CN117092434A

CN117092434A - Method and device for detecting magnetic suspension system, magnetic suspension system and storage medium

Info

Publication number: CN117092434A
Application number: CN202311080117.0A
Authority: CN
Inventors: 林润方; 唐文婕; 王运博; 林郁成
Original assignee: Gree Electric Appliances Inc of Zhuhai
Current assignee: Gree Electric Appliances Inc of Zhuhai
Priority date: 2023-08-25
Filing date: 2023-08-25
Publication date: 2023-11-21

Abstract

The invention discloses an abnormality detection method and device of a magnetic suspension bearing system, the magnetic suspension bearing system and a storage medium, wherein the method comprises the following steps: in the running process of the magnetic suspension bearing system, determining whether the suspension current of the magnetic suspension bearing system is abnormal according to the current suspension current and a predetermined standard suspension current; if the abnormal state is confirmed, changing the levitation position of the rotor to the center position of the preset magnetic bearing according to the preset standard levitation current, and determining the fault point of the abnormal levitation current according to the levitation current at the moment and the preset standard levitation current. According to the scheme, whether the current levitation current is abnormal or not is determined through comparison of the current levitation current and the standard levitation current, if so, the levitation position of the rotor is adjusted, and the abnormal reason is determined according to the current levitation current and the standard levitation current, so that whether the current levitation current is abnormal or not and the abnormal reason are found timely, and the efficiency of abnormality detection is improved.

Description

Method and device for detecting magnetic suspension system, magnetic suspension system and storage medium

Technical Field

The invention belongs to the technical field of magnetic suspension, and particularly relates to an abnormality detection method and device of a magnetic suspension bearing system, the magnetic suspension bearing system and a storage medium, in particular to an abnormality detection method and device of a suspension current abnormality of the magnetic suspension bearing system, the magnetic suspension bearing system and the storage medium.

Background

The magnetic suspension bearing system suspends the rotor at a given position through electromagnetic force, realizes high-speed friction-free operation, and has the advantages of no need of lubrication, long service life and the like. Normally, the rotor is suspended at the center position of the protection bearing, and the deviation between the center position of the protection bearing and the center position of the magnetic bearing is not large. However, due to processing, assembly errors, shaft collision and other reasons, eccentricity may occur between the central position of the protection bearing and the central position of the electromagnetic bearing, that is, the rotor is not positioned at the central position of the electromagnetic bearing when suspended in the central position of the protection bearing, and if the eccentricity is serious, the current in the static suspension stage of the rotor has larger deviation from the normal suspension current. Besides eccentricity, when the magnetic bearing characteristics change (such as the bearing magnet steel demagnetizes when the magnetic bearing operates in a high temperature state for a long time), current abnormality of the rotor in static suspension can also be caused. Therefore, the phenomenon is abnormal in levitation current, whether the eccentric or magnetic bearing characteristics are abnormal. Therefore, when the levitation current is abnormal, whether the magnetic bearing is eccentric or the magnetic bearing characteristics are abnormal cannot be judged.

The foregoing is provided merely for the purpose of facilitating understanding of the technical solutions of the present invention and is not intended to represent an admission that the foregoing is prior art.

Disclosure of Invention

The invention aims to provide an abnormality detection method and device for a magnetic suspension bearing system, the magnetic suspension bearing system and a storage medium, so as to solve the problem that whether the magnetic suspension bearing is eccentric or abnormal in magnetic bearing characteristics cannot be judged when the suspension current of the magnetic suspension bearing is abnormal in the prior art, and achieve the effects that whether the suspension current is abnormal or not is determined according to the current suspension current and the standard suspension current when the magnetic suspension bearing system is in operation, if so, the rotor position is adjusted according to the current suspension current and the standard suspension current, and whether the suspension current is eccentric or abnormal in magnetic bearing characteristics is determined according to the current suspension current and the standard suspension current at the moment, so that whether the suspension current is abnormal or not and the abnormality cause can be timely found under the condition that the magnetic suspension bearing system is not stopped, and the abnormality detection efficiency is improved.

The invention provides an abnormality detection method of a magnetic suspension bearing system, which comprises a magnetic bearing, a protection bearing and a rotor; the magnetic bearing is provided with m electrifying coils, the rotor is suspended in the magnetic bearing under the action of the m electrifying coils, and m is a positive integer; the current flowing through the m energized coils jointly forms a levitation current of the magnetic bearing system; the method comprises the following steps: in advance, under the condition that the magnetic suspension system normally operates, determining the standard suspension current of the magnetic suspension bearing system, and determining n groups of standard deflection currents of the magnetic suspension bearing system, wherein n is a positive integer; acquiring a levitation current of the magnetic bearing system in the current running process of the magnetic bearing system, and recording the levitation current as a first levitation current of the magnetic bearing system; determining whether the levitation current of the magnetic bearing system is abnormal or not according to the first levitation current of the magnetic bearing system based on the standard levitation current of the magnetic bearing system; if it is determined that the levitation current of the magnetic bearing system is abnormal, recording the levitation current of the magnetic bearing system at the moment based on n groups of standard levitation currents of the magnetic bearing system under the condition that the levitation position of the rotor is changed to a preset magnetic bearing center point position, and recording the levitation current as a second levitation current of the magnetic bearing system; and determining a fault point of abnormality of the levitation current of the magnetic bearing system according to the second levitation current of the magnetic bearing system based on the standard levitation current of the magnetic bearing system.

In some embodiments, determining a standard levitation current of the magnetic bearing system and determining n sets of standard levitation currents of the magnetic bearing system under normal operation of the magnetic bearing system comprises: under the condition that the magnetic suspension system normally operates, the suspension current of the magnetic suspension system is used as a standard suspension current when the rotor is suspended at the central position of the magnetic bearing; under the condition that the magnetic suspension system normally operates and the rotor is suspended at the central position of the magnetic bearing, the suspension current of the magnetic suspension system after the rotor is deviated along different preset directions and different preset distances is used as a standard deviation current; wherein the preset distance is a distance of a current position of the rotor with respect to a center position of the magnetic bearing.

In some embodiments, determining whether an anomaly in levitation current of the magnetic bearing system occurs based on a standard levitation current of the magnetic bearing system from a first levitation current of the magnetic bearing system comprises: subtracting the current flowing through each of the m energizing coils in the first levitation current from the current flowing through the corresponding energizing coil in the standard levitation current to obtain m difference values; determining whether the absolute value of any one of the absolute values of the m differences is larger than a preset threshold value; if any one of the absolute values of the m differences is larger than a preset threshold value, determining that the suspension current of the magnetic suspension bearing system is abnormal.

In some embodiments, based on n groups of standard levitation currents of the magnetic bearing system, when the levitation position of the rotor is changed to a preset magnetic bearing center point position, recording the levitation current of the magnetic bearing system at the moment, which is recorded as a second levitation current of the magnetic bearing system, including: determining the offset current with the smallest difference value with the first offset current in the n groups of standard offset currents as a reference offset current; adjusting the levitation position of the rotor according to the reference levitation current to enable the first levitation current to be consistent with the reference levitation current, and recording the levitation position of the rotor at the moment as the current levitation position of the rotor; and on the basis of the current suspension position of the rotor, shifting the rotor by a preset distance in the reference suspension current deflection along the opposite direction of the preset direction in the reference suspension current deflection, so that the suspension position of the rotor is positioned at the preset magnetic bearing center point position, and recording the suspension current of the magnetic suspension bearing system at the moment and recording the suspension current as the second suspension current of the magnetic suspension bearing system.

In some embodiments, determining, as the reference bias current, a bias current having a smallest difference from the first bias current among the n sets of standard bias currents, includes: subtracting the current flowing through each of m energizing coils in each group of deflection currents from the current flowing through the corresponding energizing coil in the first levitation current in the n groups of standard deflection currents, wherein each group of deflection currents respectively obtain m current difference values, adding the m current difference values in each group of deflection currents, and recording the added result as the sum of the difference values to obtain the sum of n groups of difference values; and determining the smallest sum of the differences in the obtained n groups of differences, and taking the offset current corresponding to the smallest sum of the differences as a reference offset current.

In some embodiments, determining a fault point at which an anomaly in levitation current of the magnetic bearing system occurs based on a standard levitation current of the magnetic bearing system from a second levitation current of the magnetic bearing system comprises: subtracting the current flowing through each of the m energizing coils in the second levitation current from the current flowing through the corresponding energizing coil in the standard levitation current to obtain m difference values; determining whether the absolute value of any one of the absolute values of the m differences is larger than a preset threshold value; if the absolute value of any difference value in the absolute values of the m difference values is larger than a preset threshold value, determining that the magnetic bearing characteristic of the magnetic suspension bearing system is abnormal; if the absolute value of any difference value in the absolute values of the m difference values is not greater than a preset threshold value, determining that the magnetic suspension bearing system is eccentric.

In accordance with the above method, another aspect of the present invention provides an abnormality detection apparatus of a magnetic bearing system including a magnetic bearing, a protection bearing, and a rotor; the magnetic bearing is provided with m electrifying coils, the rotor is suspended in the magnetic bearing under the action of the m electrifying coils, and m is a positive integer; the current flowing through the m energized coils jointly forms a levitation current of the magnetic bearing system; the device comprises: the processing unit is configured to determine the standard levitation current of the magnetic levitation bearing system and determine n groups of standard levitation currents of the magnetic levitation bearing system in advance under the condition that the magnetic levitation system normally operates, wherein n is a positive integer; an acquisition unit configured to acquire a levitation current of the magnetic bearing system during a current operation of the magnetic bearing system, and record the levitation current as a first levitation current of the magnetic bearing system; the processing unit is further configured to determine whether the levitation current of the magnetic bearing system is abnormal according to the first levitation current of the magnetic bearing system based on the standard levitation current of the magnetic bearing system; the processing unit is further configured to record the levitation current of the magnetic bearing system at the moment and record the levitation current as a second levitation current of the magnetic bearing system under the condition that the levitation position of the rotor is changed to a preset magnetic bearing center point position based on n groups of standard levitation currents of the magnetic bearing system if the levitation current of the magnetic bearing system is determined to be abnormal; the processing unit is further configured to determine a fault point at which an abnormality occurs in the levitation current of the magnetic bearing system according to the second levitation current of the magnetic bearing system based on the standard levitation current of the magnetic bearing system.

In some embodiments, the processing unit, in the case of normal operation of the magnetic levitation system, determines a standard levitation current of the magnetic levitation bearing system and determines n sets of standard levitation currents of the magnetic levitation bearing system, comprising: under the condition that the magnetic suspension system normally operates, the suspension current of the magnetic suspension system is used as a standard suspension current when the rotor is suspended at the central position of the magnetic bearing; under the condition that the magnetic suspension system normally operates and the rotor is suspended at the central position of the magnetic bearing, the suspension current of the magnetic suspension system after the rotor is deviated along different preset directions and different preset distances is used as a standard deviation current; wherein the preset distance is a distance of a current position of the rotor with respect to a center position of the magnetic bearing.

In some embodiments, the processing unit, based on the standard levitation current of the magnetic bearing system, determines whether an abnormality occurs in the levitation current of the magnetic bearing system according to the first levitation current of the magnetic bearing system, including: subtracting the current flowing through each of the m energizing coils in the first levitation current from the current flowing through the corresponding energizing coil in the standard levitation current to obtain m difference values; determining whether the absolute value of any one of the absolute values of the m differences is larger than a preset threshold value; if any one of the absolute values of the m differences is larger than a preset threshold value, determining that the suspension current of the magnetic suspension bearing system is abnormal.

In some embodiments, the processing unit records the levitation current of the magnetic bearing system at this time, which is recorded as the second levitation current of the magnetic bearing system, based on n groups of standard levitation currents of the magnetic bearing system, in a case of changing the levitation position of the rotor to a preset magnetic bearing center point position, and includes: determining the offset current with the smallest difference value with the first offset current in the n groups of standard offset currents as a reference offset current; adjusting the levitation position of the rotor according to the reference levitation current to enable the first levitation current to be consistent with the reference levitation current, and recording the levitation position of the rotor at the moment as the current levitation position of the rotor; and on the basis of the current suspension position of the rotor, shifting the rotor by a preset distance in the reference suspension current deflection along the opposite direction of the preset direction in the reference suspension current deflection, so that the suspension position of the rotor is positioned at the preset magnetic bearing center point position, and recording the suspension current of the magnetic suspension bearing system at the moment and recording the suspension current as the second suspension current of the magnetic suspension bearing system.

In some embodiments, the processing unit determines, as a reference bias current, a bias current having a smallest difference from the first bias current among the n sets of standard bias currents, including: subtracting the current flowing through each of m energizing coils in each group of deflection currents from the current flowing through the corresponding energizing coil in the first levitation current in the n groups of standard deflection currents, wherein each group of deflection currents respectively obtain m current difference values, adding the m current difference values in each group of deflection currents, and recording the added result as the sum of the difference values to obtain the sum of n groups of difference values; and determining the smallest sum of the differences in the obtained n groups of differences, and taking the offset current corresponding to the smallest sum of the differences as a reference offset current.

In some embodiments, the processing unit, based on the standard levitation current of the magnetic bearing system, determines a fault point at which an abnormality occurs in the levitation current of the magnetic bearing system according to the second levitation current of the magnetic bearing system, including: subtracting the current flowing through each of the m energizing coils in the second levitation current from the current flowing through the corresponding energizing coil in the standard levitation current to obtain m difference values; determining whether the absolute value of any one of the absolute values of the m differences is larger than a preset threshold value; if the absolute value of any difference value in the absolute values of the m difference values is larger than a preset threshold value, determining that the magnetic bearing characteristic of the magnetic suspension bearing system is abnormal; if the absolute value of any difference value in the absolute values of the m difference values is not greater than a preset threshold value, determining that the magnetic suspension bearing system is eccentric.

In accordance with another aspect of the present invention, there is provided a magnetic bearing system comprising: the abnormality detection device of the magnetic bearing system described above.

In accordance with the foregoing method, a further aspect of the present invention provides a storage medium, where the storage medium includes a stored program, where the program, when executed, controls a device in which the storage medium is located to perform the foregoing method for detecting an abnormality of a magnetic bearing system.

According to the scheme, the standard levitation current and n groups of standard levitation currents are determined in advance when the magnetic bearing system normally operates, and whether the levitation current of the magnetic bearing system is abnormal or not is determined according to the current levitation current and the standard levitation current in the operation process of the magnetic bearing system; if abnormality occurs, the suspension position of the rotor is adjusted according to n groups of standard deflection current, so that the current suspension position of the rotor is positioned at the center point of the magnetic bearing, and the suspension current at the moment is recorded; the abnormal cause of the levitation current is determined according to the levitation current and the standard levitation current, and the abnormal cause is specifically eccentric abnormality or abnormal magnetic bearing characteristics, so that whether the levitation current is abnormal or not and the abnormal cause can be timely found under the condition that the magnetic bearing system is not stopped, and the efficiency of abnormality detection and the operation reliability of the magnetic bearing system are improved.

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 practice of the invention.

The technical scheme of the invention is further described in detail through the drawings and the embodiments.

Drawings

FIG. 1 is a flow chart of an embodiment of an anomaly detection method for a magnetic bearing system according to the present invention;

FIG. 2 is a flow chart of an embodiment of the method of determining whether a levitation current of a magnetic bearing system is abnormal in accordance with the present invention;

FIG. 3 is a flow chart of an embodiment of the method of the present invention for changing the levitation position of a rotor according to a standard levitation current;

FIG. 4 is a flow chart of an embodiment of determining a fault point for a levitation current anomaly of a magnetic bearing system in a method of the present invention;

FIG. 5 is a schematic diagram illustrating an embodiment of an abnormality detection apparatus of a magnetic bearing system according to the present invention;

FIG. 6 is a graph of characteristics of a magnetic bearing in a magnetic bearing system;

FIG. 7 is a schematic diagram of a rotor levitation structure under normal operating conditions of a magnetic bearing system;

FIG. 8 is a schematic diagram of a rotor levitation structure with eccentricity of a magnetic bearing system;

FIG. 9 is a schematic diagram of a rotor levitation structure for controlling rotor levitation in a magnetic bearing system;

FIG. 10 is a schematic diagram of a structure for controlling rotor levitation in a magnetic bearing system;

FIG. 11 is a schematic diagram of the structure of a differentially controlled magnetic bearing in a magnetic bearing system;

FIG. 12 is a flow chart of an embodiment of determining the cause of a levitation current anomaly based on a levitation current and a standard current in the method of the present invention;

in the embodiment of the present invention, reference numerals are as follows, in combination with the accompanying drawings:

102-an acquisition unit; 104-a processing 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 specific embodiments of the present invention and corresponding drawings. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.

In the running process of the magnetic suspension bearing system, if eccentricity occurs, the current in the static suspension stage of the rotor is larger than the normal suspension current, so that the magnetic bearing easily enters a saturation region, and as shown in fig. 6, the characteristic curve diagram of the magnetic bearing in the magnetic suspension bearing system is shown in fig. 6, the abscissa is the current passing through the magnetic bearing, the ordinate is the magnetic bearing force, the magnetic bearing treatment and the current are basically in a proportional relation just beginning with the increase of the current, the magnetic bearing is slowly saturated with the continuous increase of the current, and the magnetic bearing force is slowly increased until the magnetic bearing force is not increased. That is, after the magnetic bearing enters a saturation region, the nonlinearity of the magnetic bearing can be enhanced, and the force of the magnetic bearing is slowly increased or even no longer increased along with the increase of current.

Meanwhile, the magnetic suspension bearing system also has the problem that the magnetic bearing characteristics are abnormal, unmatched parameters, mainly current loop parameters, are generated after the magnetic bearing characteristics are abnormal, PID control is generally adopted by the current loop, the PID parameters are closely related to the inductance value of the magnetic bearing, the inductance value is related to magnetic flux, when the magnetic bearing is demagnetized and the like are abnormal, the inductance value is changed, so that the PID parameters are unmatched, and the current response speed is insufficient. When the current response speed is insufficient, the magnetic bearing force is insufficient, so that the control effect is reduced, and the rotor is easy to be unstable when rotating at a high speed.

However, the phenomenon is abnormal in the levitation current no matter the eccentric or magnetic bearing characteristics are abnormal, so that it is important to effectively judge whether the eccentric or magnetic bearing characteristics are abnormal after the levitation current is abnormal. Under the normal condition, the machine is disassembled, the connecting wire of the magnetic bearing coil is disconnected, and the equivalent inductance of the magnetic bearing is measured by using equipment such as an inductance measuring instrument, etc., however, the detection mode is high in time consumption and complicated in steps, and a magnetic suspension bearing system is required to be stopped in the detection process, so that the operation of the system is greatly influenced.

The invention provides an abnormality detection method of a magnetic suspension bearing system, which is characterized in that in the running process of the magnetic suspension bearing system, the current suspension current is compared with a first reference suspension current, whether the current suspension current is abnormal or not is judged, if so, the rotor position is adjusted according to the current suspension current and a second reference suspension current, and the eccentric problem or the abnormal magnetic bearing characteristic problem of the magnetic suspension bearing system is judged according to the magnitude relation between the current suspension current and the first reference suspension current, so that the abnormal condition of the magnetic suspension bearing system is automatically detected and confirmed under the condition of no machine halt, the detection process is rapid and the steps are simple, and the abnormality detection efficiency is improved.

According to an embodiment of the present invention, there is provided an abnormality detection method of a magnetic bearing system including a magnetic bearing, a protection bearing, and a rotor; the magnetic bearing is provided with m electrifying coils, the rotor is suspended in the magnetic bearing under the action of the m electrifying coils, and m is a positive integer; the current flowing through the m energized coils jointly forms the levitation of the magnetic bearing systemA current; FIG. 7 is a schematic diagram of a rotor levitation structure in a case of normal operation of a magnetic bearing system, as shown in FIG. 7, in which the rotor is subjected to electromagnetic forces of four coils on the magnetic bearing under the conditions that the magnetic bearing performance is normal and the coaxiality of the protection bearing and the magnetic bearing is good, the electromagnetic forces act on the rotor in the x+ direction and the y+ direction to levitate the rotor in a center position (x ₀ ，y ₀ ). The current of the two coils in the x+ direction is I _x0+ And I _x0- The currents of the two coils in the y+ direction are respectively I _y0+ And I _y0- The four currents together form a levitation current, i.e. the levitation current isA schematic flow chart of an embodiment of the method of the present invention is shown in fig. 1. The abnormality detection method of the magnetic bearing system may include: step S110 to step S150.

At step S110, in advance, under the condition that the magnetic suspension system does not have any abnormality and operates normally, determining a standard levitation current of the magnetic suspension bearing system, and determining n groups of standard levitation currents of the magnetic suspension bearing system, where n is a positive integer; the deflection floating refers to actively controlling the levitation position of the rotor under the condition that the magnetic bearing system is not abnormal, so that the levitation position of the rotor is not positioned at the central position in the magnetic bearing, and the deflection floating current is the levitation current when the levitation position of the rotor is not positioned at the central position in the magnetic bearing under the condition. The n sets of standard bias currents need to be at least two sets in each control direction, as shown in fig. 7, for example: one group of the floating plates is biased towards the x+ direction and one group of the floating plates is biased towards the x-direction in the x direction; one set of bias in the x-direction toward the x + direction and one set of bias in the x-direction. The reason for this is that if the levitation position is too close to the y+ of the protection bearing when the rotor is eccentric, the protection bearing may be directly collided with if the levitation is continued in the y+ direction, and the levitation is required to be performed in the y-direction, so that the situation of the comparison limit is avoided by setting at least two sets of standard levitation currents in each control direction.

In some embodiments, in step S110, determining a standard levitation current of the magnetic bearing system and determining n sets of standard levitation currents of the magnetic bearing system under a condition that the magnetic bearing system is operating normally includes: under the condition that the magnetic suspension system normally operates, the suspension current of the magnetic suspension system is used as a standard suspension current when the rotor is suspended at the central position of the magnetic bearing; under the condition that the magnetic suspension system normally operates and the rotor is suspended at the central position of the magnetic bearing, the suspension current of the magnetic suspension system after the rotor is deviated along different preset directions and different preset distances is used as a standard deviation current; the preset direction and the preset distance can be set according to practical situations, for example: the preset direction may be set to a direction that easily occurs when eccentric, and the preset distance may be set to an offset distance that easily occurs when eccentric. Different preset distances can be shifted in the same preset direction, so that a plurality of groups of different standard deflection currents are obtained, and the rotor is conveniently shifted to the positions of the standard deflection currents; in the n groups of standard floating currents, standard floating currents with the same floating direction and distance do not exist; wherein the preset distance is a distance of a current position of the rotor with respect to a center position of the magnetic bearing.

Specifically, as shown in fig. 7, different preset directions may be set along x ₀₊ In the direction of or along y ₀₊ When the magnetic bearing performance is normal, the coaxiality of the protection bearing and the magnetic bearing is good, and the levitation current is recorded when the levitation position is the electromagnetic center positionAs a standard levitation current. FIG. 9 is a schematic view of a rotor levitation structure for controlling rotor levitation in a magnetic bearing system, as shown in FIG. 9, with the rotor along x ₀₊ The direction is shifted by a displacement Δx, and the levitation position of the rotor is (x ₀ +Δx,y ₀ ) The stress relation of the rotor is as follows:

the recording rotor is suspended at position (x ₀ +Δx,y ₀ ) At the time of levitation currentSimilarly, the rotor is moved along x _0- The displacement Δx of the direction shift records the position (x ₀ -Δx,y ₀ ) At the time of levitation currentRotor is moved along y ₀ The displacement Δy of +direction shift is recorded, and the rotor is suspended at the position (x ₀ ,y ₀ +Δy) suspension current ++Δy)>Rotor is moved along y ₀ -a direction offset displacement Δy, recording the rotor levitation in position (x ₀ ,y ₀ - Δy) at levitation current +.>And taking the obtained four suspension currents as standard deflection currents, wherein Deltax and Deltay are preset deflection distances. In order to facilitate the rotor to shift to the position of the standard bias current, the standard bias current is not limited to four groups, and more groups of standard bias currents can be added as references.

For determining the central position of the magnetic bearing, the rotor is tightly attached to the protection bearing for one circle, the rotor is positioned at the position, closest to X+, of the protection bearing, the X-direction sensor obtains a maximum value (or minimum value) V1, the X-direction sensor obtains a minimum value (or maximum value) V2, and then the central position of the X direction is (V1 +V 2)/2, and the central positions of the Y directions are similar. Because of the manufacturing differences of the sensors, there may be a large gap between the reference positions detected by different sensors, and therefore the positions read by the sensors cannot be used as the judgment of the eccentricity and the abnormality.

The levitation current is generated by the bearing controller, fig. 10 is a schematic diagram of the structure for controlling the levitation of the rotor in the magnetic levitation bearing system, and fig. 11 is a magnetic diagramThe structure of the differential control magnetic bearing in the suspension bearing system is schematically shown in fig. 10 and 11, and the current sensor on the bearing controller detects the coil current, so as to determine the current suspension current. The bearing controller collects signals of the displacement sensor, compares the displacement signals with reference positions, and then obtains reference current values of the current loop through PID calculation of the displacement loop. The magnetic bearing is usually controlled differentially, and is an active magnetic bearing due to the bias current i ₀ The currents in the two sets of poles symmetrical along the rotor are i ₀ +Δi and i ₀ Δi, in the case of a hybrid magnetic bearing, there is no bias current, and the currents in the two sets of poles symmetrical along the rotor are Δi and Δi, respectively.

At step S120, during the current operation of the magnetic bearing system, a levitation current of the magnetic bearing system is acquired and is recorded as a first levitation current of the magnetic bearing system.

At step S130, based on the standard levitation current of the magnetic bearing system, it is determined whether an abnormality occurs in the levitation current of the magnetic bearing system according to the first levitation current of the magnetic bearing system.

In some embodiments, fig. 2 is a schematic flow chart of an example of determining whether a levitation current of a magnetic bearing system is abnormal in the method of the present invention, as shown in fig. 2, in step S130, based on a standard levitation current of the magnetic bearing system, a specific process of determining whether the levitation current of the magnetic bearing system is abnormal according to a first levitation current of the magnetic bearing system includes: step S210 to step S230.

Step S210, subtracting the current flowing through each of the m energizing coils in the first levitation current from the current flowing through the corresponding energizing coil in the standard levitation current to obtain m difference values.

Step S220, determining whether any one of the absolute values of the m differences is greater than a preset threshold.

And step S230, if any one of the absolute values of the m differences is larger than a preset threshold value, determining that the suspension current of the magnetic suspension bearing system is abnormal.

Specifically, as shown in fig. 7, when there is no eccentricity, the magnetic bearing force formula is:

wherein the method comprises the steps ofμ ₀ The magnetic bearing is air permeability, N is the number of turns of a coil winding of the magnetic bearing, A is the cross-sectional area of a magnetic circuit; k is a constant when the structural parameters of the magnetic bearing are determined; i is the current flowing through the coil and x is the air gap between the rotor and the magnetic bearing.

When the rotor is suspended in the center position (x ₀ ,y ₀ ) When the air gap between the rotor and the magnetic bearing is delta, the stress relation of the rotor in the x direction is as follows:

similarly, the stress relation of the rotor in the y direction is as follows:

the force bearing relation of the rotor in the x direction and the y direction can be obtained, when the air gap value or k changes, the levitation current also changes, the air gap value is related to the levitation position of the rotor, and the k value is related to the magnetic bearing structure.

When the magnetic bearing characteristics change, such as demagnetization of magnetic steel, abnormal number of turns of a coil and the like, taking the x+ direction as an example, the k value in the direction becomes k', and the stress relation of the rotor can be obtained as follows:

Therefore, the obtained levitation current is not the same as the normal levitation current, and when the characteristic change exceeds a certain range, the current is greatly deviated from the current in normal levitation.

FIG. 8 is a schematic view of a rotor levitation structure of a magnetic bearing system when eccentricity occurs, as shown in FIG. 8, the center of the rotor is not located at the center position of the magnetic bearing when the eccentricity occurs, and the rotor levitation position is (x) _0’ ,y _0’ ) At this time, the air gap in each direction is no longer delta, so that the levitation current is no longer the same as the normal levitation current. When the eccentricity exceeds a certain range, a large deviation occurs between the current and the current in normal levitation.

Therefore, by comparing the current levitation current with the standard levitation current under normal conditions, whether the levitation current is abnormal or not can be judged, and therefore the magnetic bearing system is considered to be possibly eccentric or abnormal in magnetic bearing characteristics.

Specifically, if the present rotor levitation current is (I _x+ ,I _y+ ,I _x- ,I _y- ) The first reference levitation current isThen judge I _x0+ And I _x+ Whether the absolute value of the difference is greater than a preset threshold epsilon, I _x0- And I _x- Whether the absolute value of the difference is greater than a preset threshold epsilon, I _y0+ And I _y+ Whether the absolute value of the difference is greater than a preset threshold epsilon, I _y0- And I _y- Whether the absolute value of the difference is greater than a preset threshold epsilon, namely:

And when any current difference value is larger than a preset threshold value, the current levitation current of the magnetic bearing system is considered to be abnormal.

FIG. 12 is a schematic flow chart of an embodiment of determining the cause of the abnormal levitation current according to the levitation current and the standard current in the method of the present invention, as shown in FIG. 12, the method of the present invention comprises:

step 1, under the condition that a magnetic suspension bearing system normally operates, acquiring a suspension current when a rotor is suspended at the central position of a magnetic bearing and a bias current after a plurality of groups of rotors are biased, and taking the suspension current and the bias current as a standard suspension current and a standard bias current for subsequent judgment; and then, when the magnetic suspension bearing system is operated, executing the step 2.

Step 2, obtaining current levitation current, judging whether the absolute value of the difference between the current levitation current and the reference levitation current obtained in the step 1 is larger than a preset threshold value, if so, considering that the current levitation current is abnormal, and then executing the step 3; otherwise, the bearing is considered to be free of anomalies.

According to the scheme, in the running process of the magnetic suspension bearing system, whether the current suspension current of the magnetic suspension bearing system is abnormal or not can be judged according to the comparison result of the current suspension current and the standard suspension current, and the reason of the abnormality can be detected after the abnormality of the suspension current is confirmed, so that the machine is not required to be disassembled, complicated equipment such as an inductance measuring instrument is not required to judge the reason of the abnormality, the abnormality detection efficiency is greatly improved, and the stable running of the magnetic suspension bearing system is ensured.

At step S140, if it is determined that the levitation current of the magnetic bearing system is abnormal, recording the levitation current of the magnetic bearing system at this time based on the n sets of standard levitation currents of the magnetic bearing system, and recording the second levitation current of the magnetic bearing system under the condition that the levitation position of the rotor is changed to the preset magnetic bearing center point position.

In some embodiments, fig. 3 is a schematic flow chart of an example of changing the levitation position of the rotor according to the standard levitation current in the method of the present invention, as shown in fig. 3, in step S140, when the levitation position of the rotor is changed to a preset magnetic bearing center point position based on n sets of standard levitation currents of the magnetic bearing system, recording the levitation current of the magnetic bearing system at this time, which is recorded as a specific process of the second levitation current of the magnetic bearing system, including: step S310 to step S330.

And step S310, determining the offset current with the smallest difference value with the first offset current in the n groups of standard offset currents as a reference offset current.

In some embodiments, the determining, in step S310, the offset current with the smallest difference from the first offset current among the n sets of standard offset currents as a specific process of the reference offset current includes: subtracting the current flowing through each of m energizing coils in each group of deflection currents from the current flowing through the corresponding energizing coil in the first levitation current in the n groups of standard deflection currents, wherein each group of deflection currents respectively obtain m current difference values, adding the m current difference values in each group of deflection currents, and recording the added result as the sum of the difference values to obtain the sum of n groups of difference values; and determining the smallest sum of the differences in the obtained n groups of differences, and taking the offset current corresponding to the smallest sum of the differences as a reference offset current.

Specifically, taking the four standard bias currents determined before as an example, bias currents in the four standard bias currents are selectedWith the current of the current levitation (I _x+ ,I _y+ ,I _x- ,I _y- ) Subtracting, i.e. I _(x0+Δx)+ I is reduced _x+ 、I _(x0+Δx)- I is reduced _x- 、I _y0+ I is reduced _y+ 、I _y0- I is reduced _y- Four current differences are obtained, and the four obtained current differences are summed to obtain a sum of differences. Similarly, for other levitation currents in the second reference levitation currentThe above calculation is also performed to obtain the sum of four differences in total. And then determining the minimum sum of the four differences, and taking the offset current corresponding to the minimum sum of the differences as the reference offset current.

Step 320, adjusting the levitation position of the rotor according to the reference levitation current, so that the first levitation current is consistent with the reference levitation current, and recording the levitation position of the rotor at the moment as the current levitation position of the rotor.

And step S330, on the basis of the current levitation position of the rotor, offsetting the rotor by a preset distance in the reference levitation current levitation direction along the opposite direction of the preset direction in the reference levitation current levitation direction, so that the levitation position of the rotor is positioned at the preset magnetic bearing center point position, and recording the levitation current of the magnetic bearing system at the moment as the second levitation current of the magnetic bearing system.

Specifically, toAs an example of the reference bias current, the reference bias current corresponds to a rotor levitation center position (x) _0+Δx ,y ₀ ). After the reference levitation current is determined, the levitation position of the rotor is adjusted to obtain a current levitation current (I _x+ ,I _y+ ,I _x- ,I _y- ) And reference bias current->And keep the same. At the present levitation current (I _x+ ,I _y+ ,I _x- ,I _y- ) And reference bias current->Keeping consistent, the levitation center position of the rotor is recorded at this point as (x ₁ ,y ₁ ) If the magnetic suspension bearing has only an eccentric abnormality, theoretically, the suspension center position (x ₁ ,y ₁ ) At a center position (x) of levitation in response to a reference levitation current _0+Δx ,y ₀ )。

On the basis of adjusting the levitation position of the rotor to enable the current levitation current to be consistent with the reference levitation current, the levitation position of the rotor is moved along the reference levitation currentThe opposite bias of the bias direction x+ is negative by a predetermined distance, i.e. the rotor is controlled to shift the levitation position of the rotor by Δx distance along the x-direction, at which time the levitation position of the rotor becomes (x) ₁ -Δx,y ₁ ) The obtained levitation current at this time is recorded as a second levitation current. If the magnetic suspension bearing has only eccentric abnormality, the current rotor is in the center position of the magnetic bearing theoretically.

As shown in fig. 12, the method of the present invention further comprises:

And 3, determining a group of floating currents closest to the current floating current in the plurality of groups of standard floating currents obtained in the step 1, and then executing the step 4.

And 4, adjusting the levitation position of the rotor according to the closest levitation current found in the step 3, so that the current levitation current is the same as the closest levitation current, recording the levitation position at the moment, and executing the step 5.

And 5, adjusting the levitation position of the rotor according to the deflection amount of the nearest deflection current to enable the rotor to be positioned at the center position of the magnetic bearing theoretically, acquiring the levitation current at the moment, and executing the step 6.

At step S150, a fault point at which an abnormality occurs in the levitation current of the magnetic bearing system is determined according to the second levitation current of the magnetic bearing system based on the standard levitation current of the magnetic bearing system.

According to the scheme, in the running process of the magnetic suspension bearing system, the current suspension current is compared with the pre-stored standard suspension current, whether the current suspension current of the magnetic suspension bearing system is abnormal or not is judged, if the current suspension current is abnormal, the suspension position of the rotor is adjusted, and then whether the reason of the abnormal suspension current is eccentric or the magnetic bearing characteristic is abnormal is judged according to the comparison result of the suspension current with the standard bias current after the suspension position is adjusted. Therefore, under the condition that the magnetic suspension bearing system is not stopped, whether the suspension current is abnormal or not is rapidly and effectively detected, the cause of the abnormality is judged, and the operation reliability of the magnetic suspension bearing system is improved.

In some embodiments, fig. 4 is a schematic flow chart of an example of determining a fault point of abnormal levitation current of a magnetic bearing system in the method of the present invention, as shown in fig. 4, in step S150, a specific process of determining a fault point of abnormal levitation current of the magnetic bearing system according to a second levitation current of the magnetic bearing system based on a standard levitation current of the magnetic bearing system includes: step S410 to step S440.

Step S410, subtracting the current flowing through each of the m energizing coils in the second levitation current from the current flowing through the corresponding energizing coil in the standard levitation current to obtain m difference values.

Step S420, determining whether any one of the absolute values of the m differences is greater than a preset threshold.

Step S430, if any one of the absolute values of the m differences is greater than a preset threshold, determining that the magnetic bearing characteristic of the magnetic bearing system is abnormal.

And step S440, if the absolute value of any difference value among the absolute values of the m difference values is not greater than a preset threshold value, determining that the magnetic suspension bearing system is abnormal in eccentricity.

By adjusting the suspension position of the rotor, if the magnetic suspension bearing system only has eccentric abnormality, the suspension position of the rotor after being theoretically adjusted is positioned at the center position of the magnetic bearing, and if the magnetic bearing characteristic abnormality exists, the suspension position of the rotor after being adjusted is not positioned at the center position of the magnetic bearing; at this time, according to the magnitude relation between the second levitation current and the standard levitation current, whether the rotor is actually positioned at the center of the magnetic bearing can be judged, so that whether the reason for causing the abnormal levitation current is eccentric or the characteristic of the magnetic bearing is abnormal can be obtained.

In particular, in the acquisition of the second levitation currentThen, the standard levitation current is judgedAnd a second levitation current->Whether the absolute value of the difference value of (2) is larger than a preset threshold epsilon, i.e. judging I _x0+ And I _(x1-Δx)+ Whether the absolute value of the difference is greater than a preset threshold epsilon, I _x0- And I _(x1-Δx)- Whether the absolute value of the difference is greater than a preset threshold epsilon, I _y0+ And I _y1+ Whether the absolute value of the difference is greater than a preset threshold epsilon, I _y0- And I _y1- Whether the absolute value of the difference is greater than a preset threshold epsilon. When any one current difference value is larger than a preset threshold value, the magnetic bearing characteristics of the magnetic suspension bearing system are considered to be abnormal, otherwise, eccentricity is considered to occur, and the eccentricity is (x ₁ -Δx-x ₀ ,y ₁ -y ₀ )。

As shown in fig. 12, the method of the present invention further comprises:

Step 6, comparing the levitation current at the moment with a reference levitation current, and if the levitation current is larger than the reference levitation current, considering that the magnetic bearing characteristics of the magnetic bearing system are abnormal; otherwise, the eccentricity abnormality is considered to occur, and the eccentricity of the rotor is obtained according to the suspension position of the rotor recorded in the step 4.

By adopting the technical scheme of the embodiment, the standard levitation current and n groups of standard levitation currents are determined in advance when the magnetic bearing system normally operates, and whether the levitation current of the magnetic bearing system is abnormal or not is determined according to the current levitation current and the standard levitation current in the operation process of the magnetic bearing system; if abnormality occurs, the suspension position of the rotor is adjusted according to n groups of standard deflection current, so that the current suspension position of the rotor is positioned at the center point of the magnetic bearing, and the suspension current at the moment is recorded; the abnormal cause of the levitation current is determined according to the levitation current and the standard levitation current, and the abnormal cause is specifically eccentric abnormality or abnormal magnetic bearing characteristics, so that whether the levitation current is abnormal or not and the abnormal cause can be timely found under the condition that the magnetic bearing system is not stopped, and the efficiency of abnormality detection and the operation reliability of the magnetic bearing system are improved.

According to an embodiment of the present invention, there is also provided an abnormality detection apparatus of a magnetic bearing system corresponding to an abnormality detection method of the magnetic bearing system, the magnetic bearing system including a magnetic bearing, a protection bearing, and a rotor; the magnetic bearing is provided with m electrifying coils, the rotor is suspended in the magnetic bearing under the action of the m electrifying coils, and m is a positive integer; the current flowing through the m energized coils jointly forms a levitation current of the magnetic bearing system; FIG. 7 is a schematic diagram of a rotor levitation structure in a case of normal operation of a magnetic bearing system, as shown in FIG. 7, in which the rotor is subjected to electromagnetic forces of four coils on the magnetic bearing under the conditions that the magnetic bearing performance is normal and the coaxiality of the protection bearing and the magnetic bearing is good, the electromagnetic forces act on the rotor in the x+ direction and the y+ direction to levitate the rotor in a center position (x ₀ ，y ₀ ). The current of the two coils in the x+ direction is I _x0+ And I _x0- The currents of the two coils in the y+ direction are respectively I _y0+ And I _y0- The four currents together form a levitation current, i.e. the levitation current isReferring to fig. 5, a schematic diagram of an embodiment of the apparatus of the present invention is shown. The abnormality detection device of the magnetic bearing system may include: an acquisition unit 102 and a control unit 104./ >

A processing unit 104 configured to determine, in advance, a standard levitation current of the magnetic suspension bearing system and determine n groups of standard levitation currents of the magnetic suspension bearing system, where n is a positive integer, in case the magnetic suspension system does not have any abnormality and operates normally; the deflection floating refers to actively controlling the levitation position of the rotor under the condition that the magnetic bearing system is not abnormal, so that the levitation position of the rotor is not positioned at the central position in the magnetic bearing, and the deflection floating current is the levitation current when the levitation position of the rotor is not positioned at the central position in the magnetic bearing under the condition. The n sets of standard bias currents need to be at least two sets in each control direction, as shown in fig. 7, for example: one group of the floating plates is biased towards the x+ direction and one group of the floating plates is biased towards the x-direction in the x direction; one set of bias in the x-direction toward the x + direction and one set of bias in the x-direction. The reason for this is that if the levitation position is too close to the y+ of the protection bearing when the rotor is eccentric, the protection bearing may be directly collided with if the levitation is continued in the y+ direction, and the levitation is required to be performed in the y-direction, so that the situation of the comparison limit is avoided by setting at least two sets of standard levitation currents in each control direction. The specific function and process of the processing unit 104 refer to step S110.

In some embodiments, the processing unit, in the case of normal operation of the magnetic levitation system, determines a standard levitation current of the magnetic levitation bearing system and determines n sets of standard levitation currents of the magnetic levitation bearing system, comprising: under the condition that the magnetic suspension system normally operates, the suspension current of the magnetic suspension system is used as a standard suspension current when the rotor is suspended at the central position of the magnetic bearing; under the condition that the magnetic suspension system normally operates and the rotor is suspended at the central position of the magnetic bearing, the suspension current of the magnetic suspension system after the rotor is deviated along different preset directions and different preset distances is used as a standard deviation current; the preset direction and the preset distance can be set according to practical situations, for example: the preset direction may be set to a direction that easily occurs when eccentric, and the preset distance may be set to an offset distance that easily occurs when eccentric. Different preset distances can be shifted in the same preset direction, so that a plurality of groups of different standard deflection currents are obtained, and the rotor is conveniently shifted to the positions of the standard deflection currents; in the n groups of standard floating currents, standard floating currents with the same floating direction and distance do not exist; wherein the preset distance is a distance of a current position of the rotor with respect to a center position of the magnetic bearing.

The levitation current is generated by a bearing controller, fig. 10 is a schematic diagram of a structure for controlling levitation of a rotor in a magnetic levitation bearing system, fig. 11 is a schematic diagram of a structure for differentially controlling a magnetic bearing in the magnetic levitation bearing system, and as shown in fig. 10 and 11, a current sensor is arranged on the bearing controller to detect the coil current, so that the current levitation current can be determined. The bearing controller collects signals of the displacement sensor, compares the displacement signals with reference positions, and then obtains reference current values of the current loop through PID calculation of the displacement loop. The magnetic bearing is usually controlled differentially, and is an active magnetic bearing due to the bias current i ₀ The currents in the two sets of poles symmetrical along the rotor are i ₀ +Δi and i ₀ Δi, in the case of a hybrid magnetic bearing, there is no bias current, and the currents in the two sets of poles symmetrical along the rotor are Δi and Δi, respectively.

An obtaining unit 102, configured to obtain a levitation current of the magnetic bearing system during a current operation of the magnetic bearing system, and record the levitation current as a first levitation current of the magnetic bearing system; the specific function and process of the acquisition unit 102 refer to step S120.

The processing unit 104 is further configured to determine, based on the standard levitation current of the magnetic bearing system, whether an abnormality occurs in the levitation current of the magnetic bearing system according to the first levitation current of the magnetic bearing system; the specific function and process of the processing unit 104 refer to step S130.

In some embodiments, the processing unit 104, based on the standard levitation current of the magnetic bearing system, determines whether an abnormality occurs in the levitation current of the magnetic bearing system according to the first levitation current of the magnetic bearing system, including:

subtracting the current flowing through each of the m energizing coils in the first levitation current from the current flowing through the corresponding energizing coil in the standard levitation current to obtain m difference values; the specific function and process of the processing unit 104 refer to step S210.

Determining whether the absolute value of any one of the absolute values of the m differences is larger than a preset threshold value; the specific function and process of the processing unit 104 refer to step S220.

If any one of the absolute values of the m differences is larger than a preset threshold value, determining that the suspension current of the magnetic suspension bearing system is abnormal. The specific function and process of the processing unit 104 refer to step S230.

similarly, the stress relation of the rotor in the y direction is as follows:

Therefore, by comparing the current levitation current with the reference levitation current under normal conditions, whether the levitation current is abnormal or not can be judged, and therefore the magnetic bearing system is considered to be possibly eccentric or abnormal in magnetic bearing characteristics.

Specifically, if the present rotor levitation current is (I _x+ ,I _y+ ,I _x- ,I _y- ) The first standard levitation current isThen judge I _x0+ And I _x+ Whether the absolute value of the difference is greater than a preset threshold epsilon, I _x0- And I _x- Whether the absolute value of the difference is greater than a preset threshold epsilon, I _y0+ And I _y+ Whether the absolute value of the difference is greater than a preset threshold epsilon, I _y0- And I _y- Whether the absolute value of the difference is greater than a preset threshold epsilon, namely:

The processing unit 104 is further configured to record the levitation current of the magnetic bearing system at this time, and record the levitation current as the second levitation current of the magnetic bearing system, if it is determined that the levitation current of the magnetic bearing system is abnormal, based on n groups of standard levitation currents of the magnetic bearing system, and when the levitation position of the rotor is changed to a preset magnetic bearing center point position; the specific function and process of the processing unit 104 refer to step S140.

In some embodiments, the processing unit 104 records the levitation current of the magnetic bearing system at this time, which is recorded as the second levitation current of the magnetic bearing system, in the case of changing the levitation position of the rotor to a preset magnetic bearing center point position based on n sets of standard levitation currents of the magnetic bearing system, including:

determining the offset current with the smallest difference value with the first offset current in the n groups of standard offset currents as a reference offset current; the specific function and process of the processing unit 104 refer to step S310.

In some embodiments, the processing unit 104 determines, as a specific process of reference bias current, a bias current having a smallest difference from the first bias current among the n sets of standard bias currents, including: subtracting the current flowing through each of m energizing coils in each group of deflection currents from the current flowing through the corresponding energizing coil in the first levitation current in the n groups of standard deflection currents, wherein each group of deflection currents respectively obtain m current difference values, adding the m current difference values in each group of deflection currents, and recording the added result as the sum of the difference values to obtain the sum of n groups of difference values; and determining the smallest sum of the differences in the obtained n groups of differences, and taking the offset current corresponding to the smallest sum of the differences as a reference offset current.

Specifically, taking the four standard bias currents determined before as an example, bias currents in the four standard bias currents are selectedWith the current of the current levitation (I _x+ ,I _y+ ,I _x- ,I _y- ) Subtracting, i.e. I _(x0+Δx)+ I is reduced _x+ 、I _(x0+Δx)- I is reduced _x- 、I _y0+ I is reduced _y+ 、I _y0- I is reduced _y- Four current differences are obtained, and the four obtained current differences are summed to obtain a sum of differences. Similarly, for other levitation currents in the second reference levitation currentThe above calculation is also performed to obtain the sum of four differences in total. And then determining the minimum sum of the four differences, and taking the floating current corresponding to the minimum sum of the differences as the reference floating current.

Adjusting the levitation position of the rotor according to the reference levitation current to enable the first levitation current to be consistent with the reference levitation current, and recording the levitation position of the rotor at the moment as the current levitation position of the rotor; the specific function and process of the processing unit 104 refer to step S320.

And on the basis of the current suspension position of the rotor, shifting the rotor by a preset distance in the reference suspension current deflection along the opposite direction of the preset direction in the reference suspension current deflection, so that the suspension position of the rotor is positioned at the preset magnetic bearing center point position, and recording the suspension current of the magnetic suspension bearing system at the moment and recording the suspension current as the second suspension current of the magnetic suspension bearing system. The specific function and process of the processing unit 104 refer to step S330.

As shown in fig. 12, the method of the present invention further comprises:

The processing unit 104 is further configured to determine, based on the standard levitation current of the magnetic bearing system, a fault point at which an abnormality occurs in the levitation current of the magnetic bearing system according to the second levitation current of the magnetic bearing system. The specific function and process of the processing unit 104 refer to step S150.

In some embodiments, the processing unit 104 determines, based on the standard levitation current of the magnetic bearing system, a fault point at which an abnormality occurs in the levitation current of the magnetic bearing system according to the second levitation current of the magnetic bearing system, including:

subtracting the current flowing through each of the m energizing coils in the second levitation current from the current flowing through the corresponding energizing coil in the standard levitation current to obtain m difference values; the specific function and process of the processing unit 104 refer to step S410.

Determining whether the absolute value of any one of the absolute values of the m differences is larger than a preset threshold value; the specific function and process of the processing unit 104 refer to step S420.

If the absolute value of any difference value in the absolute values of the m difference values is larger than a preset threshold value, determining that the magnetic bearing characteristic of the magnetic suspension bearing system is abnormal; the specific function and process of the processing unit 104 refer to step S430.

If the absolute value of any difference value in the absolute values of the m difference values is not greater than a preset threshold value, determining that the magnetic suspension bearing system is eccentric. The specific function and process of the processing unit 104 refer to step S440.

As shown in fig. 12, the method of the present invention further comprises:

Since the processes and functions implemented by the apparatus of the present embodiment substantially correspond to the embodiments, principles and examples of the foregoing methods, the descriptions of the embodiments are not exhaustive, and reference may be made to the descriptions of the foregoing embodiments and their descriptions are omitted herein.

By adopting the technical scheme, the standard levitation current and n groups of standard levitation currents are determined in advance when the magnetic bearing system normally operates, and whether the levitation current of the magnetic bearing system is abnormal or not is determined according to the current levitation current and the standard levitation current in the operation process of the magnetic bearing system; if abnormality occurs, the suspension position of the rotor is adjusted according to n groups of standard deflection current, so that the current suspension position of the rotor is positioned at the center point of the magnetic bearing, and the suspension current at the moment is recorded; the abnormal cause of the levitation current is determined according to the levitation current and the standard levitation current, and the abnormal cause is specifically eccentric abnormality or abnormal magnetic bearing characteristics, so that whether the levitation current is abnormal or not and the abnormal cause can be timely found under the condition that the magnetic bearing system is not stopped, and the efficiency of abnormality detection and the operation reliability of the magnetic bearing system are improved.

According to an embodiment of the present invention, there is also provided a magnetic bearing system corresponding to the abnormality detection device of the magnetic bearing system. The magnetic bearing system may include: the abnormality detection device of the magnetic bearing system described above.

Since the processing and functions implemented by the magnetic suspension bearing system of the present embodiment basically correspond to the embodiments, principles and examples of the foregoing apparatus, the description of the present embodiment is not exhaustive, and reference may be made to the related descriptions of the foregoing embodiments, which are not repeated herein.

According to an embodiment of the present invention, there is also provided a storage medium corresponding to the abnormality detection method of a magnetic bearing system, the storage medium including a stored program, wherein the apparatus in which the storage medium is controlled to execute the abnormality detection method of a magnetic bearing system described above when the program is run.

Since the processes and functions implemented by the storage medium of the present embodiment substantially correspond to the embodiments, principles and examples of the foregoing methods, the descriptions of the present embodiment are not exhaustive, and reference may be made to the related descriptions of the foregoing embodiments, which are not repeated herein.

In summary, it is readily understood by those skilled in the art that the above-described advantageous ways 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, but various modifications and variations can be made to the present invention by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of the claims of the present invention.

Claims

1. An abnormality detection method of a magnetic bearing system, characterized in that the magnetic bearing system comprises a magnetic bearing, a protective bearing and a rotor; the magnetic bearing is provided with m electrifying coils, the rotor is suspended in the magnetic bearing under the action of the m electrifying coils, and m is a positive integer; the current flowing through the m energized coils jointly forms a levitation current of the magnetic bearing system; the method comprises the following steps:

in advance, under the condition that the magnetic suspension system normally operates, determining the standard suspension current of the magnetic suspension bearing system, and determining n groups of standard deflection currents of the magnetic suspension bearing system, wherein n is a positive integer;

Acquiring a levitation current of the magnetic bearing system in the current running process of the magnetic bearing system, and recording the levitation current as a first levitation current of the magnetic bearing system;

determining whether the levitation current of the magnetic bearing system is abnormal or not according to the first levitation current of the magnetic bearing system based on the standard levitation current of the magnetic bearing system;

if it is determined that the levitation current of the magnetic bearing system is abnormal, recording the levitation current of the magnetic bearing system at the moment based on n groups of standard levitation currents of the magnetic bearing system under the condition that the levitation position of the rotor is changed to a preset magnetic bearing center point position, and recording the levitation current as a second levitation current of the magnetic bearing system;

and determining a fault point of abnormality of the levitation current of the magnetic bearing system according to the second levitation current of the magnetic bearing system based on the standard levitation current of the magnetic bearing system.

2. The abnormality detection method of a magnetic bearing system according to claim 1, characterized in that, in a case where the magnetic bearing system is operating normally, determining a standard levitation current of the magnetic bearing system and determining n sets of standard levitation currents of the magnetic bearing system includes:

Under the condition that the magnetic suspension system normally operates, the suspension current of the magnetic suspension system is used as a standard suspension current when the rotor is suspended at the central position of the magnetic bearing;

under the condition that the magnetic suspension system normally operates and the rotor is suspended at the central position of the magnetic bearing, the suspension current of the magnetic suspension system after the rotor is deviated along different preset directions and different preset distances is used as a standard deviation current; wherein the preset distance is a distance of a current position of the rotor with respect to a center position of the magnetic bearing.

3. The abnormality detection method of a magnetic bearing system according to claim 1, wherein determining whether an abnormality occurs in a levitation current of the magnetic bearing system according to a first levitation current of the magnetic bearing system based on a standard levitation current of the magnetic bearing system, comprises:

subtracting the current flowing through each of the m energizing coils in the first levitation current from the current flowing through the corresponding energizing coil in the standard levitation current to obtain m difference values;

determining whether the absolute value of any one of the absolute values of the m differences is larger than a preset threshold value;

If any one of the absolute values of the m differences is larger than a preset threshold value, determining that the suspension current of the magnetic suspension bearing system is abnormal.

4. The abnormality detection method of a magnetic bearing system according to claim 1, wherein, based on n sets of standard levitation currents of the magnetic bearing system, in the case of changing the levitation position of the rotor to a preset magnetic bearing center point position, recording the levitation current of the magnetic bearing system at this time, as a second levitation current of the magnetic bearing system, comprising:

determining the offset current with the smallest difference value with the first offset current in the n groups of standard offset currents as a reference offset current;

adjusting the levitation position of the rotor according to the reference levitation current to enable the first levitation current to be consistent with the reference levitation current, and recording the levitation position of the rotor at the moment as the current levitation position of the rotor;

and on the basis of the current suspension position of the rotor, shifting the rotor by a preset distance in the reference suspension current deflection along the opposite direction of the preset direction in the reference suspension current deflection, so that the suspension position of the rotor is positioned at the preset magnetic bearing center point position, and recording the suspension current of the magnetic suspension bearing system at the moment and recording the suspension current as the second suspension current of the magnetic suspension bearing system.

5. The abnormality detection method of a magnetic bearing system according to claim 4, characterized in that, among the n sets of standard levitation currents, a levitation current having a smallest difference from the first levitation current is determined as a reference levitation current, comprising:

subtracting the current flowing through each of m energizing coils in each group of deflection currents from the current flowing through the corresponding energizing coil in the first levitation current in the n groups of standard deflection currents, wherein each group of deflection currents respectively obtain m current difference values, adding the m current difference values in each group of deflection currents, and recording the added result as the sum of the difference values to obtain the sum of n groups of difference values;

and determining the smallest sum of the differences in the obtained n groups of differences, and taking the offset current corresponding to the smallest sum of the differences as a reference offset current.

6. The abnormality detection method of a magnetic bearing system according to any one of claims 1 to 5, characterized in that determining a fault point at which an abnormality occurs in a levitation current of the magnetic bearing system based on a standard levitation current of the magnetic bearing system according to a second levitation current of the magnetic bearing system, comprises:

Subtracting the current flowing through each of the m energizing coils in the second levitation current from the current flowing through the corresponding energizing coil in the standard levitation current to obtain m difference values;

if the absolute value of any difference value in the absolute values of the m difference values is larger than a preset threshold value, determining that the magnetic bearing characteristic of the magnetic suspension bearing system is abnormal;

if the absolute value of any difference value in the absolute values of the m difference values is not greater than a preset threshold value, determining that the magnetic suspension bearing system is eccentric.

7. An abnormality detection device of a magnetic suspension bearing system, characterized in that the magnetic suspension bearing system comprises a magnetic bearing, a protection bearing and a rotor; the magnetic bearing is provided with m electrifying coils, the rotor is suspended in the magnetic bearing under the action of the m electrifying coils, and m is a positive integer; the current flowing through the m energized coils jointly forms a levitation current of the magnetic bearing system; the device comprises:

the processing unit is configured to determine the standard levitation current of the magnetic levitation bearing system and determine n groups of standard levitation currents of the magnetic levitation bearing system in advance under the condition that the magnetic levitation system normally operates, wherein n is a positive integer;

An acquisition unit configured to acquire a levitation current of the magnetic bearing system during a current operation of the magnetic bearing system, and record the levitation current as a first levitation current of the magnetic bearing system;

the processing unit is further configured to determine whether the levitation current of the magnetic bearing system is abnormal according to the first levitation current of the magnetic bearing system based on the standard levitation current of the magnetic bearing system;

the processing unit is further configured to record the levitation current of the magnetic bearing system at the moment and record the levitation current as a second levitation current of the magnetic bearing system under the condition that the levitation position of the rotor is changed to a preset magnetic bearing center point position based on n groups of standard levitation currents of the magnetic bearing system if the levitation current of the magnetic bearing system is determined to be abnormal;

the processing unit is further configured to determine a fault point at which an abnormality occurs in the levitation current of the magnetic bearing system according to the second levitation current of the magnetic bearing system based on the standard levitation current of the magnetic bearing system.

8. The abnormality detection device of a magnetic bearing system according to claim 7, wherein the processing unit, in a case where the magnetic bearing system is operating normally, determines a standard levitation current of the magnetic bearing system and determines n sets of standard levitation currents of the magnetic bearing system, includes:

9. A magnetic bearing system, comprising: an abnormality detection device of a magnetic bearing system according to any one of claims 7 to 8.

10. A storage medium comprising a stored program, wherein the program, when run, controls a device in which the storage medium is located to execute the abnormality detection method of the magnetic bearing system according to any one of claims 1 to 6.