example of the 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 expressed 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. As a result, the main magnetic flux is controlled and the reactance is lowered.
As a result, the electromagnetic device can make the reactance variable by the DC control current even when the current supplied to the main winding changes.
JP 2003-068539 A

When the above electromagnetic equipment is connected to the power system in series, the current of the power system becomes a small current when the load is light, and on the contrary, it becomes a large current when the load is heavy, and varies widely over time. The current supplied to the main winding varies widely from a small current to a large current.
FIG. 11 shows the magnetization characteristics of the magnetic core of an electromagnetic device. The vertical axis represents the magnetic flux density B and the horizontal axis represents the magnetomotive force H. The magnetomotive force H generated by the number of turns of the main winding × current and the magnetic flux density of the magnetic core. Although it represents the relationship of B, it shows strong nonlinearity.
Therefore, when the load of the power system is light and the system current is small, that is, the energization current of the main winding is small, harmonics are generated due to the nonlinear effect of the magnetization characteristics of the magnetic core.
Further, as shown in FIG. 12A, there is a similar problem even in a variable range of reactance even in a region where a direct current control current is not passed or a small region.
For this reason, in the conventional structure, as shown in FIG. 12 (B), a constant DC control current is always flowed so that the operation region of the electromagnetic device is out of the non-linear region where the relationship between the magnetomotive force H and the magnetic flux density B changes sharply. Needed to be used.

However, since a DC control current of a certain value or more flows, a loss due to the DC control current always occurs, an abnormality occurs in the control circuit, and a large harmonic distortion occurs when the DC control current stops flowing. There were problems such as.
In view of the above circumstances, the present invention has a simple magnetic circuit structure and winding winding structure, variable reactance, can be connected in series to a power system, and has a small area where no DC control current flows. It is an object of the present invention to provide an electromagnetic device having a small harmonic distortion and capable of reactance control in the entire region including the region.

The present invention symmetrically has a magnetic core that forms a U-shaped magnetic path with four closed magnetic paths, and the main magnetic flux passes through the first linear magnetic path of the cross-shaped magnetic path in the U-shaped magnetic path. The AC main winding is wound so as to circulate the four closed magnetic paths symmetrically facing each other at the intersection of the cross, and the control magnetic flux passes through the second linear magnetic path of the cross-shaped magnetic path in one direction. A DC control winding that circulates two magnetic paths symmetrically and adjusts the magnetic resistance of the common magnetic path of the main magnetic flux and the control magnetic flux by controlling the control magnetic flux, In the magnetic core forming the letter-shaped magnetic path, each of the four closed magnetic paths through which the main magnetic flux circulates is characterized in that at least a part is constituted by a non-magnetic part.
Further, the non-magnetic portion may be provided symmetrically with respect to the cross-shaped second linear magnetic path portion in the four closed magnetic paths through which the main magnetic flux of the U-shaped magnetic path circulates.
In addition, the non-magnetic portion is provided in a cross-shaped first linear magnetic path portion in a square-shaped magnetic path. Thereby, since a nonmagnetic part does not intervene in the magnetic path along which the control magnetic flux passes, the control current can be reduced, the loss accompanying the control can be reduced, and the efficiency of the device is improved.

  According to the present invention, an electromagnetic device that has a simple magnetic circuit structure and winding winding structure, suppresses a harmonic current regardless of a load current, and can vary a reactance over a wide range without providing a tap or the like. 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 shows an example in which an electromagnetic device according to the present invention is configured using an EI iron core. A rice field-shaped magnetic core includes a first E-shaped magnetic core 4a and a second E-shaped magnetic core 4b, and a magnetic core window portion has four. The first magnetic core 4a and the second magnetic core 4b are respectively provided with non-magnetic portions 7a and 7b so as to be symmetrically opposed to the I-shaped magnetic core 5 so as to be formed at the locations. The joining surface of the E-shaped magnetic core 4a and the I-shaped magnetic core 5 and the joining surface of the second E-shaped magnetic core 4b and the second I-shaped magnetic core 5 are configured by abutting each laminated steel plate constituting the magnetic core so as to be parallel to each other. To do. The nonmagnetic portions 7a and 7b have a constant magnetic permeability regardless of the amount of magnetic flux passing therethrough, and can be formed by providing a gap and interposing a nonmagnetic material.

  The first main winding 1a is wound around the central leg of the first E-shaped magnetic core 4a, and the second main winding 1b is wound around the central leg of the second E-shaped magnetic core 4b. The main windings 1a and 1b are connected in series so that the magnetic fluxes φ1a and φ1b generated from both main windings face each other and pass through the I-shaped magnetic core 5 symmetrically.

Control windings 2a and 2b are wound around the outer legs of the first E-shaped magnetic core 4a, and control windings 2c and 2d are wound around the outer legs of the second E-shaped magnetic core 4b. 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 on the open terminal side, and the control circuit 6 is connected to the open terminal side.
As a result, the main magnetic fluxes φ1a, φ1a ′, φ1b, and φ1b ′ return symmetrically through the four closed magnetic paths.

In addition, the control winding is one set of 2a, 2b, 2c, and 2d, in which any two windings are connected so that the induced voltage is canceled, and the remaining two windings are connected in the same way Can be connected in series or in parallel, and the control circuit 6 can be connected to the open terminal side.
As a result, the control magnetic fluxes φc1 and φc2 pass through the I-shaped magnetic core 5 in one direction and return to the two magnetic paths symmetrically.

  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 the DC control current Ic is not passed through the control winding, and the main winding has the number of turns, the magnetic resistance of the iron core, and the magnetic resistance of the nonmagnetic portions 7a and 7b. A reactance corresponding to is generated. The iron core and the I-shaped magnetic core around which the control winding is wound serve as a common magnetic path for the control magnetic fluxes φc1 and φc2 and the main magnetic fluxes φ1a, φ1a ′, φ1b, and φ1b ′.

  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 product of the number of turns of the control winding and the DC control current Ic in the control windings 2a, 2b, 2c, and 2d. When the magnetomotive force represented is generated, the magnetic flux density of the common magnetic path portion in which the control 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. The main magnetic flux is controlled and the reactance is lowered.

  When the common magnetic path approaches a magnetic saturation state by increasing the currents IL1 and IL2 flowing through the main winding or the DC control current Ic, the main magnetic flux generated from the main windings 1a and 1b is symmetrical with respect to the I-shaped magnetic core 5. Since the main windings are divided and connected so as to be in the direction of forming, 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. 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.

  Further, even if the currents IL1 and IL2 flowing through the main winding increase, the main magnetic flux by the main winding 1a and the main magnetic flux by the main winding 1b are increased so that the common magnetic path is maintained at a constant magnetic flux density. Therefore, the main magnetic flux can be controlled and the reactance can be varied by controlling the DC control current Ic. That is, the reactance can be varied by passing the DC control current Ic through the control winding regardless of the current flowing through the main winding.

Explain that the provision of the non-magnetic portions 7a and 7b improves the magnetization characteristics of the electromagnetic device, reduces harmonics with respect to energization of a wide range of main currents, and does not require constant control current. .
FIG. 11 shows the magnetization characteristics of the magnetic core. Here, when the relationship between the magnetomotive force H, the magnetic flux density B, the magnetic permeability μ, and the magnetic resistance R is arranged,
The relationship B = μH and R∝1 / μ is established.
FIG. 2 shows the magnetization characteristics of the nonmagnetic portions 7a and 7b. Since the magnetic permeability of the nonmagnetic portions is constant at μ0, there is no distortion.
Therefore, it is conceivable to construct a magnetic path of a variable reactor having excellent distortion characteristics by appropriately combining a magnetic core having nonlinear characteristics and a nonmagnetic portion having linear characteristics.
FIG. 3 shows the magnetization characteristics of the magnetic core of the electromagnetic device and the magnetization characteristics of the non-magnetic portion, and shows an image of the combined magnetization characteristics of a magnetic circuit in which both are appropriately combined.
Specifically, the thickness of the non-magnetic portion is such that the magnetic resistance of the non-magnetic portion where the permeability does not change due to the change in magnetic flux density is sufficiently larger than the magnetic resistance of the magnetic core in a region where a DC control current does not flow or a small region. Is set so that the combined magnetic resistance of the entire magnetic circuit composed of the nonmagnetic portion and the magnetic core does not change significantly even if the magnetic resistance of the magnetic core portion changes nonlinearly due to the main winding current.

  In other words, it is possible to set the magnetic resistance of the non-magnetic portion to be sufficiently large and dominant over the entire AC magnetic circuit with respect to the magnetic resistance change of the magnetic core portion caused by the current change flowing through the main winding. If possible, even when the current flowing through the main winding changes, non-linear changes in reactance are suppressed and harmonic distortion is reduced.

  As shown in FIG. 3, it is shown that a composite characteristic with high linearity can be realized by combining the linear characteristics of the nonmagnetic portion in the strain region where the magnetic permeability of the magnetic core changes sharply.

In this way, the thickness of the non-magnetic part is set so that the linearity of the non-magnetic part that is not magnetically saturated is more dominant than the non-linearity of the magnetic core caused by the magnetic saturation of the magnetic circuit of the electromagnetic device. Thus, it is possible to configure an electromagnetic device that suppresses a non-linear change in reactance due to a change in the current flowing through the main winding.
FIG. 4A shows an example of reactance control characteristics according to the present invention. The vertical axis represents reactance, and the horizontal axis represents DC control current Ic. The reactance can be varied by increasing the DC control current Ic, and the reactance value when the DC control current Ic is not passed can be set by adjusting the thickness of the nonmagnetic portion.

  FIG. 4B shows an example of the harmonic distortion rate characteristic of the excitation current when the DC control current Ic is passed through the electromagnetic device according to the present invention. The vertical axis represents the harmonic distortion rate, and the horizontal axis represents the reactance. Represents. When there is no non-magnetic portion, the harmonic distortion rate characteristic deteriorates as the direct current control current Ic is small and the reactance is large. However, by arranging the non-magnetic portion, the harmonic distortion rate is increased in a region where the reactance is large. Decreases.

  This is because when there is no non-magnetic part, it consists only of a magnetic circuit with non-linear magnetic characteristics, but by arranging the non-magnetic part, part of the magnetic path becomes a highly linear magnetic circuit. This is because the non-linearity is improved because it becomes a synthesis circuit with a non-linear magnetic circuit.

  As described above, according to the present invention, the magnetic circuit structure and the winding structure of the winding are provided by disposing the non-magnetic part in the magnetic core part constituted by the E-shaped magnetic cores 4a and 4b and the I-shaped magnetic core 5. The reactance can be varied without being affected by the main winding current, and the harmonic distortion is small in all regions including the region where the DC control current does not flow or the small region, and can be connected in series to the power system. Electromagnetic equipment can be realized easily and at low cost.

  FIG. 5A shows an example in which the nonmagnetic portions 7a and 7b are arranged symmetrically with respect to the linear magnetic path at two places of the main winding 1a and the main winding 1b winding portion of the U-shaped magnetic core 3. is there. The nonmagnetic portions 7a and 7b only need to be on the main magnetic paths of the main magnetic fluxes φ1a, φ1a ′, φ1b, and φ1b ′, and as shown in FIG. Nonmagnetic portions may be arranged at two locations of the common portions of the main magnetic fluxes φ1b and φ1b ′, and as shown in FIG. 5B, the nonmagnetic portions 7a, 7b, 7c, 7d, 7e, and 7f may be arranged.

That is, the nonmagnetic portion can be arranged in various positions and number of installations as long as the arrangement is symmetrical with respect to the linear magnetic path through which the control magnetic flux passes.
However, in view of control loss due to the control current, it is preferable not to increase the magnetic resistance of the control magnetic flux path, so it is preferable to provide the magnetic path portion through which only the main magnetic flux passes.

  FIG. 6 shows a tripod formed by opposing a first E-shaped cut core 10a and a second E-shaped cut core 10b in which a main winding 1a is wound around a central leg and control windings 2a and 2b are wound around an outer leg. A tripod magnetic core formed by opposing a magnetic core and a third E-shaped cut core 10c and a fourth E-shaped cut core 10d each having a main winding 1b on the center leg and control windings 2c and 2d wound on the outer leg. The non-magnetic portions 7a and 7b are arranged on each of the two sets of tripod magnetic cores, and are arranged so as to face each other so that the magnetic path has a square shape.

  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.

  FIG. 7 shows a first E-shaped magnetic core 4a and a first I-shaped magnetic core 5a in which a main winding 1a is wound around a central leg and control windings 2a and 2b are wound around an outer leg. The non-magnetic portion is formed by the arranged tripod magnetic core, the second E-shaped magnetic core 4b and the second I-shaped magnetic core 5b in which the main winding 1b is wound around the central leg and the control windings 2c and 2d are wound around the outer leg. The tripod magnetic core in which 7a and 7b are arranged is opposed to the first magnetic core 4a and the second magnetic core 5a by using the boundary surface 12 so that the magnetic path has a square shape. The joint surface between the E-shaped magnetic core 4b and the second I-shaped magnetic core 5b is formed by abutting each laminated steel plate constituting the magnetic core so as to be parallel to each other.

  According to this configuration, the magnetic core portion composed of the E-shaped magnetic core 4a and the I-shaped magnetic core 5a around which the main winding 1a and the control windings 2a and 2b are wound, and the main winding 1b and the control windings 2c and 2d are provided. It becomes possible to separately manufacture the magnetic core portion composed of the wound E-shaped magnetic core 4b and the I-shaped magnetic core 5b, and the structure of the magnetic circuit and the winding structure of the winding are simple and flow to the main winding. It is possible to easily and inexpensively manufacture an electromagnetic device that can change reactance at high speed and continuously in all regions including a region where a direct current control current does not flow or a small region without being influenced by a current.

  In addition, it is generally difficult to make the 5a and 5b steel plate laminated surfaces with high accuracy in the boundary surface 12, and an eddy current loss may increase due to a short circuit between the laminated steel plates, but the boundary surface 12 has high electrical resistance. By inserting an insulating film or the like, it can be easily and inexpensively prevented.

FIG. 8 is a diagram showing an application example of the present invention to a voltage compensation device for an electromagnetic device. The main winding of the electromagnetic device 11 is inserted in series with the transmission line, and the control current is adjusted to control the reactance of the main winding, thereby continuously compensating for voltage fluctuations occurring in the system. .
Since the main winding is inserted in series with the transmission line, the current flowing through the main winding varies greatly from small current to large current due to fluctuations in the power system load. Countermeasures will be strict.
In devices where the main winding is inserted in parallel with the transmission line, such as a variable transformer, the line voltage does not fluctuate significantly, so the excitation current of the main winding does not fluctuate significantly. This is a big difference.

FIG. 9 is a diagram for explaining an application example in which the electromagnetic device of the present invention is applied to a multi-function transformer.
In the electromagnetic device of the present invention shown in FIG. 1, the main windings are the primary windings 8a and 8b, and the secondary windings 9a and 9b are wound around the legs on which the primary windings 8a and 8b are wound. This is a multi-function transformer that is connected in the same manner as the primary winding.

  In FIG. 9, 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 no DC control current is passed, the primary current IL1 flows through the primary windings 8a and 8b so as to cancel the magnetic flux generated by the secondary current, and the transformer operation is shown as a whole.

  When the DC control current Ic is passed through the control winding, the magnetic permeability is changed by the generation of a magnetomotive force represented by the product of the number of turns of the control winding and the DC control current Ic, and the main magnetic flux is controlled. The main magnetic fluxes φ1a and φ1a ′ due to the primary winding 8a and the main magnetic fluxes φ1b and φ1b ′ due to the primary winding 8b are canceled out because they are opposite to each other. Decrease.

  For this reason, in order to generate the main magnetic flux necessary for maintaining the voltage between the terminals of the primary winding according to the decrease of the main magnetic flux accompanying the control of the DC control current in the primary winding, The excitation current, which is a delayed phase, increases.

Since the delayed phase current generates reactive power, in addition to the function as a transformer, a multifunction transformer capable of adjusting reactive power can be realized by adjusting the DC control current.
Even when used as a multi-function transformer, the harmonic distortion of the exciting current can be reduced even with a small current.

  In addition, although the multifunctional transformer was demonstrated and applied to the electromagnetic device of Claim 1, it is clear that it can apply also to the other electromagnetic device described by this invention.

  Moreover, although the multi-function transformer by the isolation transformer in which the primary winding and the secondary winding are independent has been illustrated, it is obvious that the same function can be realized even in the single-winding transformer.

  As described in detail above, according to the present invention, the structure of the magnetic circuit and the winding structure of the winding are simple, and can be connected in series to the power system with or without a load current without providing a tap. Therefore, it is possible to easily and inexpensively manufacture an electromagnetic device that suppresses harmonic current in all regions including a region where a DC control current does not flow or a small region, and varies reactance over a wide range. With the recent increase in power demand and diversification of loads, it is possible to provide flexible power facilities that can cope with the diversification of loads such as fluctuations in system voltage, which can contribute to stabilization of the voltage of the power system.

  In addition to the above, various modifications can be made without departing from the spirit of the present invention.

It is a connection diagram which shows an example of the basic composition of the single phase type electromagnetic equipment by this invention. It is a linear image figure of a nonmagnetic part. It is a non-linear improvement image figure by the synthesis | combination of the magnetic core and nonmagnetic part by this invention. It is a figure which shows the example of control characteristics of an electromagnetic device. It is a connection diagram which shows the other basic structural example of the electromagnetic equipment by this invention. It is a connection diagram which shows the other basic structural example of the electromagnetic equipment by this invention. It is a connection diagram which shows the other basic structural example of the electromagnetic equipment by this invention. It is a connection diagram which shows the example which applied this invention to the voltage compensation apparatus. It is a connection diagram which shows the example which applied this invention to the multifunctional transformer. It is a connection diagram which shows an example of the electromagnetic equipment previously proposed by the present applicant. It is a distortion generation image figure by the nonlinearity of the magnetic core in an electromagnetic device. It is an image figure of the fall of distortion by sending direct current control current in an electromagnetic machine.

Explanation of symbols

1 (1a, 1b) ... main winding, 2 (2a, 2b, 2c, 2d) ... control winding, 3 ... U-shaped magnetic core, 4 (4a, 4b) ... E type magnetic core, 5 (5a, 5b) ) ... I-type magnetic core, 6 ... control circuit, 7 (7a, 7b, 7c, 7d, 7e, 7f) ... non-magnetic part, 8 (8a, 8b) ... primary winding, 9 (9a, 9b) ... secondary Winding, 10 (10a, 10b, 10c, 10d) ... E-shaped cut core, 11 ... Electromagnetic device, 12 ... Boundary surface, 31 (31a, 31b) ... Main winding, 32 (32a, 32b, 32c, 32d) ... control winding, 33 ... field-shaped magnetic core, 34 ... control circuit.

Claims (6)

Symmetrically, it has a magnetic core that forms a U-shaped magnetic path with four closed magnetic paths,
The AC main winding is passed through the first linear magnetic path of the cross-shaped magnetic path in the U-shaped magnetic path, and symmetrically flows back through the four closed magnetic paths facing each other at the intersection of the cross. Wound,
Winding the DC control winding so that the control magnetic flux passes through the second linear magnetic path of the cross-shaped magnetic path in one direction and circulates the two magnetic paths symmetrically;
An electromagnetic device that adjusts the magnetic resistance of the common magnetic path of the main magnetic flux and the control magnetic flux by controlling the control magnetic flux,
In the magnetic core forming the U-shaped magnetic path, at least a part of each of the four closed magnetic paths through which the main magnetic flux circulates is constituted by a nonmagnetic part.   The non-magnetic portion is provided in four closed magnetic paths through which the main magnetic flux of the U-shaped magnetic path circulates symmetrically with respect to the cross-shaped second linear magnetic path portion. The listed electromagnetic equipment.   3. The electromagnetic device according to claim 1, wherein the non-magnetic portion is provided in a cross-shaped first linear magnetic path portion in a square-shaped magnetic path.   4. The electromagnetic device according to claim 1, wherein the magnetic core is formed in a square shape by overlapping two sets of tripod magnetic cores formed of an I-shaped magnetic core and an E-shaped magnetic core. 5. .   4. The electromagnetic device according to claim 1, wherein the magnetic core is formed in a square shape by overlapping two sets of tripod magnetic cores formed to face each other with an E-shaped cut core.   4. The electromagnetic device according to claim 1, wherein the magnetic core is configured in a square shape by opposing two E-shaped magnetic cores to an I-shaped magnetic core. 5.

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