CN115654019A

CN115654019A - Magnetic suspension active three-degree-of-freedom bearing, motor and compressor

Info

Publication number: CN115654019A
Application number: CN202211260709.6A
Authority: CN
Inventors: 董如昊; 龚高; 张超; 陈艳霞
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2022-10-14
Filing date: 2022-10-14
Publication date: 2023-01-31

Abstract

The invention provides a magnetic suspension active three-degree-of-freedom bearing, a motor and a compressor, wherein the magnetic suspension active three-degree-of-freedom bearing comprises: the bearing rotor is fixedly sleeved on the peripheral wall of the rotating shaft, the radial stator is sleeved on the outer side of the bearing rotor, the first axial stator and the second axial stator are respectively sleeved on the outer side of the rotating shaft, and the first axial stator and the second axial stator are respectively and simultaneously positioned on two sides of the bearing rotor and the radial stator. According to the invention, the thrust disc of the magnetic suspension bearing is removed, the radial position of the rotating shaft is adjusted by utilizing the electromagnetic force between the radial stator and the bearing rotor, and the axial position of the rotating shaft is adjusted by utilizing the electromagnetic force between the first axial stator and the bearing rotor, and the second axial stator and the bearing rotor, so that three-degree-of-freedom adjustment of the rotating shaft is realized. The omission of the thrust disc enables the radial magnetic suspension bearing and the axial magnetic suspension bearing to have high integration, compact structure, easy assembly and obviously reduced bearing size.

Description

Magnetic suspension active three-degree-of-freedom bearing, motor and compressor

Technical Field

The invention belongs to the technical field of magnetic suspension bearings, and particularly relates to a magnetic suspension active three-degree-of-freedom bearing, a motor and a compressor.

Background

The magnetic suspension bearing suspends the rotating shaft by utilizing the electromagnetic force on the rotor, and the rotating shaft and the stator keep a non-contact state, so the magnetic suspension bearing has the advantages of no abrasion, high rotating speed, high precision, long service life and the like. Magnetic bearings are called magnetic bearings for short, and the magnetic bearings can be divided into three types according to the working principle: active magnetic bearings, passive magnetic bearings, and hybrid magnetic bearings. The magnetic bearing comprises a radial magnetic suspension bearing and an axial magnetic suspension bearing, the radial magnetic suspension bearing adjusts the position of the rotating shaft in the radial direction through electromagnetic force between the radial magnetic suspension bearing and a bearing rotor fixedly sleeved on the rotating shaft, and the axial magnetic suspension bearing adjusts the position of the rotating shaft in the axial direction through electromagnetic force between the axial magnetic suspension bearing and a thrust disc fixedly sleeved on the rotating shaft, so that three-degree-of-freedom adjustment of the rotating shaft is realized. In the prior art, because of the existence of the thrust disc, the integration degree of the radial magnetic suspension bearing and the axial magnetic suspension bearing is not high, and the finally formed magnetic bearing has the advantages of complex structure, difficult assembly and larger size.

Disclosure of Invention

Therefore, the invention provides a magnetic suspension active three-degree-of-freedom bearing, which can overcome the defects of complex structure, difficult assembly and larger size of the existing magnetic bearing.

In order to solve the above problems, the present invention provides a magnetic suspension active three-degree-of-freedom bearing, including: the bearing rotor is fixedly sleeved on the peripheral wall of the rotating shaft, the radial stator is sleeved on the outer side of the bearing rotor, a radial working gap is formed between the radial stator and the bearing rotor, the first axial stator and the second axial stator are respectively sleeved on the outer side of the rotating shaft, and the first axial stator and the second axial stator are respectively positioned on two sides of the bearing rotor and the radial stator at the same time; the radial stator comprises four pole units divided by four quadrants, each pole unit is provided with a first pole and two second poles facing the inner side of the radial stator, the two second pole units are respectively positioned on two sides of the first pole and are symmetrical relative to the first pole along the circumferential direction of the radial stator, a first radial winding is wound on the first pole, and a second radial winding is wound on the second pole; the first axial stator comprises a first outer magnetic pole block and a first inner magnetic pole ring, a first axial winding is arranged between the first outer magnetic pole block and the first inner magnetic pole ring, and a first axial working gap is formed between the first inner magnetic pole ring and the bearing rotor; the second axial stator comprises a second outer magnetic pole block and a second inner magnetic pole ring, a second axial winding is arranged between the second outer magnetic pole block and the second inner magnetic pole ring, and a second axial working gap is formed between the second inner magnetic pole ring and the bearing rotor.

In some embodiments, the number of the first outer magnetic pole pieces is four, and the four first outer magnetic pole pieces are distributed at intervals along the circumferential direction of the first axial stator.

In some embodiments, the number of the second outer magnetic pole pieces is four, and four second outer magnetic pole pieces are distributed at intervals along the circumferential direction of the second axial stator.

In some embodiments, four first outer magnetic pole blocks are respectively adapted to the positions of four first poles, two adjacent second poles are combined to form a combined body, and four second outer magnetic pole blocks are respectively adapted to the positions of four combined bodies.

In some embodiments, the first radial winding and the second radial winding are energized to generate a radial control magnetic circuit, the first axial winding is energized to generate a first axial control magnetic circuit, and the direction of magnetic lines of the first axial control magnetic circuit in the first pole column is the same as the direction of magnetic lines of the radial control magnetic circuit in the first pole column.

In some embodiments, the first axial control magnetic circuit closes back to the first axial stator through the first inner pole ring-the first axial working gap-the bearing rotor-the radial working gap-the first pole-the first outer pole piece; the radial control magnetic circuit is closed to the radial stator through the first pole column-the radial working gap-the bearing rotor-the radial working gap-the second pole column.

In some embodiments, the second axial winding is energized to generate a second axial control magnetic circuit, and the direction of the magnetic lines of the second axial control magnetic circuit in the second pole is the same as the direction of the magnetic lines of the radial control magnetic circuit in the second pole.

In some embodiments, the second axial control magnetic circuit is closed via the second outer pole piece-the second pole post-the radial working gap-the bearing rotor-the second axial working gap-the second inner pole loop back to the second axial stator; the radial control magnetic circuit is closed to the radial stator through the first pole column, the radial working gap, the bearing rotor, the radial working gap, the second pole column.

In some embodiments, within the same pole unit, two of the second radial windings are connected in series.

In some embodiments, the first pole post has a width greater than a width of the second pole post in a circumferential direction of the radial stator.

In some embodiments, the first and second radial windings are radially outward of the first and second outer magnetic pole pieces in a radial direction of the radial stator.

The invention also provides a motor which comprises the magnetic suspension active three-degree-of-freedom bearing.

The invention also provides a compressor, which comprises the magnetic suspension active three-degree-of-freedom bearing.

The invention provides a magnetic suspension active three-degree-of-freedom bearing, a motor and a compressor, wherein a thrust disc is removed, the radial position of a rotating shaft is adjusted by utilizing electromagnetic force between a radial stator and a bearing rotor, and the axial position of the rotating shaft is adjusted by utilizing the electromagnetic force between a first axial stator and a bearing rotor and between a second axial stator and the bearing rotor, so that three-degree-of-freedom adjustment of the rotating shaft is realized, and the position of the rotating shaft in three directions of XYZ can be freely adjusted. When the magnetic bearing realizes three-degree-of-freedom adjustment of the rotating shaft, a thrust disc is omitted, so that the radial magnetic suspension bearing and the axial magnetic suspension bearing are high in integration, compact in structure, easy to assemble and obviously reduced in bearing size.

Drawings

Fig. 1 is a schematic structural diagram of a radial stator of a magnetic levitation active three-degree-of-freedom bearing according to an embodiment of the present invention;

FIG. 2 isbase:Sub>A cross-sectional view ofbase:Sub>A radial stator of the magnetically levitated active three degree-of-freedom axis of the embodiment of the present invention in FIG. 1 at plane A-A;

FIG. 3 is a cross-sectional view of the radial stator of the magnetically levitated active three degree-of-freedom axis of the embodiment of the present invention in FIG. 1 taken along plane B-B;

FIG. 4 is a front view of a first axial stator of a magnetically levitated active three degree of freedom bearing according to an embodiment of the present invention;

FIG. 5 is a front view of a second axial stator of the magnetically levitated active three degree-of-freedom bearing of the embodiment of the present invention;

fig. 6 is a schematic structural diagram of a first axial stator of a magnetic suspension active three-degree-of-freedom bearing according to an embodiment of the present invention.

The reference numerals are represented as:

1. a rotating shaft; 2. a bearing rotor; 3. a radial stator; 31. a first pole column; 32. a second pole; 33. a first radial winding; 34. a second radial winding; 4. a first axial stator; 41. a first outer magnetic pole piece; 42. a first inner pole ring; 43. a first axial winding; 5. a second axial stator; 51. a second outer magnetic pole piece; 52. a second inner pole ring; 53. a second axial winding; 6. a radial working gap; 7. a first axial working gap; 8. a second axial working gap; 9. a radial control magnetic circuit; 10. a first axial control magnetic circuit; 11. the second axial direction controls the magnetic circuit.

Detailed Description

Referring to fig. 1 to fig. 6 in combination, according to an embodiment of the present invention, there is provided a magnetic suspension active three-degree-of-freedom bearing, including: the structure comprises a rotating shaft 1, a bearing rotor 2, a radial stator 3, a first axial stator 4 and a second axial stator 5, wherein the bearing rotor 2 is fixedly sleeved on the outer peripheral wall of the rotating shaft 1, the radial stator 3 is sleeved on the outer side of the bearing rotor 2, a radial working gap 6 is formed between the radial stator 3 and the bearing rotor 2, the first axial stator 4 and the second axial stator 5 are respectively sleeved on the outer side of the rotating shaft 1, and the first axial stator 4 and the second axial stator 5 are respectively positioned on two sides of the bearing rotor 2 and the radial stator 3 at the same time; the radial stator 3 comprises four pole units separated by four quadrants, each pole unit comprises a first pole 31 and two second pole posts 32 facing the inner side of the radial stator 3, the two second pole posts 32 are respectively positioned at two sides of the first pole 31 and are symmetrical relative to the first pole 31 along the circumferential direction of the radial stator 3, a first radial winding 33 is wound on the first pole 31, and a second radial winding 34 is wound on the second pole posts 32; the first axial stator 4 comprises a first outer magnetic pole piece 41 and a first inner magnetic pole ring 42, a first axial winding 43 is arranged between the first outer magnetic pole piece 41 and the first inner magnetic pole ring 42, and a first axial working gap 7 is arranged between the first inner magnetic pole ring 42 and the bearing rotor 2; the second axial stator 5 comprises a second outer magnetic pole piece 51 and a second inner magnetic pole ring 52, a second axial winding 53 is arranged between the second outer magnetic pole piece 51 and the second inner magnetic pole ring 52, and a second axial working gap 8 is arranged between the second inner magnetic pole ring 52 and the bearing rotor 2. In the technical scheme, the thrust disc is removed, the radial position of the rotating shaft 1 is adjusted by utilizing the electromagnetic force between the radial stator 3 and the bearing rotor 2, and the axial position of the rotating shaft 1 is adjusted by utilizing the electromagnetic force between the first axial stator 4, the second axial stator 5 and the bearing rotor 2, so that three-degree-of-freedom adjustment of the rotating shaft 1 is realized, namely the positions of the rotating shaft 1 in three directions of XYZ can be freely adjusted. When the magnetic suspension active three-degree-of-freedom bearing realizes three-degree-of-freedom adjustment of the rotating shaft 1, a thrust disc is omitted, so that the radial magnetic suspension bearing and the axial magnetic suspension bearing are high in integration, compact in structure, easy to assemble and obviously reduced in bearing size. Under the condition of having the advantages, the magnetic bearing can also improve the critical rotating speed of the bearing rotor 2 and improve the stability and the applicability of a magnetic suspension system. After the first radial winding 33 and the second radial winding 34 are both electrified, the assembly of the bearing rotor 2 and the rotating shaft 1 is suspended through the generated electromagnetic force, and when the position of the rotating shaft 1 in the radial direction needs to be adjusted, the suspension can be realized by increasing the radial winding current in the corresponding quadrant or the corresponding combined quadrant; when the position of the rotating shaft 1 in the axial direction needs to be adjusted, the adjustment is realized by increasing the current of the first axial winding 43 of the first axial stator 4 or increasing the current of the second axial winding 53 of the second axial stator 5. The magnetic bearing is according to the change of self size, and the number of the polar columns that its radial stator 3 has also can be different, and the magnetic suspension bearing in certain size range corresponds corresponding polar column number, otherwise the utmost point post number will seem too big the interval between the adjacent utmost point post too little, and utmost point post number too many can make the interval between the adjacent utmost point post too little and not good the wire winding, and the active three degrees of freedom bearings of magnetic suspension of this application corresponds 12 utmost point post numbers according to self size. More importantly, in the same pole unit of the present application, the two second pole posts 32 are symmetrical with respect to the first pole post 31, and the two second pole posts 32 and the first pole post 31 can present opposite polarities by passing currents in opposite directions to the first radial winding 33 and the second radial winding 34, so that in the same quadrant, resultant force of electromagnetic force generated after energization is always located on a center line of the first pole post 31, which is more favorable for adjusting the radial position of the bearing rotor 2, that is, more favorable for adjusting the radial position of the rotating shaft 1. For the left and right first axial stators 4 and the second axial stator 5, a concave area is formed between the outer magnetic pole block and the inner magnetic pole ring by arranging the outer magnetic pole block and the inner magnetic pole ring, so that the axial winding is convenient to arrange, and meanwhile, the outer magnetic pole block can reduce the magnetic leakage of the radial stator 3 in the axial direction. Both the first axial winding 43 and the second axial winding 53 are in a single coil pattern, the first axial winding 43 is disposed around the first inner magnetic pole ring 42 and the second axial winding 53 is disposed around the second inner magnetic pole ring 52, i.e., both the first axial winding 43 and the second axial winding 53 are disposed around the rotating shaft 1. After the axial winding is electrified, the inner magnetic pole ring can apply uniform electromagnetic force to the circumferential direction of the bearing rotor 2, so that the position of the bearing rotor 2 in the axial direction, namely the position of the rotating shaft 1 in the axial direction, can be adjusted more conveniently.

Specifically, the number of the first outer magnetic pole pieces 41 is four, and the four first outer magnetic pole pieces 41 are distributed at intervals along the circumferential direction of the first axial stator 4.

Referring to fig. 4 and 6 in combination, compared with the case that the first outer magnetic pole is set as a whole outer magnetic ring, a plurality of first outer magnetic pole pieces 41 are uniformly distributed in the circumferential direction of the first axial stator 4 at intervals, so that magnetic leakage of a radial magnetic circuit on the first pole 31 or the second pole 32 adjacent to the first pole on the outer circle of the first axial stator 4 can be avoided, and only an air gap magnetic field on the radial pole is enhanced.

Specifically, the number of the second outer magnetic pole blocks 51 is four, and the four second outer magnetic pole blocks 51 are distributed at intervals in the circumferential direction of the second axial stator 5.

Referring to fig. 5 in combination, compared with the case that the second outer magnetic pole is set as a whole outer magnetic ring, a plurality of second outer magnetic pole blocks 51 are uniformly distributed in the circumferential direction of the second axial stator 5 at intervals, so that the magnetic flux leakage phenomenon of the radial magnetic circuit on the adjacent first pole column 31 or second pole column 32 on the outer circle of the second axial stator 5 can be avoided, and only the air gap magnetic field on the radial pole column is enhanced.

In a specific embodiment, four first outer magnetic pole pieces 41 respectively correspond to the positions of four first pole posts 31, two adjacent second pole posts 32 are combined to form a combined body, and four second outer magnetic pole pieces 51 respectively correspond to the positions of the four combined bodies.

In this embodiment, when the four first outer magnetic pole pieces 41 are respectively adapted to the positions of the four first poles 31 and the four second outer magnetic pole pieces 51 are respectively adapted to the positions of the four combined bodies, the magnetic field generated by the first axial winding 43 and the second axial winding 53 after being electrified can be prevented from acting on the same pole, and the magnetic flux on the same pole can be prevented from being over-saturated. The first axial stator 4 and the second axial stator 5 are identical in structure, and are offset by a certain angle when assembled.

Specifically, the first radial winding 33 and the second radial winding 34 are energized to generate the radial control magnetic circuit 9, the first axial winding 43 is energized to generate the first axial control magnetic circuit 10, and the direction of the magnetic line of the first axial control magnetic circuit 10 in the first pole 31 is the same as the direction of the magnetic line of the radial control magnetic circuit 9 in the first pole 31.

Referring to fig. 1 and fig. 2, the current flow direction in the first radial winding 33 is right-in and left-out, the magnetic pole of the first pole post 31 is S-pole, the current flow direction in the first axial winding 43 is down-in and up-out, and the magnetic pole of the first inner magnetic pole ring 42 is N-pole, so that the direction of the magnetic force line of the first axial control magnetic circuit 10 in the first pole post 31 is the same as the direction of the magnetic force line of the radial control magnetic circuit 9 in the first pole post 31. The magnetic pole of the first pole column 31 is an N pole by changing the current flow direction so that the current flow direction in the first radial winding 33 is left-in and right-out, and the magnetic pole of the first pole column 31 is an S pole by changing the current flow direction in the first axial winding 43 into up-in and down-out, and the direction of the magnetic force line of the first axial control magnetic circuit 10 in the first pole column 31 is the same as the direction of the magnetic force line of the radial control magnetic circuit 9 in the first pole column 31. When the direction of the magnetic force line of the first axial control magnetic circuit 10 in the first pole column 31 is the same as the direction of the magnetic force line of the radial control magnetic circuit 9 in the first pole column 31, that is, the axial magnetic circuit does not reduce the radial magnetic circuit, so that the radial air gap magnetic flux is enhanced, and the magnetic attraction of the first pole column 31 to the bearing rotor 2 is enhanced. However, the axial magnetic flux in only one quadrant affects the pole, and the enhancement of the axial magnetic flux in four quadrants is mutually offset, that is, although the radial magnetic path and the axial magnetic path of the integrated magnetic bearing both flow through the bearing rotor 2, the axial magnetic path does not affect the whole radial magnetic path even if changed, so that the axial magnetic path and the radial magnetic path respectively play respective roles, and the control of the magnetic bearing is simplified.

As a specific embodiment, the second axial winding 53 is energized to generate the second axial control magnetic circuit 11, and the direction of the magnetic lines of the second axial control magnetic circuit 11 in the second pole 32 is the same as the direction of the magnetic lines of the radial control magnetic circuit 9 in the second pole 32.

Referring to fig. 1 and fig. 3 in combination, the current flow direction in the second radial winding 34 is left-in and right-out, the magnetic pole of the second pole post 32 is N-pole, the current flow in the second axial winding 53 is down-in and up-out, the magnetic pole of the second inner magnetic pole ring 52 is S-pole, and the direction of the magnetic force line of the second axial control magnetic circuit 11 in the second pole post 32 is the same as the direction of the magnetic force line of the radial control magnetic circuit 9 in the second pole post 32; the direction of the magnetic force lines of the second axial control magnetic circuit 11 in the second pole column 32 can also be the same as the direction of the magnetic force lines of the radial control magnetic circuit 9 in the second pole column 32 by changing the current flow direction, so that the current flow direction in the second radial winding 34 is right-in and left-out, the magnetic pole of the second pole column 32 is an S pole, the current flow direction in the second axial winding 53 is up-in and down-out, and the magnetic pole of the second inner magnetic pole ring 52 is an N pole. When the direction of the magnetic force line of the second axial control magnetic circuit 11 in the second pole 32 is the same as the direction of the magnetic force line of the radial control magnetic circuit 9 in the second pole 32, that is, the axial magnetic circuit does not reduce the radial magnetic circuit, the magnetic field of the second axial control magnetic circuit 11 does not affect the magnetic attraction of the second pole 32 to the bearing rotor 2, that is, the radial control magnetic circuit 9 and the second axial control magnetic circuit 11 do not affect each other, and each plays a role. In summary, in the same pole unit, the magnetic poles on the three poles are arranged as NSN, and the magnetic poles on the three poles can also be arranged as SNS by changing the current flowing direction, and the current flowing directions in the first axial winding 43 and the second axial winding 53 also need to be changed adaptively.

As a specific embodiment, the first axial control magnetic circuit 10 returns to the first axial stator 4 to close through the first inner magnetic pole ring 42-the first axial working gap 7-the bearing rotor 2-the radial working gap 6-the first pole column 31-the first outer magnetic pole block 41; the second axial control magnetic circuit 11 returns to the second axial stator 5 to be closed through the second outer magnetic pole block 51, the second pole column 32, the radial working gap 6, the bearing rotor 2, the second axial working gap 8 and the second inner magnetic pole ring 52; the radial control magnetic circuit 9 is closed to the radial stator 3 through the first pole 31, the radial working gap 6, the bearing rotor 2, the radial working gap 6 and the second pole 32.

As a specific embodiment, within the same pole unit, two second radial windings 34 are connected in series.

In this embodiment, in the same pole unit, the magnetic poles of the two second pole posts 32 need to be the same, and when the two second radial windings 34 are connected in series, only one current is needed to ensure that the magnetic poles of the two second pole posts 32 are the same.

As a specific embodiment, the width of the first pole post 31 is larger than the width of the second pole post 32 in the circumferential direction of the radial stator 3.

Referring to fig. 1, in the same pole unit, two radial control magnetic circuits 9 are generated, and the two radial control magnetic circuits 9 pass through the first pole 31 and return to the corresponding second pole 32, when the width of the first pole 31 is greater than that of the second pole 32, that is, the first pole 31 is a large tooth, and the second pole 32 is a small tooth, the optimization of the magnetic circuits and the control of the intensity of the magnetic field are facilitated.

Specifically, in the radial direction of the radial stator 3, the first radial winding 33 and the second radial winding 34 are both located radially outside the first outer magnetic pole piece 41 and the second outer magnetic pole piece 51.

In the present embodiment, when the first radial winding 33 and the second radial winding 34 are both located at the radial outer sides of the first outer magnetic pole piece 41 and the second outer magnetic pole piece 51, magnetic flux leakage of the radial control magnetic circuit 9 in the axial direction can be prevented, and the circumferential non-uniformity of the axial force can be avoided.

When the rotating shaft 1 needs to be controlled to move to the left upper direction as shown in fig. 1, the current on the first radial winding 33 in the second quadrant can be increased, or the current on the second radial winding 34 in the quadrant can be increased, or the current on the first radial winding 33 and the second radial winding 34 in the quadrant can be simultaneously increased; when the rotating shaft 1 needs to be controlled to move upwards, the current on the first radial winding 33 in the first quadrant and the second quadrant can be increased simultaneously, or the current on the second radial winding 34 in the first quadrant and the second quadrant can be increased simultaneously; or to increase the current on both the first radial winding 33 and the second radial winding 34 in the first quadrant and the second quadrant. In the radial direction, the above-mentioned control principle can be applied if it is desired to control the shaft 1 to move in other directions. As shown in fig. 2, when the rotating shaft 1 needs to be controlled to move leftward along the axial direction, the current of the first axial winding 43 is increased, the electromagnetic force applied to the bearing rotor 2 to the left is increased, and the bearing rotor 2 drives the rotating shaft 1 to move leftward under the action of the electromagnetic force; as shown in fig. 3, when it is necessary to control the rotating shaft 1 to move to the right in the axial direction, the current of the second axial winding 53 is increased, the electromagnetic force applied to the bearing rotor 2 to the right is increased, and the bearing rotor 2 drives the rotating shaft 1 to move to the right under the action of the electromagnetic force, so that the position of the bearing rotor 2 in the axial direction is adjusted by controlling the current of the first axial winding 43 and the current of the second axial winding 53, and the position of the rotating shaft 1 in the axial direction is adjusted.

It is readily understood by a person skilled in the art that the advantageous ways described above can be freely combined, superimposed without conflict.

The present invention is not limited to the above preferred embodiments, and any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention. The above is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the technical principle of the present invention, and these improvements and modifications should also be regarded as the protection scope of the present invention.

Claims

1. A magnetic suspension active three-degree-of-freedom bearing is characterized by comprising a rotating shaft (1), a bearing rotor (2), a radial stator (3), a first axial stator (4) and a second axial stator (5), wherein the bearing rotor (2) is fixedly sleeved on the outer peripheral wall of the rotating shaft (1), the radial stator (3) is sleeved on the outer side of the bearing rotor (2), a radial working gap (6) is formed between the radial stator (3) and the bearing rotor (2), the first axial stator (4) and the second axial stator (5) are respectively sleeved on the outer side of the rotating shaft (1), and the first axial stator (4) and the second axial stator (5) are respectively and simultaneously positioned on two sides of the bearing rotor (2) and the radial stator (3);

the radial stator (3) comprises four pole units separated by four quadrants, each pole unit is provided with a first pole (31) and two second pole columns (32) facing the inner side of the radial stator (3), the two second pole columns (32) are respectively positioned on two sides of the first pole column (31) and are symmetrical relative to the first pole column (31) along the circumferential direction of the radial stator (3), a first radial winding (33) is wound on the first pole column (31), and a second radial winding (34) is wound on the second pole columns (32);

the first axial stator (4) comprises a first outer magnetic pole block (41) and a first inner magnetic pole ring (42), a first axial winding (43) is arranged between the first outer magnetic pole block (41) and the first inner magnetic pole ring (42), and a first axial working gap (7) is arranged between the first inner magnetic pole ring (42) and the bearing rotor (2); the second axial stator (5) comprises a second outer magnetic pole block (51) and a second inner magnetic pole ring (52), a second axial winding (53) is arranged between the second outer magnetic pole block (51) and the second inner magnetic pole ring (52), and a second axial working gap (8) is formed between the second inner magnetic pole ring (52) and the bearing rotor (2).

2. The magnetic suspension active three-degree-of-freedom bearing according to claim 1, wherein the number of the first outer magnetic pole pieces (41) is four, and the four first outer magnetic pole pieces (41) are distributed at intervals along the circumferential direction of the first axial stator (4).

3. The magnetic levitation active three-degree-of-freedom bearing as recited in claim 2, wherein the number of the second outer magnetic pole blocks (51) is four, and the four second outer magnetic pole blocks (51) are distributed at intervals along the circumference of the second axial stator (5).

4. The magnetic suspension active three-degree-of-freedom bearing according to claim 3, wherein four first outer magnetic pole pieces (41) are respectively adapted to positions of four first poles (31), two adjacent second poles (32) are combined to form a combined body, and four second outer magnetic pole pieces (51) are respectively adapted to positions of four combined bodies.

5. The magnetic suspension active three-degree-of-freedom bearing according to claim 4, wherein the first radial winding (33) and the second radial winding (34) are both energized to generate a radial control magnetic circuit (9), the first axial winding (43) is energized to generate a first axial control magnetic circuit (10), and the direction of the magnetic force line of the first axial control magnetic circuit (10) in the first pole column (31) is the same as the direction of the magnetic force line of the radial control magnetic circuit (9) in the first pole column (31).

6. Magnetic levitation active three-degree-of-freedom bearing according to claim 5, characterized in that the first axial control magnetic circuit (10) is closed back to the first axial stator (4) via the first inner magnetic pole ring (42) -the first axial working gap (7) -the bearing rotor (2) -the radial working gap (6) -the first pole column (31) -the first outer magnetic pole piece (41); the radial control magnetic circuit (9) is closed to the radial stator (3) via the first pole (31) -the radial working gap (6) -the bearing rotor (2) -the radial working gap (6) -the second pole (32).

7. The active magnetic suspension three-degree-of-freedom bearing according to claim 5, wherein the second axial winding (53) is energized to generate a second axial control magnetic circuit (11), and the direction of the magnetic force lines of the second axial control magnetic circuit (11) in the second pole column (32) is the same as the direction of the magnetic force lines of the radial control magnetic circuit (9) in the second pole column (32).

8. The magnetic levitation active three-degree-of-freedom bearing according to claim 7, wherein the second axial control magnetic circuit (11) is closed back to the second axial stator (5) via the second outer pole piece (51) -the second pole column (32) -the radial working gap (6) -the bearing rotor (2) -the second axial working gap (8) -the second inner pole ring (52); the radial control magnetic circuit (9) is closed to the radial stator (3) via the first pole (31) -the radial working gap (6) -the bearing rotor (2) -the radial working gap (6) -the second pole (32).

9. The active magnetic suspension three degree of freedom bearing according to claim 1, characterized in that within the same pole unit, two of the second radial windings (34) are connected in series.

10. The magnetic levitation active three-degree-of-freedom bearing according to claim 1, wherein the width of the first pole post (31) is greater than the width of the second pole post (32) in the circumferential direction of the radial stator (3).

11. Magnetic levitation active three-degree-of-freedom bearing according to claim 1, wherein the first radial winding (33) and the second radial winding (34) are radially outside the first outer pole piece (41) and the second outer pole piece (51) in a radial direction of the radial stator (3).

12. An electric machine comprising a magnetic levitation active three degree of freedom bearing as claimed in any one of claims 1 to 11.

13. A compressor, characterized by comprising a magnetic levitation active three degree of freedom bearing as recited in any one of claims 1 to 11.