JP7208182B2 - Stationary induction equipment and transformers - Google Patents

Description

The present invention relates to static induction machines and transformers.

Soft magnetic materials such as grain-oriented electrical steel sheets, amorphous alloys, and nanocrystalline alloys are widely used for iron cores used in static induction devices (static electromagnetic devices) such as transformers and reactors. Each of these magnetic materials is used in various stationary induction devices depending on factors such as their loss (iron loss), saturation magnetic flux density, mechanical strength, and cost. Taking a transformer, which is a type of static induction device, as an example, each of these magnetic materials is used differently depending on the application, from small-capacity power receiving/distribution transformers to large-capacity power transmission/distribution transformers. .

For example, when comparing grain-oriented electrical steel sheets and amorphous alloys, grain-oriented electrical steel sheets have a high saturation magnetic flux density, making it easy to reduce the size of the iron core. Suitable for iron cores for dexterity. Amorphous alloys, on the other hand, have lower losses than grain-oriented electrical steel sheets, so they are superior in improving the efficiency of transformers. In addition, it has been put to practical use as an iron core for transformers for small to medium-capacity power distribution.

Here, by using a "composite core" in which two or more types of core materials are combined as described above, it may be possible to realize an electromagnetic induction device with high performance and easy miniaturization. For example, it may be possible to realize a high-performance static induction device (such as a transformer) that combines the high saturation magnetic flux density and mechanical strength of a grain-oriented electrical steel sheet with the low loss of an amorphous alloy. Japanese Patent Application Laid-Open No. 8-88128 (Patent Document 1) is known as a prior art based on such an idea. This patent document 1 discloses a technique of a multi-layer transformer core in which an amorphous wound core is placed inside and an electromagnetic steel sheet wound core is arranged outside, which is effective in reducing iron loss.

Further, Japanese Patent Application Publication No. 2018-502446 (Patent Document 2) is known as a prior art related to a transformer using a composite core in which two types of magnetic materials are combined. In this patent document 2, in a three-phase wound core composed of a soft magnetic amorphous alloy mainly composed of iron and a soft magnetic nanocrystalline alloy mainly composed of iron, the cross-sectional area ratio of the former having high saturation magnetization is 2 to 50%, preferably 4 to 40%.

JP-A-8-88128 Japanese Patent Publication No. 2018-502446

The technology disclosed in Patent Document 1 realizes a stationary induction device that combines the high mechanical strength of grain-oriented electrical steel sheets with the low core loss of amorphous alloys. The technology disclosed in Patent Document 2 combines an amorphous alloy with a saturation magnetic flux density higher than that of a nanocrystalline alloy and a nanocrystalline alloy with a core loss that is even smaller than that of an amorphous alloy, and combines the superior properties of both materials. It realizes a stationary induction device.

On the other hand, both documents do not quantify the specific design conditions for making the most of the advantages of the two magnetic materials that make up the composite core, and depending on the specifications of the composite core, the sufficient characteristics of each magnetic material cannot be fully utilized. As a result, there is a possibility that a high-performance stationary induction device cannot be realized.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a static induction device and a transformer using a composite iron core that has improved performance and can be miniaturized.

As an example, the present invention is a stationary induction device using a composite core composed of two or more magnetic materials, wherein the magnetic material having the highest saturation magnetic flux density in the composite core has a magnetic flux density of From the weighted average value of the magnetic flux density that is equal to or lower than the magnetic flux density of the core composed only of magnetic materials with the highest saturation magnetic flux density and according to the ratio of the cross-sectional areas of the two or more magnetic materials in the composite core In the stationary induction device, the average magnetic flux density in the composite core is set so that

According to the present invention, it is possible to provide a static induction device and a transformer using a high-performance composite core, and to provide a static induction device and a transformer in which the cross-sectional area of the core is reduced.

1 is a diagram showing a three-phase five-legged transformer in Example 1 of the present invention; FIG. FIG. 4 is a diagram showing magnetization curves of an amorphous magnetic material and a nanocrystalline magnetic material used for the composite core in Example 1 of the present invention; FIG. 4 is a diagram showing calculation results showing the relationship between the average magnetic flux density of the composite core and the magnetic flux density in the amorphous, grain-oriented electrical steel sheet core in Example 1 of the present invention. FIG. 4 is a diagram showing calculation results showing the relationship between the cross-sectional area ratio of the amorphous core in the composite laminated core of the three-phase five-legged transformer and the average magnetic flux density of the composite core in Example 1 of the present invention. FIG. 4 is a diagram showing calculation results showing the relationship between the cross-sectional area ratio of the amorphous core in the composite core of the three-phase five-legged transformer and the outer shape relative volume of the composite laminated core in Example 1 of the present invention. FIG. 5 is a view showing a central cross section of a three-phase five-legged transformer in Embodiment 2 of the present invention; It is the front view and center cross-sectional view of the single-phase transformer in Example 3 of this invention. FIG. 10 is a front view and a central cross-sectional view of a transformer using a three-phase tripod wound core in Example 4 of the present invention;

EMBODIMENT OF THE INVENTION Hereinafter, the form (Example) for implementing this invention is demonstrated in detail using drawing. In the following embodiments, a "transformer", which is an example of static induction equipment, will be described as an example, but the present invention is not limited to transformers, and can be applied to static induction equipment in general. In the following description, the same reference numerals (numbers) are assigned to the same devices and the same operation processes, and the devices and operations that have already been described may be omitted in the description of the drawings that will be described later.

<<Example 1>>
First, Embodiment 1 of the present invention will be described with reference to FIGS. 1 to 5. FIG.
First, referring to FIG. 1, the overall configuration of the first embodiment will be described. FIG. 1 shows a cross-sectional view of a three-phase five-legged transformer in Example 1, (a) is a longitudinal cross-sectional view, and (b) is a cross-sectional view along the AA' cross section of (a). showing.

In FIG. 1, reference numeral 1 denotes a composite core, which in this example has five legs. Composite core 1 is composed of two types of composite cores: nanocrystalline core 11 using ribbon-like nanocrystalline material and amorphous core 12 using amorphous magnetic material. Further, the composite core 1 and a three-phase winding in which a high-voltage winding 21 and a low-voltage winding 22 are wound in an overlapping manner on three magnetic legs of the core 1 are provided. The nanocrystalline core 11 and the amorphous core 12 are cut into a quadrilateral, pentagon, or hexagon and combined at joints 15 . The nanocrystalline core 11 is laminated on the central portion (inner side) of the composite core 1, and the amorphous core 12 is laminated on the outer side (both ends). The thickness of the nanocrystalline core 11 is a ₁ , the thickness of the composite core 1 is a ₂ , and the ratio a ₁ :a ₂ is 75:25 as an example.
Here, Table 1 shows the meaning of the symbols indicating the parameters of the transformer in Example 1 and the values of the parameters.

Table 1

Next, the results of electromagnetic field analysis of the magnetic flux density distribution in the composite core 1 of Example 1 using the parameters shown in Table 1 will be described.

FIG. 2 shows magnetization characteristics showing the relationship between the magnetizing force and the magnetic flux density of the magnetic material forming the composite core 1 defined in the electromagnetic field analysis. In FIG. 2, 31 is the magnetization properties of the amorphous magnetic material and 32 is the magnetization properties of the nanocrystalline material. The amorphous magnetic material and the nanocrystalline material used in this analysis were the amorphous material and the nanocrystalline material sold by Hitachi Metals, Ltd.
In this electromagnetic field analysis, the electrodes of the secondary winding 22 were left open, and a three-phase 50 Hz sinusoidal voltage was applied to the primary winding 21 to calculate the magnetic flux density distribution in the iron core.

Next, FIG. 3 shows the relationship between the average magnetic flux density _Bm of the entire composite core obtained by changing the applied voltage V1, and the magnetic flux densities in the amorphous core and the nanocrystalline core. The calculation results of each iron core are indicated by curves of the magnetic flux density 33 of the amorphous iron core and the magnetic flux density 34 of the nanocrystalline iron core in the figure. That is, the calculation result of the amorphous core is as shown in 33, and the calculation result of the nanocrystalline core is as shown in 34. Here, when the effective cross-sectional area of the composite core is A _C and the frequency of the applied voltage is f, B _m is expressed by the following equation (1). Also, the effective cross-sectional area A _C is represented by the formula (2).
B _m = V ₁ /(4.44·f·N ₁ ·A _C ) (1)
_{A C} =b.( _a1.S1 + _a2.S2 ) …………( ₂ )

B _n and B _a shown in FIG. 3 are representative values of the magnetic flux density in a stationary induction device (stationary electromagnetic device) having an iron core composed only of nanocrystalline material and amorphous material, respectively. _Bm1 shown in the figure is the weighted average value of the magnetic flux densities according to the ratio of the cross-sectional areas of the two magnetic materials in the composite core, which is the average magnetic flux density of the composite core in the conventional design method. The average magnetic flux density _Bm1 of this composite core is represented by the following equation (3).
_{Bm1 = ( a1 * S1} * _Bn + _a2 *S2* _Ba ) _/ (a1*S1+ _a2 *S2)
………………(3)

Now, looking at the change in the magnetic flux density of each core ( _{nanocrystalline} core and amorphous core) in the composite core in FIG. The magnetic flux density 34 of the iron core reaches magnetic saturation and becomes a constant value. At this time, it can be seen that the gradient of the magnetic flux density 33 of the amorphous core increases. This is a phenomenon that occurs when the leakage magnetic flux from the magnetically _{saturated nanocrystalline} core flows through the amorphous core. This is a phenomenon in which the magnetic flux does not leak to the outside of the composite core even if the That is, even if the average magnetic flux density _Bm is increased to _Bm2 where the magnetic flux density of the amorphous iron core reaches _Ba , the function as a stationary induction device is maintained. According to such new findings, it can be seen that the average magnetic flux density _{Bm of the composite core may be set to Bm2 at} maximum. That is, if the average magnetic flux density _{Bm of the composite core is set to be equal to or less than Bm2 in FIG. 3 and greater than the weighted average value Bm1 , it} can be expected that the performance of the composite core will be improved.

In this way, in a stationary induction device using a composite core composed of two or more types of magnetic materials, the magnetic flux density in the magnetic material with the highest saturation magnetic flux density in the The average magnetic flux density in the composite core is set so that the magnetic flux density of the induction device is B _m2 or less, and the weighted average of the magnetic flux densities according to the ratio of the cross-sectional areas of the two or more magnetic materials in the composite core By setting the average magnetic flux density in the composite core so as to be larger than the value B _m1 , it is possible to realize a static induction device that has higher performance and can be made smaller than before.

In the case of the first embodiment, the average magnetic flux density B _m2 of the amorphous core 12 having a high internal magnetic flux density in the composite core. The average magnetic flux density B _m2 in this case is 9% higher than the weighted average value B _m1 of the magnetic flux _densities according to the ratio of the cross-sectional areas of the two or more magnetic materials _. The effective cross-sectional area of the core can be reduced by 9% compared to conventional design methods. When the effective value of the primary voltage is _3822V shown in Table 1, according to the conventional design method where Bm is _Bm1 , the dimension a1 in FIG. ₁ is 244mm and the dimension _a2 is 82mm. On the other hand, according to Example ₁ of the present invention where _Bm is _Bm2 , the dimension a1 is 225 mm and the dimension _a2 is 75 mm. Along with this, the outer volume W×H×D of the composite core is reduced by 9% compared to the conventional design.

The numerical values in the above description are the calculation results when the geometric cross _- sectional area ratio a1: _a2 of the nanocrystalline core and the amorphous core constituting the three-phase five-legged composite core is 75:25. FIG. 4 shows changes in the average magnetic flux density _Bm determined by the same calculation method while changing this ratio from 0:100 to 100:0, and changes in the external volume W×H×D of the composite core are shown in FIG. show. The horizontal axis of both figures is the ratio of the amorphous core to the geometric cross-sectional area of the entire composite core. . First, 39 shown in FIG. 4 corresponds to the weighted average value B _m1 of the magnetic flux density according to the ratio of the cross-sectional areas of the nanocrystalline core and the amorphous core, and represents the magnetic flux density of the composite core in the conventional design method. And 40 is _Bm obtained by the method in the example of the present invention. As can be seen from the figure, the method of the embodiment of the present invention can increase the magnetic flux density compared to the conventional design method based on the weighted average value. Next, the external volume W×H×D of the composite core designed from this result is obtained, and the relative volume with the amorphous transformer as 100% is shown in FIG. Corresponding to the increase in _Bm , compared with the result 41 by the conventional design method, in Example 1 of the present invention, it can be seen that the effect of reducing the external volume 42 can be obtained in a wide range of iron core ratios. .

<<Example 2>>
The principles and effects of the present invention in Embodiment 1 can be broadly obtained in composite cores for stationary induction devices of other shapes.

Next, Embodiment 2 of the present invention will be described with reference to FIG. FIG. 6 is a central cross-sectional view of a three-phase five-legged transformer according to a second embodiment of the present invention. In this second embodiment, the same reference numerals (numbers) are given to the same constituent devices as in the first embodiment, and the description thereof will be omitted. In Example 2, a composite core is constructed by alternately stacking two types of cores, that is, a ribbon-like nanocrystalline core 11 and an amorphous core 12 in units of one sheet or in units of multiple sheets. By designing the cross-sectional area ratio and magnetic flux density of the nanocrystalline core 11 and the amorphous core 12 in the same manner as in Example 1, the same effect as in Example 1 can be obtained, and the outer volume of the composite core can be reduced. can do.

<<Example 3>>
Next, Embodiment 3 of the present invention will be described with reference to FIG. FIG. 7 is a cross-sectional view of a single-phase transformer showing Embodiment 3 of the present invention, (a) is a vertical cross-sectional view, and (b) is a cross-sectional view along the AA' cross-section of (a). Figure shows. Note that the components indicated by the respective symbols (numbers) in FIG. 7 have already been described, so description thereof will be omitted here.

In this embodiment, a composite core 1 consisting of two types of cores, a ribbon-shaped nanocrystalline core 11 and an amorphous core 12, and a high-voltage winding 21 and a low-voltage winding 22 are wound on three magnetic legs of the composite core 1. A turned single-phase winding is provided. Nanocrystalline core 11 and amorphous core 12 are cut into trapezoidal shapes and combined at joints 15 . By designing the cross-sectional area ratio and the magnetic flux density of the nanocrystalline core 11 and the amorphous core 12 as shown in Example 1, the same effect as in Example 1 can be obtained, and the outer volume of the composite laminated core can be reduced. can do.

<<Example 4>>
Next, Example 4 of the present invention will be described with reference to FIG. FIG. 8 is a cross-sectional view of a three-phase tripod type transformer showing Embodiment 4 of the present invention, (a) is a vertical cross-sectional view, and (b) is a cross section along the AA' cross section of (a). shows a plan view. It should be noted that the components indicated by the respective symbols (numbers) in FIG. 8 have already been described, so description thereof will be omitted here.

In this embodiment 4, a composite core composed of two types of cores, namely, a nanocrystalline core 11 made of a ribbon-shaped nanocrystalline material and an amorphous core 12 made of an amorphous magnetic material is used. A three-phase tripod-type composite core is composed of two inner wound cores 1a and one outer wound core 1b covering the outer circumference of the inner wound cores. The three magnetic legs are provided with a three-phase winding in which a high-voltage winding 21 and a low-voltage winding 22 are wound in an overlapping manner to form a transformer. The nanocrystalline iron core 11 and the amorphous iron core 12 are cut and laminated to a predetermined length, and the outer shape is formed into a substantially rectangular shape, and the cut ends are connected at the lap joints 16 to form an annular wound iron core. By designing the cross-sectional area ratio and the magnetic flux density of the nanocrystalline core 11 and the amorphous core 12 in the same manner as in Example 1, the same effect as in Example 1 can be obtained, and the outer volume of the composite wound core can be reduced. can do.

<<Other Examples>>
In the above-described embodiments of the present invention, an example of a composite core made of two types of magnetic materials, an amorphous material and a nanocrystalline material, is shown, but any multiple materials including other magnetic materials such as grain-oriented electrical steel sheets With the design method according to the present invention, the outer volume of the core can also be reduced for a composite core composed of

Moreover, the present invention is not limited to the above-described multiple embodiments, and includes various alternatives and modifications within the scope of its technical concept.

For example, the composite core of the stationary induction device of the present invention is constructed by cutting two or more kinds of ribbon-shaped magnetic materials and laminating the respective ribbon-shaped magnetic materials continuously to stack a plurality of cores in the lamination direction. can be done. Moreover, the composite core of the stationary induction device of the present invention can be constructed by cutting two or more kinds of ribbon-shaped magnetic materials and laminating them alternately. Also, the composite core of the stationary induction device of the present invention can be constituted by a wound core obtained by cutting and laminating two or more kinds of ribbon-like magnetic materials, forming them into a ring shape, and lap-joining the cut ends. In addition, the composite core of the stationary electromagnetic device of the present invention is provided with three parallel magnetic leg groups having three-phase windings, and the magnetic leg groups are provided in parallel on both outer sides of the magnetic leg groups, and are not provided with windings. A three-phase five-legged laminated core composed of two side legs and a yoke portion connecting both ends of the magnetic leg group and the side legs can be provided. In addition, the composite core of the stationary induction device of the present invention is a three-phase tripod type composed of a group of three magnetic legs arranged in parallel each having a three-phase winding and a yoke portion connecting both ends of the group of magnetic legs. It can be a laminated core. In addition, the composite core of the stationary induction device is frame-shaped, and it is possible to use a single-phase laminated core with a single-phase winding on one side or two opposite sides of the core. In addition, the composite core of the stationary induction device has four wound cores of approximately the same size made of two or more kinds of magnetic materials arranged in parallel, and three-phase windings are provided at three magnetic legs where the wound cores are adjacent to each other. It can also be a three-phase five-leg wound core provided. In addition, the composite core of the stationary induction device is composed of one wound core made of two or more kinds of magnetic materials, and has a single-phase winding in one or two magnetic legs of the wound core. A wound iron core can also be used.

DESCRIPTION OF SYMBOLS 1... Composite core, 11... Nanocrystalline core, 12... Amorphous core, 15... Joint part, 21... High voltage winding, 22... Low voltage winding

Claims (12)

A stationary induction device using a composite core composed of two or more magnetic materials,
The magnetic flux density in the magnetic material with the highest saturation magnetic flux density in the composite core is less than or equal to the magnetic flux density of the core composed only of the magnetic material with the highest saturation magnetic flux density, and the two or more types in the composite core A stationary induction device in which the average magnetic flux density in the composite core is set to be larger than the weighted average value of magnetic flux densities according to the cross-sectional area ratio of the magnetic material. In the stationary induction device according to claim 1,
A stationary induction device, wherein the composite core is constructed by stacking a plurality of cores obtained by cutting two or more kinds of ribbon-shaped magnetic materials and laminating the respective ribbon-shaped magnetic materials continuously in the lamination direction. In the stationary induction device according to claim 1,
A stationary induction device, wherein the composite core is formed by cutting two or more kinds of ribbon-shaped magnetic materials and laminating them alternately. In the stationary induction device according to claim 1,
A stationary induction device, wherein the composite core is a wound core formed by cutting and laminating two or more kinds of ribbon-like magnetic materials, forming them into a ring shape, and lap-joining the cut ends to each other. In the stationary induction device according to claim 1,
The composite core includes three parallel magnetic leg groups with three-phase windings, two side legs provided in parallel on both outer sides of the magnetic leg groups and having no windings, A stationary induction device, characterized by being a three-phase five-legged laminated core composed of a yoke portion connecting both ends of a group of magnetic legs and side legs. In the stationary induction device according to claim 1,
The composite core is a three-phase three-legged laminated core composed of three parallel magnetic leg groups with three-phase windings and yoke portions connecting both ends of the magnetic leg groups. stationary induction equipment. In the stationary induction device according to claim 1,
A stationary induction device, wherein the composite core is a frame-shaped single-phase laminated core having a single-phase winding on one side or two opposite sides of the core. In the stationary induction device according to claim 1,
The composite core comprises four wound cores of approximately the same size made of two or more of the magnetic materials, arranged in parallel, and a three-phase winding provided with three-phase windings on three magnetic legs where the wound cores are adjacent to each other. A stationary induction device characterized by being a pentapod wound core. In the stationary induction device according to claim 1,
The composite core consists of two wound cores made of two or more magnetic materials and having approximately the same dimensions arranged side by side, and one wound core covering the outer periphery of the two wound cores, and the wound cores are adjacent to each other. A stationary induction device characterized by a three-phase tripod-type wound iron core in which a three-phase winding is provided on each magnetic leg. In the stationary induction device according to claim 1,
The composite core is a single-phase wound core composed of one wound core made of two or more of the magnetic materials, and having single-phase windings on one or two magnetic legs of the wound core. A stationary induction device characterized by: In the stationary induction device according to claim 1,
The composite core is composed of an amorphous core and a nanocrystalline core, the magnetic flux density of the amorphous core is equal to or lower than the magnetic flux density of the core composed only of the amorphous core, and the magnetic flux density is the amorphous core and the nanocrystalline core. A stationary induction device, wherein the average magnetic flux density in the composite core is set to be larger than the weighted average value of magnetic flux densities according to the cross-sectional area ratio of the crystal core. A composite core composed of two or more kinds of magnetic materials, and a transformer obtained by winding a high-voltage winding and a low-voltage winding on the composite core in an overlapping manner,
The magnetic flux density in the magnetic material with the highest saturation magnetic flux density in the composite core is less than or equal to the magnetic flux density of the core composed only of the magnetic material with the highest saturated magnetic flux density, and the two or more types in the composite core A transformer in which the average magnetic flux density in the composite core is set to be larger than the weighted average value of the magnetic flux density according to the ratio of the cross-sectional area of the magnetic material.

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