Axial position compensation method and axial position compensation system for magnetic suspension motor

Abstract

The invention discloses an axial position compensation method for a magnetic suspension motor, and relates to the technical field of magnetic suspension motor control, and the method comprises the steps: obtaining the radial size and the axial size of a motor rotor in a cold state; acquiring the radial size of the motor rotor in the thermal state; calculating the axial compensation amount of the motor rotor according to the radial size variation of the motor rotor; the axial compensation quantity is the variable quantity of the distance between the axial adjusting flange and the axial detection reference surface of the motor rotor; according to the axial compensation amount, the axial magnetic bearing adjusts the axial position of the motor rotor through an axial adjusting flange of the motor rotor; when the motor works, the axial size change caused by temperature change is considered, and the axial position is adjusted, so that the distances between the axial adjusting flange and the two axial magnetic bearings are equal, the increase of the current deviation of the two axial magnetic bearings is avoided, and the control of the axial magnetic bearings is facilitated. The axial position compensation system can achieve the technical effects of the compensation method.

Description

Technical Field

[0001] The present invention relates to the technical field of magnetic levitation motor control, and further relates to a method and a system for compensating the axial position of a magnetic levitation motor. Background Art

[0002] The common layout diagram of displacement sensors of a magnetic levitation bearing motor is shown in Figure 1 and Figure 2 As shown, a total of 4 radial displacement sensors 01 are arranged in the 45° direction of the vertical and horizontal angles of the motor. The circle O1 formed by the probe surfaces of the radial displacement sensors 01 is concentric with the inner hole of the radial magnetic bearing 06; 1 axial displacement sensor 02 is assembled in the vertical or horizontal direction of the motor. Its working logic is as follows:

[0003] a. When LA1 - LA2 = 0 and LA3 - LA4 = 0, it indicates that the motor rotor 05 is suspended at the center of the radial magnetic bearing 06.

[0004] b. Before the cold - state rotation of the motor, during static suspension, the currents of the two axial magnetic bearings 04 are equal, that is: LC1 - LC2 = 0, indicating that the axial adjustment flange 07 on the motor rotor 05 is suspended in the middle of the two axial magnetic bearings 04; at this time, the distance LB1 read by the axial displacement sensor 02 from the reference plane of the motor rotor 05 is a calibration value.

[0005] c. When the motor rotor 05 is working and rotating, the magnetic bearing controller needs to ensure by electromagnetic force that: LA1 - LA2 = 0; LA3 - LA4 = 0; the value of LB1 remains unchanged.

[0006] The above - mentioned control scheme has problems:

[0007] 1. When the perpendicularity between the axial reference plane of the motor rotor 05 and its center line is not good, during the operation of the motor, the magnetic bearing controller ensures that the value of LB1 remains unchanged by electromagnetic force, and the motor rotor 05 will axially move.

[0008] 2. When the motor is in a hot - state operation, the temperature of the motor rotor 05 will rise. As the temperature rises, the motor rotor 05 will thermally expand, that is: LD1 will increase. When the magnetic bearing controller ensures that the value of LB1 remains unchanged, LC2 < LC1, and the current deviation of the two axial magnetic bearings 04 will increase, which is not conducive to the control of the axial magnetic bearings by the magnetic bearing controller.

[0009] For those skilled in the art, how to reasonably adjust the axial position of the motor rotor when the temperature rises is a technical problem that needs to be solved currently. Summary of the Invention

[0010] The core of the present invention is to provide a method for compensating the axial position of a magnetic levitation motor. This method takes into account the axial dimensional changes caused by temperature changes during motor operation and adjusts the axial position of the motor rotor to make the distance between the axial adjustment flange and the two axial magnetic bearings equal, thereby avoiding an increase in the current deviation of the two axial magnetic bearings and facilitating the control of the axial magnetic bearings. The specific scheme is as follows:

[0011] A method for compensating an axial position of a magnetic levitation motor, comprising:

[0012] In a cold state, obtain the radial and axial dimensions of the motor rotor;

[0013] In a hot state, obtaining the radial dimension of the motor rotor;

[0014] The axial compensation amount is calculated from the radial size change of the motor rotor. ; The axial compensation amount The distance between the axial adjustment flange and the axial detection reference surface of the motor rotor is The amount of change;

[0015] According to the axial compensation The axial distance between the motor rotor and the axial displacement sensor is adjusted by the axial magnetic bearing through the axial adjustment flange of the motor rotor, so that the distance between the axial adjustment flange and the two axial magnetic bearings is equal.

[0016] Optionally, in a cold state, obtaining radial dimensions and axial dimensions of the motor rotor includes:

[0017] In cold state:

[0018] Obtain the diameter of the motor rotor at the radial detection circumference respectively , the distance between the outer surface of the motor rotor radial detection circumference and the radial displacement sensor , the distance between the axial adjustment flange and the axial detection reference surface of the motor rotor .

[0019] Optionally, in a hot state, obtaining the radial dimension of the motor rotor includes:

[0020] In hot state:

[0021] Obtain the distance between the outer surface of the motor rotor radial detection circumference and the radial displacement sensor .

[0022] Optionally, the axial compensation amount The value of is:

[0023] .

[0024] Optionally, the distance between the radial detection circumferential outer surface of the motor rotor and the radial displacement sensor is and the distance between the radial detection circumferential outer surface of the motor rotor and the radial displacement sensor It is determined by the detection value of any one of the radial displacement sensors.

[0025] Optionally, adjusting the axial position of the motor rotor by the axial magnetic bearing through the axial adjustment flange includes:

[0026] The intersection of the central axis of the motor rotor and the axial detection reference plane of the motor rotor is used as the adjustment reference point.

[0027] Optionally, the value of the adjustment reference point is the average value of the sum of distances between the axial detection reference plane of the motor rotor and two or more axial displacement sensors.

[0028] Optionally, the value of the adjustment reference point is half of the sum of the distances between the axial detection reference plane of the motor rotor and the axial displacement sensors that are 180 degrees apart in two circumferential directions.

[0029] The present invention further provides an axial position compensation system, which is applied to any of the above-mentioned axial position compensation methods for magnetic levitation motors, and comprises four radial displacement sensors and at least two axial displacement sensors;

[0030] The radial displacement sensor is used to obtain the radial dimensions of the motor rotor in cold and hot states;

[0031] The axial displacement sensor is used to adjust the axial compensation value according to the The axial position of the motor rotor is adjusted by the axial magnetic bearing through the axial adjustment flange of the motor rotor.

[0032] Optionally, the two axial displacement sensors are 180 degrees apart in the circumferential direction.

[0033] The present invention provides a method for compensating the axial position of a magnetic levitation motor. In a cold state, the radial size and axial size of the motor rotor are obtained; in a hot state, the radial size of the motor rotor is obtained; and the axial compensation amount is calculated based on the radial size change of the motor rotor. ;Axial compensation To adjust the distance between the flange and the motor rotor axial detection reference surface The change of axial compensation The axial position of the motor rotor is adjusted by the axial magnetic bearing via the axial adjustment flange of the motor rotor. During motor operation, the axial dimensional changes caused by temperature fluctuations are taken into account, and the axial position is adjusted to ensure that the distance between the axial adjustment flange and the two axial magnetic bearings is equal. This prevents increased current deviation in the two axial magnetic bearings and facilitates control of the axial magnetic bearings. The axial position compensation system of the present invention can achieve the technical effects of the above-mentioned compensation method. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0035] Figure 1 It is a front view of an existing magnetic bearing motor;

[0036] Figure 2 for Figure 1 Cross-section at the middle AA position;

[0037] Figure 3 It is a front view of the magnetic bearing motor of the present invention;

[0038] Figure 4 for Figure 3 Cross-section view of the middle BB position;

[0039] Figure 5 This is a schematic diagram of the upper portion of the axial adjustment flange deflecting to the left;

[0040] Figure 6 Schematic diagram of the upper part of the axial adjustment flange deflecting to the right.

[0041] The diagram includes:

[0042] Radial displacement sensor 1, axial displacement sensor 2, machine base 3, axial magnetic bearing 4, motor rotor 5, radial magnetic bearing 6, axial adjustment flange 7. DETAILED DESCRIPTION

[0043] In order to enable those skilled in the art to better understand the technical solution of the present invention, the axial position compensation method and axial position compensation system of the magnetic levitation motor of the present invention will be described in detail below with reference to the accompanying drawings and specific implementation methods.

[0044] The magnetic levitation motor axial position compensation method provided by the present invention is used to adjust the axial position of the motor rotor 5 of the magnetic levitation motor. When the temperature of the motor rotor 5 changes after operation, its axial position is adjusted to ensure that the distance between the axial adjustment flange 7 and the two axial magnetic bearings 4 is equal.

[0045] The axial position compensation method of the magnetic levitation motor of the present invention comprises the following steps:

[0046] Obtain the radial and axial dimensions of the motor rotor 5 in a cold state (i.e., the low-temperature state of the motor when not in operation, typically ambient temperature). Note that the motor rotor 5 has multiple stepped locations, and the outer diameter of at least one of these locations should be obtained. The axial dimension of the motor rotor 5 can be the total axial length of the entire motor rotor 5 or the axial length of a portion of the motor rotor 5.

[0047] In the hot state, the radial dimension of the motor rotor 5 is obtained; after the radial detection position is selected, the radial dimension at the same position needs to be detected in the cold state and the hot state to ensure that the radial dimensions in the cold state and the hot state are comparable.

[0048] The axial compensation amount is calculated from the radial size change of the motor rotor 5 There is a correlation between the radial size change of the motor rotor 5 and its axial size change. According to the radial size change of the motor rotor 5, the axial size change of the motor rotor 5 is calculated, which is used as the basis for the axial adjustment of the motor rotor.

[0049] Combine Figure 4 As shown, the above axial compensation The distance between the axial adjustment flange 7 and the axial detection reference surface of the motor rotor 5 is The change in distance It is the axial distance from the detection surface of the axial displacement sensor 2 (axial detection reference surface) to the axial adjustment flange 7.

[0050] According to the axial compensation The axial distance between the motor rotor 5 and the axial displacement sensor 2 is adjusted by the axial magnetic bearing 4 through the axial adjustment flange 7 of the motor rotor 5, so that the distance between the axial adjustment flange 7 and the two axial magnetic bearings 4 is equal. The axial displacement sensor 2 is used to detect the axial detection reference surface and obtain the distance between the axial detection reference surface and the axial displacement sensor 2 probe. , through this spacing The change of changes the axial position of the motor rotor 5.

[0051] The present invention takes into account the axial size changes of the motor rotor 5 caused by temperature changes when the motor is working, and adjusts the axial position of the motor rotor 5 so that the distance between the axial adjustment flange 7 and the two axial magnetic bearings 4 is equal, thereby avoiding the increase of the current deviation of the two axial magnetic bearings 4, which is beneficial to the control of the axial magnetic bearings 4.

[0052] On the basis of the above scheme, the process of obtaining the radial size and axial size of the motor rotor 5 in the cold state includes: obtaining the diameter of the motor rotor 5 at the radial detection circumference in the cold state respectively. , the distance between the outer surface of the motor rotor 5 at the radial detection circumference and the radial displacement sensor 1 , the distance between the axial adjustment flange 7 and the axial detection reference surface of the motor rotor 5 .

[0053] Combine Figure 3 As shown, there are four radial displacement sensors 1, equidistantly spaced around the circumference. The probes of the four radial displacement sensors 1 are located on the same circumference, and the angles between the four radial displacement sensors 1 and the horizontal and vertical planes are all 45 degrees. The distances between the probes of the four radial displacement sensors 1 and the radial detection circumference of the motor rotor 5 are LA1, LA2, LA3, and LA4, respectively. When the circumference of the circle containing the probes of the four radial displacement sensors 1 is concentric with the outer circumference of the motor rotor 5, LA1 = LA2 = LA3 = LA4. It can be any one of the four values LA1, LA2, LA3, and LA4 in the cold state, or it can be obtained by taking the average of the four values.

[0054] The diameter of the motor rotor 5 at the radial detection circumference The radial detection circumference of the motor rotor 5 can be measured in a cold state. When the motor is working, it is only necessary to ensure that the detection values of the four radial displacement sensors 1 are equal.

[0055] The distance between the axial adjustment flange 7 and the axial detection reference surface of the motor rotor 5 The axial dimension of the motor rotor 5 can be measured in a cold state. Figure 4 As shown, the distance between the right end face of the axial adjustment flange 7 and the axial detection reference surface facing the axial displacement sensor 2 is The distance between the probe of the axial displacement sensor 2 and the axial detection reference plane is .

[0056] In the hot state, the process of obtaining the radial size of the motor rotor 5 includes: in the hot state, obtaining the distance between the outer surface of the radial detection circumference of the motor rotor 5 and the radial displacement sensor 1 , the spacing It can be any one of the four values LA1, LA2, LA3, and LA4 in the hot state, or it can be obtained by taking the average of the four values.

[0057] The present invention provides an axial compensation The specific value of axial adjustment is made according to this value, and the axial compensation amount The value of is:

[0058] .

[0059] The specific derivation process is as follows, combined with Figure 4 As shown, the following relationship can be obtained:

[0060] .

[0061] and ; .

[0062] .

[0063] .

[0064] .

[0065] The distance between the radial detection circumferential outer surface of the motor rotor 5 and the radial displacement sensor 1 The distance between the radial detection outer surface of the motor rotor 5 and the radial displacement sensor 1 Determined by the detection value of any radial displacement sensor 1. Figure 3 As shown, during the operation of the motor, the distances between the four radial displacement sensors 1 and the motor rotor 5 need to be kept equal, so the detection value of any radial displacement sensor 1 can be used as the determination value. and The value of .

[0066] Based on any of the above technical solutions and their combinations, the present invention adjusts the axial position of the motor rotor 5 by the axial magnetic bearing 4 through the axial adjustment flange 7, including the following process: the intersection of the central axis of the motor rotor 5 and the axial detection reference plane of the motor rotor 5 is used as the adjustment reference point. Figure 5 、 Figure 6 As shown, when the motor rotor 5 is transported, the axis may deflect, which causes the axial detection reference plane of the motor rotor 5 to be not perpendicular to the central axis. Figure 5 L1 and Figure 6 L2 in the figure represents the axial distance between the intersection of the central axis and the axial detection reference plane and the axial displacement sensor 2. This distance should be used as a reference for adjustment.

[0067] In order to facilitate measurement, the value of the adjustment reference point is the average value of the sum of the distances between the axial detection reference plane of the motor rotor 5 and two or more axial displacement sensors 2, combined with Figure 5 、 Figure 6 As shown, two axial displacement sensors 2 are provided corresponding to the axial detection reference surface. Figure 5 The distance between the upper middle axial displacement sensor 2 and the axial detection reference plane is A, and the distance between the lower axial displacement sensor 2 and the axial detection reference plane is B. The average value of A and B is L1; Figure 6 The distance between the upper middle axial displacement sensor 2 and the axial detection reference plane is C, the distance between the lower axial displacement sensor 2 and the axial detection reference plane is D, and the average value of C and D is L2.

[0068] The number of the axial displacement sensors 2 is at least two, and a greater number may be provided, and the axial adjustment amount is controlled by taking an average value.

[0069] Combine Figure 5 、 Figure 6 As shown, in the present invention, the two axial displacement sensors 2 are 180 degrees apart in the circumferential direction. The two axial displacement sensors 2 can be vertical, horizontal, or in other orientations. The value of the adjustment reference point is half the sum of the distances between the axial detection reference plane of the motor rotor 5 and the two axial displacement sensors 2 180 degrees apart in the circumferential direction.

[0070] The present invention also provides an axial position compensation system, which applies the above-mentioned magnetic suspension motor axial position compensation method and combines Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 As shown, it includes four radial displacement sensors 1 and at least two axial displacement sensors 2; the four radial displacement sensors 1 are distributed at equal intervals in the circumferential direction, and the two or more axial displacement sensors 2 are distributed at equal intervals in the circumferential direction.

[0071] The radial displacement sensor 1 is used to obtain the radial dimensions of the motor rotor 5 in the cold and hot states; the axial displacement sensor 2 is used to obtain the radial dimensions of the motor rotor 5 in the cold and hot states; The axial position of the motor rotor 5 is adjusted by the axial magnetic bearing 4 through the axial adjustment flange 7 of the motor rotor 5.

[0072] The axial compensation amount is obtained by the calculation method described above , and adjust the axial position of the motor rotor 5 in combination with the detection value of the axial displacement sensor 2.

[0073] For example, when the temperature of the motor rotor 5 increases, the axial distance LD1 will expand, and thus the axial distance LB1 needs to be reduced so that the axial adjustment flange 7 can be located exactly in the middle of the two axial magnetic bearings 4 .

[0074] In a specific structure, two axial displacement sensors 2 are provided, and the two axial displacement sensors 2 are 180 degrees apart in the circumferential direction.

[0075] The system can use the radial expansion of the rotor to obtain axial expansion compensation, thereby avoiding axial movement of the motor rotor during normal operation of the motor, and helping to improve the working stability of the magnetic levitation motor.

[0076] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for compensating the axial position of a magnetic levitation motor, characterized in that: include: In a cold state, obtaining radial dimensions and axial dimensions of the motor rotor (5); In a hot state, obtaining the radial dimension of the motor rotor (5); The axial compensation amount of the motor rotor (5) is calculated from the radial size change amount thereof ; The axial compensation amount The distance between the axial adjustment flange (7) and the axial detection reference surface of the motor rotor (5) The amount of change; According to the axial compensation The axial distance between the motor rotor (5) and the axial displacement sensor (2) is adjusted by the axial magnetic bearing (4) through the axial adjustment flange (7) of the motor rotor (5), so that the distance between the axial adjustment flange (7) and the two axial magnetic bearings (4) is equal.

2. The method for compensating the axial position of a magnetic levitation motor according to claim 1, characterized in that: In a cold state, the radial and axial dimensions of the motor rotor (5) are obtained, including: In cold state: The diameter of the motor rotor (5) at the radial detection circumference is obtained respectively , the distance between the outer surface of the motor rotor (5) at the radial detection circumference and the radial displacement sensor (1) , the distance between the axial adjustment flange (7) and the axial detection reference surface of the motor rotor (5) .

3. The method for compensating the axial position of a magnetic levitation motor according to claim 2, characterized in that: In a hot state, obtaining the radial dimensions of the motor rotor (5) includes: In hot state: Obtaining the distance between the outer surface of the motor rotor (5) at the radial detection circumference and the radial displacement sensor (1) .

4. The method for compensating the axial position of a magnetic levitation motor according to claim 3, characterized in that: The axial compensation The value of is: 。 5. The method for compensating the axial position of a magnetic levitation motor according to claim 4, characterized in that: The distance between the radial detection circumferential outer surface of the motor rotor (5) and the radial displacement sensor (1) and the distance between the radial detection circumferential outer surface of the motor rotor (5) and the radial displacement sensor (1) Determined by the detection value of any one of the radial displacement sensors (1).

6. The method for compensating the axial position of a magnetic levitation motor according to any one of claims 1 to 5, characterized in that: The axial position of the motor rotor (5) is adjusted by the axial magnetic bearing (4) through the axial adjustment flange (7), comprising: The intersection of the central axis of the motor rotor (5) and the axial detection reference plane of the motor rotor (5) is used as an adjustment reference point.

7. The method for compensating the axial position of a magnetic levitation motor according to claim 6, characterized in that: The value of the adjustment reference point is the average value of the sum of the distances between the axial detection reference surface of the motor rotor (5) and two or more axial displacement sensors (2).

8. The method for compensating the axial position of a magnetic levitation motor according to claim 7, characterized in that: The value of the adjustment reference point is half of the sum of the distances between the axial detection reference plane of the motor rotor (5) and the axial displacement sensors (2) that are 180 degrees apart in two circumferential directions.

9. An axial position compensation system, characterized in that: The axial position compensation method for a magnetic levitation motor according to any one of claims 1 to 8 comprises four radial displacement sensors (1) and at least two axial displacement sensors (2); The radial displacement sensor (1) is used to obtain radial dimensions of the motor rotor (5) in cold and hot states; The axial displacement sensor (2) is used to adjust the axial displacement according to the axial compensation amount. The axial position of the motor rotor (5) is adjusted by the axial magnetic bearing (4) through the axial adjustment flange (7) of the motor rotor (5).

10. The axial position compensation system according to claim 9, characterized in that: The two axial displacement sensors (2) are 180 degrees apart in the circumferential direction.

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