Magnetic suspension bearing performance evaluation method, enhancement method, electronic equipment and medium

Abstract

The invention discloses a magnetic suspension bearing performance evaluation method, a magnetic suspension bearing performance enhancement method, electronic equipment and a medium, and belongs to the field of magnetic suspension bearing control, the input end of a current controller is additionally injected with sinusoidal current with continuous frequency change, and the evaluation method comprises the following steps: extracting a maximum value point Pmax and a minimum value point Pmin of a signal representing to-be-evaluated performance; extracting an extreme point P1 in an interval with the frequency smaller than f1 and an extreme point P2 in an interval with the frequency larger than f2 in the signal; the Pmax and the Pmin are used as fixed points, the performance value of the intersection point of the straight line l1 and the straight line l2 is used as a control point for secondary Bessel interpolation, l1 passes through the points corresponding to the P1 and the f1, l2 passes through the points corresponding to the P2 and the f2, and the performance to be evaluated is equal to the maximum value obtained through interpolation. According to the method, measurement of a plurality of performance evaluation indexes during operation of the magnetic suspension bearing can be completed within single measurement within fixed time, the data size is small, and the method is easy to implement.

Description

Technical Field

[0001] The present invention belongs to the field of magnetic bearing control, and more specifically, relates to a magnetic bearing performance evaluation method, enhancement method, electronic equipment and medium. Background Art

[0002] Magnetic bearings are contactless support devices that utilize electromagnetic force to levitate rotors. They are frictionless, lubrication-free, have a long lifespan, and offer adjustable performance, making them suitable for high- and ultra-high-speed rotating equipment. However, magnetic bearings require active control from an external controller, and their actual performance is closely related to the design of the control system.

[0003] Typically, before magnetic bearings are deployed, they require multiple sensitivity tests, actual rotation tests, and repeated adjustments to control parameters to meet the performance requirements of different application scenarios. This incurs significant time and labor costs, raising the barrier to adoption. Therefore, reducing the time and labor costs associated with performance testing during magnetic bearing deployment is crucial for achieving automated deployment and widespread adoption. Summary of the Invention

[0004] In response to the defects of the existing technology and the need for improvement, the present invention provides a magnetic bearing performance evaluation method, an enhancement method, an electronic device and a medium, the purpose of which is to reduce the amount of data required for the performance test and evaluation of magnetic bearings, thereby increasing the evaluation speed and reducing the time and manpower expenditure caused by performance evaluation during the deployment of magnetic bearings.

[0005] To achieve the above object, according to one aspect of the present invention, a method for evaluating the performance of a magnetic bearing is provided. When the magnetic bearing is in operation, a sinusoidal current with a continuously varying frequency is additionally injected into the input terminal of the current controller of its control system. The method comprises: sampling and acquiring a signal representing the performance to be evaluated of the magnetic bearing, extracting a maximum point P of the signal, and max and the minimum point P min ; Extract the extreme point P1 in the interval where the frequency is less than f1, and the extreme point P2 in the interval where the frequency is greater than f2, where f1 and f2 are P max and P min The frequency of the smaller frequency point and the frequency of the larger frequency point; if P1 or P2 is not extracted, the performance to be evaluated is equal to |P max | and |P min The larger of |P max | for P max Absolute value of performance, |P min | for P min The absolute value of the performance value; if P1 and P2 are extracted, |P max | and |Pmin Let \(P\) be a fixed point. Perform quadratic Bezier interpolation with the performance value at the intersection of line \(l_1\) and line \(l_2\) as the control point. Line \(l_1\) passes through the point corresponding to \(P_1\) and \(f_1\), and line \(l_2\) passes through the point corresponding to \(P_2\) and \(f_2\). The performance to be evaluated is equal to the maximum value obtained by interpolation.

[0006] Furthermore, the performance to be evaluated includes: linearity and / or tracking performance and / or anti-interference performance; the linearity is the ratio of the amplitude of the command differential current injected into the current controller to the amplitude of the corresponding frequency component of the sinusoidal current; the tracking performance is the ratio of the amplitude of the winding differential current to the amplitude of the corresponding frequency component of the sinusoidal current, and the winding differential current includes the command differential current and the sinusoidal current; the anti-interference performance is the ratio of the amplitude of the displacement of the magnetic levitation bearing rotor to the amplitude of the corresponding frequency component of the sinusoidal current.

[0007] Furthermore, if \(P_1\) and \(P_2\) are extracted, the performance to be evaluated is:

[0008] \(N=\max[(1 - t) 2 |P max |+(1 - t)ty c +t 2 |P min |], 0\leq t\leq1

[0009] where \(N\) is the performance to be evaluated, \(t\) is a variable parameter, and \(y\) c is the performance value at the intersection of line \(l_1\) and line \(l_2\).

[0010] According to another aspect of the present invention, a method for enhancing the performance of a magnetic levitation bearing is provided, including: S1, initializing the parameter update speed and the PID control parameters of the magnetic levitation bearing control system; S2, evaluating the linearity, tracking performance, and anti-interference performance of the magnetic levitation bearing under the current PID control parameters by using the magnetic levitation bearing performance evaluation method as described above; S3, selecting the historical best parameter \(p\) b and the historical worst parameter \(p\) w from all the PID control parameters according to the weighted sum of the linearity, tracking performance, and anti-interference performance; S4, correcting the current parameter update speed by using the difference between \(p\) b and \(p\) w , and correcting the current PID control parameters by using the corrected parameter update speed; S5, repeating the execution of S2 - S4 until the obtained linearity, tracking performance, and anti-interference performance are within the corresponding preset ranges.

[0011] Further, both the initial historical best parameter and the historical worst parameter are the PID control parameters after initialization in S1. S3 specifically includes: taking the weighted sum of linearity, tracking performance, and anti-interference performance as the objective function of the current PID control parameter; if this objective function is less than the objective function of the current historical best parameter, updating the historical best parameter p b to the current PID control parameter; if this objective function is greater than the objective function of the current historical worst parameter, updating the historical worst parameter p w to the current PID control parameter; otherwise, the historical best parameter p b and the historical worst parameter p w remain unchanged.

[0012] Further, S3 also includes: reducing the objective function of the historical worst parameter p w by a preset ratio.

[0013] Further, the updated speed of the corrected parameter in S4 is a1v + a2(p b - p w ), where v is the current parameter update speed, and a1 and a2 are the first preset parameter and the second preset parameter respectively.

[0014] Further, the corrected PID control parameter in S4 is the sum of the current PID control parameter and the updated speed of the corrected parameter.

[0015] According to another aspect of the present invention, there is provided an electronic device, including: a processor; a memory storing a computer-executable program, which when executed by the processor, causes the processor to execute the magnetic levitation bearing performance evaluation method as described above, or execute the magnetic levitation bearing performance enhancement method as described above.

[0016] According to another aspect of the present invention, there is provided a computer-readable storage medium, on which a computer program is stored, and when the program is executed by a processor, it implements the magnetic levitation bearing performance evaluation method as described above, or implements the magnetic levitation bearing performance enhancement method as described above.

[0017] Generally speaking, through the above technical solutions conceived by the present invention, the following beneficial effects can be achieved:

[0018] (1) A method for evaluating the performance of a magnetic levitation bearing is provided. Compared with the performance evaluation method of a traditional magnetic levitation bearing control system, it only needs to inject a sinusoidal current with continuously changing frequency at the input end of the current controller to complete the measurement of multiple indicators, without the need to inject a sinusoidal signal at the reference input end of the displacement controller or inject sinusoidal signals with discrete frequencies sequentially, greatly reducing the number of signals to be injected. Further, a performance evaluation method is designed to extract the maximum points, minimum points, and extreme points on both sides of the performance signal, determine the control points based on these extreme points, and perform quadratic Bezier interpolation in combination with the maximum points and minimum points to determine the final performance. This method can complete the measurement of multiple performance indicators of the magnetic levitation bearing in a single measurement within a fixed time, with a small amount of data and easy to implement, without the need to rely on external measurement equipment, saving time costs;

[0019] (2) A method for enhancing the performance of a magnetic levitation bearing is provided. The weighted sum of the linearity, tracking performance, and anti-interference performance measured by the above performance method is calculated, and the historical best parameters and historical worst parameters are determined according to the weighted value to automatically adjust the PID control parameters until the obtained performance meets the requirements, improving the performance of the magnetic levitation bearing. This method can automatically adjust the control parameters to make the performance of the magnetic levitation bearing system meet the target performance requirements, saving labor costs and greatly reducing the deployment threshold of the magnetic levitation bearing;

[0020] (3) During the process of automatically adjusting the PID control parameters, in each update iteration, the objective function of the historical worst parameters is reduced at a preset ratio, avoiding the parameter automatic adjustment direction being always restricted by the worst parameters in the early stage of the automatic adjustment process, making the parameter automatic adjustment process more sensitive to recent performance changes and expanding the parameter search range. Description of the Drawings

[0021] Figure 1 It is a block diagram of the control system of the magnetic levitation bearing provided by the embodiment of the present invention;

[0022] Figure 2 It is a flowchart of the magnetic levitation bearing performance evaluation method provided by the embodiment of the present invention;

[0023] Figure 3 It is a flowchart of the magnetic levitation bearing performance enhancement method provided by the embodiment of the present invention;

[0024] Figure 4 It is a process diagram of the implementation of the magnetic levitation bearing performance evaluation and enhancement provided by the embodiment of the present invention. Detailed Embodiments

[0025] In order to make the objectives, technical solutions and advantages of the present invention more clear and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention. In addition, the technical features involved in the various embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0026] In the present invention, terms such as "first" and "second" in the present invention and the accompanying drawings (if any) are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence.

[0027] Embodiment 1

[0028] A method for evaluating the performance of a magnetic levitation bearing. Referring to Figure 1 and Figure 2 , the method for evaluating the performance of the magnetic levitation bearing in this embodiment will be described in detail. The method includes operations S1'-S3".

[0029] When the magnetic levitation bearing is working, a sinusoidal current with continuously changing frequency is additionally injected into the input end of the current controller of its control system. The continuously changing range of the frequency of this sinusoidal current signal covers all the concerned frequency intervals and at least reaches the extreme points twice.

[0030] Referring to Figure 1 , a control block diagram of the magnetic levitation bearing control system is shown. In the block diagram, the displacement control part of the magnetic levitation bearing control system uses a proportional-integral-differential (PID) displacement controller. The input of the PID displacement controller is the reference displacement minus the feedback displacement signal provided by the displacement sensor, and the output is the command current signal. The command current signal enters the current controller, and the current controller drives the power device to convert the command current signal into the actual winding current to achieve control. This is the basic control system of the magnetic levitation bearing. This method additionally injects a sinusoidal current signal with continuously changing frequency on the basis of the basic control system, samples the control current (i.e., the command differential current), the winding differential current and the rotor displacement output by the PID displacement controller to achieve rapid performance evaluation, and further provides performance indicators to the performance enhancement parameter adjuster for enhancing performance to adjust the control parameters of the PID displacement controller until the performance requirements are met.

[0031] Operation S1', sample and obtain the signal characterizing the performance of the magnetic levitation bearing to be evaluated, and extract the maximum point P max and the minimum point P min .

[0032] According to the embodiment of the present invention, the performance to be evaluated includes: linearity L and / or tracking performance S and / or anti-interference performance F. Within the concerned frequency interval, the measured values at the frequency points are not greater than the values of this performance.

[0033] The linearity L is the ratio of the amplitude of the corresponding frequency component of the commanded differential current of the injection current controller to that of the sinusoidal current, that is Figure 1 the ratio of the amplitude of the corresponding frequency component of signal ① to that of the sinusoidal current.

[0034] The tracking performance S is the ratio of the amplitude of the corresponding frequency component of the winding differential current to that of the sinusoidal current. The winding differential current includes the commanded differential current and the sinusoidal current, that is Figure 1 the ratio of the amplitude of the corresponding frequency component of signal ② to that of the sinusoidal current.

[0035] The anti-interference performance F is the ratio of the amplitude of the corresponding frequency component of the rotor displacement of the magnetic levitation bearing to that of the sinusoidal current, that is Figure 1 the ratio of the amplitude of the corresponding frequency component of signal ③ to that of the sinusoidal current.

[0036] It should be noted that the extreme points P max , P min , P1 and P2 involved in this embodiment have the frequency as the abscissa; and the actual sampling value of the performance, such as the linearity L, the tracking performance S, and the anti-interference performance F, as the ordinate.

[0037] Operation S2', extract the extreme points P1 in the interval where the frequency in the signal is less than f1, and the extreme point P2 in the interval where the frequency is greater than f2. f1 and f2 are respectively the frequencies of the points with smaller frequency among P max and P min , and the frequencies of the points with larger frequency.

[0038] Operation S3', if P1 or P2 is not extracted, the performance to be evaluated is equal to the larger one of |P max | and |P min |. |P max | is the absolute value of the performance value of P max , and |P min | is the absolute value of the performance value of P min .

[0039] Operation S3”, if P1 and P2 are extracted, take |P max | and |P min | as the fixed points, and perform quadratic Bezier interpolation with the performance value at the intersection of the straight line l1 and the straight line l2 as the control point. The straight line l1 passes through P1 and the point corresponding to f1, and the straight line l2 passes through P2 and the point corresponding to f2. The performance to be evaluated is equal to the maximum value obtained by interpolation.

[0040] Assume that the four points P max , P min , P1 and P2 are sorted in ascending order of frequency as P1, P max , P min , P2. Take P1 and P maxDetermine the straight line l1 with P2 and P min Determine the straight line l2 and find the intersection point P of the straight lines l1 and l2 c , and then with |P max | and |P min | as fixed points, and the intersection point P c as the control point to perform quadratic Bezier interpolation, and obtain the maximum value of its ordinate as the corresponding performance index, which can be expressed as:

[0041] N = max[(1 - t) 2 |P max |+(1 - t)ty c +t 2 |P min |], 0 ≤ t ≤ 1

[0042] where N is the performance to be evaluated, t is a variable parameter, and y c is the performance value of the intersection point of the straight lines l1 and l2

[0043] Example 2

[0044] A method for enhancing the performance of a magnetic levitation bearing. Refer to Figure 3 and Figure 4 , and a detailed description of the method for enhancing the performance of the magnetic levitation bearing in this embodiment will be given. The method includes operations S1 - S5

[0045] Operation S1, initialize the parameter update speed and the PID control parameters of the magnetic levitation bearing control system

[0046] Deploy this method to the magnetic levitation bearing control system, implement the corresponding functions, and complete the static levitation of the magnetic levitation bearing. Take the current PID control parameters of the magnetic levitation bearing as the initial PID control parameter p, and the initial parameter update speed v is randomly generated

[0047] Operation S2, evaluate the linearity, tracking performance, and anti - interference performance of the magnetic levitation bearing under the current PID control parameters by using the magnetic levitation bearing performance evaluation method in Example 1

[0048] Operation S3, select the historical best parameter p b and the historical worst parameter p w from all PID control parameters according to the weighted sum of the linearity, tracking performance, and anti - interference performance

[0049] According to the embodiment of the present invention, the initial historical best parameter and historical worst parameter are both the PID control parameters initialized in Operation S1. Operation S3 specifically includes the following sub - operations S31 - S32

[0050] In sub-operation S31, the weighted sum of linearity, tracking performance, and anti-interference performance is used as the objective function loss of the current PID control parameter, which can be expressed as:

[0051] loss = k1L + k2S + k3F

[0052] Where k1, k2, and k3 are weighting factors, which should be set according to the actual application scenario. For example, when more attention is paid to anti-interference performance, the value of k3 should be larger; when more attention is paid to tracking performance, the value of k2 should be larger.

[0053] In sub-operation S32, if the objective function is less than the objective function of the current historical best parameter, update the historical best parameter p b to the current PID control parameter; if the objective function is greater than the objective function of the current historical worst parameter, update the historical worst parameter p w to the current PID control parameter; otherwise, the historical best parameter p b and the historical worst parameter p w remain unchanged.

[0054] According to an embodiment of the present invention, operation S3 further includes: reducing the objective function loss of the historical worst parameter p w at a preset ratio, and the update method is loss w ← w1loss w . w .

[0055] Operation S4, use the difference between p b and p w to correct the current parameter update speed, and use the corrected parameter update speed to correct the current PID control parameter.

[0056] According to an embodiment of the present invention, the corrected parameter update speed in operation S4 is a1v + a2(p b - p w ), where v is the current parameter update speed, and a1 and a2 are the first preset parameter and the second preset parameter, respectively.

[0057] According to an embodiment of the present invention, the corrected PID control parameter in operation S4 is the sum of the current PID control parameter and the corrected parameter update speed, and the correction method is p ← p + v.

[0058] Operation S5, repeat operations S2 - S4 until the obtained linearity, tracking performance, and anti-interference performance are within the corresponding preset ranges.

[0059] After applying the new PID control parameters to the magnetic levitation bearing control system, operations S2 - S4 are repeated until the obtained linearity, tracking performance, and anti-interference performance meet the set requirements. The specific implementation process of the above operations S1 - S5 is as Figure 4 shown.

[0060] The magnetic levitation bearing performance evaluation method and enhancement method provided by the embodiments of the present invention include three indicators for measuring the performance of the magnetic levitation bearing during operation, namely linearity L, tracking performance S (sensitivity), and anti-interference performance F. All performance indicators can be measured with a single current injection within a fixed time; and these three performance indicators are used as optimization objectives to optimize the control parameters of the magnetic levitation bearing based on the PID displacement controller, thereby completing performance enhancement. This method significantly shortens the measurement time of various performance indicators during the deployment of the magnetic levitation bearing, greatly reduces the time and labor costs during the deployment of the magnetic levitation bearing, and automatically optimizes the parameters of the PID control system of the magnetic levitation bearing, realizing the automatic deployment of the magnetic levitation bearing, reducing the deployment threshold of the magnetic levitation bearing, and is of great significance for the further popularization of the magnetic levitation bearing.

[0061] Embodiment 3

[0062] An electronic device includes: a processor; a memory that stores a computer-executable program, and when the program is executed by the processor, the processor executes the above-mentioned magnetic levitation bearing performance evaluation method, and / or executes the above-mentioned magnetic levitation bearing performance enhancement method. The related technical solutions are the same as those in Embodiment 1 and Embodiment 2, and will not be elaborated here.

[0063] Embodiment 4

[0064] A computer-readable storage medium stores a computer program, and when the program is executed by a processor, it implements the above-mentioned magnetic levitation bearing performance evaluation method, and / or implements the above-mentioned magnetic levitation bearing performance enhancement method. The related technical solutions are the same as those in Embodiment 1 and Embodiment 2, and will not be elaborated here.

[0065] Those skilled in the art can easily understand that the above are only the preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for evaluating the performance of a magnetic levitation bearing, characterized in that, When the magnetic levitation bearing works, a sinusoidal current with continuously changing frequency is additionally injected into the input end of the current controller of its control system. The method includes: Sample to obtain signals representing the performance to be evaluated of the magnetic levitation bearing, and extract the maximum point P of the signals max and the minimum point P min ; Extract the extreme points P1 in the interval where the frequency of the signal is less than f1, and the extreme points P2 in the interval where the frequency is greater than f2. f1 and f2 are the frequencies of the point with the smaller frequency and the point with the larger frequency among P max and P min respectively; If P1 or P2 is not extracted, the performance to be evaluated is equal to the larger of |P max | and |P min |, where |P max | is the absolute value of the P max performance value, and |P min | is the absolute value of the P min performance value; If P1 and P2 are extracted, using |P max | and |P min | as fixed points, and using the performance value at the intersection of line l1 and line l2 as the control point for quadratic Bezier interpolation. Line l1 passes through the point corresponding to P1 and f1, and line l2 passes through the point corresponding to P2 and f2. The performance to be evaluated is equal to the maximum value obtained by interpolation.

2. The method for evaluating the performance of a magnetic levitation bearing according to claim 1, characterized in that The performance to be evaluated includes: linearity and / or tracking performance and / or anti-interference performance; The linearity is the ratio of the amplitude of the corresponding frequency component of the command differential current injected into the current controller to the amplitude of the sinusoidal current; The tracking performance is the ratio of the amplitude of the corresponding frequency component of the winding differential current to the amplitude of the sinusoidal current, and the winding differential current includes the command differential current and the sinusoidal current; The anti-interference performance is the ratio of the amplitude of the corresponding frequency component of the rotor displacement of the magnetic levitation bearing to the amplitude of the sinusoidal current.

3. The method for evaluating the performance of a magnetic levitation bearing according to claim 1 or 2, wherein If P1 and P2 are extracted, the performance to be evaluated is: N=max[(1 - t) 2 |P max |+(1 - t)ty c +t 2 |P min |], 0 ≤ t ≤ 1 Where N is the performance to be evaluated, t is a variable parameter, and y c is the performance value at the intersection of line l1 and line l2.

4. A method for enhancing the performance of a magnetic levitation bearing, characterized in that, Including: S1, initialize the parameter update speed and the PID control parameters of the magnetic levitation bearing control system; S2, evaluate the linearity, tracking performance and anti-interference performance of the magnetic levitation bearing under the current PID control parameters by using the magnetic levitation bearing performance evaluation method according to any one of claims 1-3; S3. Select the historical best parameter p and the historical worst parameter p b from all PID control parameters according to the weighted sum of linearity, tracking performance, and anti-interference performance w ; b and w ; S4, use the difference between p b and p w to correct the current parameter update speed, and use the corrected parameter update speed to correct the current PID control parameters; S5, repeat the execution of S2-S4 until the obtained linearity, tracking performance and anti-interference performance are within the corresponding preset ranges.

5. The method for enhancing the performance of a magnetic levitation bearing according to claim 4, characterized in that, The initial historical best parameters and historical worst parameters are both the PID control parameters initialized in S1. The specific S3 includes: Take the weighted sum of the linearity, tracking performance and anti-interference performance as the objective function of the current PID control parameters; If the objective function is less than the objective function of the current historical best parameter, update the historical best parameter p b to the current PID control parameter; if the objective function is greater than the objective function of the current historical worst parameter, update the historical worst parameter p w to the current PID control parameter; otherwise, the historical best parameter p b and the historical worst parameter p w remain unchanged.

6. The method for enhancing the performance of a magnetic levitation bearing according to claim 5, wherein, The S3 further includes: a target function for reducing the historical worst parameter p by a preset ratio w of the objective function.

7. The method for enhancing the performance of a magnetic levitation bearing according to claim 4, wherein The updated speed of the corrected parameter in S4 is a1v + a2(p b - p w ), where v is the current parameter update speed, and a1 and a2 are the first preset parameter and the second preset parameter respectively.

8. The method for enhancing the performance of a magnetic levitation bearing according to claim 4, characterized in that, The corrected PID control parameters in S4 are the sum of the current PID control parameters and the corrected parameter update speed.

9. An electronic device, characterized in that, Including: A processor; A memory storing computer-executable programs, which when executed by the processor, cause the processor to execute the magnetic levitation bearing performance evaluation method according to any one of claims 1-3, or execute the magnetic levitation bearing performance enhancement method according to any one of claims 4-8.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the program is executed by the processor, it implements the magnetic levitation bearing performance evaluation method according to any one of claims 1-3, or implements the magnetic levitation bearing performance enhancement method according to any one of claims 4-8.

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