CN114635919B - Magnetic suspension bearing system, control method and device thereof and storage medium - Google Patents

Magnetic suspension bearing system, control method and device thereof and storage medium Download PDF

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Publication number
CN114635919B
CN114635919B CN202210227110.6A CN202210227110A CN114635919B CN 114635919 B CN114635919 B CN 114635919B CN 202210227110 A CN202210227110 A CN 202210227110A CN 114635919 B CN114635919 B CN 114635919B
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axial
position parameter
reference position
rotor
bearing
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CN114635919A (en
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魏航
郑安琪
林润方
唐文婕
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Gree Electric Appliances Inc of Zhuhai
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Gree Electric Appliances Inc of Zhuhai
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C32/00—Bearings not otherwise provided for
    • F16C32/04—Bearings not otherwise provided for using magnetic or electric supporting means
    • F16C32/0406—Magnetic bearings
    • F16C32/044—Active magnetic bearings
    • F16C32/0444—Details of devices to control the actuation of the electromagnets
    • F16C32/0451—Details of controllers, i.e. the units determining the power to be supplied, e.g. comparing elements, feedback arrangements with P.I.D. control
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
    • G01B7/02—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring length, width or thickness
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B7/00—Measuring arrangements characterised by the use of electric or magnetic techniques
    • G01B7/14—Measuring arrangements characterised by the use of electric or magnetic techniques for measuring distance or clearance between spaced objects or spaced apertures
    • G01B7/144—Measuring play on bearings

Abstract

The invention discloses a control method and a control device of a magnetic suspension bearing system, the magnetic suspension bearing system and a storage medium, wherein the method comprises the following steps: under the condition that the rotor stops floating, obtaining axial displacement detection parameters of a magnetic suspension bearing system as initial axial reference position parameters; controlling the rotor to suspend; controlling the initial axial reference position parameter to increase the set reference position parameter according to a set mode to obtain the current axial reference position parameter; controlling the rotor to move towards the front axial bearing and the rear axial bearing respectively based on the current axial reference position parameter so as to determine a first axial position parameter and a second axial position parameter; and determining the axial clearance of the magnetic suspension bearing system according to the first axial position parameter and the second axial position parameter. According to the scheme, in the process of detecting the axial clearance of the magnetic suspension bearing control system, the rotor thrust disk slowly leans to the axial foremost end and the axial rearmost end, and potential safety hazards to the magnetic suspension bearing system are avoided.

Description

Magnetic suspension bearing system, control method and device thereof and storage medium
Technical Field
The invention belongs to the technical field of magnetic suspension, and particularly relates to a control method and device of a magnetic suspension bearing system, the magnetic suspension bearing system and a storage medium, in particular to an axial control method and device of a magnetic suspension bearing, the magnetic suspension bearing system and the storage medium.
Background
In a magnetic suspension bearing control system, the axial clearance of the axial bearings in the magnetic suspension bearing needs to be detected to obtain the axial clearance between the axial bearings. By detecting the axial clearance of the axial bearing, the central position of the axial suspension of the axial bearing can be determined, the expansion change of the rotor before and after the operation of the magnetic suspension bearing control system and the change of the size of the clearance before and after the operation can be obtained, and the stability and the safety of the operation of the magnetic suspension bearing control system can be improved based on the obtained parameters and changes.
In a related scheme, the method for detecting the axial clearance of the axial bearing comprises the following steps: the magnetic suspension bearing control system controls the current of the axial bearing coil, generates forward electromagnetic force on the rotor by fixing the current of the axial forward bearing coil, so that the rotor thrust disc directly moves to the axial foremost end, and obtains an axial displacement signal of the rotor thrust disc moving to the axial foremost end; and (3) generating a backward electromagnetic force on the rotor by fixing the current of the axial rear bearing coil, so that the rotor thrust disk directly moves to the rearmost end of the axial direction, acquiring an axial displacement signal when the rotor thrust disk moves to the rearmost end of the axial direction, and realizing the detection of the axial gap by acquiring the axial displacement signals moving twice. However, this detection method may pose a safety hazard to the magnetic bearing system.
The above is only for the purpose of assisting understanding of the technical aspects of the present invention, and does not represent an admission that the above is prior art.
Disclosure of Invention
The invention aims to provide a control method and a control device of a magnetic suspension bearing system, the magnetic suspension bearing system and a storage medium, so as to solve the problem that potential safety hazards are caused to the magnetic suspension bearing system by directly moving a rotor thrust disk to the foremost end or the rearmost end in the axial direction in the process of detecting the axial clearance of the magnetic suspension bearing control system in a related scheme, achieve the effect that the rotor thrust disk slowly leans to the foremost end and the rearmost end in the axial direction in the process of detecting the axial clearance of the magnetic suspension bearing control system, and avoid the potential safety hazards caused to the magnetic suspension bearing system.
The invention provides a control method of a magnetic suspension bearing system, wherein the magnetic suspension bearing system comprises the following steps: an axial bearing set; the axial bearing set comprising: a front axial bearing and a rear axial bearing; the control method of the magnetic suspension bearing system comprises the following steps: under the condition that a rotor of the magnetic suspension bearing system stops floating, acquiring an axial displacement detection parameter of the magnetic suspension bearing system as an initial axial reference position parameter of the rotor; controlling the rotor to suspend; the rotor is radially suspended at a radial central position and axially suspended at an axial reference position corresponding to the initial axial reference position parameter; controlling the initial axial reference position parameter to increase a set reference position parameter according to a set mode to obtain a current axial reference position parameter of the rotor; controlling the rotor to move towards the front axial bearing and the rear axial bearing respectively based on a current axial reference position parameter of the rotor to determine a first axial position parameter of the magnetic suspension bearing system and a second axial position parameter of the magnetic suspension bearing system; and determining the axial clearance of the magnetic suspension bearing system according to the first axial position parameter and the second axial position parameter.
In some embodiments, controlling the initial axial reference position parameter to increase the set reference position parameter in a set manner comprises: controlling the initial axial reference position parameter to increase a set reference position parameter so as to obtain a current axial reference position parameter of the rotor; after the rotor is controlled to move towards one of the front axial bearing and the rear axial bearing based on the obtained current axial reference position parameter of the rotor, determining a current difference value between the coil current of the previous axial bearing and the coil current of the previous axial bearing under the condition that the increasing times of the initial axial reference position parameter is increased by once set reference position parameter; determining whether a ratio of the current difference to the set reference position parameter is greater than a set current rate of change threshold: if so, acquiring an axial displacement detection parameter of the magnetic suspension bearing system as a first axial position parameter of the magnetic suspension bearing system; otherwise, the initial axial reference position parameter is continuously controlled to increase the set reference position parameter so as to obtain a new current axial reference position parameter of the rotor.
In some embodiments, controlling the initial axial reference position parameter to increase in a set manner by a set reference position parameter further comprises: controlling the initial axial reference position parameter to increase a set reference position parameter so as to obtain a current axial reference position parameter of the rotor, and accumulating the increasing times of the initial axial reference position parameter; after controlling the rotor to move towards one of the front axial bearing and the rear axial bearing based on the obtained current axial reference position parameter of the rotor, continuously controlling the initial axial reference position parameter to increase a set reference position parameter so as to obtain a new current axial reference position parameter of the rotor; analogizing in sequence until the current difference between the coil current of the axial bearing at the n +1 th time and the coil current of the axial bearing at the n +1 th time is determined under the condition that the increasing times of the initial axial reference position parameter are increased to n and the increasing times of the initial axial reference position parameter are increased to n + 1; determining whether a ratio of the current difference to the set reference position parameter is greater than a set current rate of change threshold: if so, acquiring an axial displacement detection parameter of the magnetic suspension bearing system as a first axial position parameter of the magnetic suspension bearing system; otherwise, the initial axial reference position parameter is continuously controlled to increase the set reference position parameter so as to obtain a new current axial reference position parameter of the rotor.
In some embodiments, controlling the rotor to move towards the front axial bearing and the rear axial bearing, respectively, based on a current axial reference position parameter of the rotor to determine a first axial position parameter of the magnetic bearing system and a second axial position parameter of the magnetic bearing system, comprises: firstly, controlling the rotor to move to a protective graphite position of one of the front axial bearing and the rear axial bearing based on the current axial reference position parameter of the rotor, taking an axial displacement detection parameter of the magnetic suspension bearing system as a first axial position parameter of the magnetic suspension bearing system, and then controlling the rotor to recover to an axial reference position corresponding to the initial axial reference position parameter; and then controlling the rotor to move to a protective graphite position of the other axial bearing of the front axial bearing and the rear axial bearing based on the current axial reference position parameter of the rotor, taking the axial displacement detection parameter of the magnetic suspension bearing system as a second axial position parameter of the magnetic suspension bearing system, and then controlling the rotor to recover to an axial reference position corresponding to the initial axial reference position parameter.
In some embodiments, further comprising: in the case that a first axial position parameter of the magnetic bearing system and a second axial position parameter of the magnetic bearing system have been determined, half the absolute value of the difference between the first axial position parameter and the second axial position parameter is taken as the central levitation reference position parameter of the rotor.
In some embodiments, the first axial position parameter comprises: recording a first axial position parameter before the operation of the magnetic suspension bearing system as a first axial position parameter before the operation; recording the first axial position parameter of the magnetic suspension bearing system after operation as the first axial position parameter after operation; the second axial position parameter comprises: recording a second axial position parameter before the magnetic suspension bearing system operates as a second axial position parameter before the magnetic suspension bearing system operates; and recording the second axial position parameter of the magnetic suspension bearing system after operation as the second axial position parameter after operation; the control method of the magnetic suspension bearing system further comprises the following steps: and determining the absolute value of the difference between the first axial position parameter before operation and the first axial position parameter after operation, or the absolute value of the difference between the second axial position parameter before operation and the second axial position parameter after operation as the expansion and contraction variation of the rotor.
In accordance with the above method, another aspect of the present invention provides a control device for a magnetic suspension bearing system, the magnetic suspension bearing system comprising: an axial bearing set; the axial bearing set comprising: a front axial bearing and a rear axial bearing; the control device of the magnetic suspension bearing system comprises: an obtaining unit configured to obtain an axial displacement detection parameter of the magnetic suspension bearing system as an initial axial reference position parameter of the rotor in a case that the rotor of the magnetic suspension bearing system is stopped floating; a control unit configured to control the rotor levitation; the rotor is radially suspended at a radial central position and axially suspended at an axial reference position corresponding to the initial axial reference position parameter; the control unit is further configured to control the initial axial reference position parameter to increase a set reference position parameter in a set manner, so as to obtain a current axial reference position parameter of the rotor; the control unit is further configured to control the rotor to move towards the front axial bearing and the rear axial bearing, respectively, based on a current axial reference position parameter of the rotor, to determine a first axial position parameter of the magnetic bearing system and a second axial position parameter of the magnetic bearing system; the control unit is further configured to determine an axial gap of the magnetic bearing system from the first axial position parameter and the second axial position parameter.
In some embodiments, the control unit, controlling the initial axial reference position parameter to increase by a set reference position parameter in a set manner, includes: controlling the initial axial reference position parameter to increase a set reference position parameter so as to obtain a current axial reference position parameter of the rotor; after the rotor is controlled to move towards one of the front axial bearing and the rear axial bearing based on the obtained current axial reference position parameter of the rotor, determining a current difference value between the coil current of the previous axial bearing and the coil current of the previous axial bearing under the condition that the increasing times of the initial axial reference position parameter is increased by once set reference position parameter; determining whether a ratio of the current difference to the set reference position parameter is greater than a set current rate of change threshold: if so, acquiring an axial displacement detection parameter of the magnetic suspension bearing system as a first axial position parameter of the magnetic suspension bearing system; otherwise, the initial axial reference position parameter is continuously controlled to increase the set reference position parameter so as to obtain a new current axial reference position parameter of the rotor.
In some embodiments, the control unit controls the initial axial reference position parameter to increase the set reference position parameter in a set manner, and further includes: controlling the initial axial reference position parameter to increase a set reference position parameter so as to obtain a current axial reference position parameter of the rotor, and accumulating the increasing times of the initial axial reference position parameter; after the rotor is controlled to move towards one of the front axial bearing and the rear axial bearing based on the obtained current axial reference position parameter of the rotor, the initial axial reference position parameter is continuously controlled to increase a set reference position parameter so as to obtain a new current axial reference position parameter of the rotor; analogizing in sequence until the current difference between the coil current of the axial bearing at the n +1 th time and the coil current of the axial bearing at the n +1 th time is determined under the condition that the increasing times of the initial axial reference position parameter are increased to n and the increasing times of the initial axial reference position parameter are increased to n + 1; determining whether a ratio of the current difference to the set reference position parameter is greater than a set current rate of change threshold: if so, acquiring an axial displacement detection parameter of the magnetic suspension bearing system as a first axial position parameter of the magnetic suspension bearing system; otherwise, the initial axial reference position parameter is continuously controlled to increase the set reference position parameter so as to obtain a new current axial reference position parameter of the rotor.
In some embodiments, the control unit controlling the rotor to move towards the front axial bearing and the rear axial bearing, respectively, based on a current axial reference position parameter of the rotor, to determine a first axial position parameter of the magnetic bearing system and a second axial position parameter of the magnetic bearing system, comprises: firstly, controlling the rotor to move to a protective graphite position of one of the front axial bearing and the rear axial bearing based on the current axial reference position parameter of the rotor, taking an axial displacement detection parameter of the magnetic suspension bearing system as a first axial position parameter of the magnetic suspension bearing system, and then controlling the rotor to recover to an axial reference position corresponding to the initial axial reference position parameter; and then controlling the rotor to move to a protective graphite position of the other axial bearing of the front axial bearing and the rear axial bearing based on the current axial reference position parameter of the rotor, taking the axial displacement detection parameter of the magnetic suspension bearing system as a second axial position parameter of the magnetic suspension bearing system, and then controlling the rotor to recover to an axial reference position corresponding to the initial axial reference position parameter.
In some embodiments, further comprising: the control unit is further configured to, in case a first axial position parameter of the magnetic suspension bearing system and a second axial position parameter of the magnetic suspension bearing system have been determined, take half of an absolute value of a difference between the first axial position parameter and the second axial position parameter as a central levitation reference position parameter of the rotor.
In some embodiments, the first axial position parameter comprises: recording a first axial position parameter before the operation of the magnetic suspension bearing system as a first axial position parameter before the operation; recording the first axial position parameter of the magnetic suspension bearing system after operation as the first axial position parameter after operation; the second axial position parameter comprises: recording a second axial position parameter before the magnetic suspension bearing system operates as a second axial position parameter before the magnetic suspension bearing system operates; and recording the second axial position parameter of the magnetic suspension bearing system after operation as the second axial position parameter after operation; the control device of the magnetic suspension bearing system further comprises: the control unit is further configured to determine an absolute value of a difference between the first axial position parameter before operation and the first axial position parameter after operation, or an absolute value of a difference between the second axial position parameter before operation and the second axial position parameter after operation, as the amount of change in the expansion and contraction of the rotor.
In accordance with the above apparatus, a magnetic suspension bearing system according to another aspect of the present invention comprises: the control device for a magnetic bearing system described above.
In line with the above method, a further aspect of the present invention provides a storage medium, which includes a stored program, wherein when the program runs, a device in which the storage medium is located is controlled to execute the above control method of the magnetic bearing system.
Therefore, according to the scheme provided by the invention, in the process of detecting the axial clearance of the magnetic suspension bearing control system, the rotor thrust disc is slowly leaned to the foremost end and the rearmost end in the axial direction by changing the axial suspension position when the rotor is suspended, so that the rotor thrust disc is slowly leaned to the protective graphite in the foremost end and the rearmost end, and therefore, in the process of detecting the axial clearance of the magnetic suspension bearing control system, the rotor thrust disc is slowly leaned to the foremost end and the rearmost end in the axial direction, and potential safety hazards to the magnetic suspension bearing system are avoided.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by the practice of the invention.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
FIG. 1 is a schematic structural diagram of an embodiment of an axial bearing in a magnetic bearing control system;
FIG. 2 is a schematic flow chart diagram of an embodiment of a method of controlling a magnetic bearing system of the present invention;
FIG. 3 is a schematic flow chart illustrating an embodiment of the method of the present invention for controlling the initial axial reference position parameter to increase the set reference position parameter in a first manner;
FIG. 4 is a schematic flow chart illustrating an embodiment of a method of the present invention for controlling the initial axial reference position parameter to increase the set reference position parameter in a second manner;
FIG. 5 is a schematic flow chart of one embodiment of the movement to the forward and aft axial bearings, respectively, in the method of the present invention;
FIG. 6 is a schematic structural diagram of an embodiment of a control device of a magnetic suspension bearing system of the present invention;
FIG. 7 is a schematic diagram of an embodiment of a rotor in motion with the rotor slowly moving toward the forward-most end of the shaft after the rotor has been levitated and stabilized;
FIG. 8 is a schematic view of an embodiment of the rotor being moved after the rotor has been levitated and stabilized to move the rotor slowly toward the rearmost end of the shaft;
FIG. 9 is a flow chart illustrating an embodiment of a method for detecting an axial gap of a magnetic bearing.
The reference numbers in the embodiments of the present invention are as follows, in combination with the accompanying drawings:
102-an obtaining unit; 104-control unit.
Detailed Description
In order to make the objects, technical solutions and advantages of the present invention more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to the specific embodiments of the present invention and the accompanying drawings. It is to be understood that the described embodiments are merely exemplary of the invention, and not restrictive of the full scope of the invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
Fig. 1 is a schematic structural diagram of an embodiment of an axial bearing in a magnetic bearing control system. As shown in fig. 1, an electromagnetic force F is generated by a fixed amount of current applied to the axial bearing coil. The formula for the generated electromagnetic force F is:
Figure BDA0003536357450000071
wherein, mu 0 The magnetic permeability is air permeability, N is the number of turns of the coil winding, and A is the cross-sectional area of the magnetic circuit of the stator (or rotor) core. After the body structure of the magnetic suspension bearing system is determined, k is determined, so k is constant. i is the magnitude of the current in the bearing coil and x is the distance between the rotor and the bearing coil.
According to the calculation formula of the generated electromagnetic force F, through analysis, if the current i of the bearing coil is fixed and the magnitude of the electromagnetic force F enables the rotor to axially move towards the coil direction, x is the distance x between the rotor and the bearing coil is reduced, and the electromagnetic force F is increased. Therefore, this method causes the rotor thrust disk to impact the axially forwardmost and axially rearwardmost ends with an uncontrollable force and acceleration upon detection. The most forward end of the axial gap of the axial bearing and the most rearward end of the axial bearing are typically provided with axial protective graphite, and each time the gap is detected, the rotor thrust disk will impact the protective graphite. The long-term use of the detection method can cause loss to the rotor thrust disk and the protective graphite, and the rotor thrust disk and the protective graphite can be damaged in serious cases. In particular, in a large magnetic suspension bearing system, the rotor has large mass and the required current and electromagnetic force are also large, so that the impact between the thrust disk and the protection bearing is more severe by the detection method, the loss caused by the impact is also aggravated, and the risk of damaging the protection graphite is caused.
At least in order to solve the problem that in the axial clearance detection process of a magnetic suspension bearing control system in a related scheme, a rotor thrust disc collides with axial protection graphite with uncontrollable force and acceleration so as to generate impact loss and potential safety hazard.
According to an embodiment of the present invention, a control method for a magnetic bearing system is provided, as shown in fig. 2, which is a schematic flow chart of an embodiment of the method of the present invention. The magnetic suspension bearing system comprises: an axial bearing set; the axial bearing set comprising: a front axial bearing and a rear axial bearing. The control method of the magnetic suspension bearing system comprises the following steps: step S110 to step S150.
In step S110, in a case that the rotor of the magnetic suspension bearing system is stopped floating, an axial displacement detection parameter of the magnetic suspension bearing system is obtained as an initial axial reference position parameter of the rotor (e.g. an axial reference position parameter U of the rotor) ref )。
At step S120, the rotor is controlled to be levitated so that the rotor is in a levitated state. And the rotor is radially suspended at a radial central position and axially suspended at an axial reference position corresponding to the initial axial reference position parameter. The radial center position of the rotor radial suspension may be pre-calculated, for example, with the radial center point as the radial center position.
In step S130, under the condition that the rotor is suspended, the initial axial reference position parameter is controlled to increase the set reference position parameter in a set manner, so as to obtain the current axial reference position parameter of the rotor. Namely, the initial axial reference position parameter after the set reference position parameter is added is taken as the current axial reference position parameter of the rotor.
In some embodiments, the controlling the initial axial reference position parameter to increase the set reference position parameter in a set manner in step S130 includes: the process of increasing the initial axial reference position parameter by a set reference position parameter is controlled in a first manner.
Referring to the flowchart of an embodiment of the method of the present invention shown in fig. 3, which controls the initial axial reference position parameter to increase the set reference position parameter in the first manner, a specific process of controlling the initial axial reference position parameter to increase the set reference position parameter in the first manner is further described, including: step S210 to step S230.
Step S210, controlling the initial axial reference position parameter to increase a set reference position parameter, so as to obtain a current axial reference position parameter of the rotor.
Step S220, under the condition that the rotor is controlled to move to one of the front axial bearing and the rear axial bearing based on the obtained current axial reference position parameter of the rotor, and under the condition that the number of times of increasing the initial axial reference position parameter is determined to increase once to set the reference position parameter after the rotor is controlled to move to one of the front axial bearing and the rear axial bearing based on the obtained current axial reference position parameter of the rotor, a current difference value between a coil current of the one axial bearing at the current time and a coil current of the one axial bearing at the previous time is determined.
Step S230, determining whether the ratio of the current difference to the set reference position parameter is greater than a set current change rate threshold: and if so, acquiring an axial displacement detection parameter of the magnetic suspension bearing system as a first axial position parameter of the magnetic suspension bearing system. Otherwise, the initial axial reference position parameter is continuously controlled to increase the set reference position parameter so as to obtain a new current axial reference position parameter of the rotor.
Fig. 7 is a schematic structural diagram of an embodiment of a moving process of gradually moving a rotor to the foremost end of a shaft after the rotor is stabilized in a floating manner, fig. 8 is a schematic structural diagram of an embodiment of a moving process of gradually moving a rotor to the rearmost end of a shaft after the rotor is stabilized in a floating manner, and fig. 9 is a schematic flow chart of an embodiment of a method for detecting an axial gap of a magnetic bearing. The following describes an exemplary implementation process of the axial gap detection method for a magnetic suspension bearing according to the present invention with reference to the examples shown in fig. 7, fig. 8 and fig. 9.
As shown in fig. 9, the method for detecting an axial gap of a magnetic suspension bearing according to an embodiment of the present invention includes:
step 1, starting to detect the axial clearance of the magnetic suspension bearing, and then executing the axial clearance detection step and the axial clearance calculation step.
The following description will be given by taking an example in which the axial front clearance detection step (i.e., steps 21 to 23) is performed first, and then the axial rear clearance detection step (i.e., steps 31 to 33) is performed.
And step 21, controlling the rotor to be radially suspended at a central position (namely a radial central position) and axially suspended at a position before suspension (namely an axial reference position or an axial central position).
In step 21, specifically, when the magnetic suspension bearing control system detects the axial clearance, the displacement signal of the rotor axial displacement sensor in the rotor stop-floating state is first obtained as the axial reference position parameter U of the rotor ref The axial reference position parameter U is set ref As a parameter U of the axial center position of the rotor ref . Furthermore, the magnetic bearing control system rotor is suspended in a radial center position and axially suspended in a position before suspension (i.e. an axial reference position or an axial center position).
After the rotor of the magnetic suspension bearing control system is radially suspended at the radial center position and axially suspended at the position before suspension (i.e. the axial reference position or the axial center position), the magnetic suspension bearing control system controls the rotor to suspend in five degrees of freedom, as shown in fig. 7, after the suspension of the rotor is stabilized, the rotor starts to move forward and axially slowly until contacting with the front protection graphite, which refers to steps 22 to 23.
Step (ii) of22. Controlling an axial reference position parameter U of a rotor ref Adding a unit position parameter Δ U in the forward axial direction, i.e. the current axial reference position parameter = axial reference position parameter U of the rotor ref + Δ U unit position parameter.
The unit position parameter Δ U is determined experimentally according to actual conditions. Theoretically speaking, the smaller the unit position parameter Δ U is, the lower the axial moving speed of the rotor during detection is, the smaller the collision force on the protective graphite is, and the better the detection effect is. But slowing down also increases the detection time. The unit position parameter deltau should be as small as possible within an acceptable detection time.
Step 23, judging the current variation delta I of the front axial bearing coil f Ratio delta I to unit position parameter delta U of movement f ,/Δ U, whether greater than a set current rate-of-change threshold m: if yes, acquiring a front axial position parameter U max . Otherwise, returning to step 22, continuing to control the axial reference position parameter U of the rotor ref Adding a unit position parameter Δ U in the forward axial direction, i.e. the current axial reference position parameter = axial reference position parameter U of the rotor ref + Δ U unit position parameter.
And step 31, controlling the rotor to be radially suspended at a central position (namely a radial central position) and axially suspended at a position before suspension (namely an axial reference position or an axial central position).
The axial back clearance is detected, which is the same method as the axial forward clearance, but in a different direction. In step 31, specifically, when the magnetic suspension bearing control system detects the axial back clearance, the displacement signal of the rotor axial displacement sensor in the rotor stop-floating state is firstly obtained as the axial reference position parameter U of the rotor ref The axial reference position parameter U is set ref As a parameter U of the axial center position of the rotor ref . In turn, the magnetic bearing control system rotor is radially suspended at a radially central position and axially suspended at a suspended position (i.e., an axial reference position or an axial central position).
After the rotor of the magnetic suspension bearing control system is radially suspended at the radial center position and axially suspended at the position before suspension (i.e. the axial reference position or the axial center position), the magnetic suspension bearing control system controls the rotor to suspend in five degrees of freedom, as shown in fig. 8, after the suspension of the rotor is stabilized, the rotor starts to move backwards and axially slowly until contacting the rear protection graphite, which is specifically referred to in steps 32 to 33.
And step 32, controlling the axial reference position of the rotor to increase the unit distance delta U towards the rear axial direction.
Step 33, determining the current variation Δ I of the rear axial bearing coil r Ratio delta I to unit distance delta U of movement r ,/Δ U, whether greater than a set current rate-of-change threshold m: if yes, acquiring a rear axial position parameter U min . Otherwise, returning to step 32, continuing to control the rotor axial reference position to increase the unit distance Δ U towards the rear axial direction.
In some embodiments, the controlling the initial axial reference position parameter to increase the set reference position parameter in a set manner in step S130 further includes: and controlling the process of increasing the initial axial reference position parameter by the set reference position parameter according to a second mode.
Referring to fig. 4, a flowchart of an embodiment of the method of the present invention for controlling the initial axial reference position parameter to increase the set reference position parameter in the second manner according to the second method further illustrates a specific process for controlling the initial axial reference position parameter to increase the set reference position parameter in the second manner, including: step S310 to step S340.
Step S310, controlling the initial axial reference position parameter to increase a set reference position parameter to obtain a current axial reference position parameter of the rotor, and accumulating the increase times of the initial axial reference position parameter, such as adding 1 to the increase times of the initial axial reference position parameter.
Step S320, under the condition that the rotor is controlled to move towards one of the front axial bearing and the rear axial bearing based on the current axial reference position parameter of the rotor obtained above, after the rotor is controlled to move towards one of the front axial bearing and the rear axial bearing based on the current axial reference position parameter of the rotor obtained above, the initial axial reference position parameter is continuously controlled to increase the set reference position parameter so as to obtain a new current axial reference position parameter of the rotor, and the increasing times of the initial axial reference position parameter are continuously accumulated, such as the increasing times of the initial axial reference position parameter is added by 1.
Step S330, repeating the above steps until the number of times of increasing the initial axial reference position parameter has increased to n, and determining a current difference between the coil current of the axial bearing at the n +1 th time and the coil current of the axial bearing at the n +1 th time when the number of times of increasing the initial axial reference position parameter has increased to n + 1.
Step S340, determining whether the ratio of the current difference to the set reference position parameter is greater than a set current change rate threshold: and if so, acquiring an axial displacement detection parameter of the magnetic suspension bearing system as a first axial position parameter of the magnetic suspension bearing system. Otherwise, continuously controlling the initial axial reference position parameter to increase the set reference position parameter so as to obtain a new current axial reference position parameter of the rotor, and continuously accumulating the increasing times of the initial axial reference position parameter, for example, adding 1 to the increasing times of the initial axial reference position parameter.
Referring to the examples shown in fig. 7 to 9, in the process of detecting the axial forward clearance, in combination with steps 22 to 23, the axial center reference position parameter U is based on ref The reference position parameter Δ U is sequentially increased, such as each time the axial reference position parameter of Δ U is increased, the bearing axial closed-loop control system moves the rotor a distance Δ X in the forward axial direction. The axial reference position parameter Δ U corresponds to the axial movement distance Δ X, that is, the axial center reference position parameter U ref In the case of increasing the axial reference position parameter Δ U, the distance that the rotor moves in the forward axial direction is the axial movement distance Δ X. That is, when the rotor is moved to a set reference position (i.e., a current axial reference position corresponding to a current axial reference position parameter of the rotor)And then the reference position parameter of deltau is increased.
Until the reference position parameter delta U is increased n times (n is a positive integer), the rotor is finally contacted with the front axial protection graphite. If the rotor does not contact the front axial protection graphite after increasing the reference position parameter Δ U n times, the reference position parameter Δ U is continuously increased, for example, the reference position parameter Δ U is increased n +1 times, and so on.
If the rotor can contact the front axial protection graphite after the reference position parameter delta U is increased for n +1 times, but the rotor does not reach the preset axial reference position (namely the current reference position corresponding to the current axial reference position parameter after the reference position parameter delta U is increased for n +1 times) when the rotor contacts the protection bearing of the front shaft, at this time, because the control strength of the closed-loop control system is continuously increased along with the continuous increase of the reference position parameter delta U, the corresponding axial bearing control current is also continuously increased. Then, after the reference position parameter Δ U is increased n +1 times, in the case that the rotor contacts the protection bearing of the front shaft, but the rotor does not reach the preset axial reference position (i.e., the current reference position corresponding to the current axial reference position parameter after the reference position parameter Δ U is increased n +1 times), the control strength of the closed-loop control system is already increased, and accordingly, the front axial bearing control current is also rapidly increased.
Therefore, the current change Δ I of the front axial bearing coil is calculated by sampling the current of the front axial bearing coil after increasing the reference position parameter Δ U n +1 times and the current of the front axial bearing coil before increasing the reference position parameter Δ U n +1 times (i.e., the current of the front axial bearing coil after increasing the reference position parameter Δ U n times), and then calculating the current change Δ I of the front axial bearing coil f . Further, the current change amount Δ I of the front axial bearing coil is determined f Ratio delta I to unit reference position parameter delta U of movement f Δ U according to the ratio Δ I f The/Δ U determines whether or not the current of the front axial bearing coil is rapidly increased in the case where the rotor is moved after the reference position parameter Δ U is increased n +1 times (of course, the unit distance of movement of the rotor may be Δ X or may be less than Δ X after the reference position parameter Δ U is increased n +1 times), that is, whether or not the current of the front axial bearing coil is rapidly increasedWhether the rotor has reached the protective graphite.
Specifically, the ratio Δ I is judged f Whether/Δ U is greater than m, m being a set current rate of change threshold: if the ratio Δ I f /ΔU<If the reference position parameter is not equal to the axial reference position parameter U, the rotor is not protected by the protective graphite, and the reference position parameter delta U is increased continuously to increase the axial reference position parameter U of the rotor ref And continuing to move the rotor forward. Of course, if the ratio Δ I f /ΔU>m, the control current of the front axial bearing coil is rapidly increased, the rotor is already contacted with the protective graphite, and the value U of the rotor axial displacement sensor at the moment is recorded max As front axial position parameter U max And quickly changing the axial reference position parameter, i.e. restoring the current axial reference position parameter of the rotor to the axial reference position parameter U ref So as to return the current axial reference position parameter of the rotor to the axial reference position parameter U ref And levitated to prevent the control current of the front axial bearing coil from increasing all the time to cause overcurrent.
In the process of detecting the axial forward clearance, in combination with steps 32 to 33, the axial center reference position parameter U is based on ref The reference position parameter- Δ U is sequentially increased, such as by each increase in the axial reference position parameter of- Δ U, the bearing axial closed-loop control system moves the rotor a distance Δ X in the aft axial direction. The axial reference position parameter- Δ U corresponds to the axial movement distance Δ X, that is, the reference position parameter U at the axial center ref With the axial reference position parameter- Δ U added, the distance that the rotor moves in the rearward axial direction is the axial movement distance Δ X. That is, the reference position parameter of- Δ U is increased again when the rotor moves to the set reference position (i.e., the current axial reference position corresponding to the current axial reference position parameter of the rotor).
Until the reference position parameter-deltau is increased n times (n is a positive integer), the rotor will eventually contact the rear axial protective graphite. If the rotor does not contact the rear axial protection graphite after increasing the reference position parameter- Δ U n times, the reference position parameter- Δ U is continuously increased, for example, the reference position parameter- Δ U is increased n +1 times, and so on.
If the rotor can contact the rear axial protection graphite after the n +1 times of reference position parameter-delta U is added, but the rotor does not reach the preset axial reference position (namely the current reference position corresponding to the rear axial reference position parameter after the n +1 times of reference position parameter-delta U is added) when the rotor contacts the protection bearing of the front shaft, at this time, because the control strength of the closed-loop control system is continuously increased along with the continuous increase of the reference position parameter-delta U, the corresponding axial bearing control current is also continuously increased. Then, after the reference position parameter- Δ U is increased n +1 times, in the case where the rotor contacts the protection bearing of the front shaft, but the rotor does not reach the preset axial reference position (i.e., the current reference position corresponding to the current rear axial reference position parameter after the reference position parameter- Δ U is increased n +1 times), the control strength of the closed-loop control system is already increased, and accordingly, the rear axial bearing control current is also rapidly increased.
Therefore, the current change Δ I of the rear axial bearing coil is calculated by sampling the current of the rear axial bearing coil after the reference position parameter- Δ U is increased by n +1 times and the current of the rear axial bearing coil before the reference position parameter- Δ U is increased by n +1 times (i.e., the current of the rear axial bearing coil after the reference position parameter- Δ U is increased by n times), and calculating the current change Δ I of the rear axial bearing coil r . Further, the amount of current change Δ I of the rear axial bearing coil is determined r Ratio delta I to unit reference position parameter delta U of movement r Δ U according to the ratio Δ I r The/Δ U judges whether the current of the rear axial bearing coil is rapidly increased, that is, whether the rotor has reached the protective graphite, in the case where the rotor has moved after the reference position parameter- Δ U is added n +1 times (of course, the unit distance of movement of the rotor may be Δ X or may be less than Δ X after the reference position parameter- Δ U is added n +1 times).
Specifically, the ratio Δ I is judged r Whether/Δ U is greater than m, m being the set current rate of change threshold: if the ratio Δ I r /ΔU<= m, the rotor does not reach the protective graphite, and the reference position parameter-delta U is continuously increased at the moment so as to continuously increase the axial reference position parameter U of the rotor ref The rotor continues to move backward. Of course, if the ratio Δ I r /ΔU>m, the control current of the rear axial bearing coil is rapidly increased, the rotor is in contact with the protective graphite, and the value U of the axial displacement sensor of the rotor at the moment is recorded min As a rear axial position parameter U min And quickly stopping the control of the magnetic bearing control system on the axial freedom degree so as to prevent the control current of the rear axial bearing coil from increasing all the time to cause overcurrent.
Wherein, the control of the axial degree of freedom of the rapid stop magnetic bearing control system includes: and closing the axial bearing control current, namely, enabling the axial bearing control current to be 0, and then quickly stopping the control of the magnetic suspension bearing system on the axial degree of freedom.
At step S140, the rotor is controlled to move towards the front axial bearing and the rear axial bearing, respectively, based on the current axial reference position parameter of the rotor, still with the rotor in levitation, to determine a first axial position parameter of the magnetic bearing system and a second axial position parameter of the magnetic bearing system. Wherein the first axial position parameter is an axial position parameter of one of a forwardmost end and a rearwardmost end of the axial bearing. The second axial position parameter is an axial position parameter of the other end of the foremost end and the rearmost end of the axial bearing.
In some embodiments, the specific procedure of controlling the rotor to move towards the front axial bearing and the rear axial bearing, respectively, based on the current axial reference position parameter of the rotor in step S140 to determine the first axial position parameter of the magnetic bearing system and the second axial position parameter of the magnetic bearing system, see the following exemplary description.
Referring to fig. 5, a specific process of moving to the front axial bearing and the rear axial bearing respectively in step S140 will be further described, including: step S410 to step S420.
In the step S410, the process is executed,firstly, controlling the rotor to move to a protective graphite position of one of the front axial bearing and the rear axial bearing based on the current axial reference position parameter of the rotor, and taking the axial displacement detection parameter of the magnetic suspension bearing system as a first axial position parameter (such as a front axial position parameter U) of the magnetic suspension bearing system max ) And then controlling the rotor to recover to the axial reference position corresponding to the initial axial reference position parameter. For example: axial position parameter U before acquisition max The axial reference position parameter is changed rapidly to prevent the control current of the front axial bearing coil from increasing all the time to cause overcurrent.
Step S420, controlling the rotor to move to a protective graphite position of the other one of the front axial bearing and the rear axial bearing based on the current axial reference position parameter of the rotor, and using the axial displacement detection parameter of the magnetic suspension bearing system as a second axial position parameter (for example, a rear axial position parameter U) of the magnetic suspension bearing system min ) And then controlling the rotor to recover to the axial reference position corresponding to the initial axial reference position parameter. For example: after obtaining the axial position parameter U min The control of the axial degree of freedom by the magnetic bearing control system is stopped quickly to prevent the control current of the rear axial bearing coil from increasing all the time to cause overcurrent.
Referring to the examples shown in fig. 7 to 9, the axial gap detecting step includes: an axial forward clearance detection step and an axial rearward clearance detection step. Specifically, when the axial clearance detecting step is performed, the axial front clearance detecting step (i.e., steps 21 to 23) may be performed first, and the axial rear clearance detecting step (i.e., steps 31 to 33) may be performed next. Of course, the step of detecting the axial back clearance (i.e., step 31 to step 33) may be performed first, and the step of detecting the axial front clearance (i.e., step 21 to step 23) may be performed again.
As shown in fig. 9, the method for detecting an axial gap of a magnetic suspension bearing according to an embodiment of the present invention further includes:
step 4, calculating the axial clearance, namely: using front axial position parameter U max And a rear axial position parameter U min The axial clearance is calculated. That is, the acquired forward axial position parameter U max And a rear axial position parameter U min For maximum axial range of motion of the rotor, use is made of U max -U min The axial clearance (i.e. U) can be calculated from the difference max -U min The difference of (d) as the axial clearance of the rotor).
Wherein, U represents the voltage sampling signal of axial displacement sensor and axial detection face, and any one U can correspond to the distance length X between one axial displacement sensor and axial detection face, and they are linear relations. U shape max Corresponding to the farthest distance between the displacement sensor and the axial displacement detection surface (at the moment, the rotor is at the most front end in the axial direction), U min The corresponding displacement sensor is closest to the axial displacement detection surface (in this case, the rotor is at the axially rearmost end). So U max -U min Corresponds to X max -X min Thus, U can be used max -U min Indicating rotor axial clearance.
And 5, detecting the axial clearance to finish.
At step S150, an axial gap of the magnetic bearing system is determined according to the first axial position parameter and the second axial position parameter.
The scheme of the invention provides an axial gap detection method of a magnetic suspension bearing, when detecting the axial gap, the rotor thrust disk is slowly leaned against the protective graphite by changing the axial suspension position when the rotor is suspended instead of directly colliding the rotor thrust disk against the axial protective graphite by fixing the current of the axial bearing coil, thereby avoiding the collision when the rotor thrust disk is contacted with the protective graphite.
Like this, through the axial clearance testing process at magnetic suspension bearing for rotor thrust dish leans on slowly to axial both ends protection graphite, effectively avoids rotor thrust dish and protection bearing's striking, thereby reduces the loss between rotor thrust dish and the protection graphite, prolongs the life of protection graphite, has improved magnetic suspension bearing control system's stability and security. Therefore, the problem that impact loss and potential safety hazards are generated due to the fact that the rotor thrust disk and the protective graphite collide in the axial gap detection process of the magnetic suspension bearing control system in the related scheme is solved, so that the rotor thrust disk is protected, and the service life of the protective graphite is prolonged.
In some embodiments, the control method of a magnetic suspension bearing system described above further includes: in the case that a first axial position parameter of the magnetic bearing system and a second axial position parameter of the magnetic bearing system have been determined, half the absolute value of the difference between the first axial position parameter and the second axial position parameter is taken as the central levitation reference position parameter of the rotor.
In some further embodiments, in the solution of the invention, the axial central levitation reference position may be determined according to the determined maximum range of motion of the rotor in the axial direction. Specifically, after the detection method provided by the invention is used, the obtained front axial position parameter U is obtained max And a rear axial position parameter U min The maximum moving range of the rotor in the axial direction is defined as follows: u shape ref ＝(U max -U min )/2。
In some embodiments, the first axial position parameter comprises: the first axial position parameter before the operation of the magnetic bearing system is recorded as the first axial position parameter before the operation, such as U Before max . And a first axial position parameter after the magnetic suspension bearing system is operated, which is recorded as a first axial position parameter after the operation, such as U After max 。
The second axial position parameter, comprising: the second axial position parameter before the operation of the magnetic bearing system is recorded as the second axial position parameter before the operation, such as U Before min . And the second axial position parameter after the magnetic suspension bearing system is operated is recorded as the second axial position parameter after the operation, such as U After min 。
The control method of the magnetic suspension bearing system further includes: and determining the absolute value of the difference between the first axial position parameter before operation and the first axial position parameter after operation, or the absolute value of the difference between the second axial position parameter before operation and the second axial position parameter after operation as the expansion and contraction variation of the rotor.
In some further embodiments, in the solution of the present invention, the change of the rotor extension and retraction before and after the operation of the magnetic bearing control system can be detected according to the determined maximum moving range of the rotor in the axial direction.
Specifically, before the magnetic suspension bearing control system operates and after the magnetic suspension bearing control system operates, the U before the magnetic suspension bearing control system operates is respectively obtained by using the detection method of the invention Before max 、U Before min And U after magnetic suspension bearing control system is operated After max Such as U After min 。
For example: can represent the rotor expansion and contraction variation quantity = | U Before max -U max after |＝|U Before min Such as U After min |。
The axial clearance detection method of the magnetic suspension bearing provided by the scheme of the invention is characterized in that after a rotor is suspended, the rotor slowly moves to the foremost end and the rearmost end of a shaft by changing the axial suspension reference position, and the axial clearance is determined by the sampling voltage value of a displacement sensor, so that the axial clearance of the axial bearing is detected. The detection method avoids the impact of the rotor on the protective graphite, prolongs the service life of the rotor and the protective graphite, and avoids potential safety hazards.
Adopt the technical scheme of this embodiment, through carrying out the axial clearance testing process at magnetic suspension bearing control system, through changing the axial suspension position when the rotor suspends, make rotor thrust dish slowly lean on to axial foremost and rearmost end, so that make rotor thrust dish slowly lean on to foremost and rearmost protection graphite, thereby, carrying out the axial clearance testing process at magnetic suspension bearing control system, make rotor thrust dish slowly lean on to axial foremost and rearmost end, avoid leading to the fact the potential safety hazard to magnetic suspension bearing system.
According to an embodiment of the present invention, there is also provided a control apparatus of a magnetic bearing system corresponding to the control method of the magnetic bearing system. Referring to fig. 6, a schematic diagram of an embodiment of the apparatus of the present invention is shown. The magnetic suspension bearing system comprises: and (4) an axial bearing set. The axial bearing set comprising: a front axial bearing and a rear axial bearing. The control device of the magnetic suspension bearing system comprises: an acquisition unit 102 and a control unit 104.
Wherein, the obtaining unit 102 is configured to obtain an axial displacement detection parameter of the magnetic suspension bearing system as an initial axial reference position parameter of the rotor (such as an axial reference position parameter U of the rotor) in a case that the rotor of the magnetic suspension bearing system is stopped floating ref ). The specific functions and processes of the acquiring unit 102 are referred to in step S110.
A control unit 104 configured to control the rotor to be levitated so as to be in a levitated state. And the rotor is radially suspended at a radial central position and axially suspended at an axial reference position corresponding to the initial axial reference position parameter. The radial center position of the rotor radial suspension may be pre-calculated, for example, with the radial center point as the radial center position. The specific function and processing of the control unit 104 are referred to in step S120.
The control unit 104 is further configured to, in a case that the rotor is suspended, control the initial axial reference position parameter to increase a set reference position parameter in a set manner, so as to obtain a current axial reference position parameter of the rotor. Namely, the initial axial reference position parameter after the set reference position parameter is added is taken as the current axial reference position parameter of the rotor. The specific function and processing of the control unit 104 are also referred to in step S130.
In some embodiments, the controlling unit 104, controlling the initial axial reference position parameter to increase the set reference position parameter in a set manner, includes: controlling the process of increasing the initial axial reference position parameter by the set reference position parameter in a first manner, specifically as follows:
the control unit 104 is specifically further configured to control the initial axial reference position parameter to increase a set reference position parameter, so as to obtain a current axial reference position parameter of the rotor. The specific functions and processes of the control unit 104 are also referred to in step S210.
The control unit 104 is specifically further configured to, in a case where the rotor is controlled to move to one of the front axial bearing and the rear axial bearing based on the above-obtained current axial reference position parameter of the rotor, determine a current difference between a coil current of the one axial bearing at a current time and a coil current of the one axial bearing at a previous time in a case where the number of increases of the initial axial reference position parameter is increased by one set reference position parameter after the rotor is controlled to move to the one of the front axial bearing and the rear axial bearing based on the above-obtained current axial reference position parameter of the rotor. The specific functions and processes of the control unit 104 are also referred to in step S220.
The control unit 104 is specifically further configured to determine whether a ratio of the current difference to the set reference position parameter is greater than a set current change rate threshold: and if so, acquiring an axial displacement detection parameter of the magnetic suspension bearing system as a first axial position parameter of the magnetic suspension bearing system. Otherwise, the initial axial reference position parameter is continuously controlled to increase the set reference position parameter so as to obtain a new current axial reference position parameter of the rotor. The specific function and processing of the control unit 104 are also referred to in step S230.
Fig. 7 is a schematic view showing a structure of the axial gap detection apparatus of the magnetic bearing during movement of the embodiment in which the rotor is moved to the foremost end of the shaft after the rotor is stabilized by levitation, fig. 8 is a schematic view showing a structure of the axial gap detection apparatus of the embodiment in which the rotor is moved to the rearmost end of the shaft after the rotor is stabilized by levitation, and fig. 9 is a schematic view showing a flow of the axial gap detection apparatus of the magnetic bearing. The following describes an exemplary implementation process of the axial gap detection apparatus for magnetic bearings according to the present invention with reference to the examples shown in fig. 7, fig. 8 and fig. 9.
As shown in fig. 9, an axial gap detecting apparatus for a magnetic suspension bearing according to an aspect of the present invention includes:
step 1, starting to detect the axial clearance of the magnetic suspension bearing, and then executing the axial clearance detection step and the axial clearance calculation step.
The following description will be made by taking as an example the steps of detecting the axial front clearance (i.e., steps 21 to 23) and then detecting the axial rear clearance (i.e., steps 31 to 33).
And step 21, controlling the rotor to be radially suspended at a central position (namely a radial central position) and axially suspended at a position before suspension (namely an axial reference position or an axial central position).
In step 21, specifically, when the magnetic suspension bearing control system detects the axial clearance, the displacement signal of the rotor axial displacement sensor in the rotor stop-floating state is first obtained as the axial reference position parameter U of the rotor ref The axial reference position parameter U is set ref As a parameter U of the axial center position of the rotor ref . Furthermore, the magnetic bearing control system rotor is suspended in a radial center position and axially suspended in a position before suspension (i.e. an axial reference position or an axial center position).
After the rotor of the magnetic bearing control system is radially suspended at the radial center position and axially suspended at the position before suspension (i.e., the axial reference position or the axial center position), the magnetic bearing control system controls the rotor to suspend in five degrees of freedom, as shown in fig. 7, after the rotor is stably suspended, the rotor starts to slowly move forward and axially until the rotor contacts with the front protection graphite, specifically refer to steps 22 to 23.
Step 22, controlling an axial reference position parameter U of the rotor ref Adding a unit position parameter Δ U in the forward axial direction, i.e. the current axial reference position parameter = axial reference position parameter U of the rotor ref + Δ U unit position parameter.
Step 23, judging the current variation delta I of the front axial bearing coil f Ratio delta I to unit position parameter delta U of movement f Δ U, whether it is greater than a set current change rate threshold m: if yes, acquiring a front axial position parameter U max . Otherwise, return to step 22, continuously controlling the axial reference position parameter U of the rotor ref Adding a unit position parameter Δ U in the forward axial direction, i.e. the current axial reference position parameter = axial reference position parameter U of the rotor ref + Δ U unit position parameter.
And step 31, controlling the rotor to be radially suspended at a central position (namely a radial central position) and axially suspended at a position before suspension (namely an axial reference position or an axial central position).
The axial back clearance is detected, which is the same as the device for detecting the axial forward clearance, but in a different direction. In step 31, specifically, when the magnetic suspension bearing control system detects the axial back clearance, the displacement signal of the rotor axial displacement sensor in the rotor stop-floating state is firstly obtained as the axial reference position parameter U of the rotor ref The axial reference position parameter U is set ref As a parameter U of the axial center position of the rotor ref . In turn, the magnetic bearing control system rotor is radially suspended at a radially central position and axially suspended at a suspended position (i.e., an axial reference position or an axial central position).
After the rotor of the magnetic suspension bearing control system is radially suspended at the radial center position and axially suspended at the position before suspension (i.e. the axial reference position or the axial center position), the magnetic suspension bearing control system controls the rotor to suspend in five degrees of freedom, as shown in fig. 8, after the suspension of the rotor is stabilized, the rotor starts to move backwards and axially slowly until contacting the rear protection graphite, which is specifically referred to in steps 32 to 33.
And step 32, controlling the axial reference position of the rotor to increase the unit distance delta U towards the rear axial direction.
Step 33, determining the current variation Δ I of the rear axial bearing coil r Ratio delta I to unit distance delta U of movement r ,/Δ U, whether greater than a set current rate-of-change threshold m: if yes, acquiring a rear axial position parameter U min . Otherwise, returning to step 32, continuing to control the rotor axial reference position to increase the unit distance Δ U towards the rear axial direction.
In some embodiments, the controlling unit 104, controlling the initial axial reference position parameter to increase the set reference position parameter in a set manner, further includes: controlling the process of increasing the initial axial reference position parameter by the set reference position parameter in a second manner, specifically as follows:
the control unit 104 is specifically further configured to control the initial axial reference position parameter to increase a set reference position parameter to obtain a current axial reference position parameter of the rotor, and add the number of increases of the initial axial reference position parameter, such as adding 1 to the number of increases of the initial axial reference position parameter. The specific functions and processes of the control unit 104 are also referred to in step S310.
The control unit 104 is further specifically configured to, in a case where the rotor is controlled to move to one of the front axial bearing and the rear axial bearing based on the above-obtained current axial reference position parameter of the rotor, after the rotor is controlled to move to one of the front axial bearing and the rear axial bearing based on the above-obtained current axial reference position parameter of the rotor, continue to control the initial axial reference position parameter to increase the set reference position parameter to obtain a new current axial reference position parameter of the rotor, and continue to add up the number of increases of the initial axial reference position parameter, such as adding 1 to the number of increases of the initial axial reference position parameter. The specific functions and processes of the control unit 104 are also referred to in step S320.
The control unit 104 is specifically further configured to analogize until the current difference between the coil current of the axial bearing at the n +1 th time and the coil current of the axial bearing at the n th time is determined when the number of times of increase of the initial axial reference position parameter has increased to n and when the number of times of increase of the initial axial reference position parameter has increased to n + 1. The specific functions and processes of the control unit 104 are also referred to in step S330.
The control unit 104 is specifically further configured to determine whether a ratio of the current difference to the set reference position parameter is greater than a set current change rate threshold: and if so, acquiring an axial displacement detection parameter of the magnetic suspension bearing system as a first axial position parameter of the magnetic suspension bearing system. Otherwise, continuously controlling the initial axial reference position parameter to increase the set reference position parameter so as to obtain a new current axial reference position parameter of the rotor, and continuously accumulating the increasing times of the initial axial reference position parameter, for example, adding 1 to the increasing times of the initial axial reference position parameter. The specific functions and processes of the control unit 104 are also referred to in step S340.
Referring to the examples shown in fig. 7 to 9, in the process of detecting the axial forward clearance, in combination with steps 22 to 23, the axial center reference position parameter U is based on ref The reference position parameter Δ U is sequentially increased, such as each time the axial reference position parameter of Δ U is increased, the bearing axial closed-loop control system moves the rotor a distance Δ X in the forward axial direction. The axial reference position parameter Δ U corresponds to the axial movement distance Δ X, that is, the axial center reference position parameter U ref In the case of increasing the axial reference position parameter Δ U, the distance that the rotor moves in the forward axial direction is the axial movement distance Δ X. That is, when the rotor moves to the set reference position (i.e., the current axial reference position corresponding to the current axial reference position parameter of the rotor), the reference position parameter of Δ U is increased.
Until the reference position parameter delta U is increased n times (n is a positive integer), the rotor is finally contacted with the front axial protection graphite. If the rotor does not contact the front axial protection graphite after increasing the reference position parameter Δ U n times, the reference position parameter Δ U is continuously increased, for example, the reference position parameter Δ U is increased n +1 times, and so on.
If the rotor can contact the front axial protection graphite after the n +1 times of reference position parameter delta U is increased, but the rotor does not reach the preset axial reference position (namely the current reference position corresponding to the current axial reference position parameter after the n +1 times of reference position parameter delta U is increased) when the rotor contacts the protection bearing of the front shaft, at this time, as the reference position parameter delta U is continuously increased, the control strength of the closed-loop control system is also continuously increased, and the corresponding axial bearing control current is also continuously increased. Then, after the reference position parameter Δ U is increased n +1 times, in the case that the rotor contacts the protection bearing of the front shaft, but the rotor does not reach the preset axial reference position (i.e., the current reference position corresponding to the current axial reference position parameter after the reference position parameter Δ U is increased n +1 times), the control strength of the closed-loop control system is already increased, and accordingly, the front axial bearing control current is also rapidly increased.
Therefore, the current change Δ I of the front axial bearing coil is calculated by sampling the current of the front axial bearing coil after increasing the reference position parameter Δ U n +1 times and the current of the front axial bearing coil before increasing the reference position parameter Δ U n +1 times (i.e., the current of the front axial bearing coil after increasing the reference position parameter Δ U n times), and then calculating the current change Δ I of the front axial bearing coil f . Further, the current change amount Δ I of the front axial bearing coil is determined f Ratio delta I to unit reference position parameter delta U of movement f Δ U according to the ratio Δ I f The/Δ U determines whether or not the current of the front axial bearing coil is rapidly increased, that is, whether or not the rotor has reached the protective graphite, when the rotor has moved after the reference position parameter Δ U is increased n +1 times (of course, the unit distance of movement of the rotor after the reference position parameter Δ U is increased n +1 times may be Δ X or may be less than Δ X).
Specifically, the ratio Δ I is judged f Whether/Δ U is greater than m, m being the set current rate of change threshold: if the ratio Δ I f /ΔU<If the reference position parameter is not equal to the axial reference position parameter U, the rotor is not protected by the protective graphite, and the reference position parameter delta U is increased continuously to increase the axial reference position parameter U of the rotor ref And continuing to move the rotor forward. Of course, if the ratio Δ I f /ΔU>m, the control current of the front axial bearing coil is rapidly increased, the rotor is already contacted with the protective graphite, and the value U of the rotor axial displacement sensor at the moment is recorded max As front axial position parameter U max And quickly changing the axial reference position parameter, i.e. recovering the current axial reference position parameter of the rotor to the axial reference position parameter U ref So as to make the current axial reference position of the rotorParameter returning to axial reference position parameter U ref And levitates to prevent the control current of the front axial bearing coil from increasing all the time to cause an overcurrent.
In the process of detecting the axial forward clearance, step 32 to step 33 are combined, based on the axial center reference position parameter U ref The reference position parameter- Δ U is sequentially increased, such as by each increase in the axial reference position parameter of- Δ U, the bearing axial closed-loop control system moves the rotor a distance Δ X in the aft axial direction. The axial reference position parameter- Δ U corresponds to the axial movement distance Δ X, i.e., the reference position parameter U at the axial center ref With the axial reference position parameter- Δ U added, the distance that the rotor moves in the rearward axial direction is the axial movement distance Δ X. That is, the reference position parameter of- Δ U is increased again when the rotor moves to the set reference position (i.e., the current axial reference position corresponding to the current axial reference position parameter of the rotor).
Until the reference position parameter-delta U is increased n times (n is a positive integer), the rotor will eventually contact the rear axial protection graphite. If the rotor does not contact the rear axial protection graphite after increasing the reference position parameter- Δ U n times, the reference position parameter- Δ U is continuously increased, for example, the reference position parameter- Δ U is increased n +1 times, and so on.
If the rotor can contact the rear axial protection graphite after the n +1 times of reference position parameter-delta U is added, but the rotor does not reach the preset axial reference position (namely the current reference position corresponding to the rear axial reference position parameter after the n +1 times of reference position parameter-delta U is added) when the rotor contacts the protection bearing of the front shaft, at this time, because the control strength of the closed-loop control system is continuously increased along with the continuous increase of the reference position parameter-delta U, the corresponding axial bearing control current is also continuously increased. Then, after the reference position parameter- Δ U is increased n +1 times, in the case where the rotor contacts the protection bearing of the front shaft, but the rotor does not reach the preset axial reference position (i.e., the current reference position corresponding to the current rear axial reference position parameter after the reference position parameter- Δ U is increased n +1 times), the control strength of the closed-loop control system is already increased, and accordingly, the rear axial bearing control current is also rapidly increased.
Therefore, the current change Δ I of the rear axial bearing coil is calculated by sampling the current of the rear axial bearing coil after increasing the reference position parameter- Δ U for n +1 times and the current of the rear axial bearing coil before increasing the reference position parameter- Δ U for n +1 times (i.e., the current of the rear axial bearing coil after increasing the reference position parameter- Δ U for n times), and calculating the current change Δ I of the rear axial bearing coil r . Further, the amount of current change Δ I of the rear axial bearing coil is determined r Ratio delta I to unit reference position parameter delta U of movement r Δ U according to the ratio Δ I r The/Δ U judges whether the current of the rear axial bearing coil is rapidly increased, that is, whether the rotor has reached the protective graphite, in the case where the rotor has moved after the reference position parameter- Δ U is added n +1 times (of course, the unit distance of movement of the rotor may be Δ X or may be less than Δ X after the reference position parameter- Δ U is added n +1 times).
Specifically, the ratio Δ I is judged r Whether/Δ U is greater than m, m being the set current rate of change threshold: if the ratio Δ I r /ΔU<If the reference position parameter is not equal to the reference position parameter, the rotor reaches the protective graphite, and the reference position parameter-delta U is increased continuously to increase the axial reference position parameter U of the rotor continuously ref The rotor continues to move backward. Of course, if the ratio Δ I r /ΔU>m, the control current of the rear axial bearing coil is rapidly increased, the rotor is already contacted with the protective graphite, and the value U of the rotor axial displacement sensor at the moment is recorded min As a rear axial position parameter U min And quickly stopping the control of the magnetic bearing control system on the axial freedom degree so as to prevent the control current of the rear axial bearing coil from increasing all the time to cause overcurrent.
The control unit 104 is further configured to control the rotor to move towards the front axial bearing and towards the rear axial bearing, respectively, based on the current axial reference position parameter of the rotor, to determine a first axial position parameter of the magnetic bearing system and a second axial position parameter of the magnetic bearing system, still while the rotor is levitated. Wherein the first axial position parameter is an axial position parameter of one of a forwardmost end and a rearwardmost end of the axial bearing. The second axial position parameter is an axial position parameter of the other end of the foremost end and the rearmost end of the axial bearing. The specific function and processing of the control unit 104 are also referred to in step S140.
In some embodiments, the control unit 104, controlling the rotor to move towards the front axial bearing and the rear axial bearing, respectively, based on the current axial reference position parameter of the rotor, to determine a first axial position parameter of the magnetic bearing system and a second axial position parameter of the magnetic bearing system, comprises:
the control unit 104 is further configured to control the rotor to move to the protective graphite of one of the front axial bearing and the rear axial bearing based on the current axial reference position parameter of the rotor, and to use the axial displacement detection parameter of the magnetic suspension bearing system as the first axial position parameter of the magnetic suspension bearing system (e.g. the front axial position parameter U) max ) And then controlling the rotor to recover to the axial reference position corresponding to the initial axial reference position parameter. For example: axial position parameter U before acquisition max The axial reference position parameter is changed rapidly to prevent the control current of the front axial bearing coil from increasing all the time to cause overcurrent. The specific functions and processes of the control unit 104 are also referred to in step S410.
The control unit 104 is further configured to control the rotor to move to the protective graphite of the other one of the front axial bearing and the rear axial bearing based on the current axial reference position parameter of the rotor, and to use the axial displacement detection parameter of the magnetic suspension bearing system as the second axial position parameter of the magnetic suspension bearing system (e.g. the rear axial position parameter U) min ) And then controlling the rotor to recover to the axial reference position corresponding to the initial axial reference position parameter. For example: after obtaining the axial position parameter U min In the case of (2), rapidly stopping the magnetic bearing control system to be free in the axial directionAnd controlling the degree to prevent the control current of the rear axial bearing coil from increasing all the time to cause overcurrent. The specific function and processing of the control unit 104 are also referred to in step S420.
Referring to the examples shown in fig. 7 to 9, the axial gap detecting step includes: a step of detecting an axial forward clearance and a step of detecting an axial rearward clearance. Specifically, when the axial clearance detecting step is performed, the axial front clearance detecting step (i.e., steps 21 to 23) may be performed first, and the axial rear clearance detecting step (i.e., steps 31 to 33) may be performed next. Of course, the step of detecting the axial back gap (i.e., step 31 to step 33) may be performed first, and the step of detecting the axial front gap (i.e., step 21 to step 23) may be performed later.
As shown in fig. 9, the axial gap detection apparatus for a magnetic suspension bearing according to the present invention further includes:
step 4, calculating the axial clearance, namely: using front axial position parameter U max And a rear axial position parameter U min The axial clearance is calculated. That is, the acquired forward axial position parameter U max And a rear axial position parameter U min For maximum axial movement of the rotor, use is made of U max -U min The axial clearance (i.e., U) can be calculated from the difference max -U min The difference of (d) as the axial clearance of the rotor).
And 5, detecting the axial clearance to finish.
The control unit 104 is further configured to determine an axial gap of the magnetic bearing system based on the first axial position parameter and the second axial position parameter. The specific function and processing of the control unit 104 are also referred to in step S150.
The scheme of the invention provides an axial gap detection device of a magnetic suspension bearing, when the axial gap is detected, the rotor thrust disk is slowly leaned against the protective graphite by changing the axial suspension position when the rotor is suspended instead of directly colliding the rotor thrust disk against the axial protective graphite by fixing the current of the axial bearing coil, so that the collision generated when the rotor thrust disk is contacted with the protective graphite is avoided.
Like this, through the axial clearance testing process at magnetic suspension bearing for rotor thrust dish leans on slowly to axial both ends protection graphite, effectively avoids rotor thrust dish and protection bearing's striking, thereby reduces the loss between rotor thrust dish and the protection graphite, prolongs the life of protection graphite, has improved magnetic suspension bearing control system's stability and security. Therefore, the problems of impact loss and potential safety hazard caused by impact between the rotor thrust disk and the protective graphite in the axial gap detection process of the magnetic suspension bearing control system with the related scheme are solved, so that the rotor thrust disk is protected, and the service life of the protective graphite is prolonged.
In some embodiments, the control device of a magnetic suspension bearing system described above further includes: the control unit 104, further configured to, in case a first axial position parameter of the magnetic suspension bearing system and a second axial position parameter of the magnetic suspension bearing system have been determined, take half of the absolute value of the difference between the first axial position parameter and the second axial position parameter as the central levitation reference position parameter of the rotor.
In some further embodiments, in the solution of the present invention, the axial center levitation reference position may be determined according to the determined maximum moving range of the rotor in the axial direction. Specifically, after the detection device is used, the front axial position parameter U is acquired max And a rear axial position parameter U min The maximum moving range of the rotor in the axial direction is defined as follows: u shape ref ＝(U max -U min )/2。
In some embodiments, the first axial position parameter comprises: the first axial position parameter before the operation of the magnetic bearing system is recorded as the first axial position parameter before the operation, such as U Before max . And a first axial position parameter after the magnetic suspension bearing system is operated, which is recorded as a first axial position parameter after the operation, such as U max after 。
The second axial position parameter, comprising: the magnetic suspension shaftThe second axial position parameter before operation of the bearing system is recorded as the second axial position parameter before operation, e.g. U Before min . And the second axial position parameter after the magnetic suspension bearing system is operated is recorded as the second axial position parameter after the operation, such as U After min 。
The control device for a magnetic suspension bearing system described above further includes: the control unit 104 is further configured to determine an absolute value of a difference between the first axial position parameter before operation and the first axial position parameter after operation, or an absolute value of a difference between the second axial position parameter before operation and the second axial position parameter after operation, as the amount of change in the expansion and contraction of the rotor.
In some further embodiments, in the solution of the present invention, the change of the rotor extension and retraction before and after the operation of the magnetic bearing control system can be detected according to the determined maximum moving range of the rotor in the axial direction.
Specifically, before the magnetic suspension bearing control system operates and after the magnetic suspension bearing control system operates, the U before the magnetic suspension bearing control system operates is respectively obtained by using the detection device of the invention Before max 、U Before min And U after magnetic suspension bearing control system is operated max after Such as U After min 。
For example: can represent the rotor expansion and contraction variation quantity = | U Before max -U After max |＝|U Before min Such as U After min |。
The axial clearance detection device of the magnetic suspension bearing provided by the scheme of the invention has the advantages that after the rotor is suspended, the rotor slowly moves to the foremost end and the rearmost end of the shaft by changing the axial suspension reference position, and the axial clearance is determined by the sampling voltage value of the displacement sensor, so that the axial clearance detection of the axial bearing is realized. The detection device avoids the impact of the rotor on the protective graphite, prolongs the service life of the rotor and the protective graphite, and avoids potential safety hazards.
Since the processes and functions implemented by the apparatus of this embodiment substantially correspond to the embodiments, principles and examples of the method, reference may be made to the related descriptions in the embodiments without being detailed in the description of this embodiment, which is not described herein again.
By adopting the technical scheme of the invention, the rotor thrust disk slowly leans to the foremost end and the rearmost end in the axial direction by changing the axial suspension position when the rotor is suspended in the process of detecting the axial gap by the magnetic suspension bearing control system, so that the rotor thrust disk slowly leans to the protective graphite at the foremost end and the rearmost end, and the collision generated when the rotor thrust disk is contacted with the protective graphite is avoided.
According to an embodiment of the invention, there is also provided a magnetic bearing system corresponding to a control device of the magnetic bearing system. The magnetic bearing system may include: the control device for a magnetic bearing system described above.
Since the processing and functions of the magnetic suspension bearing system of this embodiment are basically corresponding to the embodiments, principles and examples of the apparatus, the description of this embodiment is not given in detail, and reference may be made to the related descriptions in the embodiments, which are not repeated herein.
By adopting the technical scheme of the invention, the rotor thrust disk slowly leans to the foremost end and the rearmost end in the axial direction by changing the axial suspension position when the rotor is suspended in the process of detecting the axial gap by the magnetic suspension bearing control system, so that the rotor thrust disk slowly leans to the protective graphite in the foremost end and the rearmost end, the impact of the rotor thrust disk and the protective bearing is effectively avoided, the loss between the rotor thrust disk and the protective graphite is reduced, and the service life of the protective graphite is prolonged.
According to an embodiment of the present invention, there is also provided a storage medium corresponding to a control method of a magnetic bearing system, the storage medium including a stored program, wherein when the program is executed, a device on which the storage medium is located is controlled to execute the above-mentioned control method of a magnetic bearing system.
Since the processing and functions implemented by the storage medium of this embodiment substantially correspond to the embodiments, principles, and examples of the foregoing method, reference may be made to the related descriptions in the foregoing embodiments without being detailed in the description of this embodiment.
By adopting the technical scheme of the invention, the rotor thrust disk slowly leans to the foremost end and the rearmost end of the axial direction by changing the axial suspension position when the rotor is suspended in the process of detecting the axial gap of the magnetic suspension bearing control system, so that the rotor thrust disk slowly leans to the protective graphite of the foremost end and the rearmost end, and the stability and the safety of the magnetic suspension bearing control system are improved.
In summary, it is readily understood by those skilled in the art that the advantageous modes described above can be freely combined and superimposed without conflict.
The above description is only an example of the present invention, and is not intended to limit the present invention, and it is obvious to those skilled in the art that various modifications and variations can be made in the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims (10)

1. A method of controlling a magnetic bearing system, the magnetic bearing system comprising: an axial bearing set; the axial bearing set comprising: a front axial bearing and a rear axial bearing; the control method of the magnetic suspension bearing system comprises the following steps:
under the condition that a rotor of the magnetic suspension bearing system stops floating, acquiring an axial displacement detection parameter of the magnetic suspension bearing system as an initial axial reference position parameter of the rotor;
controlling the rotor to suspend; the rotor is radially suspended at a radial central position and axially suspended at an axial reference position corresponding to the initial axial reference position parameter;
controlling the initial axial reference position parameter to increase a set reference position parameter according to a set mode to obtain a current axial reference position parameter of the rotor; wherein, control initial axial reference position parameter increase according to the mode of settlement and set up reference position parameter, include: controlling the initial axial reference position parameter to increase a set reference position parameter so as to obtain a current axial reference position parameter of the rotor; after the rotor is controlled to move towards one of the front axial bearing and the rear axial bearing based on the obtained current axial reference position parameter of the rotor, determining a current difference value between the coil current of the previous axial bearing and the coil current of the previous axial bearing under the condition that the increasing times of the initial axial reference position parameter is increased by once set reference position parameter; determining whether a ratio of the current difference to the set reference position parameter is greater than a set current rate of change threshold: if so, acquiring an axial displacement detection parameter of the magnetic suspension bearing system as a first axial position parameter of the magnetic suspension bearing system; otherwise, continuing to control the initial axial reference position parameter to increase a set reference position parameter so as to obtain a new current axial reference position parameter of the rotor;
controlling the rotor to move towards the front axial bearing and the rear axial bearing respectively based on a current axial reference position parameter of the rotor to determine a first axial position parameter of the magnetic suspension bearing system and a second axial position parameter of the magnetic suspension bearing system; wherein controlling the rotor to move towards the front axial bearing and the rear axial bearing, respectively, based on a current axial reference position parameter of the rotor to determine a first axial position parameter of the magnetic bearing system and a second axial position parameter of the magnetic bearing system comprises: firstly, controlling the rotor to move to a protective graphite position of one of the front axial bearing and the rear axial bearing based on the current axial reference position parameter of the rotor, taking an axial displacement detection parameter of the magnetic suspension bearing system as a first axial position parameter of the magnetic suspension bearing system, and then controlling the rotor to recover to an axial reference position corresponding to the initial axial reference position parameter; then controlling the rotor to move to a protective graphite position of the other axial bearing of the front axial bearing and the rear axial bearing based on the current axial reference position parameter of the rotor, taking the axial displacement detection parameter of the magnetic suspension bearing system as a second axial position parameter of the magnetic suspension bearing system, and then controlling the rotor to recover to an axial reference position corresponding to the initial axial reference position parameter;
and determining the axial clearance of the magnetic suspension bearing system according to the first axial position parameter and the second axial position parameter, so that the rotor thrust disc slowly leans to the foremost end and the rearmost end of the axial direction by changing the axial suspension position when the rotor is suspended, and the rotor thrust disc slowly leans to the protective graphite of the foremost end and the rearmost end.
2. The method of controlling a magnetic bearing system as claimed in claim 1, wherein controlling the initial axial reference position parameter to increase in a set reference position parameter in a set manner further comprises:
controlling the initial axial reference position parameter to increase a set reference position parameter so as to obtain a current axial reference position parameter of the rotor, and accumulating the increasing times of the initial axial reference position parameter;
after controlling the rotor to move towards one of the front axial bearing and the rear axial bearing based on the obtained current axial reference position parameter of the rotor, continuously controlling the initial axial reference position parameter to increase a set reference position parameter so as to obtain a new current axial reference position parameter of the rotor;
analogizing in sequence until the current difference between the coil current of the axial bearing at the n +1 th time and the coil current of the axial bearing at the n +1 th time is determined under the condition that the increasing times of the initial axial reference position parameter are increased to n and the increasing times of the initial axial reference position parameter are increased to n + 1;
determining whether a ratio of the current difference to the set reference position parameter is greater than a set current rate-of-change threshold: if so, acquiring an axial displacement detection parameter of the magnetic suspension bearing system as a first axial position parameter of the magnetic suspension bearing system; otherwise, the initial axial reference position parameter is continuously controlled to increase the set reference position parameter so as to obtain a new current axial reference position parameter of the rotor.
3. The method of controlling a magnetic bearing system according to any of claims 1 to 2, further comprising:
in the case that a first axial position parameter of the magnetic bearing system and a second axial position parameter of the magnetic bearing system have been determined, half the absolute value of the difference between the first axial position parameter and the second axial position parameter is taken as the central levitation reference position parameter of the rotor.
4. A method of controlling a magnetic bearing system according to any of claims 1 to 3, wherein the first axial position parameter comprises: recording a first axial position parameter before the operation of the magnetic suspension bearing system as a first axial position parameter before the operation; recording the first axial position parameter of the magnetic suspension bearing system after operation as the first axial position parameter after operation;
the second axial position parameter comprises: recording a second axial position parameter before the magnetic suspension bearing system operates as a second axial position parameter before the magnetic suspension bearing system operates; and recording the second axial position parameter of the magnetic suspension bearing system after operation as the second axial position parameter after operation;
the control method of the magnetic suspension bearing system further comprises the following steps:
and determining the absolute value of the difference between the first axial position parameter before operation and the first axial position parameter after operation, or the absolute value of the difference between the second axial position parameter before operation and the second axial position parameter after operation as the expansion and contraction variation of the rotor.
5. A control device for a magnetic bearing system, the magnetic bearing system comprising: an axial bearing set; the axial bearing set comprising: a front axial bearing and a rear axial bearing; the control device of the magnetic suspension bearing system comprises:
an obtaining unit configured to obtain an axial displacement detection parameter of the magnetic suspension bearing system as an initial axial reference position parameter of the rotor in a case that the rotor of the magnetic suspension bearing system is stopped floating;
a control unit configured to control the rotor levitation; the rotor is radially suspended at a radial central position and axially suspended at an axial reference position corresponding to the initial axial reference position parameter;
the control unit is further configured to control the initial axial reference position parameter to increase a set reference position parameter in a set manner, so as to obtain a current axial reference position parameter of the rotor; the control unit controls the initial axial reference position parameter to increase the set reference position parameter according to a set mode, and the control unit comprises: controlling the initial axial reference position parameter to increase a set reference position parameter so as to obtain a current axial reference position parameter of the rotor; after the rotor is controlled to move towards one of the front axial bearing and the rear axial bearing based on the obtained current axial reference position parameter of the rotor, determining a current difference value between the coil current of the previous axial bearing and the coil current of the previous axial bearing under the condition that the increasing times of the initial axial reference position parameter is increased by once set reference position parameter; determining whether a ratio of the current difference to the set reference position parameter is greater than a set current rate of change threshold: if so, acquiring an axial displacement detection parameter of the magnetic suspension bearing system as a first axial position parameter of the magnetic suspension bearing system; otherwise, continuing to control the initial axial reference position parameter to increase a set reference position parameter so as to obtain a new current axial reference position parameter of the rotor;
the control unit is further configured to control the rotor to move towards the front axial bearing and the rear axial bearing, respectively, based on a current axial reference position parameter of the rotor, to determine a first axial position parameter of the magnetic bearing system and a second axial position parameter of the magnetic bearing system; wherein the control unit controls the rotor to move towards the front axial bearing and the rear axial bearing respectively based on a current axial reference position parameter of the rotor to determine a first axial position parameter of the magnetic bearing system and a second axial position parameter of the magnetic bearing system, comprising: firstly, controlling the rotor to move to a protective graphite position of one of the front axial bearing and the rear axial bearing based on the current axial reference position parameter of the rotor, taking an axial displacement detection parameter of the magnetic suspension bearing system as a first axial position parameter of the magnetic suspension bearing system, and then controlling the rotor to recover to an axial reference position corresponding to the initial axial reference position parameter; then controlling the rotor to move to a protective graphite position of the other axial bearing of the front axial bearing and the rear axial bearing based on the current axial reference position parameter of the rotor, taking the axial displacement detection parameter of the magnetic suspension bearing system as a second axial position parameter of the magnetic suspension bearing system, and then controlling the rotor to recover to an axial reference position corresponding to the initial axial reference position parameter;
the control unit is further configured to determine an axial gap of the magnetic suspension bearing system according to the first axial position parameter and the second axial position parameter, so that the rotor thrust disk is slowly leaned to the most front end and the most rear end in the axial direction by changing the axial suspension position when the rotor is suspended, and the rotor thrust disk is slowly leaned to the protective graphite at the most front end and the most rear end.
6. The control device of a magnetic bearing system according to claim 5, wherein the control unit controls the initial axial reference position parameter to increase by a set reference position parameter in a set manner, further comprising:
controlling the initial axial reference position parameter to increase a set reference position parameter so as to obtain a current axial reference position parameter of the rotor, and accumulating the increasing times of the initial axial reference position parameter;
after controlling the rotor to move towards one of the front axial bearing and the rear axial bearing based on the obtained current axial reference position parameter of the rotor, continuously controlling the initial axial reference position parameter to increase a set reference position parameter so as to obtain a new current axial reference position parameter of the rotor;
analogizing in sequence until the current difference between the coil current of the axial bearing at the n +1 th time and the coil current of the axial bearing at the n +1 th time is determined under the condition that the increasing times of the initial axial reference position parameter are increased to n and the increasing times of the initial axial reference position parameter are increased to n + 1;
determining whether a ratio of the current difference to the set reference position parameter is greater than a set current rate-of-change threshold: if so, acquiring an axial displacement detection parameter of the magnetic suspension bearing system as a first axial position parameter of the magnetic suspension bearing system; otherwise, continuing to control the initial axial reference position parameter and increasing the set reference position parameter so as to obtain a new current axial reference position parameter of the rotor.
7. Control arrangement for a magnetic bearing system according to any of claims 5 to 6, further comprising:
the control unit is further configured to, in case a first axial position parameter of the magnetic suspension bearing system and a second axial position parameter of the magnetic suspension bearing system have been determined, take half of an absolute value of a difference between the first axial position parameter and the second axial position parameter as a central levitation reference position parameter of the rotor.
8. Control arrangement for a magnetic bearing system according to any of claims 5 to 7, characterized in that the first axial position parameter comprises: recording a first axial position parameter before the operation of the magnetic suspension bearing system as a first axial position parameter before the operation; recording the first axial position parameter of the magnetic suspension bearing system after operation as the first axial position parameter after operation;
the second axial position parameter comprises: recording a second axial position parameter before the magnetic suspension bearing system operates as a second axial position parameter before the magnetic suspension bearing system operates; and recording the second axial position parameter of the magnetic suspension bearing system after operation as the second axial position parameter after operation;
the control device of the magnetic suspension bearing system further comprises:
the control unit is further configured to determine an absolute value of a difference between the first axial position parameter before operation and the first axial position parameter after operation, or an absolute value of a difference between the second axial position parameter before operation and the second axial position parameter after operation, as the amount of change in the expansion and contraction of the rotor.
9. A magnetic bearing system, comprising: control device for a magnetic bearing system according to any of claims 5 to 8.
10. A storage medium, characterized in that the storage medium comprises a stored program, wherein the program, when executed, controls an apparatus in which the storage medium is located to perform the method of controlling a magnetic bearing system according to any of claims 1 to 4.
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