Magnetic bearing system, control method and device thereof, equipment, storage medium and product

Abstract

The invention discloses a control method and device of a magnetic bearing system, the magnetic bearing system, equipment, a storage medium and a computer program product, and the method comprises the steps: obtaining the displacement of a rotor in the magnetic bearing system under the operation condition of the magnetic bearing system, and obtaining the rotating speed of the rotor; according to the displacement of the rotor and the rotor of the rotor, whether the rotor collides with a protection bearing in the magnetic bearing system or not is determined; and if it is determined that the rotor collides with the protection bearing, a magnetic bearing in the magnetic bearing system is controlled to increase the iron loss torque of the rotor, so that the rotating speed of the rotor is reduced. According to the scheme, the rotor is accelerated to stop rotating when the rotor is collided, the rotor and the protective bearing are protected, and the reliability of the magnetic bearing system is improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of magnetic bearing systems (i.e., magnetic levitation bearing systems), and specifically relates to a control method, device, magnetic bearing system, equipment (such as a magnetic levitation motor, a magnetic levitation compressor), storage medium and computer program product of a magnetic bearing system, and especially relates to a collision control method, device, magnetic levitation bearing system, equipment (such as a magnetic levitation motor, a magnetic levitation compressor), storage medium and computer program product of a magnetic levitation bearing system. Background Art

[0002] The magnetic levitation motor uses electromagnetic bearings to suspend the rotor at a given position, thereby achieving frictionless operation, and has the advantages of high speed, low loss, and maintenance-free. However, during the operation of the magnetic levitation motor, if the magnetic bearing system (i.e., magnetic levitation bearing system or magnetic bearing control system) is abnormal, the rotor will become unstable, causing losses to the rotor and protective bearings, and even damaging the motor.

[0003] The above contents are only used to assist in understanding the technical solution of the present invention and do not constitute an admission that the above contents are prior art. Summary of the invention

[0004] The purpose of the present invention is to provide a control method, device, magnetic bearing system, equipment (such as magnetic levitation motor, magnetic levitation compressor), storage medium and computer program product of a magnetic bearing system, so as to solve the problem that when the magnetic bearing system is abnormal during the operation of the magnetic levitation motor, the rotor will become unstable, causing losses to the rotor and protective bearings or even damaging the motor, so as to achieve the effect of accelerating the rotor to stop when the rotor collides, protecting the rotor and protective bearings, and improving the reliability of the magnetic bearing system.

[0005] The present invention provides a control method for a magnetic bearing system, the magnetic bearing system comprising: a magnetic bearing, a rotor and a protective bearing; the control method for the magnetic bearing system comprises: when the magnetic bearing system is running, obtaining the displacement of the rotor and the rotational speed of the rotor; determining whether the rotor collides with the protective bearing according to the displacement of the rotor and the rotational speed of the rotor; if it is determined that the rotor has collided with the protective bearing, controlling the magnetic bearing to increase the iron loss torque of the rotor to reduce the rotational speed of the rotor.

[0006] In some embodiments, determining whether the rotor collides with the protective bearing based on the displacement of the rotor and the rotor of the rotor includes: determining a speed range corresponding to the rotation speed of the rotor, recorded as the current rotation speed range of the rotor; and determining the corresponding displacement protection number according to the current rotation speed range of the rotor, recorded as the current displacement protection number of the rotor; wherein different speed ranges correspond to different displacement protection numbers; determining whether the displacement of the rotor is greater than a preset threshold within a set time period: if so, accumulating and counting the number of times the displacement of the rotor is greater than the preset threshold to obtain the cumulative number of times the displacement of the rotor is greater than the preset threshold; determining whether the rotation speed of the rotor is zero; if it is determined that the rotation speed of the rotor is zero, controlling the rotor to stop floating; if it is determined that the rotation speed of the rotor is not zero, determining whether the cumulative number of times the displacement of the rotor is greater than the preset threshold is greater than or equal to the current displacement protection number of the rotor: if so, determining that the rotor has collided with the protective bearing; otherwise, determining that the rotor has not collided with the protective bearing.

[0007] In some embodiments, the magnetic bearing has a coil, and the number of coils in the magnetic bearing is more than one; controlling the magnetic bearing to increase the iron loss torque of the rotor to reduce the rotational speed of the rotor includes: controlling the current of more than one coil in the magnetic bearing to increase the iron loss torque of the rotor to reduce the rotational speed of the rotor.

[0008] In some embodiments, the current of one or more coils in the magnetic bearing is controlled to increase the iron loss torque of the rotor and reduce the rotational speed of the rotor, including: controlling each of the one or more coils in the magnetic bearing to output a preset fixed current to increase the iron loss torque of the rotor and reduce the rotational speed of the rotor; wherein the preset fixed current is the maximum current that the magnetic bearing can carry for at least a certain period of time.

[0009] In some embodiments, controlling the current of one or more coils in the magnetic bearing to increase the iron loss torque of the rotor and reduce the rotational speed of the rotor also includes: if the arrangement of one or more coils in the magnetic bearing is an NSSN arrangement driven by a full-bridge power amplifier, then controlling the output current direction of the full-bridge power amplifier of the one or more coils in the magnetic bearing to be a preset direction, so that the arrangement of the one or more coils in the magnetic bearing is changed from an NSSN arrangement to an NSNS arrangement, so as to increase the remagnetization frequency of the magnetic bearing, increase the iron loss torque of the rotor, and reduce the rotational speed of the rotor.

[0010] In some embodiments, it also includes: after controlling the magnetic bearing to increase the iron loss torque of the rotor to reduce the speed of the rotor, until the speed of the rotor is reduced to a preset speed range, re-controlling the rotor suspension, and then returning to determine whether the rotor collides with the protective bearing based on the displacement of the rotor and the rotor of the rotor, and repeating the cycle.

[0011] Matching the above method, the present invention provides a control device for a magnetic bearing system on the other hand, the magnetic bearing system comprising: a magnetic bearing, a rotor and a protective bearing; the control device for the magnetic bearing system comprising: an acquisition unit configured to acquire the displacement of the rotor and the rotational speed of the rotor when the magnetic bearing system is running; a control unit configured to determine whether the rotor collides with the protective bearing based on the displacement of the rotor and the rotor of the rotor; the control unit is also configured to control the magnetic bearing to increase the iron loss torque of the rotor to reduce the rotational speed of the rotor if it is determined that the rotor has collided with the protective bearing.

[0012] In some embodiments, the control unit determines whether the rotor collides with the protective bearing based on the displacement of the rotor and the rotor of the rotor, including: determining the speed interval corresponding to the speed of the rotor, recorded as the current speed interval of the rotor; and determining the corresponding displacement protection number according to the current speed interval of the rotor, recorded as the current displacement protection number of the rotor; wherein different speed intervals correspond to different displacement protection numbers; determining whether the displacement of the rotor is greater than a preset threshold within a set time period: if so, accumulating and counting the number of times the displacement of the rotor is greater than the preset threshold to obtain the cumulative number of times the displacement of the rotor is greater than the preset threshold; determining whether the speed of the rotor is zero; if it is determined that the speed of the rotor is zero, controlling the rotor to stop floating; if it is determined that the speed of the rotor is not zero, determining whether the cumulative number of times the displacement of the rotor is greater than the preset threshold is greater than or equal to the current displacement protection number of the rotor: if so, determining that the rotor has collided with the protective bearing; otherwise, determining that the rotor has not collided with the protective bearing.

[0013] In some embodiments, the magnetic bearing has a coil, and the number of coils in the magnetic bearing is more than one; the control unit controls the magnetic bearing to increase the iron loss torque of the rotor to reduce the rotational speed of the rotor, including: controlling the current of more than one coil in the magnetic bearing to increase the iron loss torque of the rotor to reduce the rotational speed of the rotor.

[0014] In some embodiments, the control unit controls the current of one or more coils in the magnetic bearing to increase the iron loss torque of the rotor and reduce the speed of the rotor, including: controlling each of the one or more coils in the magnetic bearing to output a preset fixed current to increase the iron loss torque of the rotor and reduce the speed of the rotor; wherein the preset fixed current is the maximum current that the magnetic bearing can carry for at least a certain period of time.

[0015] In some embodiments, the control unit controls the current of one or more coils in the magnetic bearing to increase the iron loss torque of the rotor and reduce the speed of the rotor, and also includes: if the arrangement of one or more coils in the magnetic bearing is an NSSN arrangement driven by a full-bridge power amplifier, then the output current direction of the full-bridge power amplifier of the one or more coils in the magnetic bearing is controlled to be a preset direction, so that the arrangement of the one or more coils in the magnetic bearing is changed from an NSSN arrangement to an NSNS arrangement, so as to increase the remagnetization frequency of the magnetic bearing, increase the iron loss torque of the rotor, and reduce the speed of the rotor.

[0016] In some embodiments, it also includes: the control unit is also configured to control the magnetic bearing to increase the iron loss torque of the rotor to reduce the speed of the rotor, until the speed of the rotor is reduced to a preset speed range, re-control the rotor suspension, and then return to determine whether the rotor collides with the protective bearing based on the displacement of the rotor and the rotor of the rotor, and repeat this cycle.

[0017] Matching the above-mentioned device, the present invention further provides a magnetic bearing system on the other hand, including: the control device of the magnetic bearing system mentioned above.

[0018] Matching the above-mentioned device, the present invention further provides a magnetic bearing device on the other hand, including: the control device of the magnetic bearing system described above, or the magnetic bearing system described above; wherein the magnetic bearing device is a magnetic levitation motor or a magnetic levitation compressor.

[0019] In accordance with the above method, the present invention provides a storage medium on the other hand, wherein the storage medium includes a stored program, wherein when the program is running, the device where the storage medium is located is controlled to execute the steps of the control method of the magnetic bearing system described above.

[0020] In accordance with the above method, the present invention further provides a computer program product, comprising a computer program, which implements the steps of the above method for controlling a magnetic bearing system when executed by a processor.

[0021] Therefore, the scheme of the present invention determines whether the rotor collides according to the displacement and rotation speed of the rotor in the magnetic suspension bearing system, and controls each coil of the magnetic bearing to output a fixed current when it is determined that the rotor collides, until the rotation speed of the rotor drops to a preset speed range and then re-controls the rotor suspension; thereby, by accelerating the rotor to stop when the rotor collides, the rotor and the protective bearing are protected, and the reliability of the magnetic bearing system is improved.

[0022] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention.

[0023] The technical solution of the present invention is further described in detail below through the accompanying drawings and embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 A schematic flow chart of an embodiment of a control method for a magnetic bearing system of the present invention;

[0025] Figure 2 A schematic diagram of a flow chart of an embodiment of determining whether the rotor collides with the protective bearing in the method of the present invention;

[0026] Figure 3 It is a structural schematic diagram of an embodiment of a control device for a magnetic bearing system of the present invention;

[0027] Figure 4 It is a structural schematic diagram of an active radial magnetic bearing structure;

[0028] Figure 5 Schematic diagrams of the structures of the magnetic pole arrangements of radial magnetic bearings, including (a) a schematic diagram of the structure of the NSSN arrangement, and (b) a schematic diagram of the structure of the NSNS arrangement;

[0029] Figure 6 It is a schematic diagram of the relationship between the magnetic flux density B and the magnetomotive force NI;

[0030] Figure 7 Schematic diagrams of the structures of power amplifiers, wherein (a) is a schematic diagram of the structure of a half-bridge power amplifier, and (b) is a schematic diagram of the structure of a full-bridge power amplifier;

[0031] Figure 8 The present invention is a flow chart of a collision control method for a magnetic bearing system.

[0032] In conjunction with the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0033] 1-magnetic bearing; 2-rotor; 3-protective bearing; 102-acquisition unit; 104-control unit. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the specific embodiments of the present invention and the corresponding drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0035] It should be taken into consideration that during the operation of the magnetic levitation motor, if there is an abnormal situation such as mismatch of magnetic bearing control system parameters, hardware circuit failure, or the rotor is suddenly subjected to an external disturbance force greater than the maximum bearing capacity of the magnetic bearing, the rotor will become unstable, causing the rotor to collide and rub violently with the protective bearing at high speed, resulting in loss of protective bearing life or even damage to the motor.

[0036] Therefore, the scheme of the present invention proposes a control method for a magnetic bearing system, specifically a collision control method for a magnetic levitation bearing system, which controls the magnetic bearing to give different control schemes according to the degree of rotor instability collision, accelerates the rotor deceleration when instability occurs, reduces the loss caused by rotor instability and collision friction with the protective bearing, increases the life of the protective bearing, and improves the reliability of the magnetic levitation motor and the magnetic levitation compressor.

[0037] According to an embodiment of the present invention, a control method for a magnetic bearing system is provided. Figure 1 The flow chart of an embodiment of the method of the present invention is shown in FIG. The magnetic bearing system comprises: a magnetic bearing, a rotor and a protective bearing; the rotor is as follows Figure 4 The rotor 2 shown in FIG. Figure 4 The magnetic bearing 1 shown, protects the bearing as Figure 4 The protective bearing 3 shown; Figure 4 Figure 1 is a schematic diagram of the structure of an active radial magnetic bearing. Figure 4 The active radial magnetic bearing structure shown in FIG. 1 comprises a magnetic bearing 1, a rotor 2 and a protective bearing 3; Figure 4 In the active radial magnetic bearing structure shown in FIG. 1 , the air gap between the rotor (i.e., rotor 2) and the protective bearing (i.e., protective bearing 3) in the suspended state is δ. In the solution of the present invention, Figure 1 As shown, the control method of the magnetic bearing system includes: steps S110 to S130.

[0038] In step S110, when the magnetic bearing system is running, the displacement of the rotor and the rotation speed of the rotor are obtained.

[0039] In step S120, it is determined whether the rotor collides with the protection bearing according to the displacement of the rotor and the rotation of the rotor. Figure 8 FIG. 1 is a flow chart of a collision control method for a magnetic bearing system. Figure 8 As shown, the collision control method of the magnetic bearing system includes: step 1, determining whether the rotor collides, and then executing step 2.

[0040] At step S130, if it is determined that the rotor has collided with the protective bearing, the magnetic bearing is controlled to increase the iron loss torque of the rotor to reduce the rotational speed of the rotor. Specifically, the current of the coil in the magnetic bearing is controlled to reduce the rotational speed of the rotor. Of course, after determining whether the rotor has collided with the protective bearing, if it is determined that the rotor has not collided with the protective bearing, the magnetic bearing system is maintained in operation, and returns to re-determine whether the rotor has collided with the protective bearing based on the displacement of the rotor and the rotor of the rotor. The solution of the present invention utilizes the braking torque caused by iron loss to accelerate the rotor to stop. Figure 8 As shown, the collision control method of the magnetic bearing system also includes: step 2, controlling the magnetic bearing to increase the rotor iron loss to accelerate the rotor deceleration, and then executing step 3.

[0041] The scheme of the present invention proposes a collision control scheme for a magnetic levitation bearing system, which controls the magnetic bearing to give different control schemes according to the degree of rotor instability collision, thereby reducing the loss caused to the rotor and the protective bearing by the rotor instability; in this way, the rotor speed is accelerated when instability occurs, the loss caused by the rotor instability and the collision and friction of the protective bearing is reduced, the service life of the protective bearing is increased, the reliability of the magnetic levitation motor is improved, and when the magnetic levitation compressor includes the magnetic levitation motor, the reliability of the magnetic levitation motor and the magnetic levitation compressor is also improved.

[0042] In some embodiments, the specific process of determining whether the rotor collides with the protective bearing according to the displacement of the rotor and the rotor of the rotor in step S120 is described in the following exemplary embodiment.

[0043] Combine the following Figure 2 The flowchart of an embodiment of determining whether the rotor collides with the protective bearing in the method of the present invention is shown, which further illustrates the specific process of determining whether the rotor collides with the protective bearing in step S120, including: steps S210 to S250.

[0044] Step S210, determine the speed range corresponding to the speed of the rotor, recorded as the current speed range of the rotor; and determine the corresponding displacement protection times according to the current speed range of the rotor, recorded as the current displacement protection times of the rotor; wherein different speed ranges correspond to different displacement protection times.

[0045] Step S220, within a set time period, determine whether the displacement of the rotor is greater than a preset threshold: if so, count the number of times the displacement of the rotor is greater than the preset threshold to obtain the cumulative number of times the displacement of the rotor is greater than the preset threshold; otherwise, do not count the number of times the displacement of the rotor is greater than the preset threshold.

[0046] Step S230, determining whether the rotation speed of the rotor is zero.

[0047] Step S240: If it is determined that the rotation speed of the rotor is zero, the rotor is controlled to stop floating.

[0048] Step S250, if it is determined that the rotational speed of the rotor is not zero, determine whether the cumulative number of times the displacement of the rotor is greater than a preset threshold is greater than or equal to the current displacement protection number of the rotor: if so, determine that the rotor has collided with the protection bearing; otherwise, determine that the rotor has not collided with the protection bearing.

[0049] like Figure 8 As shown, the collision control method of the magnetic bearing system also includes: in step 1, measuring the rotor displacement x and the speed R in real time, determining the speed range [R n , R n-1 ], and obtain the displacement protection times P of the preset speed range n , as shown in Table 1. Determine whether the rotor speed is not zero: if the rotor speed is determined to be zero, then stop the floating rotor; if the rotor speed is determined to be not zero, then detect that the displacement value is greater than the protection threshold δ in the time period T 1 The number of times is greater than or equal to the preset number P n When the rotor collides with the protective bearing, the inverter will receive a shutdown command, and the inverter will no longer drag the rotor to rotate. The rotor is in a falling state and enters step 2. Protection threshold δ 1 , which is different from the air gap δ between the rotor 2 and the protective bearing (i.e., the protective bearing 3) in the suspended state. Because the protective bearing has a clearance, the rotor displacement value is likely to be greater than the bearing air gap δ when a collision occurs. The specific value also needs to consider the clearance size of the protective bearing. Therefore, in order to ensure the accuracy of collision judgment, the protection threshold δ 1 The value of is slightly greater than or equal to the protective bearing air gap δ.

[0050] Table 1

[0051]

[0052] For example: the rotor runs at 500Hz, the time period T is 10ms, the displacement sampling frequency is 10k, and the speed range and displacement protection times can be as follows:

[0053] Speed ​​range Displacement protection times [500，400] 8 [400，300] 6 [300，200] 4 [200，100] 2 [100，0] 1

[0054] The real-time measurement of the rotor displacement x can be performed by using a displacement sensor. When the rotor approaches or moves away from the displacement sensor, the output voltage of the displacement sensor changes, and the magnetic bearing control system uses the change in the output voltage of the displacement sensor to measure the displacement.

[0055] In the scheme of the present invention, based on the displacement of the rotor and the rotor of the rotor, it is possible to accurately determine whether the rotor collides with the protective bearing; further, when it is determined that the rotor has collided with the protective bearing, that is, the rotor is unstable, the rotor deceleration is accelerated, the loss caused by the rotor instability and the collision and friction of the protective bearing is reduced, the life of the protective bearing is increased, the reliability of the magnetic levitation motor is improved, and when the magnetic levitation compressor includes the magnetic levitation motor, the reliability of the magnetic levitation motor and the magnetic levitation compressor is also improved.

[0056] In some embodiments, the magnetic bearing has a coil, and the number of coils in the magnetic bearing is more than one. In step S130, controlling the magnetic bearing to increase the iron loss torque of the rotor to reduce the speed of the rotor includes: controlling the current of more than one coil in the magnetic bearing to increase the iron loss torque of the rotor to reduce the speed of the rotor.

[0057] In the scheme of the present invention, when it is determined that the rotor is unstable, the output current I of each coil of the magnetic bearing is controlled to generate a large magnetic flux density, thereby increasing the iron loss braking torque of the magnetic bearing to accelerate the rotor to stop, and when the speed drops to a given speed, the rotor suspension control is restored; thereby, the loss of the protective bearing and the rotor caused by the instability of the rotor is reduced, the service life of the protective bearing is increased, and the reliability of the magnetic levitation motor and the magnetic levitation compressor is improved.

[0058] In some embodiments, the current of one or more coils in the magnetic bearing is controlled to increase the iron loss torque of the rotor and reduce the rotational speed of the rotor, including: controlling each of the one or more coils in the magnetic bearing to output a preset fixed current to increase the iron loss torque of the rotor and reduce the rotational speed of the rotor; wherein the preset fixed current is the maximum current that the magnetic bearing can carry for at least a certain period of time.

[0059] like Figure 8As shown, the collision control method of the magnetic bearing system also includes: in step 2, each coil of the magnetic bearing is controlled to output a fixed current I to generate a large magnetic flux density. Since the rotor is still rotating, the rotor will pass through the magnetic field generated by each magnetic pole in turn, and the generated iron loss braking torque accelerates the rotor to stop. During normal suspension, the current generated by the magnetic bearing is less than the maximum current value I. Because the greater the magnetic flux density, the better the braking effect, I can select the maximum current value that the magnetic bearing is designed to carry for a long time. Controlling each coil of the magnetic bearing to output a fixed current I is to simultaneously control each coil of the magnetic bearing to output a fixed current I, that is, to make each coil of the magnetic bearing output a fixed current I at the same time.

[0060] In the scheme of the present invention, when the rotor becomes unstable, the output current I of each coil of the magnetic bearing is controlled to generate a large magnetic flux density, and the rotor will pass through the magnetic field generated by each magnetic pole in turn, and the generated iron loss braking torque accelerates the rotor to stop. In this way, by increasing the iron loss braking torque of the magnetic bearing to accelerate the rotor to stop, the loss of the protective bearing and the rotor caused by the instability of the rotor is reduced, the service life of the protective bearing is increased, and the reliability of the magnetic levitation motor and the magnetic levitation compressor is improved.

[0061] In some embodiments, controlling the current of one or more coils in the magnetic bearing to increase the iron loss torque of the rotor and reduce the rotational speed of the rotor also includes: if the arrangement of one or more coils in the magnetic bearing is an NSSN arrangement driven by a full-bridge power amplifier, then controlling the output current direction of the full-bridge power amplifier of the one or more coils in the magnetic bearing to be a preset direction, so that the arrangement of the one or more coils in the magnetic bearing is changed from an NSSN arrangement to an NSNS arrangement, so as to increase the remagnetization frequency of the magnetic bearing, increase the iron loss torque of the rotor, and reduce the rotational speed of the rotor.

[0062] Generally, magnetic bearings cannot change the direction of the magnetic poles. However, if the magnetic bearings have an NSSN arrangement where the magnetic poles can be changed, the direction of the current in the magnetic bearing coil can be controlled so that the magnetic poles become NSNS arrangement, thereby increasing the remagnetization frequency and the iron loss torque.

[0063] like Figure 8 As shown, the collision control method of the magnetic bearing system further includes: in step 2, Figure 7 The following are schematic diagrams of the structure of power amplifiers, where (a) is a schematic diagram of the structure of a half-bridge power amplifier and (b) is a schematic diagram of the structure of a full-bridge power amplifier. Commonly used power amplifiers include half-bridge power amplifiers and full-bridge power amplifiers, such as Figure 7 As shown in the figure, a half-bridge amplifier can only output current in one direction, while a full-bridge amplifier can output current in both directions. If the NSSN magnetic bearings driven by a full-bridge amplifier are arranged, the output current direction of the amplifier can be controlled according to Figure 5As shown in (b), the magnetic poles are arranged in NSNS order, thereby increasing the remagnetization frequency and the iron loss torque. The current amplitude selects the maximum current value I that the magnetic bearing can carry for a long time, and then proceeds to step 3. The output current direction of the power amplifier is as follows: Figure 5 A set of NS level current flows marked in (b).

[0064] Figure 5 The schematic diagrams of the magnetic pole arrangement of radial magnetic bearings are shown in Figure 1, where (a) is a schematic diagram of the NSSN arrangement and (b) is a schematic diagram of the NSNS arrangement. Figure 5 The NSSN and NSNS magnetic pole arrangements of the radial magnetic bearing are shown in the figure. The magnetic pole arrangement is determined when the magnetic bearing is designed. The magnetic bearings designed with the NSSN and NSNS magnetic pole arrangements are different in structure. The actual magnetic pole arrangement is related to the direction of the current flowing through the magnetic bearing coil, such as Figure 5 As shown, the · sign indicates that the current direction is outflow, and the × sign indicates that the current direction is inflow; the remagnetization frequency of the NSNS magnetic pole arrangement is twice that of the NSSN magnetic pole arrangement.

[0065] When the rotor rotates, the N and S poles will be alternately excited, resulting in iron loss. After the magnetic bearing and rotor are manufactured, the factors affecting the rotor surface iron loss are mainly the frequency of re-magnetization of the rotor core material and the amplitude of the magnetic flux density B. The re-magnetization frequency is related to the rotor speed. The re-magnetization frequency of the magnetic bearing with NSNS magnetic pole arrangement is twice that of the magnetic bearing with NSSN magnetic pole arrangement. Figure 6 Figure 1 is a schematic diagram of the relationship between the magnetic flux density B and the magnetomotive force NI (NI is the symbol for magnetomotive force). The magnetic flux density amplitude is related to the current I passing through the magnetic bearing, and N is the number of turns of the magnetic bearing coil.

[0066] When the rotor becomes unstable and collides with the protective bearing, the inverter will receive an instruction to shut down immediately. In the most serious cases, the rotor and the protective bearing will continue to collide and rub against each other from the time the rotor becomes unstable until the rotor stops and receives the stop floating instruction. Therefore, when the rotor becomes unstable during suspension, accelerating the rotor stop will help reduce the loss of the protective bearing and the rotor.

[0067] In some embodiments, the control method of the magnetic bearing system described in the solution of the present invention further includes: in step S130, controlling the magnetic bearing to increase the iron loss torque of the rotor, reducing the speed of the rotor, until the speed of the rotor is reduced to a preset speed range, re-controlling the rotor suspension, and then returning to re-determine whether the rotor collides with the protective bearing based on the displacement of the rotor and the rotor of the rotor, and repeating the cycle. Figure 8As shown, the collision control method of the magnetic bearing system further includes: step 3, when the rotor speed decreases to a preset range [R n-1 ,R n-2 ], resuspend the rotor.

[0068] In step 3, when the rotor speed decreases to the preset range [R n-1 ,R n-2 ], the magnetic bearing controls the rotor suspension again and repeats step 1 to determine whether the rotor can be stably suspended. If the rotor can be stably suspended, the magnetic bearing continues to control the rotor suspension and falls until the rotor stops.

[0069] If the rotor cannot be stably suspended, go to step 2 until the speed reaches the preset range [R n-2 ,R n-3 ], the magnetic bearing controls the rotor suspension again, and then repeats step 1 to determine whether the rotor can be stably suspended, until the rotor stops rotating and finally stops floating.

[0070] The solution of the present invention involves a solution for handling instability or collision of a magnetic bearing rotor, which utilizes magnetic bearings to generate eddy current torque to accelerate the rotor to stop when a rotor collision occurs, thereby reducing the loss of the protective bearing caused by rotor instability, increasing the life of the protective bearing, and improving the reliability of the magnetic levitation motor and magnetic levitation compressor.

[0071] By adopting the technical solution of this embodiment, the magnetic bearing system is used to determine whether the rotor has collided based on the displacement and rotational speed of the rotor. When it is determined that the rotor has collided, each coil of the magnetic bearing is controlled to output a fixed current until the rotational speed of the rotor drops to a preset speed range and then the rotor suspension is controlled again. Thus, by accelerating the rotor to stop when the rotor collides, the rotor and the protective bearing are protected, thereby improving the reliability of the magnetic bearing system.

[0072] According to an embodiment of the present invention, a control device for a magnetic bearing system corresponding to the control method for the magnetic bearing system is also provided. Figure 3 The structure diagram of an embodiment of the device of the present invention is shown in FIG. The magnetic bearing system comprises: a magnetic bearing, a rotor and a protective bearing; the rotor is as follows Figure 4 The rotor 2 shown in FIG. Figure 4 The magnetic bearing 1 shown, protects the bearing as Figure 4 The protective bearing 3 shown; Figure 4 Figure 1 is a schematic diagram of the structure of an active radial magnetic bearing. Figure 4 The active radial magnetic bearing structure shown in FIG. 1 comprises a magnetic bearing 1, a rotor 2 and a protective bearing 3; Figure 4In the active radial magnetic bearing structure shown in FIG. 1 , the air gap between the rotor (i.e., rotor 2) and the protective bearing (i.e., protective bearing 3) in the suspended state is δ. In the solution of the present invention, Figure 3 As shown, the control device of the magnetic bearing system includes: an acquisition unit 102 and a control unit 104.

[0073] The acquisition unit 102 is configured to acquire the displacement of the rotor and the rotation speed of the rotor when the magnetic bearing system is running. The specific functions and processing of the acquisition unit 102 refer to step S110.

[0074] The control unit 104 is configured to determine whether the rotor collides with the protective bearing according to the displacement of the rotor and the rotor of the rotor. The specific functions and processing of the control unit 104 refer to step S120. Figure 8 FIG. 1 is a flow chart of a collision control method for a magnetic bearing system. Figure 8 As shown, the collision control method of the magnetic bearing system includes: step 1, determining whether the rotor collides, and then executing step 2.

[0075] The control unit 104 is also configured to, if it is determined that the rotor has collided with the protective bearing, control the magnetic bearing to increase the iron loss torque of the rotor so as to reduce the rotation speed of the rotor, specifically to control the current of the coil in the magnetic bearing so as to reduce the rotation speed of the rotor. Of course, the control unit 104 is also configured to, after determining whether the rotor has collided with the protective bearing, if it is determined that the rotor has not collided with the protective bearing, maintain the operation of the magnetic bearing system, and return to re-determine whether the rotor has collided with the protective bearing based on the displacement of the rotor and the rotor of the rotor. See step S130 for the specific functions and processing of the control unit 104. The solution of the present invention utilizes the braking torque caused by iron loss to accelerate the rotor to stop. Figure 8 As shown, the collision control method of the magnetic bearing system also includes: step 2, controlling the magnetic bearing to increase the rotor iron loss to accelerate the rotor deceleration, and then executing step 3.

[0076] The scheme of the present invention proposes a collision control scheme for a magnetic levitation bearing system, which controls the magnetic bearing to give different control schemes according to the degree of rotor instability collision, thereby reducing the loss caused to the rotor and the protective bearing by the rotor instability; in this way, the rotor speed is accelerated when instability occurs, the loss caused by the rotor instability and the collision and friction of the protective bearing is reduced, the service life of the protective bearing is increased, the reliability of the magnetic levitation motor is improved, and when the magnetic levitation compressor includes the magnetic levitation motor, the reliability of the magnetic levitation motor and the magnetic levitation compressor is also improved.

[0077] In some implementations, the control unit 104 determines whether the rotor collides with the protective bearing according to the displacement of the rotor and the rotor of the rotor, including:

[0078] The control unit 104 is further configured to determine the speed interval corresponding to the speed of the rotor, recorded as the current speed interval of the rotor; and determine the corresponding displacement protection times according to the current speed interval of the rotor, recorded as the current displacement protection times of the rotor; wherein different speed intervals correspond to different displacement protection times. The specific functions and processing of the control unit 104 are also referred to step S210.

[0079] The control unit 104 is further configured to determine whether the displacement of the rotor is greater than a preset threshold within a set time period: if so, the number of times the displacement of the rotor is greater than the preset threshold is accumulated and counted to obtain the accumulated number of times the displacement of the rotor is greater than the preset threshold; otherwise, the number of times the displacement of the rotor is greater than the preset threshold is not accumulated and counted. The specific functions and processing of the control unit 104 are also referred to step S220.

[0080] The control unit 104 is further configured to determine whether the rotation speed of the rotor is zero. The specific functions and processing of the control unit 104 are also shown in step S230.

[0081] The control unit 104 is further configured to control the rotor to stop floating if it is determined that the rotation speed of the rotor is zero. The specific functions and processing of the control unit 104 are also shown in step S240.

[0082] The control unit 104 is further configured to determine, if it is determined that the rotation speed of the rotor is not zero, whether the cumulative number of times that the displacement of the rotor is greater than a preset threshold is greater than or equal to the current displacement protection number of the rotor: if so, determine that the rotor has collided with the protection bearing; otherwise, determine that the rotor has not collided with the protection bearing. The specific functions and processing of the control unit 104 are also shown in step S250.

[0083] like Figure 8 As shown, the collision control method of the magnetic bearing system also includes: in step 1, measuring the rotor displacement x and the speed R in real time, determining the speed range [R n , R n-1 ], and obtain the displacement protection times P of the preset speed range n , as shown in Table 1. Determine whether the rotor speed is not zero: if the rotor speed is determined to be zero, then stop the floating rotor; if the rotor speed is determined to be not zero, then detect that the displacement value is greater than the protection threshold δ in the time period T 1 The number of times is greater than or equal to the preset number Pn When the rotor collides with the protective bearing, the inverter will receive a stop command, and the inverter will no longer drag the rotor to rotate. The rotor is in a falling state and enters step 2.

[0084] Table 1

[0085]

[0086] The real-time measurement of the rotor displacement x can be performed by using a displacement sensor. When the rotor approaches or moves away from the displacement sensor, the output voltage of the displacement sensor changes, and the magnetic bearing control system uses the change in the output voltage of the displacement sensor to measure the displacement.

[0087] In the scheme of the present invention, based on the displacement of the rotor and the rotor of the rotor, it is possible to accurately determine whether the rotor collides with the protective bearing; further, when it is determined that the rotor has collided with the protective bearing, that is, the rotor is unstable, the rotor deceleration is accelerated, the loss caused by the rotor instability and the collision and friction of the protective bearing is reduced, the life of the protective bearing is increased, the reliability of the magnetic levitation motor is improved, and when the magnetic levitation compressor includes the magnetic levitation motor, the reliability of the magnetic levitation motor and the magnetic levitation compressor is also improved.

[0088] In some embodiments, the magnetic bearing has a coil, and the number of coils in the magnetic bearing is more than one. The control unit 104 controls the magnetic bearing to increase the iron loss torque of the rotor to reduce the speed of the rotor, including: the control unit 104 is further configured to control the current of more than one coil in the magnetic bearing to increase the iron loss torque of the rotor to reduce the speed of the rotor.

[0089] In the scheme of the present invention, when it is determined that the rotor is unstable, the output current I of each coil of the magnetic bearing is controlled to generate a large magnetic flux density, thereby increasing the iron loss braking torque of the magnetic bearing to accelerate the rotor to stop, and when the speed drops to a given speed, the rotor suspension control is restored; thereby, the loss of the protective bearing and the rotor caused by the instability of the rotor is reduced, the service life of the protective bearing is increased, and the reliability of the magnetic levitation motor and the magnetic levitation compressor is improved.

[0090] In some embodiments, the control unit 104 controls the current of one or more coils in the magnetic bearing to increase the iron loss torque of the rotor and reduce the speed of the rotor, including: the control unit 104 is specifically configured to control each of the one or more coils in the magnetic bearing to output a preset fixed current to increase the iron loss torque of the rotor and reduce the speed of the rotor; wherein the preset fixed current is the maximum current that the magnetic bearing can carry for at least a certain period of time.

[0091] like Figure 8 As shown, the collision control method of the magnetic bearing system also includes: in step 2, controlling each coil of the magnetic bearing to output a fixed current I to generate a large magnetic flux density. Since the rotor is still rotating, the rotor will pass through the magnetic field generated by each magnetic pole in turn, and the generated iron loss braking torque will accelerate the rotor to stop. During normal suspension, the current generated by the magnetic bearing is less than the maximum current value I. Because the greater the magnetic flux density, the better the braking effect, so I can select the maximum current value that the magnetic bearing is designed to carry for a long time.

[0092] In the scheme of the present invention, when the rotor becomes unstable, the output current I of each coil of the magnetic bearing is controlled to generate a large magnetic flux density, and the rotor will pass through the magnetic field generated by each magnetic pole in turn, and the generated iron loss braking torque accelerates the rotor to stop. In this way, by increasing the iron loss braking torque of the magnetic bearing to accelerate the rotor to stop, the loss of the protective bearing and the rotor caused by the instability of the rotor is reduced, the service life of the protective bearing is increased, and the reliability of the magnetic levitation motor and the magnetic levitation compressor is improved.

[0093] In some embodiments, the control unit 104 controls the current of one or more coils in the magnetic bearing to increase the iron loss torque of the rotor and reduce the speed of the rotor, and also includes: the control unit 104 is specifically configured to control the output current direction of the full-bridge power amplifier of the one or more coils in the magnetic bearing to be a preset direction if the arrangement of the one or more coils in the magnetic bearing is an NSSN arrangement driven by a full-bridge power amplifier, so that the arrangement of the one or more coils in the magnetic bearing is changed from an NSSN arrangement to an NSNS arrangement, so as to increase the remagnetization frequency of the magnetic bearing, increase the iron loss torque of the rotor, and reduce the speed of the rotor.

[0094] Generally, magnetic bearings cannot change the direction of the magnetic poles. However, if the magnetic bearings have an NSSN arrangement where the magnetic poles can be changed, the direction of the current in the magnetic bearing coil can be controlled so that the magnetic poles become NSNS arrangement, thereby increasing the remagnetization frequency and the iron loss torque.

[0095] like Figure 8 As shown, the collision control method of the magnetic bearing system further includes: in step 2, Figure 7 The following are schematic diagrams of the structure of power amplifiers, where (a) is a schematic diagram of the structure of a half-bridge power amplifier and (b) is a schematic diagram of the structure of a full-bridge power amplifier. Commonly used power amplifiers include half-bridge power amplifiers and full-bridge power amplifiers, such as Figure 7 As shown in the figure, a half-bridge amplifier can only output current in one direction, while a full-bridge amplifier can output current in both directions. If the NSSN magnetic bearings driven by a full-bridge amplifier are arranged, the output current direction of the amplifier can be controlled according to Figure 5As shown in (b), the magnetic poles are arranged in NSNS, thereby increasing the remagnetization frequency and the iron loss torque. The current amplitude selects the maximum current value I that the magnetic bearing is designed to carry for a long time, and then proceeds to step 3.

[0096] Figure 5 The schematic diagrams of the magnetic pole arrangement of radial magnetic bearings are shown in Figure 1, where (a) is a schematic diagram of the NSSN arrangement and (b) is a schematic diagram of the NSNS arrangement. Figure 5 The NSSN and NSNS magnetic pole arrangements of the radial magnetic bearing are shown in the figure. The magnetic pole arrangement is determined when the magnetic bearing is designed. The magnetic bearings designed with the NSSN and NSNS magnetic pole arrangements are different in structure. The actual magnetic pole arrangement is related to the direction of the current flowing through the magnetic bearing coil, such as Figure 5 As shown, the · sign indicates that the current direction is outflow, and the × sign indicates that the current direction is inflow; the remagnetization frequency of the NSNS magnetic pole arrangement is twice that of the NSSN magnetic pole arrangement.

[0097] When the rotor rotates, the N and S poles will be alternately excited, resulting in iron loss. After the magnetic bearing and rotor are manufactured, the factors affecting the rotor surface iron loss are mainly the frequency of re-magnetization of the rotor core material and the amplitude of the magnetic flux density B. The re-magnetization frequency is related to the rotor speed. The re-magnetization frequency of the magnetic bearing with NSNS magnetic pole arrangement is twice that of the magnetic bearing with NSSN magnetic pole arrangement. Figure 6 Figure 1 is a schematic diagram of the relationship between the magnetic flux density B and the magnetomotive force NI. The magnetic flux density amplitude is related to the current I passing through the magnetic bearing, and N is the number of turns of the magnetic bearing coil.

[0098] When the rotor becomes unstable and collides with the protective bearing, the inverter will receive an instruction to shut down immediately. In the most serious cases, the rotor and the protective bearing will continue to collide and rub against each other from the time the rotor becomes unstable until the rotor stops and receives the stop floating instruction. Therefore, when the rotor becomes unstable during suspension, accelerating the rotor stop will help reduce the loss of the protective bearing and the rotor.

[0099] In some embodiments, the control method of the magnetic bearing system described in the solution of the present invention further includes: the control unit 104 is also configured to control the magnetic bearing to increase the iron loss torque of the rotor to reduce the speed of the rotor, until the speed of the rotor is reduced to a preset speed range, re-control the rotor suspension, and then return to re-determine whether the rotor collides with the protective bearing based on the displacement of the rotor and the rotor of the rotor, and repeat this cycle. Figure 8 As shown, the collision control method of the magnetic bearing system further includes: step 3, when the rotor speed decreases to a preset range [R n-1 ,R n-2], resuspend the rotor.

[0100] In step 3, when the rotor speed decreases to the preset range [R n-1 ,R n-2 ], the magnetic bearing controls the rotor suspension again and repeats step 1 to determine whether the rotor can be stably suspended. If the rotor can be stably suspended, the magnetic bearing continues to control the rotor suspension and falls until the rotor stops.

[0101] If the rotor cannot be stably suspended, go to step 2 until the speed reaches the preset range [R n-2 ,R n-3 ], the magnetic bearing controls the rotor suspension again, and then repeats step 1 to determine whether the rotor can be stably suspended, until the rotor stops rotating and finally stops floating.

[0102] The solution of the present invention relates to a solution for handling instability or collision of a magnetic suspension bearing rotor, which utilizes magnetic bearings to generate eddy current torque, accelerates the rotor to stop when the rotor collides, reduces the loss of the protective bearing caused by rotor instability, increases the life of the protective bearing, and improves the reliability of the magnetic suspension motor and magnetic suspension compressor.

[0103] Since the processing and functions implemented by the device of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned method, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments, and no further elaboration will be made here.

[0104] According to an embodiment of the present invention, a magnetic bearing system corresponding to the control device of the magnetic bearing system is also provided. The magnetic bearing system may include: the control device of the magnetic bearing system described above.

[0105] Since the processing and functions implemented by the magnetic bearing system of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned device, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments, and no further elaboration will be made here.

[0106] According to an embodiment of the present invention, a magnetic bearing device corresponding to the control device of the magnetic bearing system is also provided. The magnetic bearing device may include: the control device of the magnetic bearing system described above, or the magnetic bearing system described above. Wherein, the magnetic bearing device is a magnetic levitation motor or a magnetic levitation compressor.

[0107] Since the processing and functions implemented by the magnetic bearing device of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned device, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0108] According to an embodiment of the present invention, a computer program product corresponding to the control method of the magnetic bearing system is also provided, comprising a computer program, which implements the steps of the control method of the magnetic bearing system described above when executed by a processor.

[0109] Since the processing and functions implemented by the product of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned magnetic bearing system and motor, for the details not exhaustive in the description of this embodiment, please refer to the relevant descriptions in the aforementioned embodiments and will not be repeated here.

[0110] According to an embodiment of the present invention, a storage medium corresponding to the control method of the magnetic bearing system is also provided, wherein the storage medium includes a stored program, wherein when the program is running, the device where the storage medium is located is controlled to execute the steps of the control method of the magnetic bearing system described above.

[0111] Since the processing and functions implemented by the storage medium of this embodiment basically correspond to the embodiments, principles and examples of the aforementioned method, for the details not fully described in this embodiment, please refer to the relevant descriptions in the aforementioned embodiments, and no further elaboration will be made here.

[0112] In summary, 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.

[0113] The above description is only an embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent substitution, improvement, etc. made within the spirit and principle of the present invention shall be included in the scope of the claims of the present invention.

Claims

1. A control method for a magnetic bearing system, characterized in that: The magnetic bearing system comprises: a magnetic bearing, a rotor and a protective bearing; the control method of the magnetic bearing system comprises: When the magnetic bearing system is running, obtaining the displacement of the rotor and the rotation speed of the rotor; determining whether the rotor collides with the protective bearing according to the displacement of the rotor and the rotation of the rotor; If it is determined that the rotor has collided with the protective bearing, the magnetic bearing is controlled to increase the iron loss torque of the rotor to reduce the rotation speed of the rotor.

2. The control method of the magnetic bearing system according to claim 1, characterized in that: Determining whether the rotor collides with the protection bearing according to the displacement of the rotor and the rotor of the rotor includes: Determine the speed interval corresponding to the speed of the rotor, recorded as the current speed interval of the rotor; and determine the corresponding displacement protection times according to the current speed interval of the rotor, recorded as the current displacement protection times of the rotor; wherein different speed intervals correspond to different displacement protection times; Determine whether the displacement of the rotor is greater than a preset threshold value within a set time period: if so, count the number of times the displacement of the rotor is greater than the preset threshold value to obtain the cumulative number of times the displacement of the rotor is greater than the preset threshold value; determining whether the rotational speed of the rotor is zero; If it is determined that the rotation speed of the rotor is zero, controlling the rotor to stop floating; If it is determined that the rotational speed of the rotor is not zero, it is determined whether the cumulative number of times that the displacement of the rotor is greater than a preset threshold is greater than or equal to the current displacement protection number of the rotor: if so, it is determined that the rotor has collided with the protection bearing; otherwise, it is determined that the rotor has not collided with the protection bearing.

3. The control method of the magnetic bearing system according to claim 1, characterized in that: The magnetic bearing has a coil, and the number of the coils in the magnetic bearing is more than one; Controlling the magnetic bearing to increase the iron loss torque of the rotor so as to reduce the rotation speed of the rotor comprises: The current of more than one coil in the magnetic bearing is controlled to increase the iron loss torque of the rotor and reduce the rotation speed of the rotor.

4. The control method of the magnetic bearing system according to claim 3, characterized in that: Controlling the current of more than one coil in the magnetic bearing to increase the iron loss torque of the rotor and reduce the rotation speed of the rotor includes: Controlling each of the more than one coils in the magnetic bearing to output a preset fixed current to increase the iron loss torque of the rotor and reduce the rotation speed of the rotor; The preset fixed current is the maximum current that the magnetic bearing can carry at least for a certain period of time.

5. The control method of the magnetic bearing system according to claim 3 or 4, characterized in that: The method further comprises: controlling the current of more than one coil in the magnetic bearing to increase the iron loss torque of the rotor and reduce the rotation speed of the rotor; If the arrangement of one or more coils in the magnetic bearing is an NSSN arrangement driven by a full-bridge power amplifier, the output current direction of the full-bridge power amplifier of the one or more coils in the magnetic bearing is controlled to be a preset direction, so that the arrangement of the one or more coils in the magnetic bearing is changed from an NSSN arrangement to an NSNS arrangement, so as to increase the remagnetization frequency of the magnetic bearing, increase the iron loss torque of the rotor, and reduce the rotation speed of the rotor.

6. The control method of the magnetic bearing system according to any one of claims 1 to 5, characterized in that: Also includes: After controlling the magnetic bearing to increase the iron loss torque of the rotor and reducing the speed of the rotor, the rotor suspension is controlled again until the speed of the rotor is reduced to a preset speed range, and then the rotor is returned to determine whether the rotor collides with the protective bearing based on the displacement of the rotor and the rotor of the rotor, and the cycle is repeated.

7. A control device for a magnetic bearing system, characterized in that: The magnetic bearing system comprises: a magnetic bearing, a rotor and a protective bearing; the control device of the magnetic bearing system comprises: an acquisition unit, configured to acquire the displacement of the rotor and the rotation speed of the rotor when the magnetic bearing system is running; a control unit configured to determine whether the rotor collides with the protection bearing according to the displacement of the rotor and the rotor of the rotor; The control unit is further configured to control the magnetic bearing to increase the iron loss torque of the rotor so as to reduce the rotation speed of the rotor if it is determined that the rotor has collided with the protective bearing.

8. A magnetic bearing system, characterized in that: include: The control device of the magnetic bearing system as claimed in claim 7.

9. A magnetic bearing device, characterized in that: include: The control device of the magnetic bearing system according to claim 7, or the magnetic bearing system according to claim 8; wherein the magnetic bearing device is a magnetic levitation motor or a magnetic levitation compressor.

10. A storage medium, characterized in that: The storage medium includes a stored program, wherein when the program is executed, the device where the storage medium is located is controlled to execute the control method of the magnetic bearing system according to any one of claims 1 to 6.

11. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the control method of the magnetic bearing system according to any one of claims 1 to 6 are implemented.

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