Homopolar radial magnetic bearings, compressors and air conditioners

Abstract

The present application provides a homopolar radial magnetic bearing, a compressor and an air conditioner. The homopolar radial magnetic bearing includes a stator core, a rotor and a radial magnetic conductive ring. The stator core includes a yoke and stator teeth. Some stator teeth are provided with radial control windings, and some stator teeth are provided with mounting grooves. Permanent magnets are installed in the mounting grooves. The radial control windings and stator teeth are arranged alternately along the circumferential direction. A magnetic isolation groove is provided on the radial outer side of the permanent magnet. The bias magnetic field generated by the permanent magnet forms a bias magnetic circuit through the yoke, stator teeth and rotor. The control magnetic field generated by the radial control winding forms a control magnetic circuit through the stator teeth, rotor and radial magnetic conductive ring. According to the homopolar radial magnetic bearing of the present application, the bearing structure can be simplified, the power consumption can be reduced, and the bearing reliability can be improved.

Description

Technical Field

[0001] The present application relates to the field of magnetic suspension technology, and in particular to a homopolar radial magnetic suspension bearing, a compressor and an air conditioner. Background Art

[0002] Magnetic bearings are a new type of high-performance bearing that uses the magnetic force between the stator and the rotor to suspend the rotor in space, so that there is no contact between the stator and the rotor. The rotor of the magnetic bearing can reach a very high speed, and has the advantages of small mechanical wear, low energy consumption, long life, no lubrication, no pollution, etc. It is particularly suitable for special applications such as high speed, vacuum and ultra-clean.

[0003] At present, the permanent magnet biased radial magnetic bearing structures studied internationally are divided into heteropolar and homopolar structures. The axial length of the heteropolar structure can be made shorter, but hysteresis loss will occur, while the hysteresis loss of the magnetic bearing with homopolar structure is greatly reduced. However, the structure of ordinary homopolar magnetic bearings is more complicated, requiring more radial control windings, high power consumption, and occupying a larger axial space, which is not conducive to increasing the critical speed of the rotor. Summary of the invention

[0004] Therefore, the technical problem to be solved by the present application is to provide a homopolar radial magnetic bearing, a compressor and an air conditioner, which can simplify the bearing structure, reduce power consumption and improve bearing reliability.

[0005] In order to solve the above problems, the present application provides a homopolar radial magnetic levitation bearing, including a stator core, a rotor and a radial magnetic conductive ring, the stator core includes a yoke and stator teeth, some stator teeth are provided with radial control windings, some stator teeth are provided with mounting grooves, permanent magnets are installed in the mounting grooves, the stator teeth with radial control windings and the stator teeth with permanent magnets are arranged alternately along the circumference of the rotor, and magnetic isolation grooves are provided on the radial outer side of the permanent magnets. The bias magnetic field generated by the permanent magnet forms a bias magnetic circuit through the yoke, stator teeth and rotor, and the control magnetic field generated by the radial control winding forms a control magnetic circuit through the stator teeth, rotor and radial magnetic conductive ring.

[0006] Preferably, the magnetic isolation slot penetrates the stator core in the axial direction.

[0007] Preferably, the magnetic isolation groove is filled with magnetic isolation material.

[0008] Preferably, a magnetic isolation block is installed in the magnetic isolation groove.

[0009] Preferably, the magnetic isolation groove extends to the mounting groove.

[0010] Preferably, a magnetic bridge is provided between the magnetic isolation groove and the mounting groove.

[0011] Preferably, the width of the permanent magnet is L1, the width of the stator tooth is L2, and 0.7≤L1 / L2≤0.95.

[0012] Preferably, the cross-sectional shape of the magnetic isolation groove is rectangular, arc-shaped, V-shaped or U-shaped.

[0013] According to another aspect of the present application, a compressor is provided, comprising a homopolar radial magnetic bearing, wherein the homopolar radial magnetic bearing is the above-mentioned homopolar radial magnetic bearing.

[0014] According to another aspect of the present application, an air conditioner is provided, comprising a homopolar radial magnetic bearing, wherein the homopolar radial magnetic bearing is the above-mentioned homopolar radial magnetic bearing.

[0015] The homopolar radial magnetic bearing provided by the present application comprises a stator core, a rotor and a radial magnetic conductive ring, wherein the stator core comprises a yoke and stator teeth, some of the stator teeth are provided with radial control windings, some of the stator teeth are provided with mounting grooves, permanent magnets are installed in the mounting grooves, the stator teeth provided with radial control windings and the stator teeth provided with permanent magnets are arranged alternately along the circumference of the rotor, magnetic isolation grooves are provided on the radial outer side of the permanent magnets, the bias magnetic field generated by the permanent magnets forms a bias magnetic circuit via the yoke, the stator teeth and the rotor, and the control magnetic field generated by the radial control winding forms a control magnetic circuit via the stator teeth, the rotor and the radial magnetic conductive ring. In the homopolar radial magnetic bearing, radial control windings and permanent magnets are respectively arranged on stator teeth, and the stator teeth provided with radial control windings and the stator teeth provided with permanent magnets are arranged alternately along the circumference of the rotor. Magnetic isolation grooves provided on the radial outer side of the permanent magnets are used to isolate the magnetic path of the radial control winding along the circumferential direction of the stator core to avoid magnetic coupling between the radial control windings. The magnetic isolation grooves are used to guide the electromagnetic flux of the radial control winding to flow to the radial magnetic conductive ring and form a magnetic flux loop through the rotor, while shunting the permanent magnetic flux to reduce magnetic leakage and reduce the magnetic density of the stator core. Through the above structure, the permanent magnet can The plane where the bias magnetic flux is generated is perpendicular to the central axis of the stator core, and the plane where the control magnetic flux generated by the radial control winding is parallel to the central axis of the stator core, which makes the permanent magnet installation method and the bearing assembly method simpler, and the control magnetic circuits are independent of each other, shortening the control magnetic flux path and reducing the coupling of the control magnetic circuits; at the same time, the bias magnetic circuit does not need to pass through the radial magnetic conductive ring and is directly distributed in the stator core, the axial matching length of the rotor and the stator core is shortened, the difficulty of installing the rotor into the stator core is reduced, the energy consumption and heat generation of the magnetic bearing are reduced, the bearing life is increased, and the reliability of the magnetic suspension bearing is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic structural diagram of a homopolar radial magnetic bearing according to an embodiment of the present application;

[0017] Figure 2 A schematic cross-sectional view of a homopolar radial magnetic bearing according to an embodiment of the present application;

[0018] Figure 3 A schematic structural diagram of a stator core of a homopolar radial magnetic bearing according to an embodiment of the present application;

[0019] Figure 4 This is a three-dimensional exploded structural diagram of a homopolar radial magnetic bearing according to an embodiment of the present application;

[0020] Figure 5 This is a diagram showing the bias magnetic circuit structure of a homopolar radial magnetic bearing according to an embodiment of the present application;

[0021] Figure 6 This is a control magnetic circuit structure diagram of a homopolar radial magnetic bearing according to one embodiment of the present application.

[0022] The reference numerals are:

[0023] 1. Stator core; 2. Rotor; 3. Radial magnetic ring; 4. Yoke; 5. Stator teeth; 6. Radial control winding; 7. Mounting slot; 8. Permanent magnet; 9. Magnetic isolation slot; 10. Magnetic isolation block; 11. Magnetic bridge. DETAILED DESCRIPTION

[0024] See also Figures 1 to 6 As shown, according to an embodiment of the present application, a homopolar radial magnetic bearing includes a stator core 1, a rotor 2 and a radial magnetic conductive ring 3, the stator core 1 includes a yoke 4 and stator teeth 5, radial control windings 6 are arranged on some of the stator teeth 5, mounting grooves 7 are arranged on some of the stator teeth 5, permanent magnets 8 are installed in the mounting grooves 7, the stator teeth 5 with radial control windings 6 and the stator teeth 5 with permanent magnets 8 are alternately arranged along the circumference of the rotor, the bias magnetic field generated by the permanent magnet 8 forms a bias magnetic circuit through the yoke 4, the stator teeth 5 and the rotor 2, and the control magnetic field generated by the radial control winding 6 forms a control magnetic circuit through the stator teeth 5, the rotor 2 and the radial magnetic conductive ring 3.

[0025] In this embodiment, the magnetic isolation groove 9 is provided corresponding to the permanent magnet 8 , and is used to shunt the magnetic path coming out of the permanent magnet 8 .

[0026] In the homopolar radial magnetic bearing, the radial control winding 6 and the permanent magnet 8 are respectively arranged on the stator teeth 5, and the stator teeth 5 with the radial control winding 6 and the stator teeth 5 with the permanent magnet 8 are arranged alternately along the circumferential direction of the rotor. The magnetic isolation groove 9 arranged on the radial outer side of the permanent magnet 8 is used to isolate the magnetic path of the radial control winding 6 along the circumferential direction of the stator core 1 to avoid magnetic coupling between the radial control windings 6. The magnetic isolation groove 9 is used to guide the electromagnetic flux of the radial control winding 6 to flow to the radial magnetic conductive ring 3 and form a magnetic flux circuit through the rotor 2, while shunting the permanent magnet flux to reduce leakage flux and reduce the magnetic density of the stator core 1.

[0027] Through the above structure, the plane where the bias magnetic flux generated by the permanent magnet 8 is located can be perpendicular to the central axis of the stator core 1, and the plane where the control magnetic flux generated by the radial control winding 6 is located can be parallel to the central axis of the stator core 1, so that the installation method of the permanent magnet 8 and the bearing assembly method are simpler, and the control magnetic circuits are independent of each other, shortening the control magnetic flux path and reducing the coupling of the control magnetic circuits; at the same time, the bias magnetic circuit does not need to pass through the radial magnetic ring 3, but is directly distributed in the stator core 1, and the axial matching length of the rotor 2 and the stator core 1 is shortened, reducing the difficulty of the rotor 2 being installed in the stator core 1, reducing the energy consumption and heat generation of the magnetic bearing, and increasing the bearing life, thereby improving the reliability of the magnetic suspension bearing. Since one end face of the radial magnetic ring 3 and one end face of the stator core 1 are close to the casing during assembly, the difficulty of assembling the bearing can be further reduced.

[0028] In the homopolar radial magnetic bearing of the present embodiment, a plurality of permanent magnets 8 are installed in the mounting grooves 7 of the stator teeth 5 in a one-to-one correspondence. Each permanent magnet 8 is radially magnetized, so the magnetization directions are the same, which reduces the magnetization difficulty of the permanent magnet 8. Moreover, the permanent magnet 8 is a block structure and can be directly installed in the mounting groove 7, which also reduces the assembly difficulty of the permanent magnet 8.

[0029] In the homopolar radial magnetic bearing of the present embodiment, a permanent magnet 8 is provided on half of the stator teeth 5, and a radial control winding 6 is provided on the other half. The permanent magnet 8 is installed on the magnetic pole of the stator core 1 to provide a static bias magnetic field for the bearing. Therefore, the number of windings can be reduced, the number of power amplifiers used can be reduced, the energy loss of the magnetic bearing can be reduced, the reliability of the magnetic bearing can be improved, and the axial length of the bearing can be shortened. Therefore, it is more suitable for high-speed occasions such as wind power generation and flywheels.

[0030] In one embodiment, the magnetic isolation slot 9 axially penetrates the stator core 1, which can better block the magnetic path of the radial control winding 6 along the yoke 4 of the stator core 1 and more effectively avoid coupling of the control magnetic paths of adjacent magnetic poles.

[0031] In one embodiment, the magnetic isolation groove 9 is filled with magnetic isolation material.

[0032] In one embodiment, a magnetic isolation block 10 is installed in the magnetic isolation groove 9 .

[0033] By filling the magnetic isolation material in the magnetic isolation groove 9 or installing the magnetic isolation block 10, the structural strength of the bearing stator core 1 can be strengthened. At the same time, through the magnetic isolation effect of the magnetic isolation material or the magnetic isolation block 10, the electromagnetic flux can be guided to flow to the radial magnetic conductive ring 3, and at the same time, the permanent magnetic flux can be diverted.

[0034] In one embodiment, the magnetic isolation groove 9 extends to the mounting groove 7, which can more effectively isolate the circumferential magnetic circuit on the radial outside of the permanent magnet 8, avoid coupling of the control magnetic circuits of adjacent magnetic poles, reduce the control difficulty of the radial control winding 6, and improve the radial adjustment accuracy.

[0035] In one embodiment, a magnetic bridge 11 is provided between the magnetic isolation slot 9 and the mounting slot 7, which can isolate the magnetic isolation slot 9 and the mounting slot 7 and play a role in strengthening the connection, thereby effectively improving the structural strength of the stator core.

[0036] In one embodiment, the cross-sectional shape of the magnetic isolation groove 9 is rectangular, arc-shaped, V-shaped or U-shaped. The size and shape of the magnetic isolation groove 9 should be determined according to the requirements of the bearing magnetic circuit.

[0037] In this embodiment, the stator core 1 is a silicon steel sheet laminate structure, including 8 magnetic poles, of which four magnetic poles are winding magnetic poles, and the other four spaced magnetic poles are provided with mounting grooves 7, and permanent magnets 8 are installed in the mounting grooves 7.

[0038] In one embodiment, the width of the permanent magnet 8 is L1, the width of the stator tooth 5 is L2, and 0.7≤L1 / L2≤0.95. In this embodiment, the width direction of the stator tooth 5 is the circumferential direction. By limiting the relationship between the width of the permanent magnet 8 and the width of the stator tooth 5, the thickness of the stator teeth 5 on both sides of the permanent magnet 8 can be reduced while ensuring the structural strength of the mounting slot 7, and the control magnetic circuit can be avoided from passing through the stator teeth 5 on both sides of the permanent magnet 8, effectively reducing magnetic leakage.

[0039] See also Figure 5 and Figure 6 As shown, the magnetic circuit structure of the homopolar radial magnetic bearing of the embodiment of the present application is shown, wherein Figure 5 The bias flux magnetic circuit of the bearing is provided by the permanent magnet 8. The bias flux flows out from the permanent magnet 8, passes through the winding poles adjacent to it in two ways, passes through the rotor 2, and then flows back to the permanent magnet 8. The plane where the bias flux is located is perpendicular to the central axis of the rotor 2. Figure 6The figure shows the control magnetic flux circuit of the bearing, which is generated by the radial control winding 6. The magnetic flux generated starts from the winding pole, flows through the radial magnetic ring 3 and the rotor 2, and then returns to the winding pole. The plane where the control magnetic flux is located is parallel to the central axis of the rotor 2.

[0040] The working principle of the homopolar radial magnetic bearing of the embodiment of the present application is as follows: 4 radial control windings 6 are wound on the stator core 1 to provide radial control current; the radially magnetized permanent magnets 8 provide a static bias magnetic field. When the rotor 2 is subjected to a downward disturbance force and deviates from the equilibrium position, the displacement sensor detects the displacement of the rotor 2 from its reference position. The controller changes this displacement signal into a control signal, passes current into the control coil, and the generated control flux is superimposed with the bias flux in the radial air gap to synthesize an upward unipolar flux, so that the rotor 2 returns to the equilibrium position. Similarly, whether the rotor 2 is subjected to an upward, leftward or rightward disturbance force, the rotor 2 can be returned to the equilibrium position by superimposing the control flux and the bias flux.

[0041] According to an embodiment of the present application, the compressor includes a homopolar radial magnetic bearing, which is the above-mentioned homopolar radial magnetic bearing.

[0042] According to an embodiment of the present application, the air conditioner includes a homopolar radial magnetic bearing, which is the above-mentioned homopolar radial magnetic bearing.

[0043] It is easy for those skilled in the art to understand that, under the premise of no conflict, the above-mentioned advantageous methods can be freely combined and superimposed.

[0044] The above are only preferred embodiments of the present application and are not intended to limit the present application. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present application shall be included in the protection scope of the present application. The above are only preferred implementations of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and variations can be made without departing from the technical principles of the present application, and these improvements and variations should also be regarded as the protection scope of the present application.

Claims

1. A homopolar radial magnetic bearing, characterized in that: The invention comprises a stator core (1), a rotor (2) and a radial magnetic conductive ring (3), wherein the stator core (1) comprises a yoke (4) and stator teeth (5), a portion of the stator teeth (5) is provided with a radial control winding (6), a portion of the stator teeth (5) is provided with a mounting groove (7), a permanent magnet (8) is mounted in the mounting groove (7), the stator teeth (5) provided with the radial control winding (6) and the stator teeth (5) provided with the permanent magnet (8) are arranged alternately along the circumference of the rotor (2), a magnetic isolation groove (9) is provided on the radial outer side of the permanent magnet (8), the bias magnetic field generated by the permanent magnet (8) forms a bias magnetic circuit via the yoke (4), the stator teeth (5) and the rotor (2), and the control magnetic field generated by the radial control winding (6) forms a control magnetic circuit via the stator teeth (5), the rotor (2) and the radial magnetic conductive ring (3); The width of the permanent magnet (8) is L1, the width of the stator tooth (5) is L2, and 0.7≤L1 / L2≤0.

95.

2. The homopolar radial magnetic bearing according to claim 1, characterized in that: The magnetic isolation groove (9) penetrates the stator core (1) in the axial direction.

3. The homopolar radial magnetic bearing according to claim 1 or 2, characterized in that: The magnetic isolation groove (9) is filled with magnetic isolation material.

4. The homopolar radial magnetic bearing according to claim 1 or 2, characterized in that: A magnetic isolation block (10) is installed in the magnetic isolation groove (9).

5. The homopolar radial magnetic bearing according to claim 1, characterized in that: The magnetic isolation groove (9) extends to the mounting groove (7).

6. The homopolar radial magnetic bearing according to claim 1, characterized in that: A magnetic bridge (11) is provided between the magnetic isolation groove (9) and the mounting groove (7).

7. The homopolar radial magnetic bearing according to claim 1, characterized in that: The cross-sectional shape of the magnetic isolation groove (9) is rectangular, arc-shaped, V-shaped or U-shaped.

8. A compressor, characterized in that: It comprises a homopolar radial magnetic bearing, and the homopolar radial magnetic bearing is the homopolar radial magnetic bearing according to any one of claims 1 to 7.

9. An air conditioner, characterized in that: It comprises a homopolar radial magnetic bearing, and the homopolar radial magnetic bearing is the homopolar radial magnetic bearing according to any one of claims 1 to 7.

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