Detection method and device of magnetic levitation system, magnetic levitation system and storage medium

Abstract

The application discloses an abnormality detection method and device of a magnetic suspension bearing system, the magnetic suspension bearing system and a storage medium, and relates to the technical field of magnetic suspension bearing systems. The method comprises the following steps: during the operation 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 pre-determined standard suspension current; if the abnormality is confirmed, changing the suspension position of the rotor to the center position of the preset magnetic bearing according to the pre-determined standard suspension current, and determining the fault point of the abnormal suspension current according to the current suspension current and the pre-determined standard suspension current. According to the scheme, whether the current suspension current is abnormal is determined by comparing the current suspension current with the standard suspension current, the suspension position of the rotor is adjusted if the abnormality is confirmed, and the abnormality reason is determined according to the current suspension current and the standard suspension current, so that whether the suspension current is abnormal and the abnormality reason can be found in time, and the efficiency of abnormality detection is improved.

Description

Technical Field

[0001] This invention belongs to the field of magnetic levitation technology, specifically relating to an anomaly detection method, device, magnetic levitation bearing system and storage medium for a magnetic levitation bearing system, and particularly to an anomaly detection method, device, magnetic levitation bearing system and storage medium for anomaly detection of levitation current in a magnetic levitation bearing system. Background Technology

[0002] Magnetic levitation bearing systems suspend the rotor in a given position using electromagnetic force, achieving high-speed, frictionless operation with advantages such as no lubrication required and long lifespan. Under normal circumstances, the rotor suspends at the center of the protective bearing, with minimal deviation between the protective bearing's center and the magnetic bearing's center. However, due to machining or assembly errors, or shaft contact, eccentricity may occur between the protective bearing's center and the electromagnetic center. This means the rotor may not be at the electromagnetic center when suspended at the protective bearing's center. If the eccentricity is severe, the current during the rotor's static levitation phase will deviate significantly from the normal levitation current. Besides eccentricity, changes in the magnetic bearing's characteristics (such as demagnetization of the bearing magnets due to prolonged high-temperature operation) can also cause abnormal current during static levitation. Therefore, whether it's eccentricity or abnormal magnetic bearing characteristics, the resulting phenomenon is an abnormal levitation current. Consequently, it's impossible to determine whether the abnormal levitation current is due to eccentricity or an abnormal magnetic bearing characteristic.

[0003] The above content is only used to help understand the technical solution of the present invention and does not represent an admission that the above content is prior art. Summary of the Invention

[0004] The purpose of this invention is to provide an anomaly detection method, device, system, and storage medium for a magnetic levitation bearing system. This addresses the problem in existing technologies where, when the levitation current of a magnetic levitation bearing is abnormal, it is impossible to determine whether the abnormality is due to eccentricity or abnormal bearing characteristics. The invention achieves this by determining whether the levitation current is abnormal based on the current levitation current and a standard levitation current during system operation. If abnormal, the rotor position is adjusted based on the current levitation current and the standard levitation current, and the abnormality is determined to be either due to eccentricity or abnormal bearing characteristics. This allows for timely detection of abnormal levitation current and its cause without shutting down the magnetic levitation bearing system, thus improving the efficiency of anomaly detection.

[0005] This invention provides an anomaly detection method for a magnetic levitation bearing system. The magnetic levitation bearing system includes a magnetic bearing, a protective bearing, and a rotor. The magnetic bearing has m energized coils, through which the rotor is levitated within the magnetic bearing, where m is a positive integer. The currents flowing through the m energized coils collectively constitute the levitation current of the magnetic levitation bearing system. The method includes: pre-determining, under normal operating conditions of the magnetic levitation system, a standard levitation current of the magnetic levitation bearing system is determined, and n sets of standard bias currents of the magnetic levitation bearing system are determined, where n is a positive integer; during the current operation of the magnetic levitation bearing system, the levitation current of the magnetic levitation bearing system is acquired and denoted as the magnetic levitation bearing current. The system first levitation current; based on the standard levitation current of the magnetic bearing system, determine whether the levitation current of the magnetic bearing system is abnormal; if the levitation current of the magnetic bearing system is determined to be abnormal, then based on n sets of standard deflection currents of the magnetic bearing system, when the levitation position of the rotor is changed to a preset magnetic bearing center point position, record the levitation current of the magnetic bearing system at this time, and record it as the second levitation current of the magnetic bearing system; based on the standard levitation current of the magnetic bearing system, determine the fault point where the levitation current of the magnetic bearing system is abnormal according to the second levitation current of the magnetic bearing system.

[0006] In some embodiments, when the magnetic levitation system is operating normally, a standard levitation current of the magnetic bearing system is determined, and n sets of standard deflection currents of the magnetic bearing system are determined, including: when the magnetic levitation system is operating normally, the levitation current of the magnetic levitation system when the rotor is levied at the center position of the magnetic bearing is taken as the standard levitation current; when the magnetic levitation system is operating normally and the rotor is levied at the center position of the magnetic bearing, the levitation current of the magnetic levitation system after the rotor is deflected along different preset directions and different preset distances is taken as the standard deflection current; wherein, the preset distance is the distance of the current position of the rotor relative to the center position of the magnetic bearing.

[0007] In some implementations, based on the standard levitation current of the magnetic levitation bearing system, determining whether the levitation current of the magnetic levitation bearing system is abnormal according to the first levitation current of the magnetic levitation bearing system includes: subtracting the current flowing through each of the m energized coils in the first levitation current from the current flowing through the corresponding energized coil in the standard levitation current to obtain m differences; determining whether the absolute value of any of the m differences is greater than a preset threshold; if the absolute value of any of the m differences is greater than the preset threshold, then determining that the levitation current of the magnetic levitation bearing system is abnormal.

[0008] In some implementations, 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 levitation bearing system, the levitation current of the magnetic levitation bearing system at this time is recorded and denoted as the second levitation current of the magnetic levitation bearing system. This includes: determining the levitation current with the smallest difference from the first levitation current among the n sets of standard levitation currents, and using it as the reference levitation current; 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 this time as the current levitation position of the rotor; and, based on the current levitation position of the rotor, shifting the rotor along the opposite direction of the preset direction in which the reference levitation current levitates by a preset distance, so that the levitation position of the rotor is at the preset magnetic bearing center point position, and recording the levitation current of the magnetic levitation bearing system at this time as the second levitation current of the magnetic levitation bearing system.

[0009] In some implementations, determining the floating current with the smallest difference from the first floating current among the n sets of standard floating currents, and using it as a reference floating current, includes: in the n sets of standard floating currents, subtracting the current flowing through each of the m energized coils in each set of floating currents from the current flowing through the corresponding energized coil in the first floating current, so that each set of floating currents yields m current differences; summing the m current differences in each set of floating currents, and recording the sum as the sum of differences, to obtain n sets of sums of differences; and determining the smallest sum of differences among the n sets of sums of differences, and using the floating current corresponding to the smallest sum of differences as the reference floating current.

[0010] In some implementations, based on the standard levitation current of the magnetic levitation bearing system and according to the second levitation current of the magnetic levitation bearing system, the fault point where the levitation current of the magnetic levitation bearing system is abnormal is determined, including: subtracting the current flowing through each of the m energized coils in the second levitation current from the current flowing through the corresponding energized coil in the standard levitation current to obtain m differences; determining whether any absolute value of the m differences is greater than a preset threshold; if any absolute value of the m differences is greater than the preset threshold, then the magnetic bearing characteristics of the magnetic levitation bearing system are determined to be abnormal; if no absolute value of the m differences is greater than the preset threshold, then the eccentricity of the magnetic levitation bearing system is determined to be abnormal.

[0011] In conjunction with the above method, another aspect of the present invention provides an anomaly detection device for a magnetic levitation bearing system. The magnetic levitation bearing system includes a magnetic bearing, a protective bearing, and a rotor. The magnetic bearing has m energized coils, through which the rotor is levitated within the magnetic bearing, where m is a positive integer. The currents flowing through the m energized coils collectively constitute the levitation current of the magnetic levitation bearing system. The device includes: a processing unit configured to pre-determine the standard levitation current of the magnetic levitation bearing system under normal operating conditions, and to determine n sets of standard bias currents of the magnetic levitation bearing system, where n is a positive integer; and an acquisition unit configured to acquire the levitation current of the magnetic levitation bearing system during its current operation, denoted as the levitation current of the magnetic levitation bearing system. The processing unit is further configured to determine whether the suspension current of the magnetic bearing system is abnormal based on the standard suspension current of the magnetic bearing system; the processing unit is further configured to, if the suspension current of the magnetic bearing system is determined to be abnormal, change the suspension position of the rotor to a preset magnetic bearing center point position based on n sets of standard deflection currents of the magnetic bearing system, and record the suspension current of the magnetic bearing system at this time as the second suspension current of the magnetic bearing system; the processing unit is further configured to determine the fault point where the suspension current of the magnetic bearing system is abnormal based on the standard suspension current of the magnetic bearing system and the second suspension current of the magnetic bearing system.

[0012] In some embodiments, the processing unit, under normal operation of the magnetic levitation system, determines the standard levitation current of the magnetic levitation bearing system and determines n sets of standard deflection currents of the magnetic levitation bearing system, including: under normal operation of the magnetic levitation system, the levitation current of the magnetic levitation system when the rotor is levied at the center position of the magnetic bearing, as the standard levitation current; under normal operation of the magnetic levitation system and when the rotor is levied at the center position of the magnetic bearing, the levitation current of the magnetic levitation system after the rotor is deflected along different preset directions and different preset distances, as the standard deflection current; wherein, the preset distance is the distance of the current position of the rotor relative to the center position of the magnetic bearing.

[0013] In some embodiments, the processing unit determines whether the levitation current of the magnetic levitation bearing system is abnormal based on the standard levitation current of the magnetic levitation bearing system and the first levitation current of the magnetic levitation bearing system. This includes: subtracting the current flowing through each of the m energized coils in the first levitation current from the current flowing through the corresponding energized coil in the standard levitation current to obtain m differences; determining whether the absolute value of any of the m differences is greater than a preset threshold; and determining that the levitation current of the magnetic levitation bearing system is abnormal if the absolute value of any of the m differences is greater than the preset threshold.

[0014] In some embodiments, the processing unit, based on n sets of standard buoyancy currents of the magnetic levitation bearing system, changes the levitation position of the rotor to a preset magnetic bearing center point position, and records the levitation current of the magnetic levitation bearing system at this time, denoted as the second levitation current of the magnetic levitation bearing system. This includes: determining, among the n sets of standard buoyancy currents, the buoyancy current with the smallest difference from the first levitation current, as a reference buoyancy current; adjusting the levitation position of the rotor according to the reference buoyancy current so that the first levitation current is consistent with the reference buoyancy current, and recording the levitation position of the rotor at this time, denoted as the current levitation position of the rotor; based on the current levitation position of the rotor, shifting the rotor along the opposite direction of the preset direction when the reference buoyancy current buoys by a preset distance, so that the levitation position of the rotor is at the preset magnetic bearing center point position, and recording the levitation current of the magnetic levitation bearing system at this time, denoted as the second levitation current of the magnetic levitation bearing system.

[0015] In some embodiments, the processing unit determines the floating current with the smallest difference from the first floating current among the n sets of standard floating currents as a reference floating current, including: in the n sets of standard floating currents, subtracting the current flowing through each of the m energized coils in each set of floating currents from the current flowing through the corresponding energized coil in the first floating current, so that each set of floating currents yields m current differences; summing the m current differences in each set of floating currents, and recording the sum as the sum of differences, to obtain n sets of sums of differences; determining the smallest sum of differences among the n sets of sums of differences, and using the floating current corresponding to the smallest sum of differences as the reference floating current.

[0016] In some embodiments, the processing unit, based on the standard levitation current of the magnetic levitation bearing system and according to the second levitation current of the magnetic levitation bearing system, determines the fault point where the levitation current of the magnetic levitation bearing system is abnormal, including: subtracting the current flowing through each of the m energized coils in the second levitation current from the current flowing through the corresponding energized coil in the standard levitation current to obtain m differences; determining whether the absolute value of any of the m differences is greater than a preset threshold; if the absolute value of any of the m differences is greater than the preset threshold, then determining that the magnetic bearing characteristics of the magnetic levitation bearing system are abnormal; if the absolute value of no of the m differences is greater than the preset threshold, then determining that the magnetic levitation bearing system has an eccentricity abnormality.

[0017] In conjunction with the above-mentioned device, the present invention further provides a magnetic levitation bearing system, including: the abnormality detection device for the magnetic levitation bearing system described above.

[0018] In conjunction with the above method, the present invention further provides a storage medium comprising a stored program, wherein, when the program is executed, the device containing the storage medium executes the above-described method for detecting anomalies in a magnetic levitation bearing system.

[0019] The present invention determines a standard levitation current and n sets of standard eccentric levitation currents in advance during the normal operation of the magnetic levitation bearing system. During the operation of the magnetic levitation bearing system, it determines whether the levitation current of the magnetic levitation bearing system is abnormal based on the current levitation current and the standard levitation current. If an abnormality is found, the levitation position of the rotor is adjusted according to the n sets of standard eccentric levitation currents so that the current levitation position of the rotor is at the center point of the magnetic bearing, and the levitation current at this moment is recorded. Based on the current levitation current at this moment and the standard levitation current, it determines whether the abnormality of the levitation current is due to eccentricity or abnormality of magnetic bearing characteristics. Thus, without stopping the magnetic levitation bearing system, it is possible to detect whether the levitation current is abnormal and the cause of the abnormality in a timely manner, thereby improving the efficiency of abnormality detection and the operational reliability of the magnetic levitation bearing system.

[0020] Other features and advantages of the invention will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the invention.

[0021] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Attached Figure Description

[0022] Figure 1 This is a flowchart illustrating an embodiment of the anomaly detection method for the magnetic levitation bearing system of the present invention;

[0023] Figure 2 This is a flowchart illustrating an embodiment of the method of the present invention for determining whether the levitation current of a magnetic levitation bearing system is abnormal.

[0024] Figure 3 This is a schematic flowchart of an embodiment of the method of the present invention, which changes the levitation position of the rotor according to a standard buoyancy current.

[0025] Figure 4 This is a flowchart illustrating an embodiment of the method of the present invention for determining the fault point of abnormal levitation current in a magnetic levitation bearing system.

[0026] Figure 5 This is a schematic diagram of a structure of an embodiment of the abnormality detection device for the magnetic levitation bearing system of the present invention;

[0027] Figure 6 This is a characteristic curve diagram of the magnetic bearing in a magnetic levitation bearing system;

[0028] Figure 7 This is a schematic diagram of the rotor suspension structure under normal operating conditions of a magnetic levitation bearing system.

[0029] Figure 8 A schematic diagram of the rotor suspension structure when eccentricity occurs in a magnetic levitation bearing system;

[0030] Figure 9 This is a schematic diagram of the rotor suspension structure in a magnetic levitation bearing system when controlling rotor deflection.

[0031] Figure 10 This is a schematic diagram of the structure controlling rotor levitation in a magnetic levitation bearing system.

[0032] Figure 11 This is a schematic diagram of the differential control magnetic bearing in a magnetic levitation bearing system.

[0033] Figure 12 This is a flowchart illustrating an embodiment of the method of the present invention for determining the cause of an abnormal floating current based on the floating current and the standard current;

[0034] Referring to the accompanying drawings, the reference numerals in the embodiments of the present invention are as follows:

[0035] 102 - Acquisition unit; 104 - Processing unit. Detailed Implementation

[0036] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0037] If eccentricity occurs during the operation of a magnetic levitation bearing system, the current during the static levitation phase of the rotor will deviate significantly from the normal levitation current, making the magnetic bearing prone to entering the saturation region. Figure 6 The image shows the characteristic curves of the magnetic bearings in a magnetic levitation bearing system, such as... Figure 6 As shown, the horizontal axis represents the current passing through the magnetic bearing, and the vertical axis represents the output force of the magnetic bearing. Initially, as the current increases, the output force of the magnetic bearing is basically proportional to the current. However, as the current continues to increase, the magnetic bearing gradually saturates, and the output force increases slowly until it no longer increases. That is, after the magnetic bearing enters the saturation region, its nonlinearity increases, and the output force increases slowly or even stops increasing with the current.

[0038] Meanwhile, magnetic levitation bearing systems can also experience abnormal magnetic bearing characteristics. These abnormalities result in mismatched parameters, primarily in the current loop. The current loop typically employs PID control, and the PID parameters are closely related to the inductance value of the magnetic bearing. Since inductance is related to magnetic flux, when the magnetic bearing experiences demagnetization or other abnormalities, the inductance value changes, leading to a mismatch in the PID parameters and insufficient current response. Insufficient current response results in insufficient magnetic bearing output, leading to decreased control effectiveness and increased instability during high-speed rotor rotation.

[0039] However, whether it's eccentricity or abnormal magnetic bearing characteristics, the resulting phenomenon is an abnormal levitation current. Therefore, when an abnormal levitation current occurs, effectively determining whether it's due to eccentricity or abnormal magnetic bearing characteristics is crucial. Typically, this involves disassembling the machine and disconnecting the magnetic bearing coil, then measuring the equivalent inductance of the magnetic bearing using inductance measuring instruments. However, this testing method is time-consuming and cumbersome, requiring the magnetic levitation bearing system to be shut down during the testing process, significantly impacting system operation.

[0040] Therefore, this invention provides an anomaly detection method for a magnetic levitation bearing system. During the operation of the magnetic levitation bearing system, the current levitation current is compared with a first reference levitation current to determine whether the current levitation current is abnormal. If abnormal, the rotor position is adjusted according to the current levitation current and the second reference levitation current. Based on the relationship between the current levitation current and the first reference levitation current, it is determined whether the magnetic levitation bearing system has an eccentricity problem or an abnormality in the magnetic bearing characteristics. Thus, the abnormality of the magnetic levitation bearing system can be automatically detected and confirmed without stopping the machine. The detection process is rapid and the steps are simple, improving the efficiency of anomaly detection.

[0041] According to an embodiment of the present invention, an anomaly detection method for a magnetic levitation bearing system is provided. The magnetic levitation bearing system includes a magnetic bearing, a protective bearing, and a rotor. The magnetic bearing has m energized coils, and the rotor is levitated within the magnetic bearing by the action of the m energized coils, where m is a positive integer. The currents flowing through the m energized coils together constitute the levitation current of the magnetic levitation bearing system. Figure 7 This is a schematic diagram of the rotor suspension structure under normal operating conditions of a magnetic levitation bearing system, as shown below. Figure 7 As shown, under normal magnetic bearing performance and with good coaxiality between the protective bearing and the magnetic bearing, the rotor is subjected to electromagnetic forces from four coils on the magnetic bearing. These electromagnetic forces act on the rotor along the x+ and y+ directions, causing the rotor to levitate at the center position (x0, y0) within the magnetic bearing. At this time, the currents in the two coils in the x+ direction are I0 and I0, respectively. x0+ and I x0- The currents of the two coils in the y+ direction are I... y0+ and I y0- These four currents together form the suspending current, that is, the suspending current is like Figure 1 The diagram shows a flowchart of an embodiment of the method of the present invention. The anomaly detection method for the magnetic levitation bearing system may include steps S110 to S150.

[0042] In step S110, prior to the magnetic levitation system, under the condition that there are no abnormalities and the system is operating normally, the standard levitation current of the magnetic levitation bearing system is determined, and n sets of standard deflection currents of the magnetic levitation bearing system are determined, where n is a positive integer; deflection refers to actively controlling the levitation position of the rotor so that the rotor's levitation position is not at the center position within the magnetic bearing when there are no abnormalities in the magnetic levitation bearing system. The deflection current is the levitation current when the rotor's levitation position is not at the center position within the magnetic bearing under this condition. The n sets of standard deflection currents must have at least two sets in each control direction, such as... Figure 7 As shown, for example: one set of deflections in the x-direction and one set in the x-direction; another set of deflections in the x-direction and one set in the x-direction. The reason for this setting is that if the rotor is eccentric and the floating position is too close to the y+ of the protective bearing, continuing to deflect in the y+ direction may directly collide with the protective bearing. In this case, it is necessary to deflect in the y-direction. Therefore, by setting at least two sets of standard deflection currents in each control direction, we can avoid extreme situations.

[0043] In some embodiments, in step S110, under normal operation of the magnetic levitation system, a standard levitation current of the magnetic bearing system is determined, and n sets of standard levitation currents of the magnetic bearing system are determined. This includes: under normal operation of the magnetic levitation system, the levitation current of the magnetic levitation system when the rotor is levied at the center position of the magnetic bearing is taken as the standard levitation current; under normal operation of the magnetic levitation system and when the rotor is levied at the center position of the magnetic bearing, the levitation current of the magnetic levitation system after the rotor is offset along different preset directions and different preset distances is taken as the standard levitation current. The preset direction and preset distance can be set according to actual conditions. For example, the preset direction can be set to the direction that is likely to occur when eccentric, and the preset distance can be set to the offset distance that is likely to occur when eccentric. Different preset distances can be offset under the same preset direction to obtain multiple sets of different standard levitation currents, which facilitates the rotor offset to the position of the standard levitation current. Among the n sets of standard levitation currents, there are no standard levitation currents with the same offset direction and distance. The preset distance is the distance of the current position of the rotor relative to the center position of the magnetic bearing.

[0044] Specifically, such as Figure 7 As shown, different preset directions can be set along x. 0+ Direction or along y 0+ When the magnetic bearing is functioning normally, the coaxiality of the protective bearing and the magnetic bearing is good, and the levitation position is at the electromagnetic center position, record the levitation current at this time. As a standard floating current. Figure 9This is a schematic diagram of the rotor levitation structure in a magnetic levitation bearing system when controlling rotor deflection, as shown below. Figure 9 As shown, the rotor is moved along x 0+ The directional displacement is Δx, and the rotor's suspension position is (x0 + Δx, y0). The force relationship of the rotor is as follows:

[0045]

[0046] Record the levitation current when the rotor is suspended at position (x0+Δx,y0). Similarly, move the rotor along x 0- The directional displacement Δx is recorded, and the levitation current is recorded when the rotor is suspended at position (x0-Δx,y0). Offset the rotor by a displacement Δy along the y0+ direction, and record the levitation current when the rotor is suspended at the position (x0, y0+Δy). Offset the rotor by a displacement Δy along the y0- direction, and record the levitation current when the rotor is suspended at the position (x0, y0-Δy). The four obtained floating currents are used as standard deflection currents, where Δx and Δy are preset deflection distances. To facilitate rotor offset to the position of the standard deflection current, the standard deflection current is not limited to four sets; more sets of standard deflection currents can be added as references.

[0047] To determine the center position of the magnetic bearing, rotate the rotor one revolution close to the protective bearing. When the rotor is closest to the protective bearing at X+, the sensor in the X direction will register a maximum (or minimum) value V1. When it is closest to the protective bearing at X-, the sensor in the X direction will register a minimum (or maximum) value V2. Therefore, the center position in the X direction is (V1 + V2) / 2. The center position in the Y direction is similar. However, due to differences in sensor manufacturing, the reference positions detected by different sensors may vary significantly. Therefore, the positions read by the sensors cannot be used as a basis for determining eccentricity and anomalies.

[0048] The levitation current is generated by the bearing controller. Figure 10 This is a schematic diagram of the structure controlling rotor levitation in a magnetic levitation bearing system. Figure 11 This is a schematic diagram of the differential control magnetic bearing in a magnetic levitation bearing system, such as... Figure 10 and Figure 11As shown, the bearing controller has a current sensor that detects the coil current to determine the current levitation current. The bearing controller acquires the displacement sensor signal, compares the displacement signal with the reference position, and then uses a displacement loop PID calculation to obtain the reference current value for the current loop. Magnetic bearings often use differential control. In the case of an active magnetic bearing, due to the presence of the bias current i0, the currents in the two sets of magnetic poles symmetrically along the rotor are i0+Δi and i0-Δi, respectively. In the case of a hybrid magnetic bearing, there is no bias current, and the currents in the two sets of magnetic poles symmetrically along the rotor are Δi and –Δi, respectively.

[0049] In step S120, during the current operation of the magnetic levitation bearing system, the levitation current of the magnetic levitation bearing system is acquired and recorded as the first levitation current of the magnetic levitation bearing system.

[0050] In step S130, based on the standard levitation current of the magnetic levitation bearing system, it is determined whether the levitation current of the magnetic levitation bearing system is abnormal according to the first levitation current of the magnetic levitation bearing system.

[0051] In some implementations... Figure 2 This is a flowchart illustrating an embodiment of the method of the present invention for determining whether the levitation current of a magnetic levitation bearing system is abnormal, as shown below. Figure 2 As shown, in step S130, the specific process of determining whether the levitation current of the magnetic levitation bearing system is abnormal based on the standard levitation current of the magnetic levitation bearing system and the first levitation current of the magnetic levitation bearing system includes steps S210 to S230.

[0052] Step S210: Subtract the current flowing through each of the m energized coils in the first floating current from the current flowing through the corresponding energized coil in the standard floating current to obtain m difference values.

[0053] Step S220: Determine whether any of the absolute values ​​of the m differences is greater than a preset threshold.

[0054] Step S230: If the absolute value of any one of the m differences is greater than a preset threshold, then it is determined that the levitation current of the magnetic levitation bearing system is abnormal.

[0055] Specifically, such as Figure 7 As shown, when there is no eccentricity, the formula for the output force of the magnetic bearing is:

[0056]

[0057] in μ0 is the air permeability, N is the number of turns in the magnetic bearing coil winding, and A is the cross-sectional area of ​​the magnetic circuit; when the structural parameters of the magnetic bearing are determined, k is a constant; i is the current flowing through the coil, and x is the air gap between the rotor and the magnetic bearing.

[0058] When the rotor is suspended at the center position (x0, y0) of the normal magnetic bearing, the air gap between the rotor and the magnetic bearing is δ, and the force relationship of the rotor in the x direction is:

[0059]

[0060] Similarly, the force relationship of the rotor in the y direction is:

[0061]

[0062] By observing the force relationship of the rotor in the x and y directions, it can be concluded that the levitation current will also change when the air gap value or k 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.

[0063] When the characteristics of the magnetic bearing change, such as demagnetization of the magnet or abnormal number of coil turns, taking the x+ direction as an example, the value of k in this direction becomes k', and the force relationship of the rotor can be obtained as follows:

[0064]

[0065] This leads to the conclusion that the suspending current is no longer the same as the normal suspending current. When the characteristic change exceeds a certain range, the current will deviate significantly from the current during normal suspending.

[0066] Figure 8 This is a schematic diagram of the rotor suspension structure when eccentricity occurs in a magnetic levitation bearing system, as shown below. Figure 8 As shown, when eccentricity occurs, the rotor's center is no longer located at the center of the magnetic bearing; at this time, the rotor's levitation position is (x... 0’ ,y 0’ At this point, the air gap in each direction is no longer δ, therefore the suspension current is no longer the same as the normal suspension current. When the eccentricity exceeds a certain range, the current will deviate significantly from the current during normal suspension.

[0067] Therefore, by comparing the current levitation current with the standard levitation current under normal conditions, it is possible to determine whether the levitation current is abnormal, and thus it can be concluded that the magnetic levitation bearing system may have eccentricity or abnormal magnetic bearing characteristics.

[0068] Specifically, if the current rotor levitation current is (I x+ ,I y+ ,I x- ,I y- The first reference levitation current is Then determine Ix0+ with I x+ Is the absolute value of the difference greater than the preset threshold ε, I? x0- with I x- Is the absolute value of the difference greater than the preset threshold ε, I? y0+ with I y+ Is the absolute value of the difference greater than the preset threshold ε, I? y0- with I y- Whether the absolute value of the difference is greater than the preset threshold ε, that is:

[0069]

[0070] If any current difference exceeds a preset threshold, the current of the magnetic levitation bearing system is considered abnormal.

[0071] Figure 12 This is a flowchart illustrating an embodiment of the method of the present invention for determining the cause of an abnormal floating current based on the floating current and the standard current, as shown below. Figure 12 As shown, the method of the present invention includes:

[0072] Step 1: Under normal operation of the magnetic levitation bearing system, obtain the levitation current when the rotor is suspended at the center position of the magnetic bearing and the deflection current after multiple rotor deflections, as the standard levitation current and standard deflection current for subsequent judgment; then, when the magnetic levitation bearing system is running, execute Step 2.

[0073] Step 2: Obtain the current floating current and determine whether the absolute value of the difference between the current floating current and the reference floating current obtained in Step 1 is greater than a preset threshold. If it is greater, the current floating current is considered to be abnormal, and then Step 3 is executed; otherwise, the bearing is considered to be normal.

[0074] The solution of this invention can determine whether the current suspension current of the magnetic levitation bearing system is abnormal during operation by comparing the current suspension current with the standard suspension current. After confirming that the suspension current is abnormal, the cause of the abnormality can be detected. Therefore, it is not necessary to disassemble the machine or use complex equipment such as inductance measuring instruments to determine the cause of the suspension abnormality, which greatly improves the efficiency of abnormality detection and ensures the stable operation of the magnetic levitation bearing system.

[0075] In step S140, if it is determined that the levitation current of the magnetic levitation bearing system is abnormal, then based on the n sets of standard bias currents of the magnetic levitation bearing system, when the levitation position of the rotor is changed to the preset magnetic bearing center point position, the levitation current of the magnetic levitation bearing system at this time is recorded and denoted as the second levitation current of the magnetic levitation bearing system.

[0076] In some implementations... Figure 3This is a schematic flowchart of an embodiment of the method of the present invention, which changes the levitation position of the rotor according to a standard bias current. Figure 3 As shown, the specific process of recording 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 step S140 based on the n sets of standard levitation currents of the magnetic bearing system, when the levitation position of the rotor is changed to the preset magnetic bearing center point position, includes steps S310 to S330.

[0077] Step S310: Among the n sets of standard buoyancy currents, determine the buoyancy current with the smallest difference from the first floating current, and use it as the reference buoyancy current.

[0078] In some implementations, the specific process of determining the floating current with the smallest difference from the first floating current among the n sets of standard floating currents in step S310 as the reference floating current includes: in the n sets of standard floating currents, subtracting the current flowing through each of the m energized coils in each set of floating currents from the current flowing through the corresponding energized coil in the first floating current, so that each set of floating currents yields m current differences; adding the m current differences in each set of floating currents, and recording the sum of the sums as the sum of differences, to obtain n sets of sums of differences; determining the smallest sum of differences among the n sets of sums of differences, and using the floating current corresponding to the smallest sum of differences as the reference floating current.

[0079] Specifically, taking the previously determined four sets of standard bias currents as an example, the bias currents in the four sets of standard bias currents are... With the current levitation current (I) x+ ,I y+ ,I x- ,I y- Subtract from each other, i.e., I (x0+Δx)+ minus I x+ I (x0+Δx)- minus I x- I y0+ minus I y+ I y0- minus I y- Four current differences are obtained, and these four current differences are summed to obtain the sum of the differences. Similarly, for the other floating currents in the second reference floating current, Perform the same calculations as above to obtain a total of four sums of differences. Then, determine the smallest sum of these four sums and use the floating current corresponding to the smallest sum of differences as the reference floating current.

[0080] Step S320: Adjust the levitation position of the rotor according to the reference bias current so that the first levitation current is consistent with the reference bias current, and record the levitation position of the rotor at this time as the current levitation position of the rotor.

[0081] Step S330: Based on the current levitation position of the rotor, the rotor is offset by a preset distance in the opposite direction to the preset direction of the reference levitation current, so that the levitation position of the rotor is at the preset magnetic bearing center point. The levitation current of the magnetic bearing system at this time is recorded as the second levitation current of the magnetic bearing system.

[0082] Specifically, with Taking the reference buoyancy current as an example, the rotor levitation center position corresponding to this reference buoyancy current is (x 0+Δx After determining the reference buoyancy current, adjust the rotor's buoyancy position so that the current buoyancy current (I0) is equal to the reference buoyancy current (I0). x+ ,I y+ ,I x- ,I y- ) and reference bias current Maintain consistency. At the current floating current (I... x+ ,I y+ ,I x- ,I y- ) and reference bias current Assuming consistency is maintained, record the rotor's levitation center position at this moment as (x1, y1). If the magnetic levitation bearing only has an eccentricity anomaly, then theoretically, the rotor's levitation center position (x1, y1) after the current adjustment of the levitation position is at the levitation center position (x1, y1) corresponding to the reference levitation current. 0+Δx ,y0).

[0083] After adjusting the rotor levitation position to make the current levitation current consistent with the reference levitation current, the rotor levitation position is then aligned with the reference deflection current. The rotor is deflected by a preset negative distance in the x+ direction, i.e., the rotor is controlled to deviate from its levitation position by a distance Δx along the x- direction. At this time, the rotor's levitation position becomes (x1-Δx, y1), and the levitation current at this time is recorded as the second levitation current. If the magnetic levitation bearing only has an eccentricity anomaly, then theoretically the current rotor is at the center position of the magnetic bearing.

[0084] like Figure 12 As shown, the method of the present invention further includes:

[0085] Step 3: Among the multiple sets of standard buoyancy currents obtained in Step 1, determine the set of buoyancy currents that is closest to the current buoyancy current, and then proceed to Step 4.

[0086] Step 4: Based on the closest bias current found in Step 3, adjust the rotor's levitation position so that the current levitation current is the same as the closest bias current. Then record the levitation position at this moment and proceed to Step 5.

[0087] Step 5: Based on the buoyancy of the closest buoyancy current, adjust the rotor's levitation position so that the rotor is theoretically at the center of the magnetic bearing, obtain the levitation current at this moment, and then proceed to step 6.

[0088] In step S150, based on the standard levitation current of the magnetic levitation bearing system and the second levitation current of the magnetic levitation bearing system, the fault point where the levitation current of the magnetic levitation bearing system is abnormal is determined.

[0089] The present invention compares the current levitation current with a pre-stored standard levitation current during the operation of the magnetic levitation bearing system to determine whether the current levitation current is abnormal. If the current levitation current is abnormal, the rotor's levitation position is adjusted. Then, based on the comparison between the adjusted levitation current and the standard levitation current, the cause of the abnormal levitation current is determined to be either eccentricity or abnormal magnetic bearing characteristics. This allows for rapid and effective detection of abnormal levitation current and determination of the cause of the abnormality without shutting down the magnetic levitation bearing system, thus improving the operational reliability of the magnetic levitation bearing system.

[0090] In some implementations... Figure 4 This is a flowchart illustrating an embodiment of the method for determining the fault point of abnormal levitation current in a magnetic levitation bearing system according to the present invention, as shown below. Figure 4 As shown, step S150, based on the standard levitation current of the magnetic levitation bearing system and according to the second levitation current of the magnetic levitation bearing system, determines the specific process of the fault point where the levitation current of the magnetic levitation bearing system is abnormal, including steps S410 to S440.

[0091] Step S410: Subtract the current flowing through each of the m energized coils in the second floating current from the current flowing through the corresponding energized coil in the standard floating current to obtain m difference values.

[0092] Step S420: Determine whether any of the absolute values ​​of the m differences is greater than a preset threshold.

[0093] Step S430: If the absolute value of any one of the m differences is greater than a preset threshold, then the magnetic bearing characteristics of the magnetic levitation bearing system are determined to be abnormal.

[0094] Step S440: If the absolute value of any of the m differences is greater than a preset threshold, then it is determined that the magnetic levitation bearing system has an eccentricity abnormality.

[0095] By adjusting the rotor's levitation position, if the magnetic levitation bearing system only has an eccentricity abnormality, then theoretically the adjusted rotor's levitation position will be at the center of the magnetic bearing. If there is an abnormality in the magnetic bearing characteristics, then the adjusted rotor's levitation position will not be at the center of the magnetic bearing. At this time, based on the relationship between the second levitation current and the standard levitation current, it can be determined whether the rotor is actually at the center of the magnetic bearing, thus determining whether the cause of the levitation current abnormality is eccentricity or abnormality in the magnetic bearing characteristics.

[0096] Specifically, in obtaining the second levitation current Then, determine the standard floating current. With the second suspending current Whether the absolute value of the difference is greater than the preset threshold ε, that is, to determine I x0+ with I (x1-Δx)+ Is the absolute value of the difference greater than the preset threshold ε, I? x0- with I (x1-Δx)- Is the absolute value of the difference greater than the preset threshold ε, I? y0+ with I y1+ Is the absolute value of the difference greater than the preset threshold ε, I? y0- with I y1- The absolute value of the difference is greater than a preset threshold ε. If any current difference is greater than the preset threshold, the magnetic bearing characteristics of the magnetic levitation bearing system are considered abnormal; otherwise, eccentricity is considered to have occurred, and the eccentricity is (x1-Δx-x0, y1-y0).

[0097] like Figure 12 As shown, the method of the present invention further includes:

[0098] Step 6: Compare the levitation current at this moment with the reference levitation current. If the levitation current is greater than the reference levitation current, it is considered that the magnetic bearing characteristics of the magnetic levitation bearing system are abnormal; otherwise, it is considered that there is an eccentricity abnormality, and the eccentricity of the rotor is obtained according to the levitation position of the rotor recorded in Step 4.

[0099] The technical solution of this embodiment determines a standard levitation current and n sets of standard eccentric levitation currents in advance during the normal operation of the magnetic levitation bearing system. During the operation of the magnetic levitation bearing system, it is determined whether the levitation current of the magnetic levitation bearing system is abnormal based on the current levitation current and the standard levitation current. If an abnormality is found, the levitation position of the rotor is adjusted according to the n sets of standard eccentric levitation currents so that the current levitation position of the rotor is at the center point of the magnetic bearing, and the levitation current at this moment is recorded. Based on the current levitation current at this moment and the standard levitation current, it is determined whether the abnormality of the levitation current is due to eccentricity or magnetic bearing characteristic abnormality. Thus, without stopping the magnetic levitation bearing system, it is possible to detect whether the levitation current is abnormal and the cause of the abnormality in a timely manner, thereby improving the efficiency of abnormality detection and the operational reliability of the magnetic levitation bearing system.

[0100] According to an embodiment of the present invention, an anomaly detection device for a magnetic levitation bearing system corresponding to an anomaly detection method for a magnetic levitation bearing system is also provided. The magnetic levitation bearing system includes a magnetic bearing, a protective bearing, and a rotor. The magnetic bearing has m energized coils, and the rotor is levitated within the magnetic bearing by the action of the m energized coils, where m is a positive integer. The currents flowing through the m energized coils together constitute the levitation current of the magnetic levitation bearing system. Figure 7 This is a schematic diagram of the rotor suspension structure under normal operating conditions of a magnetic levitation bearing system, as shown below. Figure 7 As shown, under normal magnetic bearing performance and with good coaxiality between the protective bearing and the magnetic bearing, the rotor is subjected to electromagnetic forces from four coils on the magnetic bearing. These electromagnetic forces act on the rotor along the x+ and y+ directions, causing the rotor to levitate at the center position (x0, y0) within the magnetic bearing. At this time, the currents in the two coils in the x+ direction are I0 and I0, respectively. x0+ and I x0- The currents of the two coils in the y+ direction are I... y0+ and I y0- These four currents together form the suspending current, that is, the suspending current is See Figure 5 The diagram shows a structural schematic of an embodiment of the device of the present invention. The anomaly detection device for the magnetic levitation bearing system may include: an acquisition unit 102 and a control unit 104.

[0101] Processing unit 104 is configured to pre-determine the standard levitation current of the magnetic levitation bearing system under normal operating conditions without any abnormalities, and to determine n sets of standard deflection currents for the magnetic levitation bearing system, where n is a positive integer. Deflection refers to actively controlling the levitation position of the rotor so that it is not at the center position within the magnetic bearing when the magnetic levitation bearing system is functioning normally. The deflection current is the levitation current when the rotor's levitation position is not at the center position within the magnetic bearing under these conditions. The n sets of standard deflection currents must have at least two sets in each control direction, such as... Figure 7 As shown, for example, one set of deflections is made in the x-direction (x+) and another in the x-direction (x-); another set is made in the x-direction (x+) and another in the x-direction (x-). This is because if the rotor is eccentric and the floating position is too close to the y+ of the protective bearing, continuing to deflect in the y+ direction might directly collide with the protective bearing. In this case, deflection in the y- direction is necessary. Therefore, by setting at least two sets of standard deflection currents in each control direction, extreme situations can be avoided. The specific functions and processing of this processing unit 104 are described in step S110.

[0102] In some embodiments, the processing unit, under normal operation of the magnetic levitation system, determines the standard levitation current of the magnetic bearing system and determines n sets of standard levitation currents for the magnetic bearing system. This includes: under normal operation of the magnetic levitation system, the levitation current of the magnetic levitation system when the rotor is levied at the center position of the magnetic bearing is used as the standard levitation current; under normal operation of the magnetic levitation system and when the rotor is levied at the center position of the magnetic bearing, the levitation current of the magnetic levitation system after the rotor is offset along different preset directions and different preset distances is used as the standard levitation current. The preset directions and preset distances can be set according to actual conditions. For example, the preset direction can be set to a direction that is prone to eccentricity, and the preset distance can be set to an offset distance that is prone to eccentricity. Different preset distances can be offset within the same preset direction, thereby obtaining multiple sets of different standard levitation currents, facilitating the rotor's offset to the position of the standard levitation current. Among the n sets of standard levitation currents, there are no standard levitation currents with the same offset direction and distance. The preset distance is the distance of the rotor's current position relative to the center position of the magnetic bearing.

[0103] Specifically, such as Figure 7 As shown, different preset directions can be set along x. 0+ Direction or along y 0+ When the magnetic bearing is functioning normally, the coaxiality of the protective bearing and the magnetic bearing is good, and the levitation position is at the electromagnetic center position, record the levitation current at this time. As a standard floating current. Figure 9 This is a schematic diagram of the rotor levitation structure in a magnetic levitation bearing system when controlling rotor deflection, as shown below. Figure 9 As shown, the rotor is moved along x 0+ The directional displacement is Δx, and the rotor's suspension position is (x0 + Δx, y0). The force relationship of the rotor is as follows:

[0104]

[0105] Record the levitation current when the rotor is suspended at position (x0+Δx,y0). Similarly, move the rotor along x 0- The directional displacement Δx is recorded, and the levitation current is recorded when the rotor is suspended at position (x0-Δx,y0). Offset the rotor by a displacement Δy along the y0+ direction, and record the levitation current when the rotor is suspended at the position (x0, y0+Δy). Offset the rotor by a displacement Δy along the y0- direction, and record the levitation current when the rotor is suspended at the position (x0, y0-Δy). The four obtained floating currents are used as standard deflection currents, where Δx and Δy are preset deflection distances. To facilitate rotor offset to the position of the standard deflection current, the standard deflection current is not limited to four sets; more sets of standard deflection currents can be added as references.

[0106] To determine the center position of the magnetic bearing, rotate the rotor one revolution close to the protective bearing. When the rotor is closest to the protective bearing at X+, the sensor in the X direction will register a maximum (or minimum) value V1. When it is closest to the protective bearing at X-, the sensor in the X direction will register a minimum (or maximum) value V2. Therefore, the center position in the X direction is (V1 + V2) / 2. The center position in the Y direction is similar. However, due to differences in sensor manufacturing, the reference positions detected by different sensors may vary significantly. Therefore, the positions read by the sensors cannot be used as a basis for determining eccentricity and anomalies.

[0107] The levitation current is generated by the bearing controller. Figure 10 This is a schematic diagram of the structure controlling rotor levitation in a magnetic levitation bearing system. Figure 11 This is a schematic diagram of the differential control magnetic bearing in a magnetic levitation bearing system, such as... Figure 10 and Figure 11As shown, the bearing controller has a current sensor that detects the coil current to determine the current levitation current. The bearing controller acquires the displacement sensor signal, compares the displacement signal with the reference position, and then uses a displacement loop PID calculation to obtain the reference current value for the current loop. Magnetic bearings often use differential control. In the case of an active magnetic bearing, due to the presence of the bias current i0, the currents in the two sets of magnetic poles symmetrically along the rotor are i0+Δi and i0-Δi, respectively. In the case of a hybrid magnetic bearing, there is no bias current, and the currents in the two sets of magnetic poles symmetrically along the rotor are Δi and –Δi, respectively.

[0108] The acquisition unit 102 is configured to acquire the levitation current of the magnetic levitation bearing system during the current operation of the magnetic levitation bearing system, and record it as the first levitation current of the magnetic levitation bearing system; the specific functions and processing of the acquisition unit 102 are described in step S120.

[0109] The processing unit 104 is also configured to determine whether the levitation current of the magnetic levitation bearing system is abnormal based on the standard levitation current of the magnetic levitation bearing system and the first levitation current of the magnetic levitation bearing system; the specific functions and processing of the processing unit 104 are described in step S130.

[0110] In some embodiments, the processing unit 104, based on the standard levitation current of the magnetic levitation bearing system and according to the first levitation current of the magnetic levitation bearing system, determines whether the levitation current of the magnetic levitation bearing system is abnormal, including:

[0111] The current flowing through each of the m energized coils in the first floating current is subtracted from the current flowing through the corresponding energized coil in the standard floating current to obtain m differences; the specific functions and processing of this processing unit 104 are described in step S210.

[0112] Determine whether any of the absolute values ​​of the m differences is greater than a preset threshold; the specific functions and processing of this processing unit 104 are described in step S220.

[0113] If the absolute value of any one of the m differences is greater than a preset threshold, then the levitation current of the magnetic levitation bearing system is determined to be abnormal. For the specific functions and processing of this processing unit 104, please refer to step S230.

[0114] Specifically, such as Figure 7 As shown, when there is no eccentricity, the formula for the output force of the magnetic bearing is:

[0115]

[0116] in μ0 is the air permeability, N is the number of turns in the magnetic bearing coil winding, and A is the cross-sectional area of ​​the magnetic circuit; when the structural parameters of the magnetic bearing are determined, k is a constant; i is the current flowing through the coil, and x is the air gap between the rotor and the magnetic bearing.

[0117] When the rotor is suspended at the center position (x0, y0) of the normal magnetic bearing, the air gap between the rotor and the magnetic bearing is δ, and the force relationship of the rotor in the x direction is:

[0118]

[0119] Similarly, the force relationship of the rotor in the y direction is:

[0120]

[0121] By observing the force relationship of the rotor in the x and y directions, it can be concluded that the levitation current will also change when the air gap value or k 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.

[0122] When the characteristics of the magnetic bearing change, such as demagnetization of the magnet or abnormal number of coil turns, taking the x+ direction as an example, the value of k in this direction becomes k', and the force relationship of the rotor can be obtained as follows:

[0123]

[0124] This leads to the conclusion that the suspending current is no longer the same as the normal suspending current. When the characteristic change exceeds a certain range, the current will deviate significantly from the current during normal suspending.

[0125] Figure 8 This is a schematic diagram of the rotor suspension structure when eccentricity occurs in a magnetic levitation bearing system, as shown below. Figure 8 As shown, when eccentricity occurs, the rotor's center is no longer located at the center of the magnetic bearing; at this time, the rotor's levitation position is (x... 0’ ,y 0’ At this point, the air gap in each direction is no longer δ, therefore the suspension current is no longer the same as the normal suspension current. When the eccentricity exceeds a certain range, the current will deviate significantly from the current during normal suspension.

[0126] Therefore, by comparing the current levitation current with the reference levitation current under normal conditions, it is possible to determine whether the levitation current is abnormal, and thus it can be concluded that the magnetic levitation bearing system may have eccentricity or abnormal magnetic bearing characteristics.

[0127] Specifically, if the current rotor levitation current is (I x+ ,I y+ ,I x- ,I y- The first standard suspending current is Then determine Ix0+ with I x+ Is the absolute value of the difference greater than the preset threshold ε, I? x0- with I x- Is the absolute value of the difference greater than the preset threshold ε, I? y0+ with I y+ Is the absolute value of the difference greater than the preset threshold ε, I? y0- with I y- Whether the absolute value of the difference is greater than the preset threshold ε, that is:

[0128]

[0129] If any current difference exceeds a preset threshold, the current of the magnetic levitation bearing system is considered abnormal.

[0130] Figure 12 This is a flowchart illustrating an embodiment of the method of the present invention for determining the cause of an abnormal floating current based on the floating current and the standard current, as shown below. Figure 12 As shown, the method of the present invention includes:

[0131] Step 1: Under normal operation of the magnetic levitation bearing system, obtain the levitation current when the rotor is suspended at the center position of the magnetic bearing and the deflection current after multiple rotor deflections, as the standard levitation current and standard deflection current for subsequent judgment; then, when the magnetic levitation bearing system is running, execute Step 2.

[0132] Step 2: Obtain the current floating current and determine whether the absolute value of the difference between the current floating current and the reference floating current obtained in Step 1 is greater than a preset threshold. If it is greater, the current floating current is considered to be abnormal, and then Step 3 is executed; otherwise, the bearing is considered to be normal.

[0133] The solution of this invention can determine whether the current suspension current of the magnetic levitation bearing system is abnormal during operation by comparing the current suspension current with the standard suspension current. After confirming that the suspension current is abnormal, the cause of the abnormality can be detected. Therefore, it is not necessary to disassemble the machine or use complex equipment such as inductance measuring instruments to determine the cause of the suspension abnormality, which greatly improves the efficiency of abnormality detection and ensures the stable operation of the magnetic levitation bearing system.

[0134] The processing unit 104 is further configured to, if it is determined that the levitation current of the magnetic levitation bearing system is abnormal, then, based on the n sets of standard bias currents of the magnetic levitation bearing system, change the levitation position of the rotor to the preset magnetic bearing center point position, record the levitation current of the magnetic levitation bearing system at this time, and record it as the second levitation current of the magnetic levitation bearing system; the specific functions and processing of the processing unit 104 are described in step S140.

[0135] In some embodiments, the processing unit 104, based on n sets of standard levitation currents of the magnetic levitation bearing system, changes the levitation position of the rotor to a preset magnetic bearing center point position, and records the levitation current of the magnetic levitation bearing system at this time, denoted as the second levitation current of the magnetic levitation bearing system, including:

[0136] Among the n sets of standard buoyancy currents, the buoyancy current with the smallest difference from the first floating current is determined as the reference buoyancy current; the specific functions and processing of this processing unit 104 are described in step S310.

[0137] In some embodiments, the specific process by which the processing unit 104 determines the floating current with the smallest difference from the first floating current among the n sets of standard floating currents as a reference floating current includes: in the n sets of standard floating currents, subtracting the current flowing through each of the m energized coils in each set of floating currents from the current flowing through the corresponding energized coil in the first floating current, so that each set of floating currents yields m current differences; summing the m current differences in each set of floating currents, and recording the sum as the sum of differences, to obtain n sets of sums of differences; determining the smallest sum of differences among the n sets of sums of differences, and using the floating current corresponding to the smallest sum of differences as the reference floating current.

[0138] Specifically, taking the previously determined four sets of standard bias currents as an example, the bias currents in the four sets of standard bias currents are... With the current levitation current (I) x+ ,I y+ ,I x- ,I y- Subtract from each other, i.e., I (x0+Δx)+ minus I x+ I (x0+Δx)- minus I x- I y0+ minus I y+ I y0- minus I y- Four current differences are obtained, and these four current differences are summed to obtain the sum of the differences. Similarly, for the other floating currents in the second reference floating current, Perform the same calculations as above to obtain a total of four sums of differences. Then determine the smallest sum of these four sums and use the floating current corresponding to the smallest sum of differences as the reference bias current.

[0139] Adjust 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 record the levitation position of the rotor at this time as the current levitation position of the rotor; see step S320 for the specific functions and processing of the processing unit 104.

[0140] Based on the current levitation position of the rotor, the rotor is offset by a preset distance in the opposite direction to the preset direction of the reference levitation current, so that the levitation position of the rotor is at a preset magnetic bearing center point. The levitation current of the magnetic bearing system at this time is recorded and denoted as the second levitation current of the magnetic bearing system. For the specific functions and processing of this processing unit 104, please refer to step S330.

[0141] Specifically, with Taking the reference buoyancy current as an example, the rotor levitation center position corresponding to this reference buoyancy current is (x 0+Δx After determining the reference buoyancy current, adjust the rotor's buoyancy position so that the current buoyancy current (I0) is equal to the reference buoyancy current (I0). x+ ,I y+ ,I x- ,I y- ) and reference bias current Maintain consistency. At the current floating current (I... x+ ,I y+ ,I x- ,I y- ) and reference bias current Assuming consistency is maintained, record the rotor's levitation center position at this moment as (x1, y1). If the magnetic levitation bearing only has an eccentricity anomaly, then theoretically, the rotor's levitation center position (x1, y1) after the current adjustment of the levitation position is at the levitation center position (x1, y1) corresponding to the reference levitation current. 0+Δx ,y0).

[0142] After adjusting the rotor levitation position to make the current levitation current consistent with the reference levitation current, the rotor levitation position is then aligned with the reference deflection current. The rotor is deflected by a preset negative distance in the x+ direction, i.e., the rotor is controlled to deviate from its levitation position by a distance Δx along the x- direction. At this time, the rotor's levitation position becomes (x1-Δx, y1), and the levitation current at this time is recorded as the second levitation current. If the magnetic levitation bearing only has an eccentricity anomaly, then theoretically the current rotor is at the center position of the magnetic bearing.

[0143] like Figure 12 As shown, the method of the present invention further includes:

[0144] Step 3: Among the multiple sets of standard buoyancy currents obtained in Step 1, determine the set of buoyancy currents that is closest to the current buoyancy current, and then proceed to Step 4.

[0145] Step 4: Based on the closest bias current found in Step 3, adjust the rotor's levitation position so that the current levitation current is the same as the closest bias current. Then record the levitation position at this moment and proceed to Step 5.

[0146] Step 5: Based on the buoyancy of the closest buoyancy current, adjust the rotor's levitation position so that the rotor is theoretically at the center of the magnetic bearing, obtain the levitation current at this moment, and then proceed to step 6.

[0147] The processing unit 104 is further configured to determine the fault point where the levitation current of the magnetic levitation bearing system is abnormal, based on the standard levitation current of the magnetic levitation bearing system and the second levitation current of the magnetic levitation bearing system. The specific functions and processing of this processing unit 104 are described in step S150.

[0148] The present invention compares the current levitation current with a pre-stored standard levitation current during the operation of the magnetic levitation bearing system to determine whether the current levitation current is abnormal. If the current levitation current is abnormal, the rotor's levitation position is adjusted. Then, based on the comparison between the adjusted levitation current and the standard levitation current, the cause of the abnormal levitation current is determined to be either eccentricity or abnormal magnetic bearing characteristics. This allows for rapid and effective detection of abnormal levitation current and determination of the cause of the abnormality without shutting down the magnetic levitation bearing system, thus improving the operational reliability of the magnetic levitation bearing system.

[0149] In some embodiments, the processing unit 104, based on the standard levitation current of the magnetic levitation bearing system and according to the second levitation current of the magnetic levitation bearing system, determines the fault point where the levitation current of the magnetic levitation bearing system is abnormal, including:

[0150] The current flowing through each of the m energized coils in the second floating current is subtracted from the current flowing through the corresponding energized coil in the standard floating current to obtain m differences; the specific functions and processing of this processing unit 104 are described in step S410.

[0151] Determine whether any of the absolute values ​​of the m differences is greater than a preset threshold; the specific functions and processing of this processing unit 104 are described in step S420.

[0152] If the absolute value of any one of the m differences is greater than a preset threshold, then the magnetic bearing characteristics of the magnetic levitation bearing system are determined to be abnormal; the specific functions and processing of the processing unit 104 are described in step S430.

[0153] If none of the absolute values ​​of the m differences is greater than a preset threshold, then the magnetic levitation bearing system is determined to have an eccentricity anomaly. The specific functions and processing of this processing unit 104 are described in step S440.

[0154] By adjusting the rotor's levitation position, if the magnetic levitation bearing system only has an eccentricity abnormality, then theoretically the adjusted rotor's levitation position will be at the center of the magnetic bearing. If there is an abnormality in the magnetic bearing characteristics, then the adjusted rotor's levitation position will not be at the center of the magnetic bearing. At this time, based on the relationship between the second levitation current and the standard levitation current, it can be determined whether the rotor is actually at the center of the magnetic bearing, thus determining whether the cause of the levitation current abnormality is eccentricity or abnormality in the magnetic bearing characteristics.

[0155] Specifically, in obtaining the second levitation current Then, determine the standard floating current. With the second suspending current Whether the absolute value of the difference is greater than the preset threshold ε, that is, to determine I x0+ with I (x1-Δx)+ Is the absolute value of the difference greater than the preset threshold ε, I? x0- with I (x1-Δx)- Is the absolute value of the difference greater than the preset threshold ε, I? y0+ with I y1+ Is the absolute value of the difference greater than the preset threshold ε, I? y0- with I y1- The absolute value of the difference is greater than a preset threshold ε. If any current difference is greater than the preset threshold, the magnetic bearing characteristics of the magnetic levitation bearing system are considered abnormal; otherwise, eccentricity is considered to have occurred, and the eccentricity is (x1-Δx-x0, y1-y0).

[0156] like Figure 12 As shown, the method of the present invention further includes:

[0157] Step 6: Compare the levitation current at this moment with the reference levitation current. If the levitation current is greater than the reference levitation current, it is considered that the magnetic bearing characteristics of the magnetic levitation bearing system are abnormal; otherwise, it is considered that there is an eccentricity abnormality, and the eccentricity of the rotor is obtained according to the levitation position of the rotor recorded in Step 4.

[0158] Since the processing and functions implemented by the device in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in the description of this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0159] By employing the technical solution of this invention, a standard levitation current and n sets of standard eccentric levitation currents are pre-determined during the normal operation of the magnetic levitation bearing system. During the operation of the magnetic levitation bearing system, the system determines whether the levitation current of the magnetic levitation bearing system is abnormal based on the current levitation current and the standard levitation current. If an abnormality is found, the rotor's levitation position is adjusted according to the n sets of standard eccentric levitation currents so that the rotor's current levitation position is at the center point of the magnetic bearing, and the levitation current at this moment is recorded. Based on the current levitation current at this moment and the standard levitation current, the cause of the abnormality is determined to be either an eccentricity abnormality or a magnetic bearing characteristic abnormality. Thus, without shutting down the magnetic levitation bearing system, it is possible to promptly detect whether the levitation current is abnormal and the cause of the abnormality, improving the efficiency of abnormality detection and the operational reliability of the magnetic levitation bearing system.

[0160] According to an embodiment of the present invention, a magnetic levitation bearing system corresponding to an anomaly detection device for a magnetic levitation bearing system is also provided. This magnetic levitation bearing system may include: the anomaly detection device for a magnetic levitation bearing system described above.

[0161] Since the processing and functions implemented by the magnetic levitation bearing system in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned devices, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0162] By employing the technical solution of this invention, a standard levitation current and n sets of standard eccentric levitation currents are pre-determined during the normal operation of the magnetic levitation bearing system. During the operation of the magnetic levitation bearing system, the system determines whether the levitation current of the magnetic levitation bearing system is abnormal based on the current levitation current and the standard levitation current. If an abnormality is found, the rotor's levitation position is adjusted according to the n sets of standard eccentric levitation currents so that the rotor's current levitation position is at the center point of the magnetic bearing, and the levitation current at this moment is recorded. Based on the current levitation current at this moment and the standard levitation current, the cause of the abnormality is determined to be either an eccentricity abnormality or a magnetic bearing characteristic abnormality. Thus, without shutting down the magnetic levitation bearing system, it is possible to promptly detect whether the levitation current is abnormal and the cause of the abnormality, improving the efficiency of abnormality detection and the operational reliability of the magnetic levitation bearing system.

[0163] According to an embodiment of the present invention, a storage medium corresponding to an anomaly detection method for a magnetic levitation bearing system is also provided. The storage medium includes a stored program, wherein the program controls the device where the storage medium is located to execute the anomaly detection method for the magnetic levitation bearing system described above during runtime.

[0164] Since the processing and functions implemented by the storage medium in this embodiment are basically the same as the embodiments, principles and examples of the aforementioned methods, any details not covered in this embodiment can be found in the relevant descriptions in the aforementioned embodiments, and will not be repeated here.

[0165] By employing the technical solution of this invention, a standard levitation current and n sets of standard eccentric levitation currents are pre-determined during the normal operation of the magnetic levitation bearing system. During the operation of the magnetic levitation bearing system, the system determines whether the levitation current of the magnetic levitation bearing system is abnormal based on the current levitation current and the standard levitation current. If an abnormality is found, the rotor's levitation position is adjusted according to the n sets of standard eccentric levitation currents so that the rotor's current levitation position is at the center point of the magnetic bearing, and the levitation current at this moment is recorded. Based on the current levitation current at this moment and the standard levitation current, the cause of the abnormality is determined to be either an eccentricity abnormality or a magnetic bearing characteristic abnormality. Thus, without shutting down the magnetic levitation bearing system, it is possible to promptly detect whether the levitation current is abnormal and the cause of the abnormality, improving the efficiency of abnormality detection and the operational reliability of the magnetic levitation bearing system.

[0166] In summary, it is readily understood by those skilled in the art that, without conflict, the aforementioned advantageous methods can be freely combined and superimposed.

[0167] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for detecting anomalies in a magnetic levitation bearing system, characterized in that, The magnetic levitation bearing system includes a magnetic bearing, a protective bearing, and a rotor; the magnetic bearing has m energized coils, and the rotor is levitated within the magnetic bearing by the action of the m energized coils, where m is a positive integer; The currents flowing through the m energized coils collectively constitute the levitation current of the magnetic levitation bearing system; the method includes: In advance, under the normal operation of the magnetic levitation bearing system, the standard levitation current of the magnetic levitation bearing system is determined, and n sets of standard deflection currents of the magnetic levitation bearing system are determined, where n is a positive integer; During the current operation of the magnetic levitation bearing system, the levitation current of the magnetic levitation bearing system is acquired and recorded as the first levitation current of the magnetic levitation bearing system. Based on the standard levitation current of the magnetic levitation bearing system, determine whether the levitation current of the magnetic levitation bearing system is abnormal according to the first levitation current of the magnetic levitation bearing system. If it is determined that the levitation current of the magnetic levitation bearing system is abnormal, then based on the n sets of standard deflection currents of the magnetic levitation bearing system, when the levitation position of the rotor is changed to the preset magnetic bearing center point position, the levitation current of the magnetic levitation bearing system at this time is recorded and recorded as the second levitation current of the magnetic levitation bearing system. Based on the standard levitation current of the magnetic levitation bearing system, and according to the second levitation current of the magnetic levitation bearing system, the fault point where the levitation current of the magnetic levitation bearing system is abnormal is determined.

2. The anomaly detection method for a magnetic levitation bearing system according to claim 1, characterized in that, Under normal operating conditions of the magnetic levitation bearing system, determine the standard levitation current of the magnetic levitation bearing system, and determine n sets of standard deflection currents of the magnetic levitation bearing system, including: When the magnetic levitation bearing system is operating normally, the levitation current of the magnetic levitation bearing system when the rotor is levitated at the center position of the magnetic bearing is taken as the standard levitation current; When the magnetic levitation bearing system is operating normally and the rotor is suspended at the center position of the magnetic bearing, the levitation current of the magnetic levitation bearing system after the rotor is offset along different preset directions and different preset distances is used as the standard deflection current; wherein, the preset distance is the distance of the current position of the rotor relative to the center position of the magnetic bearing.

3. The anomaly detection method for a magnetic levitation bearing system according to claim 1, characterized in that, Based on the standard levitation current of the magnetic levitation bearing system, and according to the first levitation current of the magnetic levitation bearing system, determine whether the levitation current of the magnetic levitation bearing system is abnormal, including: Subtract the current flowing through each of the m energized coils in the first suspended current from the current flowing through the corresponding energized coil in the standard suspended current to obtain m differences. Determine whether any of the absolute values ​​of the m differences is greater than a preset threshold; If the absolute value of any one of the m differences is greater than a preset threshold, then the levitation current of the magnetic levitation bearing system is determined to be abnormal.

4. The anomaly detection method for a magnetic levitation bearing system according to claim 1, characterized in that, Based on n sets of standard levitation currents of the magnetic levitation bearing system, when the levitation position of the rotor is changed to a preset magnetic bearing center point position, the levitation current of the magnetic levitation bearing system at this time is recorded and denoted as the second levitation current of the magnetic levitation bearing system, including: Among the n sets of standard buoyancy currents, the buoyancy current with the smallest difference from the first buoyancy current is determined as the reference buoyancy current. Adjust 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 record the levitation position of the rotor at this time as the current levitation position of the rotor. Based on the current levitation position of the rotor, the rotor is offset by a preset distance in the opposite direction to the preset direction when the reference levitation current is deflected, so that the levitation position of the rotor is at the preset magnetic bearing center point. The levitation current of the magnetic bearing system at this time is recorded and denoted as the second levitation current of the magnetic bearing system.

5. The anomaly detection method for a magnetic levitation bearing system according to claim 4, characterized in that, Among the n sets of standard buoyancy currents, the buoyancy current with the smallest difference from the first buoyancy current is determined as the reference buoyancy current, including: In the n sets of standard floating currents, the current flowing through each of the m energized coils in each set of floating currents is subtracted from the current flowing through the corresponding energized coil in the first floating current. Each set of floating currents yields m current differences. The m current differences in each set of floating currents are added together, and the sum is recorded as the sum of differences, thus obtaining the sum of n sets of differences. Among the n sets of differences, the smallest sum of differences is determined, and the floating current corresponding to the smallest sum of differences is used as the reference floating current.

6. The anomaly detection method for a magnetic levitation bearing system according to any one of claims 1-5, characterized in that, Based on the standard levitation current of the magnetic levitation bearing system, and according to the second levitation current of the magnetic levitation bearing system, the fault point where the levitation current of the magnetic levitation bearing system is abnormal is determined, including: Subtract the current flowing through each of the m energized coils in the second floating current from the current flowing through the corresponding energized coil in the standard floating current to obtain m differences. Determine whether any of the absolute values ​​of the m differences is greater than a preset threshold; If the absolute value of any one of the m differences is greater than a preset threshold, then the magnetic bearing characteristics of the magnetic levitation bearing system are determined to be abnormal. If none of the absolute values ​​of the m differences is greater than a preset threshold, then the magnetic levitation bearing system is determined to have an eccentricity anomaly.

7. An anomaly detection device for a magnetic levitation bearing system, characterized in that, The magnetic levitation bearing system includes a magnetic bearing, a protective bearing, and a rotor; the magnetic bearing has m energized coils, and the rotor is levitated within the magnetic bearing by the action of the m energized coils, where m is a positive integer; The currents flowing through the m energized coils collectively constitute the levitation current of the magnetic levitation bearing system; the device includes: The processing unit is configured to pre-determine the standard levitation current of the magnetic levitation bearing system under normal operating conditions, and to determine n sets of standard deflection currents of the magnetic levitation bearing system, where n is a positive integer; The acquisition unit is configured to acquire the levitation current of the magnetic levitation bearing system during the current operation of the magnetic levitation bearing system, and record it as the first levitation current of the magnetic levitation bearing system. The processing unit is also configured to determine whether the levitation current of the magnetic levitation bearing system is abnormal based on the standard levitation current of the magnetic levitation bearing system and the first levitation current of the magnetic levitation bearing system. The processing unit is further configured to, if it is determined that the levitation current of the magnetic levitation bearing system is abnormal, then, based on the n sets of standard deflection currents of the magnetic levitation bearing system, change the levitation position of the rotor to the preset magnetic bearing center point position, record the levitation current of the magnetic levitation bearing system at this time, and record it as the second levitation current of the magnetic levitation bearing system. The processing unit is also configured to determine the fault point where the suspension current of the magnetic levitation bearing system is abnormal, based on the standard suspension current of the magnetic levitation bearing system and the second suspension current of the magnetic levitation bearing system.

8. The anomaly detection device for a magnetic levitation bearing system according to claim 7, characterized in that, The processing unit, under normal operating conditions of the magnetic levitation bearing system, determines the standard levitation current of the magnetic levitation bearing system and determines n sets of standard deflection currents of the magnetic levitation bearing system, including: When the magnetic levitation bearing system is operating normally, the levitation current of the magnetic levitation bearing system when the rotor is levitated at the center position of the magnetic bearing is taken as the standard levitation current; When the magnetic levitation bearing system is operating normally and the rotor is suspended at the center position of the magnetic bearing, the levitation current of the magnetic levitation bearing system after the rotor is offset along different preset directions and different preset distances is used as the standard deflection current; wherein, the preset distance is the distance of the current position of the rotor relative to the center position of the magnetic bearing.

9. A magnetic levitation bearing system, characterized in that, include: An anomaly detection device for a magnetic levitation bearing system as described in any one of claims 7 to 8.

10. A storage medium, characterized in that, The storage medium includes a stored program, wherein, when the program is executed, it controls the device containing the storage medium to perform the abnormal detection method for the magnetic levitation bearing system as described in any one of claims 1 to 6.

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