Magnetic Levitation Motor Levitation Center Calibration Method, System, Electronic Device and Medium

Abstract

The present invention discloses a method, system, electronic device and medium for calibrating the suspension center of a magnetic levitation motor. When calibrating the rotor, real-time compensation is carried out through a DA converter, which can reduce the number of calibrations, improve efficiency, quickly complete the calibration, and save calibration time; the rotor automatically rotates a corresponding angle during the calibration process. Through the calibration method of the present invention, the calibration can be quickly completed, and the gain and bias can be accurately calculated. Through calibration, problems such as the poor condition of the protection bearing, whether the protection bearing and the magnetic bearing are concentric, and whether the rotor is bent can be found.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic levitation motor rotor control, and particularly relates to a method, a system, an electronic device and a medium for calibrating the suspension center of a magnetic levitation motor. Background Art

[0002] A magnetic levitation motor refers to a motor that suspends the motor rotor using magnetic levitation bearings. After adopting the magnetic levitation bearing support technology, there is no contact between the rotor and the bearing of the motor, and it has the following advantages: (1) no friction and wear, long service life; (2) easy to achieve higher speeds; (3) no need for lubrication and maintenance; (4) small heat generation and low power consumption; (5) oil-free, can be used in the food, pharmaceutical and fermentation industries; (6) strong environmental adaptability, can work in vacuum and corrosive media. In view of the above advantages, magnetic levitation high-speed motors have been more and more widely used in magnetic levitation fluid machinery fields such as blowers, air compressors, vacuum pumps, refrigeration compressors, and ORCs.

[0003] To achieve suspension, a magnetic levitation rotor requires a control system that makes it suspend at the target position (reference position) by collecting the rotor position. The calibration of this target position is the first step of suspension and is very important. Secondly, the movable stroke of the rotor is also very important. If the suspension center and stroke are not calibrated properly, it will affect the suspension quality. Seriously, it will cause extremely unbalanced coil currents in the magnetic bearings, leading to instability, and the rotor will rub against the magnetic bearings.

[0004] In the prior art, to obtain the radial suspension center, the magnetic bearings suck the rotor to 8 points of the protection bearing, then compare the values of these 8 points, find the maximum and minimum values, and then calculate the gain and offset. The gain is defined as the diameter of the protection bearing, and the calculation method is the maximum value of the calibration position - the minimum value of the calibration position; the offset is defined as the center of the protection bearing, and the calculation method is (the maximum value of the calibration position + the minimum value of the calibration position) / 2.

[0005] In the existing calibration method, sucking the rotor to 8 points will cause a certain impact on the protection bearing and affect its life; if the protection bearing is damaged, deformed, or has foreign objects, and the rotor is bent or the material is uneven, the number of collected points at the 8 points is too small to detect problems, which easily leads to collisions between the rotor or motor components, damaging the components and affecting the normal operation of the magnetic levitation motor. Summary of the Invention

[0006] Technical Objective: Aiming at the deficiencies in the existing calibration of the suspension center of a magnetic levitation motor rotor, the present invention discloses a method, a system, an electronic device and a medium for calibrating the suspension center of a magnetic levitation motor that can improve the calibration accuracy and efficiency.

[0007] Technical Solution: To achieve the above technical objective, the present invention adopts the following technical solutions:

[0008] A method for calibrating the suspension center of a magnetic levitation motor, comprising the steps:

[0009] S01. Perform radial calibration of the rotor suspension center. Select the calibration method according to the relative distances of the protective bearing of the rotor, the displacement sensor for detecting the rotor displacement, and the axial center of the rotor. Use conical movement calibration when the protective bearing is far from the axial center of the rotor, and use translational movement calibration when the displacement sensor is far from the axial center of the rotor;

[0010] S02. Use the radial magnetic bearing to drive the rotor to draw a circle within the protective bearing, and control the current and direction of the radial magnetic bearing according to the moving angle of the rotor when drawing the circle;

[0011] S03. During the process of performing radial calibration of the suspension center while the rotor is drawing a circle, use a DA converter to compensate the rotor position voltage output by the displacement sensor according to the theoretical suspension center of the magnetic levitation motor, so that during the circle-drawing process, the rotor position center corresponding to the rotor position voltage output by the displacement sensor approaches the theoretical suspension center until the deviation between the rotor position center corresponding to the rotor position voltage output by the displacement sensor and the theoretical suspension center is within the allowable range or the calibration times reach the upper limit, and end the radial calibration of the rotor suspension center;

[0012] S04. After the radial calibration of the rotor suspension center is completed, perform axial calibration of the suspension center. Use the axial magnetic bearing to control the rotor to move axially, and detect the deviation between the rotor position center corresponding to the rotor position voltage output by the displacement sensor during the movement and the theoretical suspension center. Compensate the rotor position voltage output by the displacement sensor through the DA converter of the controller until the deviation between the rotor position center corresponding to the rotor position voltage output by the displacement sensor and the theoretical suspension center is within the allowable range or the calibration times reach the upper limit; end the axial calibration of the rotor suspension center;

[0013] S05. After the calibration is completed, calculate the offset and gain according to the calibration results, record the corresponding suspension current, and alarm for over-limit situations; after rotating the rotor by an angle according to the current orientation, repeat the calibration process again until the radial and axial calibrations of the suspension center at all positions of the rotor for one week are completed, and end the calibration process.

[0014] Preferably, in step S01 of the present invention, when using the conical movement calibration method to perform radial calibration of the rotor suspension center, the movement directions of the two ends of the rotor when drawing a circle are opposite, and the diameter of the circle detected by the displacement sensor is smaller than the diameter of the circle of the protective bearing; when using the translational movement calibration method to perform radial calibration of the rotor suspension center, the drawing directions of the two ends of the rotor are the same, and the diameter of the circle detected by the displacement sensor is equal to the diameter of the circle of the protective bearing; change the drawing direction of the rotor by controlling the current directions of the radial magnetic bearings at the two ends of the rotor.

[0015] Preferably, in the present invention, in steps S03 and S04, the process of using a DA converter to compensate for the rotor position voltage output by the displacement sensor during the radial and axial calibration of the rotor suspension center includes: selecting a movement range of the rotor during the calibration process, and characterizing it with a pair of rotor position voltages output by corresponding displacement sensors in the corresponding movement direction of the rotor; when performing the first calibration, determining the amplitude of the DA compensation according to the rotor movement range, and performing real-time compensation correction on the rotor position voltage output by the displacement sensor through the DA converter according to the movement angle of the rotor when drawing a circle, so that the rotor position voltage is within a limited characterization voltage range during the calibration process, and completing the first calibration process; after completing the first calibration, the subsequent calibration calculates the center value according to the maximum and minimum values of the rotor position voltage during the previous calibration process, and determines the compensation value of the DA converter during the next calibration according to the deviation between the center value and the theoretical suspension center, until the deviation between the center value of the rotor position voltage and the theoretical suspension center is within an allowable range or the number of calibrations reaches the upper limit of the set number, and the calibration process is terminated.

[0016] Preferably, during the first calibration, the rotor position voltage is compensated and corrected in real time through a DA converter, and the sinusoidal amplitude of the compensation signal DAC of the DA converter is the average of the minimum and maximum values of the moving radius of the rotor within the moving range, and the compensation signal DAC of the DA converter changes synchronously with the current phase of the corresponding magnetic bearing coil.

[0017] Preferably, the degrees of freedom in the X direction and the Y direction perpendicular to each other in the radial direction at both ends of the rotor of the present invention are respectively recorded as X1, X2, Y1 and Y2. When the radial calibration of the rotor suspension center is performed by using the cone motion method, the radial cone motion calibration current corresponding to the four degrees of freedom directions X1, X2, Y1 and Y2 is: , , and , represents the phase angle of the current applied in the direction of the X1 degree of freedom; A represents the amplitude of the calibration current;

[0018] In each degree of freedom direction, the compensation signal DAC output by the DA converter is: , , and , where C represents the DA converter output code value corresponding to when the rotor is at the theoretical suspension center, and B represents the output code value corresponding to the sinusoidal amplitude of the compensation signal DAC of the DA converter;

[0019] After compensation by the DA converter, the displacement signal of each degree of freedom of the rotor is obtained. , S represents the differential output signal of the displacement sensor in the direction of the corresponding degree of freedom.

[0020] Preferably, when the translational method is used for radial calibration of the rotor suspension center in the present invention, the radial translational calibration currents corresponding to the four degrees of freedom directions X1, X2, Y1, and Y2 are as follows: , , and .

[0021] On each degree of freedom direction, the compensation signal code values output by the DA converter are successively: , , and .

[0022] Preferably, when the axial calibration of the rotor suspension center is carried out in the present invention, taking one end of the rotor axis as the positive direction and the other end as the negative direction, on the positive direction, the compensation signal code value output by the DA converter is C + B; on the negative direction, the compensation signal code value output by the DA converter is C - B.

[0023] The present invention discloses a suspension center calibration system for a magnetic levitation motor, using the above calibration method. The calibration system includes radial magnetic bearings, radial protection bearings, radial displacement sensors, axial magnetic bearings, axial protection bearings, axial displacement sensors, as well as a controller and a DA converter located at both ends of the rotor. Each radial magnetic bearing is used to control the degrees of freedom of two mutually perpendicular directions at the corresponding end of the rotor, and the axial magnetic bearing controls the degree of freedom of movement in the rotor axis direction. The movement of the rotor in the corresponding degree of freedom direction is detected by the provided radial displacement sensors and axial displacement sensors. The controller is electrically connected to the radial magnetic bearings, radial displacement sensors, axial magnetic bearings, and axial displacement sensors. The coil currents of each magnetic bearing are controlled by the controller, and the rotor position voltages output by the radial displacement sensors and axial displacement sensors are respectively compensated by the DA converter during the calibration process.

[0024] The present invention discloses an electronic device, including: a memory for storing a computer program; a processor for executing the computer program so that the device executes the above magnetic levitation motor suspension center calibration method.

[0025] The present invention discloses a computer-readable storage medium, on which a computer program is stored. When the computer program is run, the device running the computer program implements the above magnetic levitation motor suspension center calibration method.

[0026] Beneficial effects: The magnetic levitation motor suspension center calibration method, system, electronic device, and medium disclosed by the present invention have the following beneficial effects:

[0027] 1. When calibrating the rotor of the present invention, real-time compensation is carried out through a DA converter, which can reduce the number of calibrations, improve efficiency, quickly complete the calibration, and save calibration time.

[0028] 2. When calibrating the radial center of the rotor suspension of the present invention, according to the relative positions of the displacement sensor and the rotor protection bearing, the conical calibration or translational calibration method is selected correspondingly, which can obtain more accurate gain and offset, effectively avoid the rotor rubbing against the magnetic bearing, and reduce collisions.

[0029] 3. During the calibration process of the rotor of the present invention, it automatically rotates by a corresponding angle, which can detect whether the rotor is bent, whether the material is uniform, whether the protection bearing and the magnetic bearing are concentric, etc. during the calibration process, ensuring the smooth and normal operation of the magnetic levitation motor after calibration. Brief Description of the Drawings

[0030] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art.

[0031] Figure 1 It is a schematic diagram of the 5 degrees of freedom of the rotor of the present invention;

[0032] Figure 2 It is a schematic diagram of the rotor drawing a circle when performing conical movement calibration on the rotor radial direction of the present invention. Detailed Embodiments

[0033] Now, reference will be made in detail to the embodiments of the present disclosure, one or more examples of which are set forth below. Each embodiment and example is provided by way of explanation of the apparatus, composition, and materials of the present disclosure, and not by way of limitation. On the contrary, the following description provides a convenient illustration for implementing the exemplary embodiments of the present disclosure. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made within the teachings of the present disclosure without departing from the scope or spirit of the present disclosure.

[0034] The present invention discloses a method for calibrating the suspension center of a magnetic levitation motor, including the steps:

[0035] S01. Perform radial calibration of the rotor suspension center, select the calibration method according to the relative distances of the protection bearing of the rotor, the displacement sensor for detecting the rotor displacement, and the axial center of the rotor. Use conical calibration when the protection bearing is far from the axial center of the rotor, and use translational calibration when the displacement sensor is far from the axial center of the rotor;

[0036] When performing radial calibration of the rotor suspension center using the conical movement calibration method, the movement directions of the circles drawn at both ends of the rotor are opposite, the center position of the rotor remains stationary, and circular motions are performed at both ends to draw circles. The diameter of the circle detected by the displacement sensor is smaller than the diameter of the protection bearing circle; when performing radial calibration of the rotor suspension center using the translational movement calibration method, the directions of the circles drawn at both ends of the rotor are the same, and they move synchronously in the same direction. The diameter of the circle detected by the displacement sensor is equal to the diameter of the protection bearing circle; the direction of the circle drawn by the rotor is changed by controlling the current directions of the radial magnetic bearings at both ends of the rotor.

[0037] As Figure 2 shown, during conical movement calibration, the rotation radius of the rotor at the position corresponding to the sensor is smaller than the rotation radius at the protection bearing position, which is convenient for using the gain and offset detected by the displacement sensor for protection warning, thereby avoiding the rotor rubbing against the protection bearing during the operation of the motor.

[0038] S02. Use the radial magnetic bearings to drive the rotor to draw circles within the protection bearing, and control the current and direction of the radial magnetic bearings according to the moving angle of the rotor when drawing circles.

[0039] S03. During the process of performing radial calibration of the suspension center by the rotor drawing circles, use a DA converter to compensate the rotor position voltage output by the displacement sensor according to the theoretical suspension center of the magnetic levitation motor, so that during the circle-drawing process, the rotor position center corresponding to the rotor position voltage output by the displacement sensor approaches the theoretical suspension center until the deviation between the rotor position center corresponding to the rotor position voltage output by the displacement sensor and the theoretical suspension center is within the allowable range or the calibration times reach the upper limit, and end the radial calibration of the rotor suspension center.

[0040] S04. After the radial calibration of the rotor suspension center is completed, perform axial calibration of the rotor suspension center. Use the axial magnetic bearings to control the rotor to move axially, and detect the deviation between the rotor position center corresponding to the rotor position voltage output by the displacement sensor during the movement process and the theoretical suspension center. Compensate the rotor position voltage output by the displacement sensor through the DA converter until the deviation between the rotor position center corresponding to the rotor position voltage output by the displacement sensor and the theoretical suspension center is within the allowable range or the calibration times reach the upper limit; end the axial calibration of the rotor suspension center.

[0041] In steps S03 and S04 of the present invention, the process of using a DA converter to compensate the rotor position voltage output by the displacement sensor during the radial and axial calibration of the rotor suspension center includes: selecting the moving range of the rotor during the calibration process, which is characterized by the rotor position voltages output by a pair of displacement sensors corresponding to the respective moving directions of the rotor. During the first calibration, the amplitude of the DA compensation is determined according to the moving range of the rotor, and according to the moving angle of the rotor when drawing a circle, the rotor position voltage output by the displacement sensor is corrected in real time through the DA converter, so that the rotor position voltage during the calibration process is within the limited characterization voltage range, and the first calibration process is completed; after the first calibration is completed, for subsequent calibrations, the central value is calculated based on the maximum and minimum values of the rotor position voltage during the previous calibration process, and according to the deviation between the central value and the theoretical suspension center, the compensation value of the DA converter for the next calibration is determined until the deviation between the central value of the rotor position voltage and the theoretical suspension center is within the allowable range or the number of calibration times reaches the upper limit of the set number of times, and the calibration process ends.

[0042] When the present invention corrects the rotor position voltage in real time through the DA converter, the sine amplitude of the compensation signal DAC of the DA converter takes the average value of the minimum and maximum values of the moving radius within the moving range of the rotor, and the compensation signal DAC of the DA converter changes synchronously with the current phase of the corresponding magnetic bearing coil.

[0043] Specifically, as Figure 1 shown, the five degrees of freedom of movement of the rotor are sequentially divided into the X direction, the Y direction, and the Z direction according to the coordinate system directions. At the same time, the rotor also has a rotational degree of freedom in the direction; at both ends of the rotor in the X direction and the Y direction, there are two degrees of freedom each, which are respectively denoted as X1, X2, Y1, and Y2; when the present invention uses the conical movement method for radial calibration of the rotor suspension center, the radial conical calibration currents corresponding to the four degrees of freedom directions X1, X2, Y1, and Y2 are: 、 and , where

[0044] represents the phase angle of the current applied in the X1 degree of freedom direction; A represents the amplitude of the calibration current; 、 、 and respectively represent the compensation signals DAC output by the DA converter in each degree of freedom direction, where C represents the output code value of the DA converter when the rotor is at the theoretical suspension center, and B represents the output code value corresponding to the sine amplitude of the compensation signal DAC of the DA converter;

[0045] When calibrating the radial center of the rotor suspension in a translational manner, the radial translational calibration currents corresponding to the four degrees of freedom directions X1, X2, Y1, and Y2 are as follows: , , and ;

[0046] In each degree of freedom direction, the compensation signal code values output by the DA converter are in sequence: , , and ;

[0047] When calibrating the axial center of the rotor suspension, taking one end of the rotor axis as the positive direction (0V direction) and the other end as the negative direction (5V direction), in the positive direction, the compensation signal code value output by the DA converter is C + B; in the negative direction, the compensation signal code value output by the DA converter is C - B.

[0048] After the DA converter performs compensation, the displacement signal of each degree of freedom of the rotor is obtained , where S represents the differential output signal of the displacement sensor in the corresponding degree of freedom direction.

[0049] When calibrating the radial center of the rotor suspension, the angle for the rotor to move one circle is 360°. During calibration, the circumference is divided into 10,000 points, and each point stays for 20 control cycles for data acquisition, with θ moving 0.036° each time.

[0050] Assume that the representative voltage corresponding to the theoretical suspension center is 2.5V, and the full scale is 0 - 5V. During calibration, control the moving stroke range of the rotor within 2.8V to 4.8V to avoid exceeding the range.

[0051] When the stroke is 2.8V, the radius is 1.4V; when the stroke is 4.8V, the radius is 2.4V. Then the sine amplitude range of the DA converter compensation signal should be greater than 1.4V and less than 2.4V, generally taking an average value of about 1.9V to ensure that during the rotor calibration process, the rotor position voltage can be within the set range, and the center value of the corresponding rotor position voltage is close to the representative voltage 2.5V corresponding to the theoretical suspension center.

[0052] During the DA conversion process, the output code value represents the magnitude of the input digital quantity and is presented in the form of an analog quantity. This analog quantity is usually voltage or current. Therefore, it is necessary to convert the compensated sine amplitude into the output code value of the DA converter. The floating center of 2.5V corresponds to the output code value C of the DA converter being 2048. Let the code value corresponding to the sine amplitude compensated by DA be B, and B is determined according to the selected sine amplitude range. The DACs for the four degrees of freedom directions X1, X2, Y1, and Y2 during conical motion calibration are as follows: , , and ;

[0053] Similarly, during translational motion calibration, the output code values of the DA converter are: , , and ..

[0054] During the axial calibration of the rotor floating center, in the positive direction (0V direction), the compensated signal code value output by the DA converter is 2048 + B; in the negative direction (5V direction), the compensated signal code value output by the DA converter is 2048 - B.

[0055] Taking the X1 degree of freedom direction as an example, the differential output of a pair of displacement sensors in the X1 degree of freedom direction is S1, DAC1 is the output of the DA converter for the X1 degree of freedom, and SIN1 is the final displacement signal in the X1 degree of freedom, , during conical motion calibration: ; Similarly, the displacement signals after compensation by the DA converter in other degrees of freedom directions can be obtained.

[0056] After the first circle of radial calibration is completed, starting from the second circle, after each circle is drawn, take the maximum and minimum values of the rotor position voltages corresponding to each degree of freedom direction of the rotor X1, X2, Y1, and Y2 in the previous circle-drawing process, calculate the center value corresponding to each degree of freedom direction. If the center value is not within the specified range, use the DA converter to supplement the difference between 2.5V and the center value on the basis of the previous output to adjust the compensation value of the DA converter; otherwise, the output of the DA converter remains unchanged.

[0057] For the axial calibration of the rotor suspension center, the rotor is sucked by the axial magnetic bearing and moved along the axis. During the first adsorption movement, the position voltage output by the axial displacement sensor is compensated in real time through a DA converter. Starting from the second adsorption movement, find the maximum and minimum values of the rotor position change during the movement in the axial degree of freedom direction in the previous calibration process. Similarly, calculate the center value of the rotor position. If the center value is not within the specified range, use the DA converter to supplement the difference between the theoretical suspension center of 2.5V and the center value on the basis of the compensation output in the previous calibration process. Otherwise, the output of the DA converter remains unchanged.

[0058] Through the calibration compensation adjustment method of the present invention, complete rotor data can be collected during the first calibration, avoiding the rotor moving beyond the limit, resulting in missing output data of the displacement sensor and affecting the accuracy of the collected data. Thus, the overall calibration times can be reduced, making the deviation between the rotor radial and axial position voltages output by the displacement sensor after compensation and the corresponding center positions within the allowable range and improving the calibration efficiency.

[0059] S05: After the calibration is completed, calculate the offset and gain according to the calibration results, record the corresponding suspension current, and alarm for overlimit situations; after rotating the rotor by a certain angle in the current orientation, repeat the calibration process again to perform a new round of radial and axial calibration of the rotor suspension center until the radial and axial calibration of the rotor suspension center at all positions of one week is completed, and the calibration process ends; in the embodiment of the present invention, the rotor rotates by 45° each time to balance the calibration accuracy and calibration time. The rotation angle of the rotor each time can also be changed according to the calibration requirements until 360° is rotated and the calibration process ends.

[0060] Let the offset stored in the controller EEPROM be offset Ref, and the gain stored be gain Ref. If abs( is overlimit, an offset reference alarm is reported; if abs( is overlimit, a gain reference alarm is reported, where both "offset" and "gain" are data obtained based on the calibration process.

[0061] The present invention discloses a suspension center calibration system for a magnetic levitation motor. Using the above calibration method, the calibration system includes radial magnetic bearings, radial protective bearings, radial displacement sensors, axial magnetic bearings, axial protective bearings, axial displacement sensors, as well as a controller and a DA converter located at both ends of the rotor. Each radial magnetic bearing is used to control the degrees of freedom of the corresponding end of the rotor in two mutually perpendicular directions, and the axial magnetic bearing controls the degree of freedom of the rotor's movement in the axial direction. The radial displacement sensors and axial displacement sensors are provided to detect the movement of the rotor in the corresponding degrees of freedom directions. There are 4 degrees of freedom for the radial movement of the rotor, and the number of corresponding radial displacement sensors is 4 pairs. The controller is electrically connected to the radial magnetic bearings, radial displacement sensors, axial magnetic bearings, and axial displacement sensors. The coil currents of each magnetic bearing are controlled by the controller, and the rotor position voltage output by the corresponding displacement sensors is compensated by the DA converter.

[0062] The present invention discloses an electronic device, including: a memory for storing a computer program; a processor for executing the computer program to enable the device to execute the above magnetic levitation motor suspension center calibration method.

[0063] The present invention discloses a computer-readable storage medium, on which a computer program is stored. When the computer program is run, the device running the computer program implements the above magnetic levitation motor suspension center calibration method.

[0064] The above is only the preferred embodiment of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for calibrating the suspension center of a magnetic levitation motor, characterized in that, Including the steps: S01. Perform radial calibration of the rotor suspension center. Select the calibration method according to the relative distances of the protective bearing of the rotor, the displacement sensor for detecting the rotor displacement, and the axial center of the rotor. Use conical movement calibration when the protective bearing is far from the axial center of the rotor, and use translational calibration when the displacement sensor is far from the axial center of the rotor; S02. Use the radial magnetic bearing to drive the rotor to draw a circle within the protective bearing, and control the current and direction of the radial magnetic bearing according to the moving angle of the rotor when drawing the circle; S03. During the process of performing radial calibration of the rotor suspension center while the rotor is drawing a circle, use a DA converter to compensate the rotor position voltage output by the displacement sensor according to the theoretical suspension center of the magnetic levitation motor, so that during the circle-drawing process, the rotor position center corresponding to the rotor position voltage output by the displacement sensor approaches the theoretical suspension center until the deviation between the rotor position center corresponding to the rotor position voltage output by the displacement sensor and the theoretical suspension center is within the allowable range or the calibration times reach the upper limit, and end the radial calibration of the rotor suspension center; S04. After the radial calibration of the rotor suspension center is completed, perform axial calibration of the rotor suspension center. Use the axial magnetic bearing to control the rotor to move axially, and detect the deviation between the rotor position center corresponding to the rotor position voltage output by the displacement sensor during the movement and the theoretical suspension center, and perform compensation on the rotor position voltage output by the displacement sensor through the DA converter until the deviation between the rotor position center corresponding to the rotor position voltage output by the displacement sensor and the theoretical suspension center is within the allowable range or the calibration times reach the upper limit; End the axial calibration of the rotor suspension center; S05. After the calibration is completed, calculate the offset and gain according to the calibration results, record the corresponding suspension current, and alarm for over-limit situations; after rotating the rotor by an angle according to the current orientation, repeat the calibration process again until the radial and axial calibrations of the rotor suspension center for one full rotation position are completed, and end the calibration process; In steps S03 and S04, the process of using a DA converter to compensate the rotor position voltage output by the displacement sensor during the radial and axial calibrations of the rotor suspension center includes: selecting the moving range of the rotor during the calibration process, which is characterized by the rotor position voltages output by a pair of displacement sensors corresponding to the rotor's respective moving directions. When performing the first calibration, determine the amplitude of the DA compensation according to the moving range of the rotor, and according to the moving angle of the rotor when drawing the circle, perform real-time compensation and correction on the rotor position voltage output by the DA converter through the DA converter, so that the rotor position voltage is within the limited characterization voltage range during the calibration process, and complete the first calibration process; after the first calibration is completed, for subsequent calibrations, calculate the center value according to the maximum and minimum values of the rotor position voltage during the previous calibration process, and determine the compensation value of the DA converter for the next calibration according to the deviation between the center value and the theoretical suspension center until the deviation between the center value of the rotor position voltage and the theoretical suspension center is within the allowable range or the calibration times reach the upper limit of the set number of times, and end the calibration process.

2. A method for calibrating the suspension center of a magnetic levitation motor according to claim 1, characterized in that, In step S01, when performing radial calibration of the rotor suspension center using the conical movement calibration method, the movement directions of the circles drawn at both ends of the rotor are opposite, and the diameter of the circle detected by the displacement sensor is smaller than the diameter of the protective bearing circle; when performing radial calibration of the rotor suspension center using the translational movement calibration method, the directions of the circles drawn at both ends of the rotor are the same, and the diameter of the circle detected by the displacement sensor is equal to the diameter of the protective bearing circle; the direction of the circle drawn by the rotor is changed by controlling the current directions of the radial magnetic bearings at both ends of the rotor.

3. A method for calibrating the suspension center of a maglev motor according to claim 1, characterized in that, During the first calibration, the rotor position voltage is compensated and corrected in real time through a DA converter. The sine amplitude of the compensation signal DAC of the DA converter takes the average value of the minimum and maximum values of the moving radius within the moving range of the rotor. The compensation signal DAC of the DA converter changes synchronously with the current phase of the corresponding magnetic bearing coil.

4. A method for calibrating the suspension center of a maglev motor according to claim 3, characterized in that, The degrees of freedom in the X and Y directions, which are perpendicular to each other in the radial direction at both ends of the rotor, are denoted as X1, X2, Y1, and Y2 respectively. When calibrating the radial center of the rotor suspension using the conical movement method, the radial conical movement calibration currents corresponding to the four degrees of freedom directions X1, X2, Y1, and Y2 are as follows: , , and , represents the phase angle of the current applied in the X1 degree of freedom direction; A represents the amplitude of the calibration current; In each degree of freedom direction, the compensation signals DAC output by the DA converter are successively as follows: , , and , where C represents the output code value of the DA converter corresponding to the rotor at the theoretical suspension center, and B represents the output code value corresponding to the sine amplitude of the compensation signal DAC of the DA converter; After compensation by the DA converter, the displacement signals in the directions of each degree of freedom of the rotor are obtained , where S represents the differential output signal of the displacement sensor in the corresponding degree-of-freedom direction.

5. A method for calibrating the suspension center of a maglev motor according to claim 4, characterized in that When calibrating the radial center of the rotor suspension in a translational mode, the radial translational calibration currents corresponding to the four degrees of freedom directions X1, X2, Y1, and Y2 are as follows: , , and ; In each degree of freedom direction, the compensation signal code values output by the DA converter are successively as follows: , , and .

6. A method for calibrating the suspension center of a maglev motor according to claim 4, characterized in that When performing axial calibration of the rotor suspension center, one end of the rotor axis is taken as the positive direction and the other end as the negative direction. In the positive direction, the code value of the compensation signal output by the DA converter is C + B; in the negative direction, the code value of the compensation signal output by the DA converter is C - B.

7. A suspension center calibration system for a magnetic levitation motor, using the calibration method according to any one of claims 1-6, characterized in that, The calibration system includes radial magnetic bearings, radial protective bearings, radial displacement sensors, axial magnetic bearings, axial protective bearings, axial displacement sensors, as well as a controller and a DA converter located at both ends of the rotor. Each radial magnetic bearing is used to control the degrees of freedom of the two mutually perpendicular directions of the corresponding end of the rotor. The axial magnetic bearing controls the moving degree of freedom in the direction of the rotor axis. The movement of the rotor in the direction of the corresponding degree of freedom is detected by the provided radial displacement sensor and axial displacement sensor. The controller is electrically connected to the radial magnetic bearings, radial displacement sensors, axial magnetic bearings, and axial displacement sensors. The coil currents of each magnetic bearing are controlled through the controller, and the rotor position voltages output by the radial displacement sensor and axial displacement sensor are compensated respectively by the DA converter during the calibration process.

8. An electronic device, characterized in that, Comprising: A memory for storing computer programs; A processor for executing the computer program to enable the device to execute the method for calibrating the suspension center of the magnetic levitation motor according to any one of claims 1 - 6.

9. A computer-readable storage medium, characterized in that, A computer program is stored on the computer-readable storage medium. When the computer program is run, the device running the computer program implements the method for calibrating the suspension center of the magnetic levitation motor according to any one of claims 1 - 6.

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