CN101886670A - Radial magnetic bearing with independent electromagnet structure - Google Patents

Abstract

The invention discloses a radial magnetic bearing with an independent electromagnet structure, which includes: a rotor; a stator, arranged on the periphery of the rotor; the stator includes a casing and several independent electromagnets, and the several independent electromagnets Spacers are mounted on the housing. The structure of the present invention is flexible in assembly, and can be made into a semi-open stator structure according to needs; the electromagnets are independent of each other, which can effectively avoid the mutual crosstalk of the magnetic circuit between the magnetic poles, and avoid the signal interference between the magnetic poles and the sensor. It is conducive to improving the reliability of the system; each independent electromagnet can be used to directly carry out winding off-line, and generally does not need additional processing of molds and design of special off-line process; it is easy to become an independent structural unit, forming serialization and Standardized components greatly reduce the cost of maintenance and replacement of equipment components.

Description

Radial magnetic bearing with independent electromagnet structure

technical field

The invention relates to a magnetic bearing, in particular to a radial magnetic bearing with an independent electromagnet structure.

Background technique

Generally, according to the direction in which the magnetic bearing exerts force on the rotor, magnetic bearings are divided into two categories: radial magnetic bearings and axial magnetic bearings. The radial bearing is divided into two parts, the stator and the rotor. The stator part is the most commonly used 8-pole structure, as shown in Figure 1. The 8-pole radial magnetic bearing stator is divided into 4 electromagnets with closed magnetic circuits, each electromagnet controls the magnitude of the electromagnetic force applied to the rotor in a single direction; while the combination of the two opposite electromagnets can control its position The magnitude of the electromagnetic force in the positive and negative directions of the degree of freedom; further, the combination of 4 electromagnets arranged in 2 orthogonal directions can provide a combination of forces on 2 orthogonal degrees of freedom, that is, provide any direction in a radial plane and magnitude of the electromagnetic force.

Based on the above control principles, the design of radial magnetic bearings generally adopts a structure of 8 magnetic poles or 4×2 ⁿ (n is an integer ≥ 1) magnetic poles. Figure 1 shows an 8-pole structure, and Figure 2 shows a schematic structural diagram of a 16-pole radial magnetic bearing, which is different from an 8-pole radial bearing in that it consists of 4 magnetic poles to form a direction electromagnet.

When the rotor has a radial offset from the center position in a certain direction, the control system of the magnetic bearing automatically calculates the corresponding reverse electromagnetic force according to the offset, and decomposes it into the component forces on the electromagnets , and then control the magnitude of the current on the coil to generate a corresponding force to pull the rotor back to the center position.

As shown in Figure 1 and Figure 2, the radial electromagnet design with overall processing and overall assembly will have the following disadvantages in some applications.

1. Insufficient utilization of winding space. In order to achieve a better excitation effect, it is necessary to utilize the space between the magnetic poles 3 as much as possible, especially the space 7 at the root of the magnetic poles, so as to accommodate more turns of the coil winding. In terms of technology, a mold for magnetic poles is usually made first. On the mold, the wires are first wound and bundled into a regular-shaped wire package, and then installed on the magnetic poles of the bearing and fixed, as shown in Figure 3. Since the distance between the front end of the magnetic pole and the root of the magnetic pole is different, the space 7 at the root of the magnetic pole is often not fully utilized in order to facilitate the installation of the winding wire package 6 .

2. There may be crosstalk between each closed magnetic circuit, especially when the coil has a fault such as inter-turn short circuit or iron strike, according to the excitation current design of the excitation coil, the closed magnetic circuit that should have been formed on the adjacent magnetic pole is formed by other magnetic poles. Closed, because the control system still controls the current according to the logic of normal working conditions, the magnetic field distribution on each magnetic pole will have uncertain crosstalk, which is not conducive to fault diagnosis and maintenance.

3. When a mechanical failure of the magnetic bearing requires maintenance or replacement of stator parts, even if only one of the magnetic poles has a problem, it has to be replaced as a whole, resulting in waste and increased maintenance costs.

4. Sometimes the radial magnetic bearings have different forces in each direction. For example, when the rotor is designed horizontally, that is, when the rotor axis is arranged horizontally, the electromagnet at the upper end of the magnetic bearing bears the weight of the rotor additionally than the electromagnet at the lower end. In fact, the electromagnet at the lower end hardly needs to provide any carrying capacity, and the traditional fully axisymmetric magnetic bearing design is obviously unscientific.

Contents of the invention

(1) Technical problems to be solved

The technical problem to be solved by the present invention is: how to improve the utilization rate of radial magnetic bearing winding space, simplify the magnetic bearing winding process, reduce the cost of use and maintenance, and avoid the mutual crosstalk between electromagnets under various circumstances, and improve the failure rate. Efficient diagnosis and convenient maintenance of the entire system.

(2) Technical solutions

In order to solve the above technical problems, the present invention provides a radial magnetic bearing with an independent electromagnet structure, which includes:

rotor;

a stator disposed on the periphery of the rotor;

The stator includes a casing and several independent electromagnets, and the several independent electromagnets are installed on the casing at intervals.

Wherein, the independent electromagnet is U-shaped.

Wherein, the independent electromagnet is formed by stacking silicon steel sheets.

Wherein, the angle between two magnetic poles of the independent electromagnet is 360°/(4×2 ⁿ ), wherein: n is a positive integer greater than or equal to 1.

Wherein, the diameter of the inner circle of the magnetic pole of the independent electromagnet is larger than the outer diameter of the rotor.

Wherein, the outer circle of the magnetic pole of the independent electromagnet matches the inner circle of the housing.

Wherein, the interval between two adjacent independent electromagnets is greater than the gap between the magnetic poles of the independent electromagnets and the rotor.

Wherein, the magnetic poles of the independent electromagnets are provided with winding wires.

Wherein, an installation hole is opened on the independent electromagnet.

(3) Beneficial effects

The above-mentioned technical scheme has the following advantages:

1. The structural assembly is flexible, and the stator can be made into a semi-open structure according to the needs, which is convenient for application in large shafting systems; a variety of electromagnets can be combined, for example, the design of electromagnets in different directions and different gaps, and the use of two electromagnets Iron bears gravity etc., can not need the electromagnet of lower end for most horizontal rotors, can make the upper end electromagnet of bearing rotor gravity bigger simultaneously.

2. The electromagnets are independent of each other, which can effectively avoid the mutual crosstalk of the magnetic circuit between the magnetic poles and the signal interference between the magnetic poles and the sensor, which is conducive to improving the reliability of the system.

3. Each independent electromagnet can be used to directly carry out the winding off-line, and generally there is no need for additional processing of molds and special off-line process design.

4. It is easy to become an independent structural unit and form serialized and standardized components, which greatly reduces the cost of maintenance and replacement of equipment components.

Description of drawings

Fig. 1 is a structural schematic diagram of a magnetic pole radial magnetic bearing with 8 magnetic poles in the prior art;

Fig. 2 is a structural schematic diagram of a magnetic pole radial magnetic bearing with 16 magnetic poles in the prior art;

Fig. 3 is a schematic diagram of a magnetic pole winding wire package in the prior art;

Fig. 4 is the structural representation of the independent electromagnet unit of the embodiment of the present invention;

Fig. 5 is a schematic structural diagram of a magnetic bearing with an independent electromagnet according to an embodiment of the present invention;

6 is a side sectional view of a magnetic bearing with independent electromagnets according to an embodiment of the present invention;

Fig. 7 is a schematic structural diagram of an asymmetric magnetic bearing according to an embodiment of the present invention.

Among them, 1: rotor; 2: stator; 3: magnetic pole; 4: coil; 5: closed magnetic circuit; 6: winding wire package; 7: pole root space; 8: installation hole; 9: winding; 10: bolt; 11: independent electromagnet; 12: shell; 13: inner circle; 14: outer circle.

Detailed ways

The specific implementation manners of the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following examples are used to illustrate the present invention, but are not intended to limit the scope of the present invention.

Fig. 4 is a schematic structural view of an independent electromagnet unit in an embodiment of the present invention; Fig. 5 is a schematic diagram of a magnetic bearing with an independent electromagnet in an embodiment of the present invention; Fig. 6 is a side view of a magnetic bearing with an independent electromagnet in an embodiment of the present invention Sectional view; FIG. 7 is a schematic structural view of an asymmetric magnetic bearing according to an embodiment of the present invention.

The present invention provides the most basic U-shaped independent electromagnet unit that can form a closed magnetic circuit with the rotor, as shown in FIG. 4 . In order to prevent the generation of eddy currents, the main body of the independent electromagnet 11 is formed by stacking silicon steel sheets. The shape of the silicon steel sheets is shown in Figure 4, wherein there is a certain angle between the two magnetic poles, and the angle is 360°/( 4×2 ⁿ ) (where n is an integer ≥ 1), n is the number of closed magnetic circuits on the independent electromagnet 11, and the thickness of the independent electromagnet 11 is designed according to the structure of the rotor 1 and the bearing capacity requirements of the magnetic bearing, which can be obtained by Changes can be made by increasing or decreasing the number of silicon steel sheets, as shown in the cross-sectional view in Figure 5. As shown in FIG. 5 , the design of the inner circle and outer circle of the magnetic poles of the electromagnet unit is related to the application. The diameter of the inner circle 13 is slightly larger than the outer diameter of the rotor 1 , and the outer circle 14 should be compatible with the installation shell 12 . After the overall installation is completed, a structure similar to that of the traditional magnetic bearing shown in Figure 1 or Figure 2 can be formed, the difference is that each independent electromagnet 11 is installed and disassembled separately, and there is a large distance between them, which is much larger than the magnetic pole 3 of the stator 2 Clearance with rotor 1. Another difference from the traditional structure magnetic bearing is that the winding 9 of the independent electromagnet 11 is completed before its overall installation, that is, the excitation coil is directly wound on it without using a mould, and then each electromagnet The units together with the windings are mounted one by one on the housing 12 and tightened by fixing bolts 10 .

In this embodiment, the original integral electromagnet structure on the stator of the radial bearing is split into multiple independent electromagnet units; each electromagnet unit is directly wound with an excitation winding, and then installed on the structure one by one; after the installation, the whole It has a similar structural appearance to traditional radial magnetic bearings, but retains a large gap between individual electromagnets.

It can be seen from the above embodiments that the embodiment of the present invention adopts a modular new radial magnetic bearing structure design, and the magnetic poles of the magnetic bearing are made into several U-shaped electromagnet unit modules of different sizes, thereby simplifying the magnetic field. The process of bearing winding, and the combination of this electromagnet unit module can be flexibly designed and selected according to the needs of magnetic bearing applications, which reduces the cost of use and maintenance, and effectively avoids the interaction between electromagnets in various situations. Mutual crosstalk improves the efficiency of fault diagnosis, and the maintenance of the entire system becomes more convenient.

The above is only a preferred embodiment of the present invention, it should be pointed out that for those of ordinary skill in the art, without departing from the technical principle of the present invention, some improvements and replacements can also be made, these improvements and replacements It should also be regarded as the protection scope of the present invention.

Claims (9)

1. the radial direction magnetic bearing with independent electromagnet structure is characterized in that, comprising:

Rotor (1);

Stator (2) is arranged on described rotor (1) periphery;

Described stator (2) comprises shell (12) and several independent electromagnets (11), and described several independent electromagnets (11) are installed on the described shell (12) at interval.

2. the radial direction magnetic bearing with independent electromagnet structure as claimed in claim 1 is characterized in that, described independent electromagnet (11) is a U-shaped.

3. the radial direction magnetic bearing with independent electromagnet structure as claimed in claim 1 is characterized in that, described independent electromagnet (11) is formed by the silicon steel sheet closed assembly.

4. the radial direction magnetic bearing with independent electromagnet structure as claimed in claim 2 is characterized in that, the angle between two magnetic poles of described independent electromagnet (11) is 360 °/(4 * 2 ⁿ), wherein: n is the positive integer more than or equal to 1.

5. the radial direction magnetic bearing with independent electromagnet structure as claimed in claim 2 is characterized in that, the interior circular diameter of the magnetic pole of described independent electromagnet (11) is greater than the external diameter of described rotor (1).

6. the radial direction magnetic bearing with independent electromagnet structure as claimed in claim 2 is characterized in that, the interior circle of the cylindrical of the magnetic pole of described independent electromagnet (11) and described shell (12) is complementary.

7. the radial direction magnetic bearing with independent electromagnet structure as claimed in claim 1 is characterized in that, the interval between adjacent two described independent electromagnets (11) is greater than the magnetic pole of described independent electromagnet (11) and the gap between described rotor (1).

8. as each described radial direction magnetic bearing among the claim 1-7, it is characterized in that the magnetic pole of described independent electromagnet (11) is provided with coiling (9) with independent electromagnet structure.

9. the radial direction magnetic bearing with independent electromagnet structure as claimed in claim 1 is characterized in that, offers mounting hole (8) on the described independent electromagnet (11).

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