JP7503783B2 - Flux-controlled variable transformer - Google Patents

Description

The present invention relates to a flux-controlled variable transformer.

In recent years, the introduction of renewable energy, primarily solar power generation, has been expanding. This expansion of the introduction of renewable energy has led to a deterioration in the power quality of the power system, particularly in power systems centered on distribution lines, where fluctuations in power generation output cause system voltage fluctuations, and power generation output exceeds demand in the power system, generating a different power flow (reverse flow) and causing an increase in system voltage. For this reason, there is a demand for a low-cost, effective voltage regulator that maintains power quality.

As a conventional technology for voltage regulation devices, Figure 12 shows the basic configuration of a normal transformer. The basic characteristics of this transformer are determined by the primary winding 11, secondary winding 12, and magnetic core 13, and the relationship between the voltage and current on the primary and secondary sides is almost fixed. Therefore, in conventional technology, voltage fluctuations are dealt with by transformers by changing the turns ratio of the primary and secondary windings, which is related to the relationship between the voltage on the primary and secondary sides, using mechanical contacts to change the taps on the windings (the so-called tap changing mechanism). This has resulted in maintenance and performance constraints due to wear and contact failures in the contacts, and operating time delays in the operating mechanism.

Conventional technologies for variable transformers that do not have mechanical contacts and have the function of controlling the secondary (load) voltage quickly and continuously by adjusting the control current include, for example, a flux-linkage controlled transformer device (Patent Document 1), a variable transformer (Patent Document 2), a voltage regulating transformer (Patent Document 3), and a flux-controlled variable transformer (Patent Document 4).

Figure 13 is a connection diagram explaining an example of a flux linkage control type variable transformer device previously proposed by the present applicant. As shown in Figure 13, this flux linkage control type variable transformer device is composed of a primary winding 20, a secondary winding 21, a leakage flux control winding 26, a flux control winding 27, and U-shaped cut cores 22 and 23 that are rotated 90 degrees in the torsional direction and in contact with each other, as well as U-shaped cut cores 24 and 25 that are rotated 90 degrees in the torsional direction and in contact with each other. Note that structures such as the U-shaped cut cores 22 and 23 and the U-shaped cut cores 24 and 25 are called orthogonal magnetic cores.

The secondary voltage V2 of this transformer is determined by the value of φ1-2, which is linked to the secondary winding 21, of the magnetic fluxes φ1-1 and φ1-2 generated by the primary winding 20. When a load current I2 flows through the secondary winding, a magnetic flux φ2 is generated in the opposite direction to φ1-2, and φ1-2 shifts toward the magnetic circuit side of φ1-1 and decreases, causing the secondary voltage to drop.

When a control current Ic1 is passed through the leakage flux control winding 26, the contact portion 28 of the U-shaped cut core is magnetically saturated, and the magnetic resistance of the magnetic circuit of φ1-1 increases, changing the magnetic flux distribution of φ1-1 and φ1-2, thereby making it possible to increase the secondary side voltage. When there is no load, a control current Ic2 is passed through the flux control winding 27, causing the contact portion 29 of the U-shaped cut core to be magnetically saturated, increasing the magnetic resistance of the magnetic circuit of φ1-2, changing the magnetic flux distribution of φ1-1 and φ1-2, thereby suppressing the voltage increase.

Figure 14 is a connection diagram explaining an example of a variable transformer previously proposed by the present applicant. This variable transformer is composed of a flux control circuit in which a primary winding 30 and a secondary winding 31 are wound on the magnetic circuit of a magnetic core 32, a window 33 is provided in a portion of the magnetic circuit of the magnetic core 32, and control windings 34a and 34b are wound around the two sides of the window, respectively.

When a control current Ic is passed through the control winding, the control magnetic flux φc generated by the magnetomotive force Nc x Ic (ampere turns), which is expressed as the product of the number of turns Nc of the control winding and the control current Ic, can magnetically saturate a part of the magnetic core through which the magnetic flux passes, reducing the permeability of the magnetic circuit of the magnetic flux from the primary winding or secondary winding. This reduces the excitation reactance value of the transformer and increases the leakage magnetic flux of the primary winding or secondary winding, allowing the leakage reactance value to be increased.

In other words, when viewed as an equivalent circuit, controlling the excitation reactance controls the value of the reactance inserted in parallel on the primary side of the transformer, thereby controlling the lagging reactive power. Also, when viewed as an equivalent circuit, controlling the leakage reactance of the primary winding controls the value of the reactance inserted in series on the primary side of the transformer, thereby controlling the secondary voltage V2.

In addition, controlling the leakage reactance of the secondary winding means, when viewed as an equivalent circuit, controlling the value of the reactance inserted in series on the secondary side of the transformer, thereby controlling the secondary voltage V2.

Figure 15 is a connection diagram for explaining an example of a voltage regulating transformer. This voltage regulating transformer is composed of a main core consisting of first and second iron cores (magnetic cores) 40, 41 divided into two parts that form a laminated closed magnetic circuit, bypass iron cores 42, 43 similarly divided into two parts, a primary winding 44 wound around all of these, a secondary winding 45 wound around the first and second iron cores 40, 41, control windings 46a, 46b wound in series and in opposite directions with the same number of turns around the first and second iron cores 40, 41, and bypass iron core control windings 47a, 47b wound in series and in opposite directions with the same number of turns around the two bypass iron cores 42, 43.

When no control current is flowing, when an AC voltage is applied to the primary winding 44, magnetic fluxes φ1, φ2 and bypass magnetic fluxes φ3, φ4 are induced in the first and second iron cores 40, 41 and the bypass iron cores 42, 43, and the magnetic flux is reduced by the bypass magnetic fluxes φ3, φ4 due to the amount bypassed by the bypass iron cores 42, 43, so the secondary voltage also decreases by the same ratio. Then, when a control current Ic2 is flowed through the bypass iron core control windings 47a, 47b, the magnetic permeability of the bypass iron cores 42, 43 decreases, the magnetic resistance increases, and the bypass magnetic fluxes φ3, φ4 decrease, so the secondary voltage increases.

Furthermore, when the control current Ic1 is passed through the control windings 46a, 46b, the magnetic permeability of the first and second iron cores 40, 41 decreases, the magnetic resistance increases, and the bypass magnetic flux φ3, φ4 increases, so the secondary voltage decreases. In other words, by passing the control current Ic1 or Ic2 through the control windings 46a, 46b or the bypass iron core control windings 47a, 47b, the amount of bypass magnetic flux can be increased or decreased, the amount of magnetic flux in the main iron core can be controlled, and therefore the secondary voltage can be variably controlled.

Figure 16 is a connection diagram explaining an example of a flux-controlled variable transformer. In this flux-controlled variable transformer, when an AC primary voltage V1 is applied to the primary winding 53, a magnetic flux φ1 is induced in the central leg of the three-legged core 51, and a magnetic flux of 1/2φ1 is branched to each of the outer legs. Similarly, a magnetic flux φ2 is induced in the central leg of the three-legged core 52, and a magnetic flux of 1/2φ2 is branched to each of the outer legs. When no control is performed, the magnetic fluxes φ1 and φ2 are equal.

On the other hand, when a control current is applied from the control circuit to the first control winding 56a and the second control winding 56b, the control magnetic flux generated by the magnetomotive force (ampere turn) represented by the product of the number of turns of the control winding and the control current flows back around the outer periphery of the three-legged magnetic core, increasing the magnetic resistance. The magnetic path through which the control magnetic flux flows is a common magnetic path with the magnetic path of the magnetic flux φ1, so the magnetic flux φ1 does not pass easily, and the magnetic flux distribution of the magnetic flux φ1 and the magnetic flux φ2 is controlled in the three-legged magnetic cores 51 and 52. Similarly, when a control current is applied from the control circuit to the third control winding 57a and the fourth control winding 57b, the magnetic path through which the control magnetic flux flows is a common magnetic path with the magnetic path of the magnetic flux φ2, so the magnetic flux φ2 does not pass easily, and the magnetic flux distribution of the magnetic flux φ1 and the magnetic flux φ2 is controlled in the three-legged magnetic cores 51 and 52.

When the magnetic flux distribution in the three-leg core 51 and the three-leg core 52 changes due to the control current, the induced voltage in the first auxiliary winding 55a and the second auxiliary winding 55b connected in series with the secondary winding 54 changes. Since the voltage phases induced in the first auxiliary winding 55a and the second auxiliary winding 55b are opposite to each other, the secondary terminal voltage connected in series (the sum of the induced voltages in the secondary winding 54, the first auxiliary winding 55a, and the second auxiliary winding 55b) changes in response to the control current as the magnetic flux distribution changes, i.e., the induced voltage changes.

In other words, it is possible to control the secondary terminal voltage by controlling the control current. The control of the secondary terminal voltage due to an increase or decrease in the load is basically unchanged, and is only affected by the change in the amount of magnetic flux due to the load current, so it only affects a slight change in the voltage variable range.

Japanese Patent No. 3343083 Patent No. 3789285 JP 2005-252113 A Japanese Patent No. 5520613

However, the above-mentioned flux linkage control transformer device (Patent Document 1) has an orthogonal core structure, which results in a complex core structure. In addition, as a countermeasure against eddy current generation at the core joint surface of the orthogonal U-shaped cut cores, an insulating film must be inserted at the joint surface to prevent short circuits between the laminated steel plates at the core joint surface, making it difficult to secure an insulating film material with sufficient durability. In addition, the inclusion of an insulating film increases the magnetic resistance of the magnetic circuit, making it difficult to make large inductance changes, resulting in a problem of a reduced voltage variable range.

Although the variable transformer (Patent Document 2) described above is capable of varying the voltage on the secondary side, this is achieved by controlling the excitation reactance and leakage reactance, and therefore a change in the voltage on the secondary side is accompanied by a change in the lagging reactive power, resulting in problems such as increased power loss and a decrease in power factor. In addition, since the voltage is varied by controlling the leakage reactance, a large leakage magnetic flux is generated, which causes problems such as overheating of the peripheral components housing the variable transformer and increased equipment loss.

Although the voltage regulation transformer (Patent Document 3) described above is capable of varying the voltage on the secondary side, when not in control, the magnetic flux passing through the bypass core reduces the magnetic flux passing through the main core, requiring a greater number of turns compared to the number of turns of the secondary winding in a normal transformer, and there is concern that the load current may cause a drop in the secondary voltage due to the increased leakage impedance. To address this issue, for example, it may become necessary to constantly pass a control current through the bypass core control winding, which may lead to problems such as increased control loss.

In addition, while the above-mentioned magnetic flux control type variable transformer (Patent Document 4) is capable of varying the voltage on the secondary side, it is composed of two iron cores and eight windings, which means that it has many components, is heavy, and tends to increase iron loss and copper loss. In addition, the number of assembly steps also increases, which raises the issue of increased manufacturing costs.

The present invention was made in consideration of these circumstances, and aims to provide a flux-controlled variable transformer that is small, has little effect on leakage flux and control loss, and is capable of continuously changing the secondary voltage.

In order to solve the above problem, the technical means of claim 1 is a flux-controlled variable transformer comprising a first magnetic core, a second magnetic core, and a first leg magnetic core, a second leg magnetic core, and a third leg magnetic core, which are magnetically coupled to the first magnetic core and the second magnetic core, respectively, the second leg magnetic core having a split magnetic path portion in which the magnetic path of the second leg magnetic core is split into two, a core having an air gap in the magnetic path of the third leg magnetic core, a primary winding wound around at least the first leg magnetic core, a secondary winding wound around at least the second leg magnetic core, and a magnetic path of each of the split magnetic path portions of the second leg magnetic core. The motor has a wound first control winding, which is connected in series to a first DC power supply circuit so that an induced voltage generated in the first control winding by the magnetic flux interlinked with the primary winding is cancelled, and a DC control current is passed through the first control winding to return the control magnetic flux to the closed magnetic path formed by the split magnetic path section, saturating a portion of the magnetic path of the second leg magnetic core through which the magnetic flux passes, thereby controlling the magnetic resistance of the magnetic path of the second leg magnetic core and shunting a portion of the magnetic flux to the third leg magnetic core.

The second technical means is the first technical means, characterized in that the secondary winding is wound around the first leg core and is connected in series with the secondary winding wound around the second leg core.

The third technical means is the first or second technical means, characterized in that a wedge-shaped gap is provided at any location in the divided magnetic path section.

The fourth technical means is any one of the first to third technical means, further comprising a fourth leg core and a fifth leg core magnetically coupled to the first magnetic core and the second magnetic core, respectively, and a second primary winding wound around the fourth leg core, the second primary winding wound around the fourth leg core and the primary winding wound around the first leg core are connected in series, there is an air gap in the magnetic path of the fifth leg core, and the first leg core and the fourth leg core, and the third leg core and the fifth leg core are each arranged in a symmetrical position with respect to the second leg core.

The fifth technical means is any one of the first to third technical means, further comprising a fourth leg core magnetically coupled to the first magnetic core and the second magnetic core, the magnetic path of the fourth leg core having a second divided magnetic path section in which the magnetic path is divided into two, a second secondary winding wound around the fourth leg core and the secondary winding wound around the second leg core are connected in series, and a second control winding is provided wound around each of the magnetic paths of the second divided magnetic path section of the fourth leg core, and the second control winding is connected to the first control winding. The second control winding is connected in series to a second DC power supply circuit so that the induced voltage generated in the second control winding by the magnetic flux linking with the secondary winding is cancelled out, and a DC control current is passed through the second control winding to return the control magnetic flux to the closed magnetic path formed by the second divided magnetic path section, saturating a portion of the magnetic path of the fourth leg magnetic core through which the magnetic flux passes, thereby controlling the magnetic resistance of the magnetic path of the fourth leg magnetic core and shunting a portion of the magnetic flux to the third leg magnetic core.

The sixth technical means is the fifth technical means, further comprising a fifth leg core magnetically coupled to the first magnetic core and the second magnetic core, and characterized in that the fifth leg core has an air gap in its magnetic path.

The present invention makes it possible to obtain a flux-controlled variable transformer that is small, has little effect on leakage flux and control loss, and is capable of continuously changing the secondary voltage.

1 is a diagram showing a magnetic circuit and a winding configuration of a flux control type variable transformer according to a first embodiment of the present invention; 2 is a diagram for explaining the operation of the flux control type variable transformer shown in FIG. 1 . 2 is a diagram showing an example of control characteristics of the magnetic flux control type variable transformer shown in FIG. 1 . FIG. 2 is a diagram showing a modified example of the flux control type variable transformer shown in FIG. 1 . FIG. 2 is a diagram showing a modified example of the flux control type variable transformer shown in FIG. 1 . FIG. 6 is a diagram showing a magnetic circuit and a winding configuration of a flux control type variable transformer according to a second embodiment of the present invention. FIG. 11 is a diagram showing a magnetic circuit and a winding configuration of a flux control type variable transformer according to a third embodiment of the present invention. FIG. 13 is a diagram showing a magnetic circuit and a winding configuration of a flux control type variable transformer according to a fourth embodiment of the present invention. FIG. 13 is a diagram showing a magnetic circuit and a winding configuration of a flux control type variable transformer according to a fifth embodiment of the present invention. FIG. 13 is a diagram showing a magnetic circuit and a winding configuration of a flux control type variable transformer according to a sixth embodiment of the present invention. FIG. 13 is a diagram showing a magnetic circuit and a winding configuration of a flux control type variable transformer according to a seventh embodiment of the present invention. FIG. 1 is a circuit diagram showing an example of a conventional transformer. FIG. 1 is a connection diagram showing a conventional flux linkage control transformer device. FIG. 1 is a connection diagram showing a variable transformer of a conventional example. FIG. 1 is a connection diagram showing a conventional voltage regulating transformer. FIG. 1 is a connection diagram showing a conventional flux-controlled variable transformer.

Below, with reference to the drawings, a preferred embodiment of the magnetic flux controlled variable transformer of the present invention will be described. In the following description, configurations with the same reference numerals in different drawings are considered to be similar, and their description may be omitted. Note that the present invention is not limited to the examples of these embodiments, and includes all modifications within the scope of the matters described in the claims and within the scope of equivalents. Furthermore, to the extent that multiple embodiments can be combined, the present invention includes any combination of the embodiments.

[First embodiment]
FIG. 1 is a diagram showing a magnetic circuit and a winding configuration of a flux-controlled variable transformer according to a first embodiment of the present invention, in which FIG. 1(A) shows the magnetic circuit and the winding configuration, and FIG. 1(B) shows an equivalent circuit of the variable transformer portion of the component circuit shown in FIG. 1(A).

As shown in FIG. 1A, this embodiment shows an example of a single-phase circuit, and the flux-controlled variable transformer 100A includes a core having a first magnetic core 104, a second magnetic core 105, and a first leg magnetic core 101, a second leg magnetic core 102, and a third leg magnetic core 103 that are magnetically coupled at both ends to the first magnetic core 104 and the second magnetic core 105, respectively. The core of the flux-controlled variable transformer 100A has a structure generally known as a three-leg core. The second leg magnetic core 102 has a split magnetic path portion consisting of split magnetic paths 102a and 102b in which the magnetic path is divided into two by a window 120. The third leg magnetic core 103 also has a gap portion G in the middle of the magnetic path.

In this embodiment, a primary winding 111 and a secondary winding 112 are wound around the first leg core 101, and a secondary winding 113 is wound around the second leg core 102. An AC primary voltage _V1 is applied to the primary winding 111. The secondary windings 112 and 113 are connected in series, and both ends are connected to a load. In this embodiment, the primary winding 111 and the secondary windings 112, 113 have a structure equivalent to that of an insulating transformer. A control winding 114 consisting of control windings 114a and 114b is wound around each of the divided magnetic paths 102a, 102b of the second leg core 102. Although an induced voltage is generated in the control windings 114a and 114b when the magnetic flux linking the primary winding 111 changes due to the current flowing through the primary winding 111, the control windings 114a and 114b are connected in series to cancel out both induced voltages, and are connected to the first DC power supply circuit 110. Therefore, no induced voltage due to the magnetic flux linking the primary winding 111 is applied to the control winding 114. The control winding 114 corresponds to the first control winding of the present invention.

In the equivalent circuit shown in FIG. 1(B), the || mark (vertical double line portion) indicates the arrangement symbol of a normal transformer core, and shows the primary winding 111 and secondary windings 112 and 113, and the control windings 114a and 114b rotated by 90 degrees. In this embodiment, the voltages induced in the secondary windings 112 and 113 are connected so as to be added.

Next, the operation of the flux-controlled variable transformer 100A in this embodiment when the control current Ic is passed through the control winding 114 will be described. Figure 2 is a diagram for explaining the operation of the flux-controlled variable transformer shown in Figure 1, where Figure 2(A) shows the case where the control current Ic is not passed and Figure 2(B) shows the case where the control current Ic is passed.

When control current Ic is not flowing through control winding 114, magnetomotive force _N1 × _I1 (ampere turns) is generated in first leg core 101, which is expressed as the product of current I1 flowing through primary winding ₁₁₁ and the number of turns of the primary winding _N1 , and magnetic flux φ flows through first leg core 101, first magnetic core 104, second leg core 102, and second magnetic core 105. Here, third leg core 103 has an air gap G in the middle of the magnetic path and has a large magnetic resistance, so that almost no magnetic flux due to current _I1 flowing through primary winding 111 flows through third leg core 103. Note that divided magnetic paths 102a and 102b of second leg core 102 have a magnetic resistance that does not become magnetically saturated even when magnetic flux φ flows.

In this way, when no control current I _C is flowing through the control winding 114, the flux-controlled variable transformer 100A has the same winding configuration as a normal single-phase transformer, except that it has a controllable flux control circuit consisting of the control windings 114a, 114b, the first DC power supply circuit 110, and the window 120 provided on the second leg core 102. As a result, a secondary voltage V ₂ of V 2 = V ₁ × (N _2-1 + N _2-2 )/N ₁ is generated in the secondary windings 112, 113, where N ₁ is the number of turns in the primary winding and N _2-1 , N _2-2 are _the numbers of turns in the secondary windings.

Next, as shown in Fig. 2B, when a DC control current Ic is passed through the control winding 114, a control magnetic flux φc is returned to the closed magnetic path formed by the divided magnetic paths 102a and 102b. The control magnetic flux φc is a control magnetic flux φc generated by a magnetomotive force 2Nc x _Ic (ampere turns) represented by the product of the number of turns Nc of the control windings 114a and 114b and the control current Ic, and magnetically saturates a part of the magnetic core through which the magnetic flux φ passes. As a result, the permeability of the second leg core 102 decreases, so that the amount of the magnetic flux φ that links with the primary winding 111 that passes through the second leg core 102 decreases, and the magnetic flux φ is divided into a magnetic path mainly consisting of the path of the first leg core 101, the first magnetic core 104, the third leg core 103, and the second magnetic core 105, and the voltage induced in the secondary winding 113 decreases. It is desirable to adjust the position of the window 120 so that the return of the control magnetic flux φc does not cause magnetic saturation in magnetic paths other than the divided magnetic paths 102a and 102b, for example, in the first magnetic core 104.

In this way, in the flux-controlled variable transformer 100A, by passing a control current Ic through the control windings 114a and 114b, a portion of the magnetic circuit of the second leg core 102 around which the secondary winding 113 is wound is saturated, and the magnetic flux φ that intersects with the primary winding 111 is diverted to the third leg core 103, which is different from the second leg core 102.

For example, if the third leg core 103 is not provided, only the magnetic path around the window 120 around which the control winding 114 is wound is magnetically saturated, and the leakage magnetic flux from around the window 120 generates eddy currents in the surrounding conductive materials, making it necessary to take measures against local overheating of the surrounding conductive materials and device loss. In this embodiment, the third leg core 103 having the gap G is provided magnetically in parallel with the second leg core 102, so that the magnetic flux φ that has stopped flowing through the second leg core 102 due to the increased magnetic resistance of the second leg core 102 begins to flow through the third leg core 103. This makes it possible to reduce the leakage magnetic flux from around the window 120 of the second leg core 102.

In this way, when a control current Ic is passed through the control winding 114, the third leg core 103 serves as a bypass magnetic path to prevent the magnetic flux φ interlinking with the primary winding 111 from becoming a leakage magnetic flux passing through the air layer around the window portion 120, and to pass the leakage magnetic flux that is not interlinked with the secondary winding 113. Also, when a control current Ic is not passed through the control winding 114, a gap portion G is provided to increase the magnetic resistance of the third leg core 103 so that the magnetic flux φ interlinking with the primary winding 111 does not flow into the third leg core 103.

FIG. 3 is a diagram showing an example of the control characteristics of the flux-controlled variable transformer shown in FIG. 1, where the vertical axis represents the transformation ratio of the secondary voltage _V2 based on the primary voltage _{V1 , and} the horizontal axis represents the control current Ic. As shown in the equivalent circuit of FIG. 1(B), the secondary windings 112 and 113 are connected so that the voltages generated by the change in magnetic flux are added. Therefore, as the control current Ic increases, the magnetic flux φ flowing through the second leg core 102 decreases, and the voltage excited in the secondary winding 113 wound around the second leg core 102 decreases. As a result, as shown in FIG. 3, the secondary voltage _V2 relative to the primary voltage _V1 decreases with an increase in the control current Ic. The maximum variable width of the secondary voltage can be freely set by setting the number of turns of the secondary windings 112 and 113. It is also possible to increase the secondary voltage _V2 relative to the primary voltage _V1 with an increase in the control current Ic by connecting the secondary winding 113 inversely to the secondary winding 112.

Figure 4 is a diagram showing a modified example of the flux-controlled variable transformer shown in Figure 1. The core of the flux-controlled variable transformer 100A shown in Figure 1 (A) is approximately shaped like the character "日", but in the flux-controlled variable transformer 100A' shown in Figure 4, the first magnetic core 104' is arranged in the center, the second magnetic core 105' is arranged concentrically around the periphery, and the first leg magnetic core 101r, the second leg magnetic core 102', and the third leg magnetic core 103r are arranged radially. Here, the first magnetic core 104' in the center may be solid rather than ring-shaped. Also, the lower half of the magnetic core connecting the first leg magnetic core 101r and the third leg magnetic core 103r of the second magnetic core 105' may be omitted.

The primary winding 111 and the secondary winding 112 are wound around the first leg core 101r, and the secondary winding 113 is wound around the second leg core 102'. An AC primary voltage V1 is applied to the primary winding 111. The secondary windings 112 and 113 are connected in series, and both ends are connected to the load. In the flux-controlled variable transformer 100A', the primary winding 111 and the secondary windings 112, 113 have a structure equivalent to that of an insulating transformer. A control winding 114 consisting of control windings 114a and 114b is wound around each of the divided magnetic paths 102a', 102b' of the second leg core 102'. The control windings 114a and 114b are connected in series so that the induced voltage due to the current flowing through the primary winding 111 is canceled, and are connected to the first DC power supply circuit 110. The flux-controlled variable transformer 100A' shown in FIG. 4 has the same effects and performance as the flux-controlled variable transformer 100A shown in FIG. 1, so a description of it will be omitted.

Figure 5 is a diagram showing a modified example of the flux-controlled variable transformer shown in Figure 1. In Figure 5, the connections of each winding, the power source, the load, and the first DC power supply circuit 110 are not shown. As is the case in the following explanations, in the present invention, the leg core around which the main winding is wound becomes the first leg core, the magnetic core having a split magnetic path section and around which the secondary winding is wound becomes the second leg core, and the leg core with an air gap in the magnetic path becomes the third leg core.

The flux-controlled variable transformer 100A shown in FIG. 5(A) is the same as the flux-controlled variable transformer 100A shown in FIG. 1, and shows an example configuration in which the first leg core 101 is arranged on the left side, the second leg core 102 is arranged in the center, and the third leg core 103 is arranged on the right side. The flux-controlled variable transformer 100B shown in FIG. 5(B) shows an example configuration in which the first leg core 101 is arranged on the left side, the second leg core 102 is arranged on the right side, and the third leg core 103 is arranged in the center. Furthermore, the flux-controlled variable transformer 100C shown in FIG. 5(C) shows an example configuration in which the first leg core 101 is arranged in the center, the second leg core 102 is arranged on the right side, and the third leg core 103 is arranged on the left side. In this way, even if the order of the arrangement of the first leg core 101, the second leg core 102, and the third leg core 103 is changed, the magnetic circuit has the same configuration, and the action and effect and performance as a flux-controlled variable transformer are also the same.

The flux-controlled variable transformer 100D shown in FIG. 5(D) shows an example in which the first leg core 101 is arranged on the left side, the second leg core 102 in the center, and the third leg core 103 on the right side. Here, the third leg core 103 is U-shaped and has a gap G between the first core 104 and the second core 105. Note that the gap G may be provided on only one of the cores. In this way, the gap G provided in the third leg core may be provided between the first core 104 or the second core 105. The flux-controlled variable transformer 100D has the same magnetic circuit configuration as the other flux-controlled variable transformers 100A to 100C, and the effects and performance of the flux-controlled variable transformer are also the same.

Second Embodiment
Fig. 6 is a diagram showing the magnetic circuit and winding configuration of a flux-controlled variable transformer according to a second embodiment of the present invention. In the flux-controlled variable transformer 100A shown in Fig. 1, the primary winding 111 and the secondary windings 112 and 113 are electrically insulated from each other, and the transformer has a structure equivalent to that of an insulating transformer, whereas the flux-controlled variable transformer 100E of this embodiment has a structure equivalent to that of an autotransformer, in which the primary winding and the secondary winding are electrically connected to each other.

Specifically, the primary winding 111 is wound around the first leg core 101, and the secondary winding is a winding in which the primary winding 111 and the secondary winding 113 wound around the second leg core 102 are connected in series. In this manner, in the flux-controlled variable transformer 100E, the primary winding 111 is shared with the secondary winding. In this embodiment, the secondary winding 113 is wound such that the voltage generated in the secondary winding 113 by the change in magnetic flux generated by the primary winding 111 is subtracted from the primary voltage _V1 , so that the secondary voltage _V2 increases as the control current Ic increases.

[Third embodiment]
7 is a diagram showing the magnetic circuit and winding configuration of a flux-controlled variable transformer according to a third embodiment of the present invention. The flux-controlled variable transformer 100F of this embodiment has a structure equivalent to that of an insulating transformer having an electrically insulated primary winding 111 and secondary winding 113. In the flux-controlled variable transformer 100F of this embodiment, as the control current Ic increases, a part of the divided magnetic paths 102a and 102b becomes saturated and the magnetic resistance increases, so that the secondary voltage _V2 induced in the secondary winding 113 decreases.

[Fourth embodiment]
Fig. 8 is a diagram showing a magnetic circuit and a winding configuration of a flux-controlled variable transformer according to a fourth embodiment of the present invention. In Fig. 8, the connection of each winding, the power source, the load, and the first DC power source circuit 110 are not shown. In the flux-controlled variable transformer 100G of this embodiment, compared to the flux-controlled variable transformer 100A of the first embodiment, notches are made in the divided magnetic paths 102a and 102b provided in the second leg core 102, and wedge-shaped gaps 120a and 120b are provided. The wedge-shaped gaps 120a and 120b are intended to suppress current distortion.

According to this embodiment, by making cuts in parts of the divided magnetic paths 102a and 102b, the magnetic path of the divided magnetic path 102a is composed of a parallel circuit of the connecting part where the cut is made and the wedge-shaped gap 120a, and the magnetic path of the divided magnetic path 102b is composed of a parallel circuit of the connecting part where the cut is made and the wedge-shaped gap 120b, so that the magnetic characteristics are improved and the current _I1 in the primary winding 111 has low current distortion with few harmonic components.

[Fifth embodiment]
FIG. 9 is a diagram showing the magnetic circuit and winding configuration of a flux-controlled variable transformer according to a fifth embodiment of the present invention. In FIG. 9, the connection of each winding, the power source, the load, and the first DC power source circuit 110 are not shown. In the flux-controlled variable transformer 100H of this embodiment, the window 120 provided in the second leg core 102 is made larger than that of the flux-controlled variable transformer 100A of the first embodiment, and the second leg core 102 is composed of the divided magnetic paths 102a and 102b in its entirety. The secondary winding 113 is wound across the divided magnetic paths 102a and 102b. The magnetic circuit configuration is the same as that of the other flux-controlled variable transformers 100A to 100C, and the effects and performance of the flux-controlled variable transformer are also the same.

Sixth embodiment
FIG. 10 is a diagram showing a magnetic circuit and a winding configuration of a flux-controlled variable transformer according to a sixth embodiment of the present invention. In FIG. 10, the connection of each winding, the power supply, the load, and the first DC power supply circuit 110 are not shown. In the flux-controlled variable transformer 100I of this embodiment, the configuration from the center to the left shown in FIG. 10 is the same as that of the flux-controlled variable transformer 100C shown in FIG. 5(C), and the first third leg core 103, the first first leg core 101, and the second leg core 102 are arranged in order from the left. Furthermore, on the right side of the second leg core 102, the second first leg core 101' as the fourth leg core and the second third leg core 103' as the fifth leg core are arranged. The first third leg core 103 and the second third leg core 103' have gaps G in the middle of the magnetic path. The first to fifth leg cores are magnetically coupled to the first magnetic core 104 and the second magnetic core 105 at both ends thereof.

The primary winding 111 is wound around the first first leg core 101 on the left side, and the primary winding 111' is also wound around the second first leg core 101' on the right side, and the primary winding 111 and the primary winding 111' are connected in series and connected to an AC power source (not shown). Secondary windings 113, 112, and 112' are wound around the second leg core 102 in the center, the first first leg core 101 on the left side, and the second first leg core 101' on the right side, respectively, and these secondary windings 113, 112, and 112' are connected in series and connected to a load (not shown). In this way, the flux-controlled variable transformer 100I of this embodiment has a good weight balance and is suitable for installation because the cores and windings are arranged symmetrically on the left and right sides. The primary winding 111' wound around the second first leg core 101' corresponds to the second primary winding of the present invention.

[Seventh embodiment]
Fig. 11 is a diagram showing a magnetic circuit and a winding configuration of a flux-controlled variable transformer according to a seventh embodiment of the present invention. Fig. 11(A) shows a flux-controlled variable transformer 100J of this embodiment, and Fig. 11(B) shows the flux-controlled variable transformer 100J of Fig. 11(A) magnetically divided into two in order to explain the flux-controlled variable transformer 100J of this embodiment shown in Fig. 11(A).

First, in FIG. 11(B), the flux-controlled variable transformer 100A shown on the right has the same configuration as the flux-controlled variable transformer 100A described in the first embodiment. Also, the flux-controlled variable transformer 100A' shown on the left is a symmetrical inversion of the flux-controlled variable transformer 100A on the right, and has the same configuration as the flux-controlled variable transformer 100A.

The secondary winding 112A wound around the first leg core 101A and the secondary winding 113A wound around the second leg core 102A of the flux control variable transformer 100A are connected in series so that the secondary voltage _V2 decreases when the control current Ic1 is increased. The secondary winding 112B wound around the first leg core 101B and the secondary winding 113B wound around the second leg core 102B of the flux control variable transformer 100A' are connected in series so that the secondary voltage _V2 increases when the control current Ic2 is increased.

The flux-controlled variable transformer 100J shown in FIG. 11(A) is configured by combining the first leg cores 101A and 101B of the flux-controlled variable transformer 100A and the flux-controlled variable transformer 100A' shown in FIG. 11(B) into a single first leg core 101. The flux-controlled variable transformer 100J is also configured by combining the primary windings 111A and 111B wound around the first leg cores 101A and 101B of the flux-controlled variable transformers 100A and 100A', respectively, into a single primary winding 111, and combining the secondary windings 112A and 112B wound around the first leg cores 101A and 101B, respectively, into a single secondary winding 112.

In addition, the control windings 114aA and 114bA are wound around the split cores 102aA and 102bA provided in the first second leg core 102A, respectively, and the control windings 114aA and 114bA are connected in series to the first DC power supply circuit 110A so that the induced voltage due to the change in magnetic flux generated by the current in the primary winding 111 is canceled. Similarly, the control windings 114aB and 114bB are wound around the split cores 102aB and 102bB provided in the second second leg core 102B, respectively, and the control windings 114aB and 114bB are connected in series to the second DC power supply circuit 110B so that the induced voltage due to the change in magnetic flux generated by the current flowing in the primary winding 111 is canceled. The split magnetic cores 102aB and 102bB provided in the second second leg magnetic core 102B correspond to the second split magnetic path section of the present invention, and the control windings 114aB and 114bB correspond to the second control winding of the present invention.

The secondary winding 112 wound around the central first leg core 101, the secondary winding 113A wound around the first second leg core 102A on the right side, and the secondary winding 113B wound around the second second leg core 102B on the left side provided as the fourth leg core are connected in series and connected to a load not shown. In this case, the secondary windings 112 and 113A are connected in series so that the electromotive force of the secondary winding 113A is added to the electromotive force of the secondary winding 112, and the secondary windings 112 and 113A are connected in series so that the electromotive force of the secondary winding 113B is subtracted from the electromotive force of the secondary winding 112.

As a result, the secondary voltage _V2 generated in the series-connected secondary windings 112, 113A, and 113B decreases with an increase in the control current Ic1 from the first DC power supply circuit 110A, and the secondary voltage _V2 generated in the series-connected secondary windings 112, 113A, and 113B increases with an increase in the control current Ic2 from the second DC power supply circuit 110B. In this way, the flux-controlled variable transformer 100J of this embodiment can reduce or increase the secondary voltage V2 by changing either the control current Ic1 from the first DC power supply circuit 110A or the control current _Ic2 from the second DC power supply circuit 110B, compared to the case where the control current Ic1 and the control current Ic2 are not flowing. The secondary winding 113B corresponds to the second secondary winding of the present invention.

In addition, in this embodiment, a first third leg core 103A and a second third leg core 103B are provided as the fifth leg core, and the first third leg core 103A and the second third leg core 103B each have a gap G in the magnetic path. The first third leg core 103A and the second third leg core 103B are provided symmetrically with respect to the central first leg core 101, so that the left and right weight balance is also good in this embodiment, which is desirable. Note that, in order to reduce weight, a configuration in which only one of the first third leg core 103A and the second third leg core 103B is provided may be used.

11...primary winding, 12...secondary winding, 13...magnetic core, 20...primary winding, 21...secondary winding, 22-25...U-shaped cut core, 26...leakage flux control winding, 27...flux control winding, 28, 29...contact portion, 30...primary winding, 31...secondary winding, 32...magnetic core, 33...window, 34a, 34b...control winding, 40, 41...second core, 42, 43...bypass core, 44...primary winding, 45...secondary winding, 46a, 46b...control winding, 47a, 47b...bypass Pass core control winding, 51, 52...three-leg core, 53...primary winding, 54...secondary winding, 55a...first auxiliary winding, 55b...second auxiliary winding, 56a...first control winding, 56b...second control winding, 57a...third control winding, 57b...fourth control winding, 100A to 100J...flux-controlled variable transformer, 101, 101r, 101', 101A, 101B...first leg core, 102, 102', 102A, 102B...second leg core, 102a, 102b, 102aA, 102aB, 102bA, 102bB...split core, 103, 103r, 103', 103A, 103B...third leg core, 104, 104'...first core, 105, 105'...second core, 110, 110A...first DC power supply circuit, 110B...second DC power supply circuit, 111, 111', 111A, 111B...primary winding, 112, 112A, 112B, 113, 113A, 113B...secondary winding, 114, 114a, 114aA, 114aB, 114b, 114bA, 114bB...control winding, 120...window, 120a, 120b...air gap.

Claims (6)

a core including a first magnetic core, a second magnetic core, a first leg core, a second leg core, and a third leg core magnetically coupled to the first magnetic core and the second magnetic core, respectively, the core having a divided magnetic path portion in which the magnetic path of the second leg core is divided into two, and a gap portion in the magnetic path of the third leg core;
a primary winding wound around at least the first leg core;
a secondary winding wound around at least the second leg core;
a first control winding wound around each of the divided magnetic path portions of the second leg core;
the first control winding is connected in series to a first DC power supply circuit so that an induced voltage generated in the first control winding by a magnetic flux linking the primary winding is cancelled;
a DC control current is passed through the first control winding, causing a control flux to flow back through a closed magnetic path formed by the divided magnetic path portion, saturating a portion of the magnetic path of the second leg core through which the magnetic flux passes, thereby controlling the magnetic resistance of the magnetic path of the second leg core, and shunting a portion of the magnetic flux to the third leg core. 2. The flux-controlled variable transformer according to claim 1, wherein the secondary winding is wound around the first leg core and is connected in series with the secondary winding wound around the second leg core. The magnetic flux control type variable transformer according to claim 1 or 2, characterized in that a wedge-shaped gap is provided at any location of the divided magnetic path section. the rotor further includes a fourth leg core and a fifth leg core magnetically coupled to the first magnetic core and the second magnetic core, respectively, and a second primary winding wound around the fourth leg core,
the second primary winding wound around the fourth leg core and the primary winding wound around the first leg core are connected in series,
a gap is provided in the magnetic path of the fifth leg magnetic core,
4. A flux-controlled variable transformer according to claim 1, characterized in that the first leg core and the fourth leg core, and the third leg core and the fifth leg core are respectively arranged in symmetrical positions with respect to the second leg core. a fourth leg core magnetically coupled to the first magnetic core and the second magnetic core,
The magnetic path of the fourth leg core has a second divided magnetic path portion divided into two,
a second secondary winding wound around the fourth leg core and the secondary winding wound around the second leg core are connected in series,
a second control winding wound around each of the second divided magnetic path portions of the fourth leg magnetic core,
the second control winding is connected in series to a second DC power supply circuit such that an induced voltage generated in the second control winding by the magnetic flux interlinked with the primary winding is cancelled;
4. The flux-controlled variable transformer according to claim 1, characterized in that a DC control current is passed through the second control winding to return a control flux to a closed magnetic path formed by the second divided magnetic path portion, thereby saturating a portion of the magnetic path of the fourth leg core through which the magnetic flux passes, thereby controlling the magnetic resistance of the magnetic path of the fourth leg core, and shunting a portion of the magnetic flux to the third leg core. 6. The flux-controlled variable transformer according to claim 5, further comprising a fifth leg core magnetically coupled to the first magnetic core and the second magnetic core, and a gap is provided in a magnetic path of the fifth leg core.