Permanent magnet biased radial magnetic bearing and magnetic bearing rotating machine

Abstract

The application provides a permanent magnet bias radial magnetic suspension bearing and a magnetic suspension rotating machine, which comprises a stator assembly, a main shaft and a control unit; the stator assembly comprises an end magnetic conducting plate, a permanent magnet assembly and a stator core with a control coil embedded in sequence along the up and down coaxial stacking; the main shaft is coaxially inserted into the stator assembly, an end air gap is formed between the outer peripheral wall of the main shaft and the inner peripheral end surface of the end magnetic conducting plate, and an electromagnet air gap is formed between the outer peripheral wall of the main shaft and the inner peripheral end of the stator core; the control unit drives the control coil to generate control current in the positive and negative directions. The permanent magnet assembly is used to provide a bias magnetic field for the permanent magnet bias radial hybrid magnetic suspension bearing and to provide an electromagnetic force unloading working magnetic field for the radial passive magnetic suspension bearing, and the electromagnetic coil is used to provide a suspension control magnetic field for the magnetic suspension bearing, so that the radial suspension active control and the radial bias load passive unloading of the rotor can be realized.

Description

Technical Field

[0001] This application belongs to the field of magnetic levitation technology, and particularly relates to a permanent magnet biased radial magnetic levitation bearing and a magnetic levitation rotating machine. Background Technology

[0002] In most magnetically levitated rotating machinery used in industrial applications, such as magnetically levitated pumps, fans, spindles, and energy storage flywheels, the magnetic bearing support system needs to provide a constant radial force to unload the radial offset load borne by the rotor, thus controlling the rotor's radial levitation, due to factors such as inlet and outlet pressures, reaction forces from the machined surfaces, and rotor gravity. Existing radial electromagnetic or permanent magnet offset magnetic bearings typically use control coils to generate a control current proportional to the radial bearing load to provide a radial electromagnetic force, unloading the rotor's constant radial load. However, this increases the power consumption of the magnetic bearing. Some magnetic bearings employ asymmetric structures or asymmetric air gaps to generate a passive radial electromagnetic force to unload the offset load without consuming power, thus reducing the power consumption of the magnetic bearing. However, this increases the nonlinearity of the electromagnetic force, making the system prone to saturation, reducing control margin, and decreasing system reliability. Summary of the Invention

[0003] This application provides a permanent magnet biased radial magnetic levitation bearing and a magnetic levitation rotating machine to solve the technical problems of high power consumption and inability to efficiently provide radial bias load unloading capacity of existing radial magnetic levitation bearings.

[0004] In a first aspect, embodiments of this application provide a permanent magnet biased radial magnetic levitation bearing, the permanent magnet biased radial magnetic levitation bearing comprising:

[0005] The stator assembly includes end magnetic plates, permanent magnet assembly, and stator core with embedded control coils, which are coaxially stacked in sequence from top to bottom.

[0006] The main shaft is coaxially inserted into the stator assembly. An end air gap is formed between the outer peripheral wall of the main shaft and the inner peripheral end face of the end magnetic plate, and an electromagnet air gap is formed between the outer peripheral wall of the main shaft and the inner peripheral end of the stator core.

[0007] The control unit is used to drive the control coil to generate control current in positive and negative directions.

[0008] Optionally, the stator core includes an outer yoke and multiple pairs of magnetic pole groups extending inward from the end of the outer yoke. Each pair of magnetic pole groups and the inner peripheral wall of the outer yoke form a receiving groove with an opening facing the main shaft. Each receiving groove corresponds to accommodating one control coil.

[0009] Optionally, the magnetic pole assembly includes two magnetic poles arranged axially spaced apart, the two magnetic poles extending radially toward the main shaft from the top and bottom faces of the outer yoke, respectively, and an electromagnet air gap is formed between the end of each magnetic pole and the outer peripheral wall of the main shaft.

[0010] Optionally, the permanent magnet assembly includes a plurality of permanent magnets arranged at uniform intervals along the axial direction, the permanent magnets being magnetized along the axial direction.

[0011] Optionally, the end magnetic guide plate has a circular structure, and the end face of the end magnetic guide plate is hollowed out and divided into multiple evenly spaced magnetic guide parts. The magnetic guide parts and the magnetic poles have the same shape and size, and the end air gap is formed between the end of the magnetic guide part and the outer peripheral wall of the main shaft.

[0012] Optionally, the number of permanent magnets, magnetic poles, and control coils are the same and they are arranged in a one-to-one correspondence in the axial direction.

[0013] Optionally, the permanent magnet biased radial magnetic levitation bearing further includes a displacement sensor, which is used to detect the radial offset of the rotor and send a deviation signal. The control unit is communicatively connected to the displacement sensor and configured to:

[0014] Receive the deviation signal sent by the displacement sensor;

[0015] Based on the deviation signal, the control coil is driven to generate a control current corresponding to the offset of the rotor.

[0016] Optionally, the end magnetic guide plate and the stator core are both made of one or more magnetic materials selected from carbon steel, electrical pure iron, ferrite or amorphous alloy.

[0017] Optionally, the control coil is a multi-turn coil made of enameled coil wound in a circumferential manner.

[0018] Secondly, embodiments of this application also provide a magnetically levitated rotating machine, which includes a permanent magnet biased radial magnetic levitation bearing as described above.

[0019] The permanent magnet biased radial magnetic levitation bearing provided in this application has its main shaft coaxially inserted into the stator assembly. An end air gap is formed between the outer peripheral wall of the main shaft and the inner peripheral end face of the end magnetic guide plate, and an electromagnet air gap is formed between the outer peripheral wall of the main shaft and the inner peripheral end of the stator core. A control unit drives the control coil to generate control currents in positive and negative directions. The magnetic levitation bearing of this application integrates a permanent magnet biased hybrid radial magnetic levitation bearing and a passive radial magnetic levitation bearing. The permanent magnet provides both the bias magnetic field for the permanent magnet biased radial hybrid magnetic levitation bearing and the electromagnetic unloading working magnetic field for the radial passive magnetic levitation bearing. The electromagnetic coil provides the levitation control magnetic field for the permanent magnet biased radial hybrid magnetic levitation bearing, which can realize the active control of the rotor's radial levitation and the passive unloading of the radial bias load. Furthermore, the permanent magnet biased radial magnetic levitation bearing of this application has a simple and compact structure and low manufacturing cost. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings. In the following description, the same reference numerals denote the same parts.

[0022] Figure 1 This is a schematic diagram of the structure of a permanent magnet biased radial magnetic levitation bearing provided in an embodiment of this application;

[0023] Figure 2 A partial structural schematic diagram of a permanent magnet biased radial magnetic levitation bearing provided in an embodiment of this application;

[0024] Figure 3 This is a schematic diagram illustrating the working principle of the permanent magnet biased radial magnetic levitation bearing provided in the embodiments of this application.

[0025] Explanation of reference numerals in the attached figures:

[0026] 10. Stator assembly; 11. End magnetic guide plate; 111. Magnetic guide section; 12. Permanent magnet assembly; 121. Permanent magnet; 13. Stator core; 131. Outer yoke; 132. Magnetic pole group; 133. Receiving slot; 14. Control coil; 15. End air gap; 16. Electromagnet air gap; 20. Displacement sensor; 30. Bias magnetic field; 40. Suspension control magnetic field; 50. Spindle. Detailed Implementation

[0027] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the scope of protection of this application.

[0028] Magnetic bearings utilize the magnetic force generated by an electromagnetic field to control the position of an object and thus support it. Because their stator and rotor do not need to contact, magnetic bearings offer advantages such as no wear, long lifespan, low loss, high peak speed, and no lubrication required, leading to their widespread application in defense, industrial control, and aerospace fields. Magnetic bearings are generally classified into axial and radial types. Radial magnetic bearings are typically used to non-contactly constrain the translational degrees of freedom of rotating objects along a direction perpendicular to the axis of rotation, and are an indispensable key component in magnetically levitated placement equipment. Existing radial magnetic bearings typically employ a multi-pair electromagnet thrust pole structure. These bearings usually use a constant current in the control coil 14 to generate a bias magnetic field 30 to avoid the limitations imposed on the dynamic performance of the bearing by magnetic hysteresis effects and to improve the bearing's stiffness. However, the constant current flowing through the coil generates losses, significantly increasing the power consumption of the bearing, producing excessive heat, and deteriorating the bearing's operating environment. To avoid this problem, some existing technologies typically use a permanent magnet 121 to provide a bias electromagnetic field for the radial magnetic bearing, thereby reducing the power consumption of existing radial magnetic bearings. However, these permanent magnet biased magnetic levitation bearings generally have a complex structure, low electromagnetic load capacity or stiffness, are difficult to manufacture, and cannot provide efficient unloading of biased loads.

[0029] To address the technical problems of high power consumption and inefficient axial offset load unloading capabilities in existing axial permanent magnet biased radial magnetic levitation bearings, this application provides a permanent magnet biased radial magnetic levitation bearing and a magnetic levitation rotating mechanism. This bearing can be widely used in magnetic levitation pumps, fans, main shafts 50, and energy storage flywheels to provide low-power, high-efficiency, and structurally simple magnetic levitation supports. The following description, in conjunction with the accompanying drawings, will illustrate this feature.

[0030] like Figure 1 As shown, the permanent magnet biased radial magnetic levitation bearing of this application includes a stator assembly 10, a main shaft 50, and a control unit; the stator assembly 10 includes an end magnetic plate 11, a permanent magnet assembly 12, and a stator core 13 with a control coil 14 embedded therein, which are coaxially stacked in sequence from top to bottom; the main shaft 50 is coaxially inserted into the stator assembly 10, and an end air gap 15 is formed between the outer peripheral wall of the main shaft 50 and the inner peripheral end face of the end magnetic plate 11, and an electromagnet air gap 16 is formed between the outer peripheral wall of the main shaft 50 and the inner peripheral end of the stator core 13; the control unit is used to drive the control coil 14 to generate control current in positive and negative directions.

[0031] The magnetic levitation bearing of this application integrates a permanent magnet biased hybrid radial magnetic levitation bearing and a passive radial magnetic levitation bearing. The permanent magnet 121 provides both the bias magnetic field 30 for the permanent magnet biased radial hybrid magnetic levitation bearing and the electromagnetic force unloading working magnetic field for the radial passive magnetic levitation bearing. The electromagnetic coil provides the levitation control magnetic field 40 for the permanent magnet biased radial hybrid magnetic levitation bearing. This enables active control of the rotor's radial levitation and passive unloading of the radial bias load, achieving zero-current bias of the permanent magnet biased radial hybrid magnetic levitation bearing and zero-current unloading of the bias load. Furthermore, the permanent magnet biased radial magnetic levitation bearing of this application has a simple and compact structure and low manufacturing cost.

[0032] Optionally, the permanent magnet biased radial magnetic levitation bearing also includes a displacement sensor 20, which is used to detect the radial offset of the rotor and send a deviation signal. The control unit is communicatively connected to the displacement sensor 20 and configured as follows:

[0033] Receive the deviation signal sent by the displacement sensor 20;

[0034] Based on the deviation signal, the drive control coil 14 generates a control current corresponding to the rotor's offset.

[0035] The working principle of the permanent magnet biased radial magnetic levitation bearing with biased load unloading capacity in this application is as follows: Figure 3 As shown, specifically:

[0036] The permanent magnet 121, located between the end magnetic plate 11 and the stator core 13 containing the coil, is axially magnetized, possessing an axial magnetomotive force, and generating permanent magnet flux. This flux flows through the left and right permanent magnets 121, the end magnetic plate 11, the end air gap 15, the main shaft 50, the electromagnet air gap 16, and the stator core 13, returning to the permanent magnet assembly 12. This flux flows through the end air gap 15, forming an electromagnetic field in the end air gap 15. This field, through the end magnetic plate 11, generates a radial passive electromagnetic force acting on the shaft end. Through the design of the left and right permanent magnets 121, this electromagnetic force is of the same magnitude but opposite in direction to the external load borne by the rotor, thus unloading the radial offset load carried by the rotor. The flux generated by the permanent magnet 121 flows through the electromagnet air gap 16, generating a control bias magnetic field 30. When the rotor has no radial offset, there is no control current in the control coil 14. The bias magnetic field 30 in the electromagnet air gap 16 generates an electromagnetic force acting on the shaft through the stator core 13. The electromagnetic forces in the electromagnet air gap 16 are of the same magnitude but opposite in direction, thus canceling each other out. When the rotor experiences radial offset, the displacement sensor 20 measures this error and inputs the error signal to the magnetic levitation bearing controller, driving the control coil 14 to generate a controllable current related to the rotor offset. This control current generates a levitation control magnetic field 40. The levitation control magnetic field 40 returns to the stator core 13 via the stator core 13, the electromagnet air gap 16, and the main shaft 50, forming a loop. When the control coil 14 is energized with current of different magnitudes or directions, it generates a levitation control magnetic field 40 of different magnitudes and directions. This magnetic field 40 is superimposed on the bias magnetic field 30 in the air gap 16 of the electromagnet, making the magnetic field magnitudes of the air gap 16 on the left and right sides of the main shaft 50 different. This generates an unbalanced electromagnetic force on the main shaft 50 through the stator core 13. This electromagnetic force is opposite to the direction of rotor offset, causing the rotor to return to the radial balance position.

[0037] The aforementioned permanent magnet biased radial magnetic levitation bearing with biased load unloading capability can generate passive electromagnetic force to unload the radial biased load of the rotor, and can also generate levitation control electromagnetic force in multiple radial degrees of freedom directions.

[0038] Optionally, the stator core 13 includes an outer yoke 131 and multiple pairs of magnetic pole groups 132 extending inward from the end of the outer yoke 131. Any two adjacent magnetic pole groups 132 are spaced apart with the same spacing. The multiple pairs of magnetic pole groups 132 are arranged around the outer wall of the main shaft 50, and their arrangement forms a closed ring structure. Each pair of magnetic pole groups 132 and the inner peripheral wall of the outer yoke 131 form a receiving groove 133 with an opening facing the main shaft 50. Each receiving groove 133 corresponds to accommodating a control coil 14. In this way, the current generated by the control coil 14 can surround the entire main shaft 50, providing a basis for unloading the radial bias load.

[0039] Furthermore, such as Figure 2As shown, the magnetic pole assembly 132 includes two magnetic poles arranged axially at intervals. The two magnetic poles extend radially toward the main shaft 50 from the top and bottom end faces of the outer yoke 131, respectively, so that the upper and lower magnetic poles and the outer yoke 131 form a receiving groove 133. An identical electromagnet air gap 16 is formed between the end of each magnetic pole and the outer peripheral wall of the main shaft 50. When the control coil 14 is energized, a radial active levitation control electromagnetic force can be generated on the side of the electromagnet air gap 16. Furthermore, from the top to the bottom, the inner ends of the magnetic pole assembly 132 of each stator core 13 form an installation space for the main shaft 50 to be inserted, so as to ensure the coaxiality of the main shaft 50 during installation.

[0040] Optionally, the permanent magnet assembly 12 includes a plurality of permanent magnets 121 evenly spaced along the axial direction. The permanent magnets 121 are magnetized along the axial direction. The permanent magnets 121 can be rare earth permanent magnets, ferrite permanent magnets, or iron-nickel permanent magnets, etc. The plurality of permanent magnets 121 correspond to multiple magnetic poles and control coils 14. The magnetization is carried out axially, and the magnetization direction can be upward or downward. The upper end face of each magnet abuts against the magnetic conductive part 111, and the lower end face is arranged on the magnetic pole located above. The outer peripheral wall of the permanent magnet 121, the outer yoke 131, and the outer peripheral wall of the end magnetic conductive plate 11 all coincide in the circumferential direction.

[0041] Optionally, the end magnetic plate 11 has a circular ring structure. The end face of the end magnetic plate 11 is hollowed out and divided into multiple evenly spaced magnetic conductive parts 111. The magnetic conductive parts 111 and the magnetic poles have the same shape and size. An end air gap 15 is formed between the end of the magnetic conductive part 111 and the outer peripheral wall of the main shaft 50. When the control coil 14 is energized, a radial passive unloading electromagnetic force can be generated in the end air gap 15. All magnetic conductive parts 111 have the same shape and size, and the distance between any two adjacent magnetic conductive parts 111 is equal. The shape of the magnetic conductive parts 111 and the magnetic poles can be triangular, trapezoidal, etc., and is not limited here. However, regardless of the shape of the magnetic conductive parts 111 and the magnetic poles, the end face facing the main shaft 50 needs to be set as an arc-shaped concave surface to fit the outer peripheral wall of the main shaft 50. This ensures that the end air gap 15 formed between each magnetic conductive part 111 and the main shaft 50 is the same.

[0042] To ensure that the center position of the spindle 50 is not offset, the number of permanent magnets 121, magnetic poles and control coils 14 are the same and they are arranged in a one-to-one correspondence in the axial direction.

[0043] Optionally, the end magnetic plate 11 and the stator core 13 are both made of one or more magnetic materials selected from carbon steel, electrical pure iron, ferrite or amorphous alloy.

[0044] Optionally, the control coil 14 is a multi-turn coil with enameled coil wound in a ring. The multi-turn coil is embedded in the receiving slot 133 of the stator core 13. The control unit drives the multi-turn coil to generate control current in positive and negative directions, thereby generating positive and negative magnetic fields through the stator core 13, forming a magnetic field controllable electromagnet. The field of action is on the main axis 50 to generate a multi-directional active suspension control force with multiple radial translational degrees of freedom.

[0045] Secondly, embodiments of this application also provide a magnetically levitated rotating machine, which includes the permanent magnet biased radial magnetic levitation bearing described above. Since this magnetically levitated rotating machine employs all embodiments of the aforementioned permanent magnet biased radial magnetic levitation bearing, it possesses all the beneficial effects brought about by the permanent magnet biased radial magnetic levitation bearing, which will not be elaborated upon here.

[0046] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0047] In the description of this invention, it should be understood that the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0048] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a connection that allows communication between them; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0049] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0050] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A permanent magnet biased radial magnetic levitation bearing, characterized in that, The permanent magnet biased radial magnetic levitation bearing includes: The stator assembly includes end magnetic plates, permanent magnet assembly, and stator core with embedded control coils, which are coaxially stacked in sequence from top to bottom. The main shaft is coaxially inserted into the stator assembly. An end air gap is formed between the outer peripheral wall of the main shaft and the inner peripheral end face of the end magnetic plate, and an electromagnet air gap is formed between the outer peripheral wall of the main shaft and the inner peripheral end of the stator core. A control unit is used to drive the control coil to generate control current in positive and negative directions; The stator core includes an outer yoke and multiple pairs of magnetic pole groups extending inward from the end of the outer yoke. Each pair of magnetic pole groups and the inner peripheral wall of the outer yoke form a receiving groove with an opening facing the main shaft. Each receiving groove corresponds to accommodating one control coil. The magnetic pole group includes two magnetic poles arranged axially spaced apart. The two magnetic poles extend radially towards the main shaft from the top and bottom end faces of the outer yoke, respectively. An electromagnet air gap is formed between the end of each magnetic pole and the outer peripheral wall of the main shaft. The permanent magnet assembly includes multiple permanent magnets arranged uniformly spaced axially and magnetized axially. The end magnetic guide plate has a circular structure. The end face of the end magnetic guide plate is hollowed out and divided into multiple uniformly spaced magnetic guide parts. The magnetic guide parts and the magnetic poles have the same shape and size. An end air gap is formed between the end of the magnetic guide part and the outer peripheral wall of the main shaft.

2. The permanent magnet biased radial magnetic levitation bearing according to claim 1, characterized in that, The number of permanent magnets, magnetic poles, and control coils are the same, and they are arranged in a one-to-one correspondence in the axial direction.

3. The permanent magnet biased radial magnetic levitation bearing according to claim 1 or 2, characterized in that, The permanent magnet biased radial magnetic levitation bearing also includes a displacement sensor, which is used to detect the radial offset of the rotor and send a deviation signal. The control unit is communicatively connected to the displacement sensor and configured to: Receive the deviation signal sent by the displacement sensor; Based on the deviation signal, the control coil is driven to generate a control current corresponding to the offset of the rotor.

4. The permanent magnet biased radial magnetic levitation bearing according to claim 1 or 2, characterized in that, Both the end magnetic guide plate and the stator core are made of one or more magnetic materials selected from carbon steel, electrical pure iron, ferrite, or amorphous alloy.

5. The permanent magnet biased radial magnetic levitation bearing according to claim 1 or 2, characterized in that, The control coil is a multi-turn coil made of enameled coil wound in a circular manner.

6. A magnetically levitated rotating machine, characterized in that, The magnetically levitated rotating machinery includes a permanent magnet biased radial magnetic levitation bearing as described in any one of claims 1 to 5.

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