JPH0462809A - Static induction equipment with wound core - Google Patents

Abstract

PURPOSE:To enable a minimum iron-loss property which an no-cut wound core has to be secured and achieve a low noise by forming a combinational wound core which consists of a second wound core in that a high silicon steel plate containing a certain amount of silicon is wound at an outer-periphery side of a first wound core. CONSTITUTION:A coil 1 is assembled so that each insulation conductor of primary and secondary sides is wound in rectangular shape and a sectional shape is inscribed to a circular shape as much as possible and is a mold coil which is produced by casting an insulation resin. A wound core 2 is formed by winding a thin amorphous magnetic alloy band at both leg parts of this mold coil 1 so that a certain lamination thickness may be reached. Further, a wound core 3 is formed by winding a silicon steel containing silicon exceeding 3% which is a low magnetic distortion magnetic material onto an outer periphery of this wound core 2 to a prescribed lamination thickness, thus constituting a no-cut combinational wound core 4 by both core materials.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to stationary induction equipment such as transformers and reactors having a wound core wound with an amorphous magnetic alloy ribbon.

(Prior art) As an iron core for stationary induction equipment such as transformers and reactors,
It is desirable to have magnetic properties such as low iron loss, high saturation magnetic flux density, and low excitation current, and soft magnetic materials such as grain-oriented silicon steel plates are used for boat fishing. In recent years, there have been remarkable advances in technology to reduce the loss of these iron core materials, but in particular, amorphous magnetic alloy ribbon produced by ultra-quenching molten magnetic alloy has a core loss of 1/2 compared to conventional silicon steel sheets. It has excellent magnetic properties, such as a significantly smaller size of /3 to 1/4. Therefore, with the aim of saving energy, studies are actively being conducted on the use of amorphous magnetic alloy ribbons as core materials for transformers and the like.

Iron cores using amorphous magnetic alloy ribbons can be made into a rectangular laminated core by laminating the required number of strip steel plates of appropriate lengths while alternately wrapping them, as in the case of using ordinary silicon steel plates. Wound cores made by winding thin strips multiple times are considered, and these cores are actually used as cores for stationary induction equipment. Although each method has its advantages and disadvantages, the wound core has the following characteristics. Firstly, there is no need to manually stack each thin strip like a laminated core, and automatic winding using a winding device is possible, which improves work efficiency.Secondly, the same core Even when obtaining the cross-sectional area, a laminated core has a rectangular shape with four right-angled corners, but in the case of a wound core, even if it is formed into a rectangle, the four corners are formed with curvature, so the magnetic path becomes shorter. The overall size of the core is smaller and the weight of the core is smaller. Thirdly, due to the manufacturing method of the laminated core, there are seams and gaps in the core that inevitably cause an increase in iron loss, but the wound core is thinner. After the band is continuously wound and formed, the coil is wound by winding the conductor around the parts corresponding to the legs, so it is possible to use the iron core without cutting it. The goal is to reduce losses.

For wound cores, the so-called C-cut core or one-turn cut method is a method in which a thin ribbon is wound, then a part of it is cut open, a pre-fabricated conductor coil is inserted into the core legs, and the core is closed again. Alternatively, there is a lap joint method (Japanese Unexamined Patent Publication No. 63-170907), but these methods create a joint in the core magnetic path, resulting in an increase in iron loss. In particular, considering that the main purpose of using amorphous magnetic alloy ribbon as a core wire is to reduce core loss in transformers, etc., it is preferable to use the wound core as it is without any seams. is ideal because it can maximize its effects.

For example, there are two main methods for manufacturing a single-phase transformer having an uncut wound core as described in "2" below.

The first method is to form an amorphous magnetic alloy ribbon by winding it so that it has a rectangular outer shape, and then to reduce the iron loss that has increased due to the residual strain inherent in the ribbon and the strain generated by the winding. The second method is to perform annealing for recovery and then wind an insulated conductor around both legs of the wound core to form a coil. After forming a coil and winding an amorphous magnetic alloy ribbon around the outer periphery of both legs of this coil, a high-frequency current is applied to an excitation coil that is temporarily wound around the wound core to remove distortion of the core. This is a method in which only the iron core is heated and annealed by applying electricity. In the first method, iron loss is reduced by annealing, but a coil is formed around the wound core that has undergone the embrittlement phenomenon that is a characteristic of amorphous magnetic alloy ribbon. Therefore, there is an increased risk that some external force will act on the core during the process or handling, causing damage. Damage to the iron core leads to deterioration of quality such as deterioration of magnetic properties. A possible method for preventing this is to heat only the wound core by excitation annealing after forming the coil, as was done in the second method. We also believe that the second method is superior in terms of ease of insulation treatment such as resin impregnation and casting on the coil after the conductor is wound, and ease of manufacturing the wound core by winding ribbons. It will be done.

(Problem to be solved by the invention) Since the transformer manufactured by the method described above has an uncut wound core made of amorphous magnetic alloy ribbon with low iron loss, it has low iron as a device characteristic. Satisfactory results can be obtained in terms of loss resistance, but due to large magnetostriction, which is another property of amorphous magnetic alloy ribbons, noise during equipment operation can be reduced, for example by using grain-oriented silicon steel sheets used for boat fishing. It cannot be avoided that it is rather expensive compared to wound core equipment.

In recent years, with advances in electronics technology, the use of devices using inverter power supplies, such as UPS power supplies, has increased significantly. Inverter power supply transformers generally have a fundamental wave frequency of 50 or 60H2, which is the commercial frequency, but a switching element uses several Kl+2 as a carrier wave.
Since harmonics of ~10-odd KHz are contained, noise due to magnetostrictive vibrations is a problem as well as increased iron loss.

In addition, similar problems have come to the fore as the frequency of switching is increasing in order to generally downsize induction devices such as transformers.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to provide static induction equipment such as a transformer that secures the lowest possible core loss of an uncut wound core and also achieves low noise. It is in.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the second object, the stationary induction equipment such as a transformer of the present invention has both legs of a molded coil wound in a rectangular shape and insulated. A first wound core in which an amorphous magnetic alloy ribbon is wound to a constant stacking thickness, and a high silicon steel plate containing 3% or more silicon is wound around the outer periphery of this first wound core. The present invention is characterized in that a combined winding core is formed from a wound second winding core. In this case, the cross-sectional area of the outer core made of a low magnetostriction high-silicon steel plate is suitably in the range of 10 to 50% of the total core cross-sectional area.

(Function) In stationary induction equipment with such a wound core configuration, the equipment can achieve low iron loss due to the low iron loss characteristics of the inner amorphous magnetic alloy ribbon, which accounts for more than 50% of the cross-sectional area. At the same time, the iron core material with low magnetostriction characteristics is placed in the outer part of the large noise-generating radiation surface, so that the noise level of the entire device can be reduced.

When such a wound iron core is applied to equipment that contains harmonics or is used at high frequencies, such as an inverter power transformer, the iron loss of high silicon steel sheet is lower than that of amorphous magnetic alloy ribbon. Although it is larger, it is smaller than a general grain-oriented silicon steel sheet, so it is more advantageous due to lower core loss. Recently developed 6 is an example of high-silicon steel sheet.
FIG. 3 shows a comparison diagram of the change in iron loss value of a 5% silicon steel sheet with that of a grain-oriented silicon steel sheet and an amorphous magnetic alloy ribbon.

It can be seen that the low core loss property of the 6.5% silicon steel sheet is smaller than that of the grain-oriented silicon steel sheet at frequencies of 400112 or higher.

On the other hand, since the source of noise in stationary induction equipment such as transformers is vibration due to magnetostriction of the iron core, noise can be reduced by using a material with low magnetostriction as the iron core material. The magnetostriction of the amorphous magnetic alloy ribbon (2605S2) is 3~5X10
6 (B = 1.3 T), and the magnetostriction of grain-oriented silicon steel plate for boat fishing is approximately 1.5 × 10 6 (B = 1°7 T).
However, if a 6.5% silicon steel plate is used as a high-silicon steel plate for the outer part of the wound core, the core material 0
．． Since it has an extremely small magnetostriction of 3×106, noise can be significantly reduced.

(Example) Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a sectional view taken along line II in FIG. 2, and FIG. 2 is an external view of a single-phase outer iron type uncut wound core transformer manufactured according to an embodiment of the present invention.

In Fig. 2, the coil 1 is assembled by winding each insulated conductor on the primary side and the secondary side in a rectangular shape, so that the cross-sectional shape is inscribed in a circle as much as possible, and is manufactured by casting insulating resin. It is a molded coil. This mold coil 1
．． Amorphous magnetic alloy ribbons (Fe-8i-B material 26053 manufactured by Allied Signal, Inc.
2) is wound to form a wound core 2 until it has a constant thickness. Furthermore, a 6.5% silicon steel plate, which is a low magnetostrictive magnetic material, is wound around the outer circumference of the wound core 2 to a specified thickness.
1, and an uncut combination-wound core 4 with both cores is constructed. In this case, the cross-sectional area occupied by the wound core 3 made of 6.5% silicon steel plate disposed on the outside is 10 to 50% of the total cross-sectional area of the combined wound core 4.

A gap 5 of an appropriate size is provided between the coil 1- and the combination-wound core 4. A plurality of spacing pieces 6 are inserted to hold the spacer in position and keep the gap size constant. This gap 5 is necessary as a duct for cooling the heat generated from the coil 1 and the combination wound core 4 when the transformer is energized, and at the same time, it is necessary during excitation annealing performed after winding the wound core during manufacturing. It is used as a space for inserting a heat-resistant insulating sheet to prevent the heat generated by the excitation coil (not shown) or the iron core from affecting the coil.

For strain relief annealing after winding the core, since it is combined with a coil that has already been insulated and integrated, it is impossible to insert it into a furnace and heat it in the atmosphere because this will cause burnout of the insulation H. . Therefore, the excitation annealing method is adopted as strain relief annealing of the wound core in this embodiment. The heating temperature in this case is set in the range of 380 to 400°C, which is optimal for the amorphous magnetic alloy ribbon that constitutes most of the inside of the wound core.

The optimal annealing temperature for the high-silicon steel plate that makes up the outer periphery of the wound core is originally higher than this, at 700°C or higher, and although the above temperature range is insufficient, since the material is originally a material with extremely low magnetostriction. The effect of bending strain due to winding on the increase in iron loss is small and can be ignored. Therefore, the excitation annealing of the combination wound core 4 made of two types of core materials may be performed by heating at 380 to 400° C. for the purpose of improving the iron loss characteristics of the amorphous magnetic alloy ribbon.

1φ-50011 manufactured to have the configuration as shown in 2.
Table 1 shows the iron loss (no-load loss) and noise characteristics of a 2°30KVA single-phase transformer. Table 1 shows uncut wound core transformers of the same capacity with various ratios of 6.5% silicon steel plate to the total area of the core, including examples according to the present invention; 6.
Although it is a combination wound core with a 5% silicon steel plate, it is the most common standard for wound core transformers of the same capacity with a rectangular core and a cut core in order to insert the coil, and an uncut wound core. A wound core transformer made of grain-oriented silicon steel plate is also shown.

Table 1 According to Table 1, even if the same uncut wound core is made of amorphous magnetic alloy ribbon, the no-load loss is 1/3 that of a transformer made of only grain-oriented silicon steel sheets. has been significantly reduced. However, in terms of noise, when the ratio of 6.5% silicon steel plate to the total cross-sectional area of the iron core is as small as 5% or less, the result is about 6 dB or more higher. 6.5%
When the ratio of the silicon steel plate is 10% or more, the noise reduction effect is remarkable and is equal to or slightly lower than that of the grain-oriented silicon steel plate, but the no-load loss increases. When the ratio is about 50%, the noise is lower than that of an uncut wound core transformer made of grain-oriented silicon steel sheets, and the no-load loss can be maintained at a considerably low value. Even if the ratio of 6.5% silicon steel sheet is increased beyond this, a reduction in noise can be expected, but the no-load loss will further increase, so the effect of using a combination core containing amorphous magnetic alloy ribbon will be small. Become.

Furthermore, when comparing an uncut wound core and a cut wound core with the same ratio of 6.5% silicon steel plate at 30%, the uncut wound core has lower no-load loss and noise, and the effect of this example is clear. .

Furthermore, in the transformer according to this embodiment, the iron core is not rectangular but has a circular hoop shape, so the weight of the iron core is minimized and the magnetic path of the iron core is also the shortest. Iron loss and excitation current are kept to a minimum.

Note that the 6.5% silicon steel plate used on the outer side of the wound core in this example has a higher silicon content than general grain-oriented silicon steel sheets, so it is relatively hard and brittle. However, the wound core according to this embodiment has a circular hoop shape and does not have corners like a rectangular wound core.
The amorphous magnetic alloy ribbon-wound core wound on the inner portion increases the winding curvature, making it easy to wind.

[Effects of the Invention] As explained above, according to the method of manufacturing a stationary induction device having a wound core according to the present invention, the core material is mostly made of amorphous magnetic alloy ribbon with extremely low core loss. It is composed of a circular uncut wound core with no seams, and a part of the outer circumference is made of high-silicon steel plate with extremely low magnetostriction, which reduces noise due to the high distortion characteristics of the amorphous magnetic alloy ribbon. It is possible to reduce the increase in iron loss and achieve both low iron loss and low noise at the same time.

[Brief explanation of the drawing]

Fig. 1 is a sectional view taken along line I-I in Fig. 2, Fig. 2 is an external view of a wound core transformer manufactured according to the present invention, and Fig. 3 is an amorphous magnetic alloy ribbon. % silicon steel plate and grain-oriented silicon steel plate, each frequency being a parameter. FIG. 1... Coil 2... Amorphous magnetic alloy ribbon 3... High silicon steel plate wound core 4... Combined spiral wound core 5... Gap portion 6... Spacing piece (8733) agent Patent attorney Yoshiaki Inomata (and others)
1 person)

Claims (1)

[Claims] A first wound core in which an amorphous magnetic alloy ribbon is wound to a constant thickness around both legs of a molded coil wound in a rectangular shape and insulated, and the outer periphery of this first wound core. A stationary induction device having a wound core, characterized in that a combined wound core is formed on the side thereof and a second wound core further wound with a high-silicon steel plate containing 3% or more silicon.