CN105990002B

CN105990002B - Three-dimensional full-symmetry iron core three-phase reactor

Info

Publication number: CN105990002B
Application number: CN201510087505.0A
Authority: CN
Inventors: 於岳亮; 雷雪
Original assignee: SHANGHAI WIND NEW ENERGY TECHNOLOGY CO LTD
Current assignee: SHANGHAI WIND NEW ENERGY TECHNOLOGY CO LTD
Priority date: 2015-02-25
Filing date: 2015-02-25
Publication date: 2020-12-04
Anticipated expiration: 2035-02-25
Also published as: CN105990002A

Abstract

A three-phase reactor with three-dimensional fully-symmetrical iron cores is a major technical progress in the field of manufacturing medium-sized and large-sized reactors, a novel magnetic circuit structure can effectively solve the problem of voltage and current imbalance caused by asymmetry of a magnetic circuit of the reactor, wherein a zero-gap magnetic circuit is used as a basic structure technology, iron cores and iron yokes are manufactured respectively to obtain specific structures, process treatments and manufacturing methods of various laminated, wound and even mixed iron cores and iron yokes, the iron cores and the iron yokes are formed with the lowest iron loss and the lowest man-hour manufacturing cost, and the three-phase reactor has the characteristics of combination of creativity and practicability, is mature in technology and can enter the production field quickly.

Description

Three-dimensional full-symmetry iron core three-phase reactor

Technical Field

The invention belongs to the technical field of electric reactors in electricity, relates to a magnetic circuit structure and a manufacturing process of an electric reactor, and particularly relates to a three-phase electric reactor which is a novel process for creating a large class of three-dimensional new structures.

Background

A reactor is an important electrical device and in the narrow sense is generally a device that provides inductive reactance. The material is widely applied to power systems, power electronic systems and electronic circuits, and is an indispensable or indispensable electrical device and electronic element.

The reactor is based on the principle that an alternating current exhibits an impedance or a current limiting effect by electromagnetic induction. When alternating current with a certain frequency enters the reactor, the reactor generates induced voltage, and the induced voltage resists the induced current to play a role in limiting current. The vast majority of the current is just the conversion of electromagnetic energy and does not do useful work, so the current is a reactive current or inductive current. The part doing work is only the loss generated by the winding resistance, which is called copper loss, and the iron loss caused by magnet eddy current, magnetic hysteresis and the like.

As an electromagnetic induction device, in order to obtain a larger inductance, the device is made more compact, or in order to limit the magnetic flux of a winding in a certain space, an iron core is often required to be arranged in the winding, so that an iron core reactor is formed, and the iron core-added reactor greatly reduces the copper consumption and copper loss of the reactor and also reduces the manufacturing cost, so that the device is widely applied.

In the structure of the traditional high-power planar three-phase reactor, the magnetic circuit of the middle phase is short, the gaps are few, the magnetic circuits of the two side phases are long, and the gaps are too many, so that the inherent asymmetry of the three phases on the magnetic circuit structure is caused, the unbalance of three-phase exciting current is caused, the unbalanced three-phase current can cause negative-sequence current, the adverse effect is generated on a power grid and a generator, and the three-phase current becomes a significant restriction factor of normal power supply.

In order to reduce magnetic energy loss and achieve three-phase balance, a small three-phase transformer is improved from a laminated plane type to a three-dimensional R-shaped wound iron core structure, and inherent asymmetry of a magnetic circuit structure is solved. However, the reactor often needs a magnetic circuit for preventing saturation, and the R-shaped wound core structure just lacks the capacity. The lamination type still continues to use a fine lamination process to ensure the minimum gap of the magnetic circuit, but the process has low working hour efficiency, the quality seriously depends on the artificial process level, the quality cannot be well ensured, and a new idea and a new structure are required to be fundamentally solved. It is seen that how the reactor is improved from a planar type to a three-dimensional type, and in order to thoroughly solve the three-phase balance problem of the reactor, especially in the aspects of high power and extra-high power application, the existing products and technologies have a considerable distance and a great burden.

Disclosure of Invention

The invention aims to find a better way to solve the problem of asymmetric magnetic circuit by the reform of the magnetic circuit structure of the reactor; the problem of energy saving and efficiency improvement of the reactor is solved through a new structure; meanwhile, the process of the three-dimensional winding reactor is simplified, so that the manufacturing cost of the reactor is reduced. The invention relates to a significant improvement of a magnetic circuit structure of a reactor, innovativeness and simplification of a lamination and winding process, and a novel three-dimensional reactor structure, namely a full-symmetry mixed magnetic circuit, is expanded.

The invention applies the structural knowledge of the transformer magnetic circuit to the reactor with a similar magnetic circuit structure on the basis of the reformation of various transformer magnetic circuits. The basic technology is zero-gap magnetic circuit structure technology and technology, the technical core of the technology is that a magnetic circuit is divided into an iron core and an iron yoke, so that the traditional laminated magnetic circuit and winding magnetic circuit technology is simplified, the cost is reduced, and the performance is optimized; meanwhile, a novel three-phase reactor three-dimensional magnetic circuit structure and a novel three-phase reactor three-dimensional magnetic circuit process between a laminated magnetic circuit and a wound magnetic circuit are further created, and a new type of reactor iron core with an updated structure, which is generated by the complementary advantages of the laminated magnetic circuit and the wound magnetic circuit, is called a mixed magnetic circuit reactor.

The invention is realized in this way, a three-dimensional iron core three-phase reactor mainly comprising three parts of a winding, an iron core and an iron yoke is characterized in that the reactor has a three-dimensional full-symmetrical zero-gap magnetic circuit structure; the iron core and the iron yoke are manufactured and stacked as two independent units.

In the invention, a fully symmetrical condition can be obtained on the magnetic circuit structure no matter a laminated structure, a winding structure or a mixed structure is adopted, so that a three-phase magnetic circuit is three-dimensional, and the problem of electric interphase balance is solved; the zero-gap magnetic circuit structure ensures that the reactor is completely symmetrical, and has the characteristics of easy manufacture, low cost, quality guarantee, labor saving and time saving; in addition, the zero-gap magnetic circuit structure also reduces the number of laminated air gaps and magnetic resistance, and achieves the energy-saving effect. The novel three-dimensional iron core opens up a brand new road for the balanced development of the reactor to high power and extra-high power three phases, and creates a plurality of series of new product varieties which are easy to industrialize.

Drawings

Fig. 1 is a laminated shape diagram of a conventional planar three-phase reactor without air gap.

Fig. 2 is a magnetic circuit analysis diagram of a conventional planar three-phase reactor without air-gap iron core.

Fig. 3 is a laminated shape diagram of the zero-gap magnetic circuit planar iron core three-phase reactor without air gaps.

Fig. 4 is a simplified diagram of the overall magnetic circuit structure of a conventional three-dimensional R-type three-phase transformer.

Fig. 5 is a split view of a magnetic circuit of a conventional three-dimensional R-type three-phase transformer.

Fig. 6 shows a conventional three-dimensional R-shaped core winding pattern.

Fig. 7 is a view of a core of a three-dimensional lamination type reactor of the present invention.

Fig. 8 is a view of a rectangular-section iron yoke of a three-dimensional lamination type reactor.

Fig. 9 is a view of a three-dimensional laminated reactor arc-section yoke.

Fig. 10 is a view showing the relationship between the core lamination and the yoke lamination of the present invention.

Fig. 11 is a diagram illustrating the cause of eddy current generation in the wound core.

Fig. 12 is a schematic view of a wound core manufactured according to the present invention.

Fig. 13 is a top view of a reactor with a circularly wound iron yoke.

Fig. 14, top view of a reactor with an outer annular inner side delta-wound iron yoke.

Fig. 15 is a top view of the concave circular groove winding iron yoke of the present invention.

Fig. 16 is a partial longitudinal sectional view of a magnet with a concave round slot iron yoke.

FIG. 17 is a schematic diagram showing the relationship between the magnetic flow orientation of the silicon steel strip and the cutting line in the conventional commercial coil stock.

Fig. 18, using the relationship between the direction of opening of the sheet and the orientation of the magnetic flow.

Fig. 19 is an outline view of a three-dimensional hybrid three-phase reactor magnet composed of a "wound core + laminated iron yoke".

Fig. 20 is a three-dimensional hybrid three-phase reactor magnet profile composed of "laminated core + wound iron yoke".

Fig. 21 is an outline view of a three-dimensional hybrid three-phase reactor magnet, which is "upper lamination yoke + lower winding yoke + winding core".

Detailed Description

The iron core reactor and the transformer have commonality and similarity in magnetic circuit. The research goal of the zero-gap magnetic circuit is to reduce the gap of the transformer magnetic circuit so as to reduce the magnetic resistance and improve the efficiency of the transformer. However, the practice of innovation for a year proves that the structural reform and the process scheme of dividing the magnetic circuit into the iron core and the iron yoke play a role in promoting the innovation of the transformer structure and the manufacturing process, and the contribution of the structural reform and the process scheme to the improvement of the efficiency is far exceeded.

The requirement of the iron core reactor for reducing the magnetic circuit gap is not high, in practice, in order to limit the iron core reactor from entering saturation, the iron core reactor is also required to be additionally provided with a certain magnetic circuit gap, but the zero-gap magnetic circuit thought has the same important technical significance as the transformer for the three-dimensional iron core reactor.

For this reason, the magnetic circuit structure of the reactor of the present invention is defined differently from the conventional reactor, and the following must be made in order not to cause confusion.

In the present specification:

core (1): only the magnetic devices in the windings.

Winding (2): refers to the electric chain of the transformer, and is a device for the alternating current of the reactor to enter.

Iron yoke (3): the magnetic device in the reactor makes the magnetic current in the iron core communicate with each other to complete the loop.

Magnetic circuit: the magnetic flux linkage of the reactor is a general name of the whole magnet comprising the iron core and the iron yoke in the reactor.

In a conventional reactor:

core part: also called core, stem, core leg, and core leg, correspond to the core (1) of the present invention.

Yoke part: also called yoke, refers to the device in the reactor that makes the core complete the flux linkage, including the upper yoke, the lower yoke, and possibly the side yoke, corresponding to the yoke (3) of the invention.

Iron core: the term "core" refers to the flux linkage of a reactor, and the entire assembly of magnets, including the core and yoke of a reactor, corresponds to the magnetic circuit of the present invention.

Winding (2): also called coil, is defined as the winding (2) of the invention.

To adapt to the habit of the skilled person, the word "iron core" is still used in the name of the present invention, which, by definition of the present invention, actually refers to a magnetic circuit.

Redefinition is used for the purpose of clearly distinguishing the structural concepts of the present invention from the prior art and preventing confusion. The definition of the winding (2) in the invention is the same as that of the traditional reactor, but the name of the iron core is greatly different from that of the traditional iron core, and the traditional iron core refers to all magnetic devices and comprises a core part and a yoke part. Although the traditional three-phase reactor is formed by stacking a plurality of laminated sheets like a transformer, the core part and the yoke part are connected into a common magnetic circuit and cannot be divided, so that the core part and the yoke part of the reactor are also called as a general term. The iron core definition in the invention only refers to a magnetic device in a winding, which is equivalent to the core part in the traditional definition, so the definition needs to be redefined, and the aim is to completely different process thinking. Therefore, the process and the structure of the reactor are original inventions, and different structural definitions are needed to distinguish the process and the structure.

With respect to a stack-up type reactor which is widely used, the traditional idea is that the core part and the yoke part of the reactor are connected together, and the magnetic resistance can be reduced by mutually compensating the joint gap through the cross transposition and stacking of the lamination layer. However, in practical practice, this concept neither makes it possible to significantly reduce the gap reluctance, nor makes the stacking process complicated, time-consuming and labor-consuming.

Taking a small-sized transformer which is proved by practice as an example, the evolution of the small-sized E-shaped shell type transformer from a gap magnetic circuit to a zero-gap magnetic circuit of the C-shaped core type transformer is substantially the conversion of a magnetic circuit gap which cannot be controlled in the cutting and stacking process to a fine processing of a magnetic circuit joint surface, is a typical zero-gap magnetic circuit, represents the direction of the development of a new technical structure and a new process, and suggests that a large-sized reactor can also be improved from an artificial fine process stacking to the zero-gap magnetic circuit. In order to enable the iron core and the iron yoke joint surface to be in zero-clearance tight fit, except for the need of finish machining the joint surface, how to reduce or even eliminate the magnetic circuit clearance of the iron core and the iron yoke joint surface in the actual reactor, how to utilize the special structure of a zero-clearance magnetic circuit to be combined with a new structure which cannot be adopted by the original laminated structure, not only has simple and reasonable structure, but also has simple and easy construction, and certainly more important and final results, and the aims of achieving higher technical performance of the reactor and reducing the material and assembly cost are also achieved.

Fig. 1 is a laminated shape diagram of a conventional planar type gapless iron core three-phase reactor.

In fig. 1, three sizes of cut pieces are assembled into a laminated sheet, and the two sheets on the left side are firstly stacked, and then the two sheets on the right side are stacked until the required thickness is reached. However, the rectangular winding uses a larger amount of copper than the circular winding, which is not economical, and the larger amount of copper means an increase in the resistance value of the winding, resulting in a large load loss. In addition, the lamination gap is large, the magnetic resistance is high, no-load current is increased, so that no-load loss is large, the efficiency of the reactor is reduced, and the core part is generally not rectangular but mostly circular. The key is that the core part of the circular iron core needs to be folded by adopting cut pieces with different widths and sizes, so that the cutting and folding process is greatly increased, and the folding difficulty is more multiple times.

In the manufacturing process of the core with the circular section, the requirement related to the lamination stacking process of the iron core is high, firstly, the assembly precision is improved to ensure that the product has the minimum magnetic circuit gap, and secondly, the core is stacked into an accurate similar-to-circular section. In order to prevent the occurrence of deformation, skew and the like, the correction, trimming and measurement of the laminated part are needed for each layer and even each layer. In the process of stacking, in order to ensure a certain stacking speed, a stacking person and a sheet passing person are required, at least a plurality of persons participate in the stacking work of one iron core together, the work efficiency can be ensured, the labor waste is very large, and finally, the processes of binding, standing up, inserting sheets, drying, annealing, insulating, sealing and the like are very labor-consuming and time-consuming.

Although the traditional three-phase reactor is formed by stacking a plurality of laminated sheets, the core part and the yoke part are connected into a common magnetic circuit and stacked together but not divided, so that the iron core also becomes a general name of the reactor core part and the yoke part, the core part and the yoke part are stacked together, and the difficulty is obviously much greater than that of separately stacking the core part and the yoke part.

Three windings are arranged on the three core columns to form a three-phase core type reactor, and compared with three single-phase reactors with the same function, the three-phase core type reactor saves magnetic circuit materials, so that the three-phase core type reactor is widely applied to a global three-phase system.

Fig. 2 is a magnetic circuit analysis diagram of a conventional planar three-phase reactor without air-gap iron core. In the figure, three iron cores (1) are rectangular in cross section, and after the windings (2) are sleeved on the three iron cores, three iron core columns are connected into a closed magnetic circuit through iron yokes (3).

For convenience, the magnetic circuit characteristics of the conventional three-phase reactor are analyzed by taking the simplest rectangular core in fig. 2 as an example. Firstly, it is found that there are more than 7 air gaps in each laminated sheet on the magnetic circuit, and these magnetic circuit gaps have magnetic resistance, in order to reduce the magnetic resistance, except that the right laminated sheet is used as the upper and lower layers to reduce the magnetic resistance at the gap in a staggered stacking manner, the fine stacking must be used as much as possible for gap control, and the magnetic circuit gaps multiply by many times as many laminated sheets as possible, so that much energy is put on the fine stacking.

If A, B, C three windings are respectively arranged in three core columns from left to right to generate magnetic currents, it can be found that the magnetic currents flowing from the column A to the column B need to cross 4 gaps, the magnetic currents flowing from the column A to the column C need to cross 6 gaps, the flowing magnetic path length is also twice as long as that of the magnetic currents in the phase B, so that the resistance of the magnetic currents between the AC columns is obviously higher than that of the magnetic currents in the column AB, and meanwhile, the resistance of the magnetic currents in the column B is also found to be minimum, and the path is also shortest. Therefore, the magnetic circuit of the conventional planar iron core three-phase transformer reactor is inherently asymmetric, and the induced voltage and current of the three-phase winding are also unbalanced.

Fig. 3 is a laminated shape diagram of a three-phase reactor with a zero-gap magnetic circuit planar iron core.

The magnetic circuit of the zero-gap magnetic circuit three-phase reactor is actually simpler than that of the traditional reactor, firstly, the iron core and the iron yoke are respectively stacked, the core returns to the center, the yoke returns to the yoke and are respectively stacked, and 5 iron cores and 5 iron yokes are separately stacked, so that the zero-gap magnetic circuit three-phase reactor is obviously easier than the existing process of stacking 5 iron cores and 2 iron yokes together. And secondly, the iron core and iron yoke joint surface is subjected to finish machining to realize a zero-gap magnetic circuit, the magnetic resistance, the exciting current and the magnetic loss are naturally lower, and higher product energy efficiency can be achieved.

Compared with a common planar three-phase reactor, the symmetry of the zero-gap magnetic circuit is better than that of a traditional reactor because each phase column of the zero-gap magnetic circuit flows to 4 equal gaps of the phase column, and although the magnetic circuit between the AC circuits is still longer, the magnetic resistance difference between the AC circuits is smaller than that of the traditional laminated structure because the magnetic circuit gaps are equal, the symmetry degree is improved, and the balance is better. This advantage is not erasable and the rationale for these advantageous improvements comes from the zero-gap magnetic circuit, which is therefore said to be the technical basis of the structure of the present invention.

Although the reactor does not necessarily care about the increased magnetic circuit gap, since it is itself necessary to avoid saturation of the core by the magnetic circuit gap, the contribution of the zero-gap magnetic circuit to the improvement of the symmetry of the core reactor has been reflected in the above description.

The zero-gap magnetic circuit reactor without air gaps still has the energy-saving effects of reducing magnetic resistance and increasing inductance in some reactors which are not affected by magnetic field saturation, such as partial shunt reactors. If the air gap width needs to be increased, the epoxy insulating plate with the required thickness can be solved desirably by being padded between the iron core yokes, and the air gap width is light and easy to lift.

However, the balanced structure is not a completely symmetrical magnetic structure, but only a positive effect of a zero-gap magnetic circuit.

It is further explained below how a short-cut to the fully symmetric reactor is created by a zero-gap magnetic circuit solution. In order to better introduce the shortcut, the magnetic circuit of the conventional three-dimensional winding R-type three-phase transformer is first explained and developed as a lead.

The planar R-type transformer magnetic circuit, namely the R-type single-phase transformer magnet, is equivalent to a symmetric structure magnet with a round section and a square frame in appearance, the section is circular from a coil tape with smaller width to a coil tape with wide diameter, and then the coil tape with smaller width is recovered, the geometric figure is simple and visual, and the winding algorithm is very simple.

However, as can be seen from fig. 5, the three-dimensional R-type three-phase transformer has a very simple magnetic circuit configuration and structure, and is formed by surrounding three cores having a semi-circular cross section and a complicated three-dimensional shape. A single iron core is a three-dimensional asymmetric geometric structure figure, core columns are iron cores with two semicircular sections, the semicircular sections are not in the same plane, and an included angle between the semicircular planes is 120 degrees. The upper and lower yokes should also be oblique semicircles, and the sectional area of the yokes should be equal to the sectional area of half of the core. Such a core is similarly manufactured in the winding manner of fig. 6, and is difficult to design and manufacture.

Fig. 6 is a conventional three-dimensional R-shaped core winding pattern. The winding is designed according to the vertical direction of the iron core section vertical to the horizontal line of the iron yoke, starting from the point a at the innermost end, a semicircle inclined at an angle of 30 degrees is wound to the outermost end to the point z, a plane is formed at the upper end, and a semicircular section is formed at the lower end.

That is to say, since the existing three-dimensional R-type three-phase transformer is already industrialized, the same three-dimensional full-symmetric reactor magnetic circuit can be realized by using other simpler and feasible structures according to the structural shape, and the common features of the three-dimensional reactor magnetic circuit with the full-symmetric new structure include:

1. three iron cores of the reactor are distributed in a triangular three-dimensional manner, and iron yokes among the three iron cores are equidistant;

2. the magnetic circuit is one of a lamination structure, a winding structure or a hybrid structure;

3. the magnetic combination plane of the iron core and the iron yoke adopts a special magnetic circuit structure and a connecting structure.

According to the R-type three-phase transformer magnet diagrams of fig. 5 and 6, it is very simple and easy if the core and the yoke are separately manufactured using the lamination stack according to the method of separately manufacturing the zero-gap magnetic circuit core and the yoke. According to the magnetic circuit structure shown in fig. 4 and 5, the magnetic circuit is divided into two large parts of the iron core and the iron yoke, and the total number of the two large parts is 9, namely 3 iron cores and 6 iron yoke blocks, cut pieces are manufactured, and are respectively stacked and finally assembled to manufacture the magnetic circuit of the three-phase reactor of the three-dimensional full-symmetric stack type.

Fig. 7 is a view of a core of a three-dimensional lamination-type reactor. In the figure, according to the conventional method for cutting the iron core with the circular cross section, a group of cutting pieces with the same length and different widths are cut, and are stacked according to the shape of the circular cross section, and the horizontal stacking method is generally adopted. For cut pieces with high flexibility, even vertical stacking can be adopted. When the transformer iron core yoke is vertically stacked, the cutting pieces are acted on the mounting platform by gravity, the correction and the moving are very convenient, and obviously, the process is much easier than the integral stacking of the existing transformer iron core yoke. The three iron cores can be separately and independently stacked and are not coherent with each other; and the three iron cores of the traditional three-phase reactor must be jointly stacked together with the iron yoke.

Fig. 8 is a view of a rectangular-section iron yoke of a three-dimensional lamination type reactor. The upper and lower iron yokes are also divided into 3 sections, 6 sections of single iron yokes are manufactured and stacked respectively, and the shape and the size of each iron yoke are identical.

Fig. 9 is a view of a three-dimensional laminated reactor arc-section yoke. The upper half of fig. 9 is a top view of the yoke, and it can be seen that the illustrated single block is formed of 11 laminations of the same width and different lengths into a yoke unit that can be coupled to and cover two just half-round cores. The yoke must be entirely covered on the arc surface of the core to prevent the leakage flux of the core from spreading to the space, but at the diameter of the semicircle, the lamination exceeding the diameter of the semicircle will collide with the yoke at the other half, so after the lamination is finished and the shape is fixed, the extra part must be cut and removed to form the semicircle. The lower portion of fig. 9 is a side view of the yoke in several stages, with the width of each stage being greater, depending on the particular product, and the more stages, the more precise the stack of semi-circles, and possibly no further cutting. The yoke shown in fig. 9 has a rectangular cross-sectional structure covering half of the core, and the yoke cross-section also corresponds to half of the core cross-sectional area.

Since the width of each yoke lamination is equal in the iron yoke with the rectangular cross-section structure, and the chord lengths of the half-circles of the iron core are unequal, for example, the chord lengths of the half-circle portions where the half-circles are located are marked as b1-b11 for 11 steps, b11 is shortest and b4 is longest in the drawing. Assuming that the magnetic current generated by the winding current in the core leg is uniform, the magnetic current conducted from the core to the layer b4 of the yoke is necessarily larger than the magnetic current conducted to the layer b11, but the widths of all the lamination sheets of the yoke including the lamination sheets b4 to b11 in the rectangular constant-section yoke structure shown in fig. 10 are the same, the magnetic resistance is the same, different magnetic currents generate a magnetic potential difference between different lamination sheets of the yoke, and under the drive of the magnetic potential difference, part of the magnetic current is transferred between the lamination layers to achieve relative balance, and the magnetic current layers generate additional magnetic loss. Therefore, the arc-shaped cross-section structure shown in fig. 10 is adopted, and iron yoke cutting pieces with different lengths and widths are adopted, so that the width of each iron yoke cutting piece is equal to the arc length of the iron core lamination in contact with the iron yoke cutting piece in a semicircle, thus achieving the natural balance of magnetic potential and magnetic current, eliminating laminar flow, reducing magnetic loss and improving the efficiency of the reactor. In fig. 9, the upper part is a plan view of the lamination of the iron yoke, and the lower part is a side view of the iron yoke.

The three-dimensional laminated three-phase reactor can adopt a structure that the upper iron yoke and the lower iron yoke are both in arc sections, but considering that the uneven arc of the lower yoke can generate adverse effects on final assembly and future installation, the upper yoke can also adopt an arc section structure, and the lower yoke still adopts a rectangular section structure with higher stability. Considering the influence of the laminar flow of the rectangular iron yoke of fig. 9, the sectional area can be enlarged as appropriate. Whether the upper iron yoke or the lower iron yoke is adopted, the cambered surface can be placed upwards or downwards.

When the iron yoke lamination with the rectangular cross section is cut, several iron yoke cut pieces with different sizes are obtained through a cutting machine, the iron yoke cut pieces are a group of silicon steel sheets with the same width but different lengths, and the iron yoke with the rectangular cross section can be formed after the iron yoke cut pieces are stacked, bound and molded; if the iron yoke with the arc-shaped cross section is needed, the cut pieces are a group of silicon steel sheets with different widths and different lengths; because the iron yoke is separately stacked, the iron core is simpler and more convenient than the traditional iron core and iron yoke which are stacked together.

The traditional overlapping is horizontal overlapping, the cut pieces are horizontally placed and overlapped layer by layer, the upper surface is pressed on the lower surface, even if the overlapping deviation is found, the adjustment is difficult, and the severe deviation is not corrected by other means except rework.

The stack-up of the invention is easy to adopt the vertical stack-up, especially the yoke, the gravity of the cut-parts acts on the platform, will not press each other, as long as insert the cut-parts of different length into assembling frame of yoke on the assembly platform in order, the scale of the frame is greater than the width of cut-parts, so insert very easy, after all cut-parts are inserted, can also put in order and regulate. Then the vertical push plate of the assembly frame is horizontally pushed to gradually push the cut pieces, if the cut pieces are found to be irregularly stacked, the cut pieces can be loosened and adjusted at any time until the required shape of the design is achieved, so that the iron yoke stacking of the invention can achieve a more precise and compact degree compared with the traditional stacking.

Finally, the iron yoke cut pieces are tightly overlapped to form a solid geometric body with two ends in the shape of circular arc and tangent with straight line, and the solid geometric body is bound, adhered and sealed. The binding method is similar to the traditional method and is not described, and various methods are adopted for binding, wherein one example is that thermosetting glue or thermosetting paint is adopted, after the lamination is finished and the forming is finished, the glue is melted into sticky paste by heating, and the iron yoke is solidified after cooling.

Three yoke units (as shown in fig. 5 to 9) are spliced into a triangular yoke (as shown in fig. 4), two yokes, an upper yoke and a lower yoke, are required for one transformer, and the two yokes may be identical or different in size and shape.

Fig. 10 is a view showing the relationship between the core lamination and the yoke lamination.

In order to enable the magnetic current in the iron core lamination to uniformly flow into two adjacent iron yoke laminations, the principle of the lamination direction relationship of the two iron yoke laminations is as follows: each core lamination can be communicated with any yoke lamination, so that magnetic current generated in each lamination of the core can be conveniently and directly transferred from one phase to another phase. The directional relationship shown in fig. 11 is: the core lamination layers are at a 60 intersection angle with any alternate yoke lamination layer.

In order to reduce the magnetic resistance and increase the magnetic current circulation, a zero-gap magnetic circuit structure is formed between the joint surfaces of the two iron yoke units, so that the three iron yoke units are connected with each other in a low magnetic resistance manner, and the magnetic current of any iron core can enter one iron core phase through the direct connection iron yoke or enter the iron core of the adjacent phase through the iron yoke on the third phase.

It can be seen from the above-mentioned structural concept of the laminated three-dimensional fully-symmetric three-phase reactor that the laminated process can also realize three-dimensional operation by adopting the structure of the zero-gap magnetic circuit, and is not necessarily a winding type. Therefore, a product of a new structural idea of fully-symmetrical magnetic circuits and three-phase balance of large and extra-large reactors can be created on the basis of the mature process and industry of the traditional large laminated structure.

A simpler structure using a wound core and a yoke in a three-dimensional fully-symmetric three-phase reactor is discussed below, but of course, this discussion is still premised on a zero-gap magnetic circuit structure.

First, a conventional wound core will be described.

According to the manufacturer data, the winding iron core used for the small and medium-sized reactors has the following advantages:

1) under the same conditions, compared with the traditional laminated iron core, the no-load loss of the wound iron core is reduced by 7-10 percent; the no-load current can be reduced by 50 to 75 percent;

2) the wound iron core can adopt a very thin high-permeability cold-rolled silicon steel sheet, and a transformer with lower loss can be produced;

3) the winding iron core has good manufacturability, no shearing waste material and nearly 100 percent of utilization rate; the mechanical operation can be adopted, the stacking procedure is omitted, and the production efficiency is improved by 5-10 times compared with that of a stacked iron core;

4) the wound iron core is an integral body, a supporting piece is not needed to clamp and fix, and no seam exists, so that the noise of the reactor can be reduced by 5-10 dB under the same condition with the stacked iron core.

The present invention will make it possible to use a wound core structure in a larger capacity reactor.

Of course, the used wound core is the same as the wound core of the present invention and also different, the same is that the same basic material is adopted, and the winding process is adopted by adopting the oriented strip material; the difference is that the traditional wound iron core is usually made into a closed magnetic circuit, and iron core yokes are wound together, so that the winding is difficult to put into the iron core.

In addition, the power of the three-phase reactor can be far larger than that of a small and medium-sized reactor using a winding iron core.

However, it cannot be ignored that the wound core of the present invention has a great disadvantage, that is, the problem of eddy current in the core. Therefore, the problem of eddy current of the wound core must be solved first, and the wound core can be put to practical use.

Fig. 11 is a diagram illustrating an analysis of the cause of eddy current generated in the wound core. It can be seen from the figure that the metallic iron core is equivalent to the iron core part with the winding wound on the iron core, and the magnetic field is enclosed in the iron core part, and the iron core not only allows the magnetic current to flow up and down, but also is a winding conductor, the magnetic current coupled by the winding is the magnetic current enclosed in the winding circle of the coil, and the more the outer layer is, the more the enclosed magnetic current is, the higher the induced voltage is. For the outermost coil iron core, the voltage of each turn of the 1MVA three-phase reactor wound iron core may reach or even exceed 10V, due to the series connection, if a silicon steel sheet with the thickness of 0.20mm is adopted, the voltage between 2mm layers of the outer layer of the iron core may reach hundreds of volts, and the induced voltage of the whole continuous coil iron core from the inner layer to the outer layer may reach tens of thousands of volts, the high voltage is blocked by the interlayer insulation of the iron core coil, and in case that the interlayer insulation is insufficient to form electric connection, a large amount of eddy current is generated, so that the reactor iron core is heated and damaged. The eddy current problem is a significant limiting factor that must be overcome in advance for the coil core structure.

The invention relates to a solution for overcoming eddy current, which is to open an axial groove on the outer surface of a rolled iron core, wherein the axial groove is opened to an insulating core rod, which is equivalent to cutting off all series-connected wire turns, and the induced voltage is not accumulated and increased from series connection, thereby eliminating a voltage source generating the eddy current.

For large iron cores with higher power, a plurality of axial grooves can be formed according to different radial positions, and the axial grooves are uniformly distributed in a divergent shape, so that the induced voltage of each section does not exceed 10V, and is even lower. Thus, the possibility of generating eddy currents will be very small. The axial slots are in the same direction as the magnetic flow and therefore do not impede the flow of the magnetic flow. Because of the limited cross-sectional area of the core lost by the slots, the diameter of the core can be ignored or increased appropriately to compensate for the loss of effective cross-sectional area due to the slots.

Fig. 12 is a schematic view of a completed wound core. The shape is divergent, similar to the chrysanthemum flakes used in selenium rectifiers, although the wound core is much larger in size than the chrysanthemum flakes and cylindrical in shape, which is a difference. In general, it has been found that the wound core of the present invention is characterized by one or more axial slots in the core to eliminate eddy currents in the core.

In order to enhance the heat dissipation of the large-scale reactor, the insulation groove can be reserved as a hot air flow or a hot oil flow channel for ventilation and heat dissipation. It is characterized in that one or more heat dissipation channels formed by axial insulation grooves are arranged in the transformer core.

Next, the iron yoke of the winding type reactor will be described.

Fig. 13 is a top view of a reactor with a circularly wound iron yoke. The iron yoke is in a simple geometric shape of a circular ring shape and is similar to an iron core of a single-phase annular reactor. The inner circle of the iron yoke is circumscribed with the iron core circle, the outer circle of the iron yoke is inscribed with the iron core circle, and the cross section is rectangular. In the figure, the large circle parts are all visible and are circular iron yokes (3); the small circle parts are invisible and are cylindrical iron cores (1) marked by dotted lines; and the middle circle part is a winding (2) which is partially visible and partially invisible.

Each coil iron yoke can be manufactured by one-time winding, the process is simple and efficient, and three unit bodies do not need to be spliced like a laminated type.

In the present invention, the magnetic field lines flow in the axial direction, i.e., in the vertical direction in the drawing. In the yoke of the present invention, the magnetic lines of force flow in the circumferential direction, i.e., in the horizontal direction in the drawing, so that a serious eddy current problem occurring in the core does not exist in the yoke. If the iron core is designed in a cylindrical shape, and the iron winding yoke is designed in a circular ring shape, the iron winding yoke is manufactured by winding respectively, and compared with the integral magnet winding of the three-dimensional R-type transformer, the method is a process which is very easy to operate.

The yoke in fig. 13 is a pure circle, so that the yoke between the phases has a large length, a long magnetic path, and increased magnetic loss, and the material consumption is not saved as much. For this reason, it is attempted to start winding by using a triangular inner hole instead, in order to reduce the amount of magnetic material and to reduce the magnetic path loss.

Fig. 14 is a top view of a transformer with an outer annular inner delta-wound iron yoke. Firstly, the top angle of the inner triangle is changed into a circular arc shape, so that the requirement of the winding inner core die is met. Since the thickness of the yoke at the corner must reach the core diameter in order for the yoke to fully cover the core magnet, it is impossible that the thickness at the corner is certainly smaller than the core diameter if the yoke periphery is also straight. According to the rule of winding rectangular coils, the thickness of the coil at the corner is certainly smaller than that of the coil at the straight line, and the coil is wound from the inner circle of the iron core to the outer circle of the iron core. According to the winding rule, the acute angle part is wound more tightly than the obtuse angle part, so that the winding is started, most of the straight line parts close to the triangle are wound, the straight line parts are wound to the outside, the arc line is formed, and the winding is continued to form a circle. The rule is the most common phenomenon in a rectangular winding of a reactor, and an inner coil or a rectangular wire frame is wound to the outermost side and then becomes a circular coil. That is, the thickness measured outward from the inner frame being a straight portion should be greater than the thickness measured outward at a small angle. This causes a phenomenon that the expansion between the yoke pieces is loosened at the non-core position, which causes the yoke to generate a serious noise. For this purpose, heat-dissipating ducts (30) may be added to the yoke of the inner frame section of the straight section to solve the problem of expansion loosening. The number of the heat dissipation pipes can be determined according to design calculation, the number of the heat dissipation pipes is three, the number of the heat dissipation pipes is six, nine or more, and the heat dissipation pipes can be distributed symmetrically and dissipate heat uniformly. The figure shows the design of nine heat dissipation pipes (only three are shown, and six of the other two are not shown). After the heat dissipation pipe is added, the usage amount of magnetic materials can be reduced, and the loss and heat of the iron yoke part can be reduced, thereby achieving three purposes at one stroke.

The winding iron yoke, which has an outer circle in a ring shape and an inner side in a triangle shape, may be used in the upper and lower yokes or in one of the upper and lower yokes. The heat dissipation device is characterized in that a heat dissipation pipe (30) can be additionally arranged in the arc-shaped inner triangular iron yoke.

The two winding type iron yokes with different shapes are both rectangular in cross section, the rectangular cross section has the advantages that winding is easy, the utilization rate of magnetic materials is high, and the lower iron yoke is very suitable to be used as the lower iron yoke.

However, in the rectangular-section yoke, the widths of the magnetic yoke pieces in each layer are equal, and the chord lengths of the magnetic yoke pieces in the positions of the core circle are different, so that the magnetic flow rate from the core to the middle of the arc section with a longer position is large, and the magnetic flow rates from two sides are much smaller. The magnetic current generated by the winding current in the iron core column is uniform, so that the magnetic current conducted to the middle section of the iron yoke by the iron core is certainly larger than the magnetic flow conducted to the two sides of the iron yoke, but the widths of all iron yoke magnetic sheets in the rectangular iron yoke structure with the uniform cross section are the same, the magnetic resistances are basically the same, different magnetic currents can generate magnetic potential difference among different layers of the iron yoke, under the action of the magnetic potential difference, part of the magnetic current can be transferred among the layers to achieve relative balance, and the magnetic current transfer among the layers can generate extra magnetic loss. For this purpose, it is necessary to use a yoke having an arc-shaped cross-sectional structure in which the middle portion of the yoke ring is protruded and both sides are depressed, like a circular mountain. The arc-section iron yoke is widely applied to the traditional laminated plane type large-scale reactor, and is easy to understand. By adopting the iron yoke with the arc-shaped cross section, the natural balance of magnetic potential and magnetic current between the iron yoke diversion layers can be achieved, laminar flow is reduced or eliminated, magnetic loss is reduced, and the energy efficiency of the reactor is improved.

The arc-shaped section iron yoke is also suitable for the upper and lower iron yokes, particularly the upper iron yoke. But the stability of the lower iron yoke with the upward cambered surface is also good, and the convection heat dissipation of heat flow among windings is facilitated.

In summary, the winding iron yoke is divided into two shapes of a pure circular shape and an outer circular shape, namely an inner triangular shape; and two cross-sectional structures of rectangle and arc; the method can be used for the upper yoke and/or the lower yoke, and the cambered surfaces are in different directions, so that about 32 structural combinations are provided in total, and the diversity of the product variety is seen.

The material for the wound core comprises soft magnetic materials such as a high-permeability ultrathin cold-rolled silicon steel strip, a permalloy soft magnetic strip, an amorphous core strip and the like.

The thickness of the silicon steel strip is 0.18-0.30; the thickness of the permalloy strip is 0.03-0.10 mm; the thickness of the amorphous iron core strip is 0.03 mm.

The amorphous iron core can be made of iron-based amorphous alloy, iron-nickel-based amorphous alloy, cobalt-based amorphous alloy or nano amorphous alloy and other materials, wherein the iron-based amorphous alloy is low in price, high in yield and suitable for being used in industrial frequency transformers.

The iron-based amorphous alloy consists of 80% of Fe and 20% of Si and B metal elements, has the characteristics of high saturation magnetic induction (1.54T), better magnetic conductivity, exciting current, iron loss and the like than silicon steel sheets, particularly has low iron loss (1/3-1/5 of oriented silicon steel sheets), and can save energy by 60-70% by replacing the silicon steel as a distribution transformer. The thickness of the strip of the iron-based amorphous alloy is about 0.03mm, and the iron-based amorphous alloy is widely applied to distribution transformers, high-power switching power supplies, pulse transformers, magnetic amplifiers, medium-frequency transformers and inverter iron cores and is suitable for frequencies below 10 kHz.

Due to the super-quenching solidification, atoms are not in time of orderly arranged crystallization when the alloy is solidified, and the obtained solid alloy is in a long-range disordered structure, does not have crystal grains and crystal boundaries of crystalline alloy, is called amorphous alloy and is called a revolution of metallurgical materials science. The amorphous alloy has a plurality of unique properties, such as excellent magnetic property, corrosion resistance, wear resistance, high strength, hardness and toughness, high resistivity, electromechanical coupling property and the like. Because of its excellent performance and simple process, it has become the key point of research and development in the scientific field of materials at home and abroad from the 80 s.

Amorphous cores are also typically wound from metallurgical plant tapes, in the same way as wound cores are manufactured. In the future, mass production can be carried out by a metallurgical material factory according to the size specification required by a transformer factory by directly adopting a powder compression or powder metallurgy mode.

The magnetic material used in the invention is iron-silicon alloy, iron-aluminum alloy, iron-silicon-aluminum alloy, nickel-iron alloy, iron-cobalt alloy, carbonyl iron, soft magnetic ferrite, amorphous soft magnetic alloy, ultra-microcrystalline soft magnetic alloy, iron-based amorphous alloy and amorphous nanocrystalline alloy soft magnetic composite material.

The eddy current mentioned above is the first technical problem to be solved by the zero-gap magnetic circuit three-dimensional reactor of the present invention, and the structural rigidity strength is the second specific technical problem to be solved by the present invention. For example, the core leg in the present invention is liable to horizontal slippage and is inferior in rigidity to the R-type transformer.

One way to enhance the stiffness of the transformer of the present invention is to use an iron yoke with concave circular slots.

Fig. 15 is a top view of a wound iron yoke with concave circular grooves.

The concave circular slot is a cylindrical slot with a plane bottom dug out on the iron yoke part contacted with the iron core, the diameter of the slot is larger than that of the iron core so as to enable the iron core to be embedded into the slot and prevent the iron core from moving horizontally, and a proper amount of bonding and curing glue is filled into the slot to play a role in reinforcing the structural strength and rigidity of the magnet.

As can be seen, the diameter of the circular recess in the yoke is larger than the cross-sectional circular dimension of the core so that the core can be received in the recess. The adhesive curing glue and the magnetic particles can be just accommodated in the fine circular ring. Meanwhile, the design width of the iron yoke with the concave circular groove is inevitably larger than the width of the iron core, so that the iron core can be covered to form a circular groove type cuvette, the adhesive curing glue and the magnetic particles in the groove can be accommodated, and the overflow is not easy to occur. In this way, the magnetic resistance and the magnetic leakage can be reduced more. The upper iron yoke and the lower iron yoke have the width larger than that of the iron core, just like a hat and a shoe, and cover the three-dimensional iron cores, so that the appearance is more attractive. However, since such a design requires a certain yoke width, which increases the cost, whether to use a concave circular-groove yoke, and the design depth and width of the concave circular-groove yoke should be determined appropriately according to the cost performance balance of the specific product. The iron yoke of the invention is characterized in that the iron yoke is provided with a reinforcing and magnetic conducting structure with a concave circular groove.

The other method for strengthening the rigidity of the reactor adopts a component which is tightened by a long screw rod between the upper yoke clamping plate and the lower yoke clamping plate, and the clamping plate and the screw rod are electrically insulated and magnetically isolated from a magnetic circuit, so that eddy current generated by the action of magnetic leakage and a stray magnetic field is prevented.

The third specific technical problem to be solved by the present invention is a new problem brought by using the oriented magnetic material.

It is known that oriented silicon steel sheets or coils have high magnetic permeability and lower magnetic loss than non-oriented silicon steel sheets. In a conventional three-phase reactor, oriented silicon steel sheets are generally used in order to increase magnetic permeability of a magnetic circuit, reduce magnetic resistance and magnetic loss, and improve efficiency of the reactor. For example, the laminated planar iron core and yoke adopt 45 ° mitered laminations, and the integral magnetic circuit of R-shaped solid transformer turns the magnetic current according to the bending of the winding sheet, so the turning problem of the magnetic current in the oriented magnetic material is solved.

However, in the iron core yoke of the present invention, the direction of high permeability and the flow direction of magnetic lines of force in the iron core are both axial, i.e. vertical; and the magnetic flow in the yoke is horizontal. If both of them directly adopt oriented magnetic materials according to the zero-gap magnetic circuit structure, extra magnetic loss will be encountered at the joint of the laminated core iron yoke or the wound core iron yoke when the magnetic current turns.

Since the magnetic flux flows vertically in the core and flows horizontally in the yoke, that is, when the magnetic flux flows from the core to the yoke, the flow direction changes, and intergranular flow loss occurs when the magnetic flux of the grain-oriented silicon steel sheet is turned.

In order to solve the problem, the non-oriented magnetic material is selected from the iron core and the iron yoke, namely, the iron core adopts the oriented magnetic material and the iron yoke adopts the non-oriented magnetic material, or the iron core adopts the non-oriented magnetic material and the iron yoke adopts the oriented magnetic material, only the aim of combining fish and bear palms can be abandoned, so that the problem of steering magnetic loss during magnetic current steering can be avoided by selecting the non-oriented magnetic material from the iron core and the iron yoke. The magnetic core is characterized in that one of the iron core and the iron yoke is an oriented magnetic material, and the other is a non-oriented magnetic material.

The implementation method is that in order to reduce the magnetic loss of the whole reactor, a longer oriented iron core can be adopted, the thickness of the winding is reduced, and the iron yoke is shortened to reduce the loss of the iron yoke; or on the contrary, the iron core adopts non-oriented magnetic materials, the problem of large magnetic loss in magnetic current steering is solved, and in order to reduce the magnetic loss of the whole reactor, a scheme of adopting a short large-diameter winding of the iron core and increasing the size of the iron yoke can be adopted. The goal of these schemes is to minimize the amount of non-oriented magnetic material used to reduce the magnetic loss.

The other structure for thoroughly solving the magnetic flow steering loss between the iron core and the iron yoke is that a magnetic flow transition layer is added between the iron core and the iron yoke, and the extra loss generated during magnetic flow steering can be reduced. The magnetic current transition layer is made of non-orientation magnetic materials, the diameter of the magnetic current transition layer can be the same as or slightly larger than that of the iron core, the magnetic current flowing into the iron core is diffused and turned firstly, then the magnetic current and the contact surface of the iron yoke extend in an oval shape, the magnetic current can easily permeate into the iron yoke in multiple angles, and loss during magnetic current turning is reduced.

The magnetic flow transition layer does not need to be too thick to achieve the aim of magnetic flow turning, so that the additional magnetic loss in the transition layer is not large. After the magnetic current transition layer is adopted, if the transition layer is made of a rigid magnetic material, the joint of the transition layer and the iron yoke iron core needs to be finished, if the transition layer is made of a flexible magnetic material, the joint of the iron yoke iron core and the iron core needs not to be processed due to the transition layer, and the rough joint not only increases the contact area of the magnetic current and reduces the magnetic resistance, but also is beneficial to the diffusion and transfer of the magnetic current and the overcoming of the magnetic resistance, and is also beneficial to the increase of the rigidity strength of the whole structure of the reactor through the bonding curing agent, thereby achieving two purposes at one stroke. Without machining, the manufacturing cost of the magnet can be saved.

The magnetic flow transition layer is more suitable for being combined with the concave circular groove, the concave circular groove is properly deeply opened to be larger or even elliptic, the magnetic flow transition layer is filled in the groove and is filled in the groove with an adhesive curing agent containing nano or non-nano fine magnetic powder, the magnetic flow transition layer extends along the direction of the iron yoke piece, the magnetic flow steering effect is better, and therefore the problem that the magnetic flow steering loss is increased in the magnetic flow steering device can be solved. The magnetic core and the yoke are both made of oriented magnetic materials, and a rigid or flexible magnetic flow transition layer is arranged in the concave circular groove.

In the figure, the depth and the width of a concave circular groove (31) are obviously increased, a small amount of bonding and curing glue (33) containing magnetic powder is filled into the groove, then a magnetic current transition layer (32) is arranged, the size of the transition layer is smaller than the diameter of the groove and larger than the diameter of an iron core, the bonding and curing glue containing the magnetic powder is filled again until the bonding and curing glue overflows, and the bonding and curing glue overflows along the iron yoke towards the winding direction.

Fig. 16 shows that the concave round slot iron yoke has two functions: firstly, the iron core is firmly inserted into the pit like a structural tenon pit, the iron core is prevented from moving in the horizontal direction, the bonding and curing glue is contained and retained in the groove, the iron core and the iron yoke are firmly combined, and the defect of strength and rigidity of a zero-gap magnetic circuit is overcome, so that the structural function of the iron core is realized.

Secondly, the second function of the concave circular groove is a magnetic conduction function, which is represented as follows: on the one hand, even if a macroscopically zero-gap magnetic circuit is achieved, the gap will still exist and directly influence the magnitude of the magnetic resistance of the joint surface. Even if the bonding surface is polished smooth like a mirror surface, if observed with a microscope, there may be some uneven gaps left on the surface, and the pits may block magnetic flux, increasing magnetic reluctance and iron loss.

In order to better reduce the magnetic resistance of the joint surface, magnetic conductive particles can be added into the bonding curing agent, the magnetic conductive particles can be inorganic magnetizers or organic magnetizers, particularly nano magnetizers, the performance is better, and the nano magnetizers can only flow into the pits before the bonding curing agent is solidified due to tiny particles, so that the magnetic conductivity is increased, the magnetic resistance of the joint surface is smaller, and the gap width cannot be increased by embedding the nano magnetizers into a plane.

In the second aspect, the magnetic flow transition layer can be contained in the larger and deeper concave circular groove, is a non-oriented magnetizer and is in a magnetic medium position of the iron core and the iron yoke, and through the transition of the magnetic flow transition layer, the magnetic flow smoothly transits from the vertical flow direction in the iron core to the horizontal flow direction in the iron yoke, and the steering magnetic loss is reduced. The magnetic iron core and the iron yoke are both made of oriented magnetic materials, and a magnetic current transition layer is arranged in the concave circular groove.

The structure improvement enables the silicon steel sheets and the silicon steel strips used in the iron core yoke of the invention to adopt the oriented soft magnetic materials with smaller magnetic loss.

The original purpose of the zero-gap magnetic circuit structure is to reduce the magnetic resistance of the air gap of the magnetic circuit of the reactor, reduce the magnetic loss, improve the efficiency of the reactor and achieve the aim of saving energy. The technical progress of the structure after more than one year shows that the zero-gap magnetic circuit structure is more innovative and is the innovative potential of the structure and the process method brought by the separation operation of the iron core and the iron yoke. For example, a three-dimensional fully-symmetrical three-phase reactor can be easily manufactured by adopting a zero-gap magnetic circuit structure, and a winding type iron core and an iron yoke as described in the previous part of the specification are convenient to manufacture and have no more process difficulty or operation difficulty. Meanwhile, compared with an R-type transformer, the utilization rate of the magnetic material is also improved.

When cutting or punching oriented materials, care should be taken that the orientation characteristics of the material should coincide with the direction of the magnetic flow in the transformer component. In the core, the magnetic current flows vertically, and in the yoke, the magnetic current flows horizontally.

In particular, it should be noted that the existing finished silicon steel strip is mainly used for manufacturing ring type transformers, C-type transformers, R-type transformers, etc., so the magnetic current orientation is consistent with the strip spreading direction, and longitudinal cutting winding can be adopted along the strip spreading direction, as shown in fig. 18, but in the core of the present invention, such commercial coiled materials must adopt transverse cutting strips.

In order to ensure that magnetic current flows in the iron core in the axial direction, if the existing commercial oriented silicon steel tape is adopted, the iron core is transversely cut into small sections, then the small sections are spliced into long sections to be wound, and during splicing, the front section material tape and the rear section material tape can be electrically isolated and connected, namely the front metal tape and the rear metal tape are not contacted, namely, insulation is added between the material tapes, so that eddy current can be eliminated, and whether slot insulation is needed or not can be determined according to specific conditions.

Or the silicon steel strip which is vertical to the strip spreading direction is adopted, so that the strip can be longitudinally cut to prepare the material strip without splicing, but the iron core prepared by the method needs to be provided with an insulating groove.

Fig. 18 is a relationship between a blanking direction using a plate material and magnetic flow orientation. It can be seen that the trim line is always in a perpendicular relationship to the magnetic flow direction.

After the zero-gap magnetic circuit structure is adopted, the three-dimensional full-symmetrical three-phase reactor is easy to manufacture, as introduced in the invention, the three-phase reactor is convenient to manufacture regardless of the adoption of a laminated type or a winding type, and the geometric figure is simple and neat, and no process difficulty or operation difficulty exists.

In the above analysis, it can be found that, since the zero-gap magnetic circuit structure frees the structural constraint of the reactor on the core yoke, the core yoke can adopt different structural forms, such as a winding-type core-by-core laminated core or a winding-type core-by-core laminated yoke, and becomes a third main type of reactor magnetic circuit new structure in the present invention, which is called a hybrid type.

If the consumption of the silicon steel strip of the three-dimensional full-symmetrical winding type iron yoke is large and the material cost is high, the winding type iron yoke can be replaced by the laminated iron yoke, and the three-dimensional full-symmetrical three-phase reactor with the mixed structure of the winding type iron core and the laminated iron yoke is formed. Of course, considering that the manufacturing difficulty of the winding type iron core is higher than that of the laminated iron core, a hybrid type reactor of the winding type iron yoke and the laminated iron core can also be adopted, and the winding type iron yoke has the advantages that magnetic current of one iron core can flow to an adjacent iron core from two directions of a winding ring, namely two parallel resistors can reduce the value of the total resistance in a circuit, and the magnetic resistance is favorably reduced. Even the lower yoke is implemented by a winding type and the upper yoke is implemented by a lamination type. Any hybrid product can be easily manufactured according to the specific needs of different functions, and the present invention cannot be exemplified by all the different types but only by a representative description of a few exemplary structures.

The laminated reactor has the characteristics of multiple and wide products, high power, high voltage and mature process technology. The winding type is characterized by low working time cost, high energy efficiency index and small volume and weight. However, both of them are not perfect and mature in the aspect of three-dimensional reactors, so that both of them can use the advantages of zero-gap magnetic circuits for reference in the three-dimensional process of reactors, realize mutual capacitance through and complementary advantages, and become a series of new products. So to say, because the core and the iron yoke cannot be manufactured and combined separately without the basic technology of the zero-gap magnetic circuit, the core and the iron yoke are all in a laminated structure or a winding structure, the structure and the variety are single, and the basic magnetic circuit changes little. Only in the present invention, there is a space for mixing and matching two different kinds of structures and complementing their advantages.

As the name implies, the so-called three-dimensional hybrid reactor is a reactor magnet which has a laminated structure and a winding structure, and is a large type of magnetic circuit new structure of the reactor. Several exemplary protocols are listed below.

Wound core + laminated yoke for hybrid solution

The winding iron core has the advantages of high mechanical processing production efficiency, high winding process quality higher than that of manual stacking, the laminated iron yoke has the shortest magnetic path and the highest material utilization rate, and the laminated iron yoke are combined to form the hybrid reactor which is formed by combining the winding iron core with the laminated iron yoke structure with the concave circular groove and the magnetic flow transition layer.

Fig. 19 is a profile view of a three-dimensional hybrid three-phase reactor magnet composed of a wound core and a laminated yoke. In the figure, the upper yoke is of an arc-section laminated type, and has no concave circular groove, and an air gap determined by the thickness of the resin plate is left between the yoke and the core. The lower yoke is of a rectangular cross-section laminated type with concave circular slots (31) into which 3 cores are inserted. The 3 cores are of a wound type and have 6 axial slots.

The concave circular groove (31) is deeper and larger, a rigid pot-shaped magnetic current transition layer made of non-oriented magnetic powder metallurgy sintering or bonding materials is adopted, and the lower iron yoke is subjected to finish machining to be matched with the iron yoke iron core to form a zero-gap magnetic circuit structural member.

During installation, the lower iron yoke provided with the clamping plate clamping piece insulating plate is horizontally placed on the reactor seat stand, the concave circular groove faces upwards, the magnetic powder-containing bonding curing agent is firstly smeared in the concave circular groove and on the outer surface of the magnetic flow transition layer, and then the magnetic flow transition bowl is placed in the concave circular groove.

And then, filling the magnetic powder-containing bonding curing agent into the magnetic flow transition pot, inserting the iron core into the magnetic flow transition pot, and after the measurement and the positioning are accurate, overflowing the magnetic powder-containing bonding curing agent to the periphery of the pot and waiting for curing.

The following steps are as follows: the windings are mounted and fastened to the core, the upper yoke is mounted in a similar way as the lower yoke, clamping, auxiliary fitting mounting etc.

Second mixing scheme

Because the laminated iron core is combined with the zero-gap magnetic circuit technology according to the traditional technology, only a group of cut pieces with equal length and different width are required to be cut, the single iron core is more convenient to stack, and the process is more mature than the process of winding the iron core. On the contrary, the processing of the winding iron yoke is more convenient, the process of the winding iron yoke is only equivalent to the manufacture of the toroidal transformer iron core, and the difficult winding problem of the toroidal transformer does not exist. Therefore, the two are combined, the advantages are complementary, and the laminated core and the wound iron yoke are combined to form a mixed scheme of laminated core and wound iron yoke.

Fig. 20 is a profile view of a three-dimensional hybrid three-phase reactor magnet composed of a laminated core and a wound yoke.

In the figure, 3 cores (1) are formed by stacking and solidifying oriented laminations. The iron yoke is wound by an oriented tape, the upper iron yoke is a winding iron yoke with an arc-shaped cross section and an outer circular inner triangular shape, and the lower yoke is a circular winding iron yoke with a rectangular cross section.

The lower yoke can also adopt an arc-shaped cross section, the arc surface is placed upwards to be beneficial to structural stability and radiating fluid to enter the winding to rapidly take out the heat of the winding, and the lower iron yoke is provided with 3 concave circular grooves (31).

In the scheme, the flexible magnetic current transition layer modulated by dense non-oriented magnetic powder is adopted. One of the two schemes is to adopt a flexible organic material as a carrier, to incorporate dense high-permeability magnetic powder into the carrier, to make a tangible flexible transition body according to the sizes of a concave circular groove and an iron core, and to fill the groove with the magnetic powder; the other scheme is an intangible scheme that dense high-permeability magnetic powder is uniformly infiltrated into a bonding curing agent, and the bonding curing agent forms a permeability transition layer after being cured. In the scheme, the iron core, the iron yoke and the concave circular groove do not need to be machined or finished.

Three-upper lamination yoke + lower winding yoke + winding iron core in mixed scheme

The scheme is a variation of the scheme, namely the lower iron yoke in the mixed scheme is replaced by a winding iron yoke.

The winding iron yoke is integrally manufactured in a winding mode, particularly the iron yoke with the incremental magnetic conduction rectangular cross section is used as a stable foundation for the lower iron yoke, the rigidity and the strength of the reactor are ideal, and the slotting is easy. The upper iron yoke adopts a laminated type with the shortest magnetic path, the least magnetic loss and the highest utilization rate of magnetic materials, and is also an improvement of light weight.

Fig. 21 is an outline view of a three-dimensional hybrid three-phase reactor magnet of "upper lamination iron yoke + lower winding iron yoke + winding iron core".

Alternatively, the magnet may be a three-dimensional hybrid type of "lower laminated yoke + upper wound yoke + wound core".

According to the above examples, the invention can be found to have a three-dimensional hybrid type full-symmetric three-phase reactor which is composed of a plurality of different structural component combination schemes. Different schemes have characteristics, are suitable for different occasions, form three-phase reactors with various shapes and colors of three-dimensional fully-symmetrical magnetic circuits, and can quickly enter the field of industrialized product manufacturing.

Claims

1. A three-dimensional three-phase iron core reactor mainly comprises three parts, namely a winding, iron cores and iron yokes, and is characterized in that the three iron cores of the reactor are distributed in a triangular three-dimensional manner, the iron yokes are equidistant, and the reactor is provided with a three-dimensional fully-symmetrical magnetic circuit structure; the iron core and the iron yoke are manufactured and stacked as two independent units in a split mode, a magnetic combination plane is finished to form a zero-gap magnetic circuit, a concave circular groove is formed in the iron yoke, the iron core is placed in the concave circular groove, the iron core and the iron yoke are both made of oriented magnetic materials, a rigid or flexible magnetic flow transition layer is arranged in the concave circular groove, the magnetic flow transition layer is made of non-oriented magnetic materials, and the iron core and the iron yoke form a zero-gap magnetic combination plane connecting structure; the whole magnetic circuit is one of a lamination structure, a winding structure or a hybrid structure.

2. The reactor of claim 1, wherein the core has a circular cross-section; the diameter of the concave circular groove on the yoke is larger than that of the core so that the core is put into the groove.

3. The three-dimensional three-phase core reactor according to claim 1 or claim 2, wherein the core and the yoke have a laminated structure or a wound structure; the iron yoke has a rectangular cross section or an arc cross section.

4. The three-dimensional three-phase iron-core reactor according to claim 1 or claim 2, wherein the iron core and the iron yoke are of a wound-type structure; one or more axial slots are provided in the core.

5. The three-dimensional three-phase iron-core reactor according to claim 1 or 2, wherein the magnet is a three-dimensional hybrid type of "wound core + laminated iron yoke".

6. The three-dimensional three-phase iron-core reactor according to claim 1 or 2, wherein the magnet is a three-dimensional hybrid type of "laminated core + wound iron yoke".

7. The three-dimensional three-phase iron-core reactor according to claim 1 or claim 2, wherein the magnet is a three-dimensional hybrid type consisting of an "upper laminated iron yoke + a lower wound iron yoke + a wound iron core"; or a three-dimensional mixed type consisting of a lower laminated iron yoke, an upper winding iron yoke and a winding iron core.