JPS6112008A - Electric induction device and method of producing same - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates not only to electric induction devices, but also to ferromagnetic materials and processing methods thereof, and more particularly to transformer laminates, transformer cores, and transformers made of grain-oriented silicon steel. .

Since the loss rating levels specified by users of power and power transmission and distribution transformers are currently high, it is becoming extremely important to reduce the no-load loss, or core loss, of power and power transmission and distribution transformers. For this reason, efforts are being made to reduce core losses in power and power transmission and distribution transformers.

In the past, electrical steel manufacturers have increased the permeability of steel by increasing the degree of directionality in order to reduce core losses in electrical steel. As a result of these efforts, the magnetic permeability is higher than (1) regularly oriented silicon steels such as A-S engineering M-5 to M-8 and (2) regularly oriented silicon steels.
A grain-oriented silicon steel with high magnetic permeability and low iron loss has been developed.

The use of insulating stress coatings on the major faces of bidirectional steels further improves iron loss WI and scribes them laterally (i.e. transversely to the rolling direction) to reduce the domain dimensions of these materials. ) further improvements have been made in coated grain-oriented steel in braided form.

However, the measured core loss WC (watts/pounds of iron (or watts/Ky) in commercial transformer cores
) ) is significantly higher than the measured iron loss value W (watts/pounds of iron) of the electrical steel that makes up the core. Therefore, the reduction in core loss achieved by the above-mentioned improvements in grain-oriented electrical steel has not been completely realized as an isometric reduction in core loss in commercial transformers using these materials.

Changes in roughtance between the various parallel magnetic paths in the transformer core cause large changes in magnetic flux density between these paths. Changes in reluctance can be caused by changes in core geometry (path length, cross section), air gaps, and magnetic permeability of the core steel itself. As a result, if the magnetic flux density is non-uniform, loss increases. However, with proper control of the non-uniform distribution, the losses in a core made of two different steels can be smaller than expected. To take advantage of this phenomenon, various combinations of steel core schemes have been proposed.

For example, U.S. Pat. No. 4,205,288 combines regular grain oriented silicon steel and high permeability grain oriented silicon steel. Reference is made herein to the specification of US Pat. No. 4,205,288.

Furthermore, laser scribing in parallel to the rolling direction is disclosed as a method of reducing core loss at the T-joint of a three-phase stacked transformer core (French Patent Application No. 80.22231, April 30, 1981). (See Public Notice No. 2.468, 191, which was viewed by the public in
.

The inventors have proposed an improvement by combining grain-oriented electrical steels laterally scribed in two or more ways in a transformer to vary the magnetic properties between a single transformer core laminate or laminates of the same electrical steel. We believe that we can manufacture transformers and cores for transformers.

According to one embodiment of the invention, a transformer is obtained which is designed to operate during induction 3 and has a ferromagnetic core and an electrical winding arranged to induce. The ferromagnetic core consists of layered insulating coated grain-oriented steel plates, one group of which is easily magnetized by the AC in the direction of easy magnetization. Iron loss WIS smaller than loss WI by ΔWIS
It was scribed horizontally to make it look like this. A second group of these steel plates is characterized by substantially conventional AC peak permeability and iron loss W2 in the direction of easy magnetization. This second group of steel sheets may be unscribed, but is preferably transversely scribed to reduce core losses without significantly reducing magnetic permeability.

This ferromagnetic core has a core loss WICS that is less than the core loss WC, of the same ferromagnetic core constructed entirely of grain-oriented steel with an insulating coating in the specified condition, by ΔWC5. The inventors have determined that in these ferromagnetic cores, the core loss improvement amount ΔWC by laser scribing is
It has been discovered that S is greater than or equal to the weighted average value of the iron loss improvements of the two groups of steel plates that make up the ferromagnetic core.

Expressed mathematically, ΔWas 〉WI-(XIWIS + X2 W2)
becomes.

Here, X is the weight of the steel plates in the first group, X2 is the weight of the steel plates in the second group, and ΔWcs
> 1.1 (:WI - (XIWIS +XzW2)
) Preferably.

More preferably, the observed core loss ΔWCS is at least 11%, and most preferably at least about 12% of the core loss We of the fully unscribed core.

In a preferred embodiment of the invention, the ferromagnetic core is a three-phase stacked core, with the first group of steel plates forming the top and bottom yokes and the outer legs, and the second group of steel plates forming the center leg.

The present invention relates to a method for generating non-uniform magnetic properties in the easily magnetized direction of ferromagnetic steel sheets by transverse laser scribing techniques, and to products resulting therefrom. According to this feature of the invention, the laser beam is repeatedly scanned transversely to the rolling direction of the insulating coated ferromagnetic steel sheet to subdivide the magnetic domain dimensions within the steel sheet. The scanning of the laser beam is characterized by parameters including the size as well as the shape of the laser beam spot on the steel plate surface and the laser beam incident power and scanning speed. The inventors believe that by controlling and varying one or more of the above parameters, the AC peak permeability can be controlled and varied at a given location within the steel plate. It is preferable that these changes in magnetic permeability occur simultaneously with improvements in iron loss.

In preferred embodiments of these methods and products, the scribe line has a width A that varies in a predetermined relationship along the length of the scribe line. Like this A
The C-peak magnetic permeability varies in a controlled manner across the width of the steel sheet.

In another preferred embodiment of these methods and products, the width A of the scribe lines varies in a predetermined relationship to each other. The AC peak permeability thus varies in a controlled manner along the length of the sheet.

These and other features of the invention will become more apparent from the following detailed description in conjunction with the accompanying drawings.

In the invention, the inventors describe grain-oriented electrical steel that has been laterally laser scribed and grain-oriented electrical steel of the same grade that has not been scribed but has an insulating coating (wherein the laterally laser scribed steel is significantly It has been discovered that the core loss of the transformer can be significantly improved by combining the AC peak permeability lowered to 100% and the core loss improved by laser scribing during the induction. Further in accordance with the present invention, the same grade of insulating coated grain-oriented electrical steel and said lateral material are laser scribed in a different direction to improve iron losses while substantially maintaining the original AC peak permeability. A combination of laser scribed materials may also be used.

As used herein, the lateral laser scribing method means that the scribe lines are aligned in the direction perpendicular to the rolling direction of the steel sheet (i.e., the direction of easy magnetization) (17) between approximately ±30°. Further, as used herein, a significant reduction in AC peak permeability means that the original permeability of the steel sheet at a given induction prior to laser scribing is reduced by between about 60% and about 85 degrees.

Considering the following example, which is intended only to illustrate the invention:
The above features of the invention will become clearer.

First, TRAN coated with CARL TE-3
-C! A nominally 0.28 m (0.011 inch) thick steel plate consisting of ORB was obtained. TRA'N-00RH is
A of Middletown, Ohio, for high magnetic permeability grain-oriented silicon steel in which promotion of secondary recrystallization is inhibited using A-N.
0ARL Engineering TE-'3 is a trademark of RMOO Company.
ARM for insulating glass stress paint consisting of aluminum-magnesium-phosphate-chromium-silica
It is a trademark of CiO Company. This stress paint applies tension to the underlying silicon steel, causing subdivision of the magnetic domains. This starting material is divided into three groups: a control group, a second control group laser scribed on one surface according to the B-section treatment method (see Table 1) which does not result in large permeability changes, and a second control group with a large permeability change. A third group was divided into one surface laser scribed according to the processing method of Section A (see Table 1) which causes degradation.

Table 1 Para A of high-speed laser scribing 27,500 (1160 (m/5ee)'
450. 0011 30.8B 88,00
0 (3730 working value) 450. 0034
9.52* is an approximate value. It is based on the assumption that the rest time, the incident energy density, and the incident path (o, o o 511x o, s'') are rectangular (2) Beam power density is simplified.

Meter 2.8X + 0 2.71 +5.2
'iA' (0,62cm)2.8X + o
1.52 7.37 ”773
(Oj2cm) The beam density is (1) The beam spot is 0.013 crn x 1.3 and is constant over the entire beam spot surface. It was a model V500 Co2CW laser manufactured by Co., Ltd.

Materials of groups A and B have approximately 0. o 15cm (
The scribe was performed at essentially a 90° angle to the rolling direction with a laser beam focused on an elongated elliptical spot approximately 1.3 crn (0.5 in.) wide and approximately 1.3 crn (0.5 in.) long. The longitudinal direction of the spots at this time was aligned in the laser scanning direction. The resulting scribe lines are approximately 0.32 cm (0.125 inch) apart,
There was no adverse effect on either the insulation value of the coating or the scooking factor of the material. Pending U.S. Patent Application No. 435
．． Nos. 444, 435, 822 and 435.44
No. 5 (all filed October 20, 1980), the wide range of capabilities of the laser scribing technology used as well as the equivalent technology will become more apparent. These applications describe methods for laser scribing insulating coated ferromagnetic steel sheets and the products produced as a result, as well as apparatus for laser scribing. The specifications of U.S. Patent Application Nos. 435, 444 and 435,822 also (1) reduce iron loss (i.e., core loss) without significantly reducing or reducing permeability, and (2) significantly reduce iron loss. discloses a laser scribing method that reduces magnetic permeability without changing the magnetic permeability. The specifications of all three applications mentioned above are incorporated herein by reference.

Table 2 shows the magnetic permeability change and iron loss characteristics caused by laser scribing according to terms A and B. A
Materials treated according to Section B did not have as much improvement in iron loss (i.e., single sheet core loss) as material treated under Section B at 15 and 17 kilogauss, the maximum commercial flux density; The permeability of the A-term material in density has decreased significantly, even though there is no significant change in the original permeability of the B-term material.

Material from each of the six groups was sheared to form the core elements for a compact three-leg three-phase laminated transformer shown in Figure 1 and in plan view. Both ends of each element were sheared at 45° with respect to the rolling direction (ie, the direction of easy magnetization) indicated by arrow 5 in FIG. The core 1 of the transformer was constructed by stacking seven layers. In FIG. 1, only the top layer 10 and the bottom layer 70 (indicated by dotted lines) are shown for clarity. Each element or elongated steel that makes up each layer is approximately 7.6 and 14.0 cm (3,0 and 5 cm).
．． a window of sufficient length and 7.6 cm (5 in.) to form a window having dimensions a and b, respectively, equal to 5 in.
, 0 inches). As shown in FIG. 1, the joint portions 75 formed at adjacent ends of the steel in the longitudinal direction all form an angle of 45° with respect to the rolling direction, and as shown schematically by a phantom line in FIG. primary and secondary electrical windings 77 paired around each leg of the core of the transformer.
．． 78 and 79 were placed so that they could be guided freely.

As shown in FIG.
A joint portion 75 formed between adjacent ends of insulatively coated high permeability grain-oriented silicon steel within 0j5J60 and 70 is disposed. The stepped lap joint shape 80 means that the joint portion formed in each of the four stacked layers is offset by a substantially fixed distance 1 in the same direction from the position of the joint portion in the next adjacent layer. It means there is. In this way, for example, the elongated coated steel 201 in layer 20 is exposed to the layer 30 immediately below it.
Element 603 of uncoated end 305 is adjacent to uncoated end 307 of element 301 . In the layer 10 immediately above the layer 20, the element 201 only contacts the corresponding element 101 in this joint shape 80, and in this model transformer core 1 manufactured in this example, 1 is approximately 2.3 m ( o, o 9 inches).

Between adjacent longitudinal uncoated ends of the insulatingly coated grain-oriented electrical steel in one layer,
An opening or gap 90 is formed. gap 90
The dimensions or distances of can vary from joint to joint and from layer to layer. In the model transformer tested, gap 90 contained air.

Although other joint shapes are possible, a stepped lap joint shape is preferred to minimize core loss.

Having described the geometry of the model cores tested in these examples, Table 1 shows the results of tests conducted on cores formed entirely from each group of materials. From Table 1, 15
and 17 kilogauss, the A-term treated material (reduced permeability) is the B-term material (substantially conventional permeability)
shows superior core loss measurements compared to
At 5KG it is about 0.018 W/9 (0,008 Watts/lb) and at 17 KG it is about 0.055W/kg (
0,015 watts/lb). It will be recalled that in single sheet testing, the A, term, material had inferior core loss compared to the B-term material (see Table ■).

Table Three-phase transformer results 15. 435(,757) -17,588
(1,294) - scribed 1′B”
1s, 27s(,6o1) −,051
(,112)15. 369(,812) −,0
66(,145)17. 496 (t, 091)
−,092(,205) scribed “A” 1
3. 272(,598) −,052(,1
15)15. 577C,829) -,058(
, 128) 17. 508(1,118) −,0
80(,176)(60H2) ,420(,924) − ,560(1,232) −,726(1,
597) -0376(,+1127)
-',044(,097) 10.5.50
5(1,111)' −,055(,121)
9.8.652 (1,454) −,074
(,163) 10.2.376(,827
) =,044(,097) 10.5
．． 497(1,093) -,063(,141)
11.3.6-37 (1,401) -
,089(,196) 12.3 center leg 8
1 and other parts of the core, namely the top and bottom yokes and the outer legs, and by combining the materials of the three groups as shown in Table ■ to be composed of laminates from different groups. As shown in FIG. 2, the shape of the transformer core was three-pressed. Examination of Table ■ shows that the material of term B (substantially the original or conventional permeability) is placed in the center leg 81 and the remainder of the core is the material of term A (low permeability).
The core loss ΔWas can be improved to the maximum when compared with not only the core made entirely of one group of materials shown in Table 1 but also the other combinational cores shown in Table ■. I understand.

Even if we consider the result of the combination core in Table
If the center leg is made of unscribed material and the rest of the core is made of scribed material, the maximum Δ
It can be seen that Was can be obtained. However, unexpectedly, when the scribed material forming the remainder of the core is of Group A type (low permeability), 15
The core loss improvement rates at 1 and 17 KG clearly exceed the single sheet weighted average improvement rate ΔW by 1.1 and 1.2, respectively. If the rest of the core is made of the scribed material of item B as shown in Table ■,
An improvement rate of only about 0.6-0.7 is obtained.

The table consists of a central leg made of scribed material,
If the remainder of the core is made of non-scribed material, ΔWO8
Although the absolute value of is relatively low, the improvements for these core geometries at 16 and 15 KG are relatively large and are greatest when the center leg is made of a low permeability material.

Another embodiment provides the top and bottom yokes and center legs with laterally scribed laminates (e.g., A
B material), while the outer lugs are constructed from transversely scribed (e.g. B material) with improved iron loss but substantially the original (pre-scribed) magnetic permeability. Implement the configured three-phase laminated core.

In the previous examples, some embodiments of the invention were illustrated in connection with a combination of laminates with different magnetic permeabilities between the laminates. Examples will serve to illustrate the present invention as it relates to the processing and use of laminates having AC peak permeability in the easily magnetized direction that varies from position to position in each laminate. .

We have discovered that in laser scribed grain-oriented silicon steel, the AC peak permeability can be varied over a large range in the direction of easy magnetization while keeping the iron loss improvement rate relatively constant. This effect is reflected in Figure 3, which shows iron loss improvement (%) and AC peak permeability as a function of scribe speed when other scribe parameters are held constant, such as power, beam shape and dimensions, and scribe line spacing. It is schematically illustrated by a graph. for example,
It can be seen that between points 402 and 404, C4 and iron loss improvement rate 406 are relatively constant and remain near the maximum value, while magnetic permeability 408 decreases with laser scribing speed. It is observed that when the laser scribe speed is slowed down, the width of the damage zone generated in the laser scribe line increases, resulting in a decrease in magnetic permeability. Magnetic permeability can also be reduced by increasing the incident power of the beam while holding other parameters constant. Permeability can also be varied by scribe spacing or beam spot size or geometry. Some of these effects are clearly shown in Tables 1 and 2 and the following examples.

In the following examples, all specimens were 12 mil TRAN-00RH stress-relaxed Nibstein sets with an OARL TE-3 coating and a continuous wave CO2 laser was used. All data are at 15KG, 60Hz and are expressed as percent change. Unless otherwise noted, the scribe lines were in corresponding locations on each side of the IJ knob and spaced 0.25 inches apart.

Example I The scanning speed was varied while keeping other conditions constant.

Beam Electric Crab 2 Watt Lens Focal Length: 2.5 inches Defocus: Focal Position () Incoming Beam Dimensions: (0,002 inches diameter) Table ■ shows the percent change in iron loss and peak permeability for various scan speeds .

Table V Chi change sample at 15KG Scanning speed (inch 7 minutes) Iron loss Peak permeability LS-JA-74100-8,4-61LS-, rA
-72200-8,3-44LS-JA-75600-
8, 1-8, in this series, the magnetic permeability could be varied over a wide range while keeping the core loss improvement rate constant.

In practice, this effect can be exploited by varying the scanning speed at different locations within the stack. For example, when using a rotating scanning mirror with varying magnetic permeability across the width, the scanning mirror can be shaped to allow the beam to scan faster in some parts of the width than in other parts without changing the rotational speed of the mirror assembly. Example 2 The beam spot diameter was changed by changing the amount of defocus (spot size), and other conditions were held constant.

Beam No. 2: 5 Watt Lens Focal Length: 5 inches Table 1 shows the percent change in iron loss and peak permeability for two defocus conditions and two scan speeds.

The method of changing the amount of defocus is to
Alternatively, it is a simple method to control the permeability along the length of the steel plate, where it is sufficient to tilt the steel plate away from the focal plane to change the permeability as desired.

FIG. 4 shows a core 4 for a single-phase stacked transformer according to the present invention.
20 embodiments are shown.

This ferromagnetic core has a top yoke 422, a bottom yoke 42
4, and two legs 426 and 428 joining said top and bottom yokes. The joining point of each of these parts is a joint area 43
It is 0. Each member is preferably constructed from insulating coated grain-oriented silicon steel sheets in superimposed layers 44a, with the superimposed ferromagnetic steel sheets 440 in each member being superimposed on the superimposed ferromagnetic steel sheets in the adjacent member in joint region 430. ferromagnetic steel plate 440, preferably forming a stepped ramp joint shape. In this embodiment of the invention, each laminate is preferably non-uniformly lateral laser scribed. For example, in FIG. 5, an enlarged plan view of a stack 440 showing lateral laser scribe lines 450 is shown. This scribe line 450 is 1
Although preferably invisible to the naked eye, these lines are readily observable and their width A can be measured using domain image sensitization methods known to those skilled in the art. These scribe lines are generated by repeatedly scanning a laser beam in a direction transverse to the rolling direction of the grain-oriented ferromagnetic steel sheet coated with an insulating coating to generate scribe lines 450 having a width A and spaced apart by a distance in the rolling direction. It is formed by The width A of each scan line varies in a predetermined relationship along the longitudinal direction of the scribe line. In the embodiment shown in FIGS. 4 and 5, the width A is the width of the laminate 460 adjacent the window 460 of the core 420.
It is preferable that the scribe line 450 reaches a maximum at the inner edge 465 of the stack and decreases continuously along the longitudinal direction of each scribe line 450 until reaching the outer edge 465 of the stack. In this embodiment, the magnetic permeability increases as one moves from the inner edge 455 to the outer edge 465 of each laminate forming the core 420. For example, the magnetic permeability of the material near the inner edge 455 can be reduced to about the value before laser scribing, while the material near the outer edge 465 may have the same permeability as before or the permeability as described above. It decreased from about 1% to about 20%.

FIG. 6 shows another embodiment of the invention. This figure shows one layer of the stack in the central leg joint region (or T-joint) of a three-phase transformer core. The center leg laminate 601 is the bottom yoke laminate 6
03 and 605, each laminate was laterally scribed such that the AC peak permeability varied in the direction of easy magnetization along the length of each laminate.

This change in magnetic permeability is indicated by the change in width of the illustrated scribe line. The scribe line 607 is
A lower permeability was generated in the joint region compared to the permeability in the stacks 601, 603, and 605 in the region with scribe line 609 away from the T-joint region. Preferably, each laminate in each T-joint of the core is scribed as shown in FIG.

Scribe line 607 and scribe line 609
Both regions of the laminate having an improved core loss.

Other embodiments of the invention will be apparent to those skilled in the art from consideration of the specification or practice of the invention disclosed herein. The specification and examples are considered to be exemplary only, with the scope and spirit of the invention being indicated by the claims.

[Brief explanation of drawings]

FIG. 1 is a plan view of one embodiment of the transformer according to the present invention, FIG. 2 is a partial cross-sectional view along arrows...-■ of the transformer core in FIG. 1 showing a preferred embodiment of the joint shape, and FIG. Figure 4 is a schematic graph showing the effect of laser scribing speed on percent improvement in iron loss and peak permeability with other scan parameters held constant; Figure 4 is a perspective view showing an example of a single-phase stacked transformer core; , 5th
The figure is an enlarged partial plan view showing one embodiment of the insulating coated grain-oriented steel plate according to the present invention, which constitutes the ferromagnetic core shown in Figure 4, and Figure 6 is a three-phase three-phase steel plate according to the present invention. FIG. 3 is a partial plan view showing the area around the central leg joint region of the stacked transformer core. 5...Rolling direction, 10...Top layer, 70...Bottom layer, 7
2. Window, 75. Joint part, 77.78, 79.
・Winding wire. FIG, 1 FIG, 3

Claims (7)

[Claims] (1) consisting of a ferromagnetic core and an electrical winding disposed in an inductive relationship with respect to the core, the ferromagnetic core being constructed of superimposed layers of insulating coated grain-oriented ferromagnetic steel sheets; The first part of is scribed in the transverse direction, and the A_C peak permeability is significantly reduced in the direction of easy magnetization at the magnetic flux density B and the magnetic flux density B
The steel sheet is characterized by an iron loss W_I_S that is lower than the iron loss W_I before scribing by an amount ΔW_I_S, and the second portion of the steel sheet has a substantially conventional A_C peak permeability and a direction in which it is easily magnetized at a magnetic flux density B. The ferromagnetic core is characterized by an iron loss W_2, and the ferromagnetic core has a magnetic flux density B of ΔW_C_S greater than the core loss W_C of an identical ferromagnetic core constructed entirely of grain-oriented steel with an insulating coating in a specified state.
ΔW_C_S is ΔW_C_S>W_I−[X_1W_I_S+X_2W
_2] (where X_1 is equal to the weight of the first portion of the steel plate constituting the core, and X_2 is equal to the weight of the second portion of the steel plate constituting the core). An electrical induction device designed to operate at 2. The apparatus of claim 1, wherein the second portion of the steel plate is laterally scribed to reduce iron loss. (3) A laser beam is repeatedly scanned in a direction transverse to the rolling direction of the steel sheet to subdivide the magnetic domain dimensions of the grain-oriented ferromagnetic steel sheet coated with an insulating coating, and scribes having a width A and spaced apart from each other in the rolling direction are created. A method comprising: generating a line and varying the width A in a predetermined relationship along the length of said scribe line. (4) A laser beam is repeatedly scanned in a direction transverse to the rolling direction of the steel sheet to subdivide the magnetic domain dimensions of the grain-oriented ferromagnetic steel sheet coated with an insulating coating, and scribes having a width A and spaced apart from each other in the rolling direction are created. A method consisting of generating a line and varying its width A in a mutually defined relationship to the scribe line. (5) an insulating-coated steel plate of grain-oriented ferromagnetic steel having an easily A_C magnetizing direction aligned substantially parallel to the rolling direction of the insulating-coated steel plate of grain-oriented ferromagnetic steel; a scribe line in the steel plate extending transversely to the direction of magnetization and subdividing the magnetic domain dimensions of the steel plate, the scribe line having a width A that varies along the longitudinal direction of the scribe line;
Manufactured products with (6) an insulating-coated steel plate of grain-oriented ferromagnetic steel having an easily A_C magnetizing direction aligned substantially parallel to the rolling direction of the insulating-coated steel plate of grain-oriented ferromagnetic steel; A manufactured article comprising scribe lines in the steel plate extending transversely to the direction of magnetization and subdividing the magnetic domain dimensions of the steel plate, the scribe lines having widths A that vary from line to line. (7) Repeatedly scanning a laser beam in a direction transverse to the rolling direction of the steel plate so as to subdivide the magnetic domain size of the grain-oriented ferromagnetic steel plate coated with an insulating coating, and the scanning of the laser beam is performed on the surface of the steel plate. characterized by parameters consisting of a laser beam spot shape and size, a laser beam incident power and a scanning speed, and at least one of said parameters is controlled to vary the A_C peak permeability at a predetermined position within said steel plate during a predetermined guidance. A method consisting of controlled changes.