Magnetic suspension motor suspension center calibration method and system, electronic equipment and medium

Abstract

The invention discloses a magnetic suspension motor suspension center calibration method and system, an electronic device and a medium, when rotor calibration is carried out, compensation is carried out in real time through a DA converter, the calibration frequency can be reduced, the efficiency can be improved, calibration can be rapidly completed, and the calibration time can be saved; the rotor automatically rotates by a corresponding angle in the calibration process, calibration can be rapidly completed and gain and offset can be accurately calculated through the calibration method, and the problems that the protection bearing is poor, whether the protection bearing and the magnetic bearing are concentric or not and whether the rotor is bent or not can be found through calibration.

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 uses a magnetic levitation bearing to levitate the motor rotor. 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 levitation, a magnetic levitation rotor requires a control system that collects the rotor position to levitate it at the target position (reference position). The calibration of this target position is the first step of levitation 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 current in the magnetic bearing coil, resulting in instability, and the rotor will rub against the magnetic bearing.

[0004] In the prior art, to obtain the radial suspension center, the magnetic bearing sucks the rotor to 8 points of the protection bearing, then compares the values of these 8 points, finds the maximum and minimum values, and then calculates 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 8 points is too small to detect problems, which easily leads to collisions between the rotor and 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, which can improve the calibration accuracy and efficiency.

[0007] Technical Solution: To achieve the above technical objective, the present invention adopts the following technical solutions: A method for calibrating the suspension center of a magnetic levitation motor, comprising the steps: S01. Perform radial calibration of the rotor suspension center. Select a 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; 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 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 process of drawing the circle, 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 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; 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.

[0008] 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; the drawing direction of the rotor is changed by controlling the current directions of the radial magnetic bearings at the two ends of the rotor.

[0009] 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.

[0010] 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.

[0011] 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; 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; 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.

[0012] Preferably, when calibrating the radial center of the rotor suspension in a translational manner 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 ; In each degree of freedom direction, the compensation signal code values output by the DA converter are successively: , , and .

[0013] Preferably, when calibrating the axial center of the rotor suspension in the present invention, taking one end of the rotor axis as the positive direction and the other end as the negative 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.

[0014] The present invention discloses a magnetic levitation motor suspension center calibration system. 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 two mutually perpendicular directions at the corresponding end of the rotor, and the axial magnetic bearing controls the degree of freedom of the rotor's movement in the axial direction of the axis. By setting the radial displacement sensors and axial displacement sensors to detect the movement of the rotor in the corresponding degrees of freedom directions, the controller is electrically connected to the radial magnetic bearings, radial displacement sensors, axial magnetic bearings, and axial displacement sensors. The controller controls the coil currents of each magnetic bearing, and the DA converter compensates the rotor position voltages output by the radial displacement sensors and axial displacement sensors respectively during the calibration process.

[0015] 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.

[0016] The present invention discloses a computer-readable storage medium. 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 above magnetic levitation motor suspension center calibration method.

[0017] 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: 1. When calibrating the rotor in the present invention, real-time compensation is performed through the DA converter, which can reduce the number of calibration times, improve efficiency, quickly complete the calibration, and save calibration time.

[0018] 2. When calibrating the radial center of the rotor suspension of the present invention, the conical calibration or translational calibration method is selected according to the relative positions of the displacement sensor and the rotor protection bearing, which can obtain more accurate gain and offset, effectively avoid the rotor rubbing against the magnetic bearing, and reduce collisions.

[0019] 3. During the calibration process of the rotor of the present invention, it automatically rotates by a corresponding angle, which can detect problems such as whether the rotor is bent, whether the material is uniform, and whether the protection bearing and the magnetic bearing are concentric during the calibration process, ensuring the smooth and normal operation of the magnetic levitation motor after calibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] 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.

[0021] Figure 1 It is a schematic diagram of the 5 degrees of freedom of the rotor of the present invention; Figure 2 It is a schematic diagram of the rotor drawing a circle during the radial conical calibration of the rotor of the present invention. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0022] 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 in the teachings of the present disclosure without departing from the scope or spirit of the present disclosure.

[0023] The present invention discloses a method for calibrating the suspension center of a magnetic levitation motor, including the steps of: 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; When using the conical calibration method for radial calibration of the rotor suspension center, the movement directions of the circles drawn at both ends of the rotor are opposite, the center position of the rotor remains stationary, and the two ends make circular motions to draw circles. The diameter of the circle detected by the displacement sensor is smaller than the diameter of the circle of the protection bearing; when using the translational calibration method for radial calibration of the rotor suspension center, the drawing directions of the circles at both ends of the rotor are the same, moving synchronously in the same direction, and the diameter of the circle detected by the displacement sensor is equal to the diameter of the circle of the protection bearing; the drawing direction of the rotor is changed by controlling the current directions of the radial magnetic bearings at both ends of the rotor.

[0024] AsFigure 2 As shown, during conical calibration, the rotational radius of the rotor at the position corresponding to the sensor is smaller than the rotational radius at the position of the protective bearing, which is convenient for using the gain and bias detected by the displacement sensor for protection warning, thereby avoiding the rotor rubbing against the protective bearing during the operation of the motor.

[0025] S02. Use a 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.

[0026] S03. During the process of radially calibrating the suspension center of the rotor while 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 process of drawing a circle, 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 the radial calibration of the rotor suspension center ends.

[0027] S04. After the radial calibration of the rotor suspension center is completed, perform the axial calibration of the rotor suspension center. Use an 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 a 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.

[0028] 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 rotor in the corresponding moving direction. During 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 a circle, perform real-time compensation and correction on the rotor position voltage output by the displacement sensor through the DA converter, so that the rotor position voltage during the calibration process is within the limited characterization voltage range, 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 times, and end the calibration process.

[0029] When the present invention performs real-time compensation and correction on the rotor position voltage 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, and the compensation signal DAC of the DA converter changes synchronously with the current phase of the corresponding magnetic bearing coil.

[0030] 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 direction. 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 to calibrate the radial center of the rotor suspension, the radial conical movement calibration currents corresponding to the four degrees of freedom directions X1, X2, Y1, and Y2 are: , , and , where \(\varphi\) 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 sequentially: , , and , 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; When using the translational movement method to calibrate the radial center of the rotor suspension, the radial translational movement calibration currents corresponding to the four degrees of freedom directions X1, X2, Y1, and Y2 are: , , and ; In each degree of freedom direction, the compensation signal code values output by the DA converter are sequentially: , , and ; 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.

[0031] 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.

[0032] When calibrating the radial center of the rotor suspension, the angle of the rotor moving 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. θ moves 0.036° each time.

[0033] Assume that the representative voltage corresponding to the theoretical suspension center is 2.5V, and the full scale is 0 - 5V. During calibration, the moving stroke range of the rotor is controlled within 2.8V - 4.8V to avoid exceeding the range.

[0034] 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, the average value is taken around 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.

[0035] 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 output code value C of the DA converter corresponding to the suspension center of 2.5V is 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 of the four degrees of freedom directions X1, X2, Y1, and Y2 during conical movement calibration are as follows: , , and ; Similarly, during translational movement calibration, the output code values of the DA converter are: , , and ..

[0036] During the axial calibration of the rotor suspension 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.

[0037] 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 movement calibration: ; Similarly, the displacement signals after compensation by the DA converter in other degrees of freedom directions can be obtained.

[0038] After the radial calibration of the first circle 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 of the rotor X1, X2, Y1, and Y2 during 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, and adjust the compensation value of the DA converter; otherwise, the output of the DA converter remains unchanged.

[0039] For the axial calibration of the rotor suspension center, the rotor is adsorbed by the axial magnetic bearing and moved along the axial direction. During the first adsorption movement, the DA converter compensates the position voltage output by the axial displacement sensor in real time. 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 during the previous calibration process, and also calculate the center value of the rotor position. If the center value is not within the specified range, also use the DA converter to supplement the difference between 2.5V of the theoretical suspension center and the center value on the basis of the compensated output during the previous calibration process; otherwise, the output of the DA converter remains unchanged.

[0040] Through the calibration compensation adjustment method of the present invention, during the first calibration, complete rotor data can be collected, 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, enabling the deviation between the rotor radial and axial position voltages output by the compensated displacement sensor and the corresponding center positions to be within the allowable range, and improving the calibration efficiency.

[0041] 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 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 for one full week of positions is completed, ending the calibration process; in the embodiment of the present invention, the rotor rotates by 45° each time to balance the calibration accuracy and calibration time. It is also possible to change the rotation angle of the rotor each time according to the calibration requirements until 360° is rotated, ending the calibration process.

[0042] Let the offset stored in the controller EEPROM be offset Ref and the gain stored be gain Ref. If abs( is over-limit, report the offset reference alarm; if abs( is over-limit, report the gain reference alarm, where both "offset" and "gain" are data obtained based on the calibration process.

[0043] The present invention discloses a suspension center calibration system for a magnetic levitation motor. Using the above-mentioned 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 the rotor at the corresponding end 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 pairs of radial displacement sensors is 4. 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 voltage output by the corresponding displacement sensor is compensated through the DA converter.

[0044] 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-mentioned magnetic levitation motor suspension center calibration method.

[0045] 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-mentioned magnetic levitation motor suspension center calibration method.

[0046] The above are only the preferred embodiments of the present invention. It should be noted 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 suspension motor, characterized in that: Includes steps: S01. Perform radial calibration of the rotor suspension center. Select a calibration method based on the relative distance between the rotor protection bearing, the displacement sensor for detecting the rotor displacement and the rotor axial center. When the protection bearing is far away from the rotor axial center, use cone calibration. When the displacement sensor is far away from the rotor axial center, use translation calibration. S02, using a radial magnetic bearing to drive the rotor to draw a circle in the protective bearing, and controlling the current and direction of the radial magnetic bearing according to the moving angle of the rotor when drawing a circle; S03, during the process of radial calibration of the rotor suspension center by the rotor drawing a circle, the DA converter is used to compensate the rotor position voltage output by the displacement sensor according to the theoretical suspension center of the magnetic suspension 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 number reaches the upper limit, and the radial calibration of the rotor suspension center is terminated; S04. After the radial calibration of the rotor suspension center is completed, the axial calibration of the rotor suspension center is performed. The axial magnetic bearing is used to control the rotor to move axially, and the deviation between the rotor position center corresponding to the rotor position voltage output by the displacement sensor and the theoretical suspension center is detected during the movement. The rotor position voltage output by the displacement sensor is compensated by 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; Complete the axial calibration of the rotor suspension center; S05. After the calibration is completed, the bias and gain are calculated according to the calibration results, the corresponding suspension current is recorded, and an alarm is issued for the over-limit situation; after the rotor is rotated according to the current azimuth angle, the calibration process is repeated again until the radial and axial calibration of the rotor suspension center in one position is completed, and the calibration process is ended.

2. A method for calibrating the suspension center of a magnetic levitation motor according to claim 1, characterized in that: In step S01, when the radial calibration of the rotor suspension center is performed using the cone calibration method, the movement directions of the circles drawn at the two 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 the radial calibration of the rotor suspension center is performed using the translation calibration method, the directions of the circles drawn at 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 protective bearing circle; the direction of the rotor's circles is changed by controlling the current direction of the radial magnetic bearings at both ends of the rotor.

3. A method for calibrating the suspension center of a magnetic levitation motor according to claim 1, characterized in that: In steps S03 and S04, the process of using the 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 movement range of the rotor during the calibration process, and characterizing it with the rotor position voltage output by a pair of displacement sensors corresponding to 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 the 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 the allowable range or the calibration times reaches the upper limit of the set times, and the calibration process is terminated.

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

5. A method for calibrating the suspension center of a magnetic levitation motor according to claim 4, characterized in that: The degrees of freedom in the X and Y directions perpendicular to each other in the radial direction at both ends of the rotor are recorded as X1, X2, Y1 and Y2 respectively. When the radial calibration of the rotor suspension center is performed 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; 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; 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.

6. A method for calibrating the suspension center of a magnetic levitation motor according to claim 5, characterized in that: When using the translation method to calibrate the rotor suspension center radially, the radial translation calibration currents corresponding to the four degrees of freedom directions X1, X2, Y1 and Y2 are: , , and ; In each degree of freedom direction, the compensation signal code values ​​output by the DA converter are: , , and .

7. A method for calibrating the suspension center of a magnetic levitation motor according to claim 5, 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 is taken as the negative 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 CB.

8. A magnetic levitation motor suspension center calibration system, using the calibration method according to any one of claims 1 to 7, characterized in that: The calibration system includes radial magnetic bearings, radial protection bearings, radial displacement sensors, axial magnetic bearings, axial protection bearings, axial displacement sensors, 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 in two mutually perpendicular directions at the corresponding ends of the rotor. The axial magnetic bearing controls the freedom of movement 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 radial displacement sensor and the axial displacement sensor. The controller is electrically connected to the radial magnetic bearings, the radial displacement sensor, the axial magnetic bearings and the axial displacement sensor. The coil current of each magnetic bearing is controlled by the controller, and the rotor position voltage output by the radial displacement sensor and the axial displacement sensor is compensated by the DA converter during the calibration process.

9. An electronic device, characterized in that: include: Memory for storing computer programs; A processor is used to execute the computer program so that the device executes the magnetic levitation motor suspension center calibration method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program. When the computer program is executed, a device executing the computer program implements the method for calibrating the suspension center of a magnetic levitation motor according to any one of claims 1 to 7.

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