Bearing-free permanent magnet motor rotor suspension eccentricity self-optimization compensation method and system and computer program product

Abstract

The invention discloses a bearingless permanent magnet motor rotor suspension eccentricity self-optimization compensation method and system and a computer program product, and belongs to the technical field of bearingless permanent magnet motor control, and the method comprises the steps: displacement harmonic amplitude calculation and eccentricity vector iterative search; according to the rotor radial displacement signal and the rotor angular speed signal, the amplitude of a radial displacement double-frequency harmonic component is obtained through calculation, and the amplitude comprises rotor suspension eccentricity information; according to the eccentric vector iterative search, a function of a double-frequency displacement harmonic amplitude is used as a value function, a suspension eccentric vector of a rotor is repeatedly identified and updated through an iterative search method, and the suspension eccentric vector is compensated to a radial displacement control ring to suppress suspension eccentricity of the rotor. The problem of rotor suspension eccentricity caused by non-ideal factors such as sensor assembly errors and temperature excursion can be effectively solved, the rotor position is compensated to the stator center position in a self-optimizing mode, and therefore rotor radial displacement pulsation and motor shell vibration are reduced.

Description

Technical Field

[0001] The present application relates to the field of bearingless permanent magnet motor control, and particularly to a method, system and computer program product for rotor suspension eccentricity self-optimizing compensation of a bearingless permanent magnet motor. Background Art

[0002] Bearingless permanent magnet motors combine magnetic levitation technology with permanent magnet motors, featuring no mechanical wear, no need for lubrication, and high power density, making them the best choice for high-cleanliness electric drive fields such as semiconductor manufacturing, medical treatment, and pharmaceuticals. In a bearingless permanent magnet motor, precise and stable radial suspension control of the rotor is an important prerequisite for the high-performance and reliable operation of the motor system. However, a series of non-ideal factors such as irregular pump chamber machining, sensor assembly errors, and temperature drift will inevitably cause radial displacement detection errors, leading to the problem of rotor suspension eccentricity, that is, there is a fixed deviation between the center of the radial displacement sensor and the geometric center of the stator. The rotor suspension eccentricity problem will form an eccentric disturbance magnetic pull force acting on the rotor, increasing the radial displacement pulsation. In severe cases, the rotor even faces the risk of hitting the wall and losing stability, posing a great challenge to radial suspension control. In addition, rotor suspension eccentricity will also cause problems such as housing vibration. To reduce the radial displacement pulsation, existing solutions use technologies such as resonance control and disturbance observation to observe and compensate the eccentric disturbance magnetic pull force in real time. However, in essence, they cannot change the state of rotor suspension eccentricity and will also cause additional losses to the system.

[0003] Therefore, there is an urgent need for a method to solve the rotor suspension eccentricity problem to ensure the high-performance and reliable operation of bearingless permanent magnet motors. Summary of the Invention

[0004] Aiming at the problem of large radial displacement pulsation caused by rotor suspension eccentricity of a bearingless permanent magnet motor, the present application provides a method, system and computer program product for rotor suspension eccentricity self-optimizing compensation of a bearingless permanent magnet motor, so that the rotor position is self-optimized and compensated to the stator center position to reduce the rotor radial displacement pulsation and motor housing vibration.

[0005] To achieve the above object, the technical solution of the present application is:

[0006] A method for rotor suspension eccentricity self-optimizing compensation of a bearingless permanent magnet motor includes:

[0007] Step S1: Calculation of displacement harmonic amplitude: Obtain the amplitude of the radial displacement second harmonic component according to the rotor radial displacement signal and the rotor angular velocity signal, and obtain the merit function according to the calculation result of the displacement harmonic amplitude;

[0008] Step S2: Eccentric vector iterative search judgment: Determine whether the value function is greater than the starting threshold. If so, start the eccentric vector iterative search algorithm and proceed to Step S3; if not, stop the eccentric vector iterative search algorithm and proceed to Step S5;

[0009] Step S3: Determine the search direction based on the value function;

[0010] Step S4: Update the search direction vector according to the search direction judgment result;

[0011] Step S5: Update the eccentric vector;

[0012] Step S6: Use the current moment's eccentric vector as the eccentric compensation for radial suspension control, and return to Step S1.

[0013] Optionally, the radial displacement signal of the rotor includes: the displacement signal of the rotor in the x direction and the displacement signal of the rotor in the y direction;

[0014] Use the Fourier series discrete calculation method to calculate the amplitudes of the sine component and the cosine component of the second harmonic in the displacements in the x direction and the y direction respectively, expressed as:

[0015]

[0016] In the formula, T is the discrete sampling period, N is the number of discrete integration periods, ω is the rotor angular velocity signal, D x is the displacement signal of the rotor in the x direction, D y is the displacement signal of the rotor in the y direction, a x is the amplitude of the sine component of the second harmonic in the x direction, b x represents the amplitude of the cosine component of the second harmonic in the x direction, a y is the amplitude of the sine component of the second harmonic in the y direction, b y is the amplitude of the cosine component of the second harmonic in the y direction, n represents the discrete sampling signal count, D x (nT) is the discrete sampling signal obtained by the rotor in the x direction at the nth sampling period, D y (nT) is the discrete sampling signal obtained by the rotor in the y direction at the nth sampling period;

[0017] The amplitude of the second harmonic component of the radial displacement is expressed as:

[0018]

[0019] Among them, A x represents the amplitude of the second harmonic component of the displacement in the x direction, A y represents the amplitude of the second harmonic component of the displacement in the y direction.

[0020] Optionally, the value function expression includes: a combined form with the amplitude of the second-harmonic component of the displacement in the x direction and the amplitude of the second-harmonic component of the displacement in the y direction, and the weights of the two parts are the same.

[0021] Optionally, the starting threshold is initially set to the value function in the case of a 2% rotor suspension eccentricity.

[0022] Optionally, it is determined whether the value function at the current moment is less than or equal to the value function at the previous moment. If so, it is determined that the search direction is correct; if not, it is determined that the search direction is incorrect.

[0023] Optionally, when the search direction is correct, the search direction vector at the current moment remains the same as the search direction vector at the previous moment; when the search direction is incorrect, the search direction vector at the current moment is obtained by transforming the search direction vector at the previous moment according to the direction switching matrix.

[0024] Optionally, when the eccentric vector iterative search algorithm is started, the eccentric vector at the current moment is obtained by adding the product of the search direction vector at the current moment and the search step r to the eccentric vector at the previous moment; when the eccentric vector iterative search algorithm stops, the eccentric vector at the current moment remains the same as the eccentric vector at the previous moment.

[0025] Optionally, the eccentric vector at the current moment is used as the eccentric compensation for radial suspension control, including: taking the difference between the set reference displacement, the feedback of the rotor radial displacement signal, and the eccentric compensation obtained by iterative search, and through PID control adjustment, outputting an active control signal for radial suspension control.

[0026] Optionally, before calculating the amplitude of the second-harmonic component of the radial displacement, it also includes: initializing the values of the eccentric vector and the search direction vector; the search direction vector is a unit vector with a constant amplitude of 1, and the direction of the initial value of the search direction vector includes any direction between 0 and 360 degrees.

[0027] A bearingless permanent magnet motor rotor suspension eccentricity self-optimizing compensation system includes: one or more processors; a storage device for storing one or more programs. When the one or more programs are executed by the one or more processors, the one or more processors implement the bearingless permanent magnet motor rotor suspension eccentricity self-optimizing compensation method as described in any one of the above, and perform suspension eccentricity self-optimizing compensation on the bearingless permanent magnet motor rotor according to the bearingless permanent magnet motor rotor suspension eccentricity self-optimizing compensation method.

[0028] A computer program product includes a computer program, which implements the bearingless permanent magnet motor rotor suspension eccentricity self-optimizing compensation method as described in any one of the above when executed by a processor.

[0029] The rotor suspension eccentricity self-optimizing compensation method, system and computer program product proposed in this application can effectively solve the rotor suspension eccentricity problem caused by non-ideal factors such as sensor assembly errors and temperature drifts, self-optimize and compensate the center of the radial displacement sensor to the stator center position, and achieve the optimal position suspension of the rotor. The method of this application identifies the suspension eccentricity information from the radial displacement signal itself and performs real-time compensation for the suspension eccentricity based on the iterative search method. It neither depends on an accurate mathematical model nor requires additional hardware devices, and the implementation is simple with a good compensation effect. At the same time, this application reduces the rotor radial displacement pulsation, improves the radial suspension control accuracy of the bearingless permanent magnet motor, and also has the functions of suppressing the vibration of the motor housing and reducing the additional losses of the system.

[0030] To make the above features and advantages of the application more obvious and understandable, specific embodiments are given below and described in detail in conjunction with the accompanying drawings. Brief Description of the Drawings

[0031] Figure 1 Figure (a) in [the drawings] is a schematic diagram of a bearingless permanent magnet motor without rotor suspension eccentricity.

[0032] Figure 1 Figure (b) in [the drawings] is a schematic diagram of a bearingless permanent magnet motor with rotor suspension eccentricity.

[0033] Figure 2 It is a flowchart of the rotor suspension eccentricity self-optimizing compensation method for the bearingless permanent magnet motor of this application.

[0034] Figure 3 It is a schematic diagram of the three-dimensional finite element simulation result of the rotor force under the condition of suspension eccentricity.

[0035] Figure 4 Figure (a) in [the drawings] is a schematic diagram of the experimental result of the amplitude of the double-frequency harmonic component of the radial displacement at different rotor suspension eccentricity distances when the rotational speed is 500 rpm.

[0036] Figure 4 Figure (b) in [the drawings] is a schematic diagram of the experimental result of the amplitude of the double-frequency harmonic component of the radial displacement at different rotor suspension eccentricity distances when the rotational speed is 1000 rpm.

[0037] Figure 5 It is a control block diagram of the radial displacement control loop.

[0038] Figure 6 It is a schematic diagram of the eccentric vector iterative search process.

[0039] Figure 7 It is a schematic diagram of the experimental waveforms of the radial displacement pulsation and the merit function before and after eccentric compensation.

[0040] In the drawings, similar reference numerals refer to the same drawing elements. Detailed implementation manners

[0041] To make the objectives and technical solutions of the embodiments of the present application clearer, the technical solutions of the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the described embodiments of the present application without creative efforts shall fall within the scope of protection of the present application.

[0042] The present application provides a method for self-optimizing compensation of rotor suspension eccentricity of a bearingless permanent magnet motor, which is applied to the radial displacement control loop of a bearingless permanent magnet motor. There is no mechanical fixation or connection between the rotor and the stator of the bearingless permanent magnet motor. The rotor is made of a permanent magnet material, and the suspension and rotation of the rotor can be realized by controlling the superposition of the stator magnetic field and the rotor magnetic field.

[0043] Please refer to Figure 1 , Figure 1 Figure (a) in Figure 1 is a schematic diagram of a bearingless permanent magnet motor without rotor suspension eccentricity, Figure 1 and figure (b) in Figure 1 is a schematic diagram of a bearingless permanent magnet motor with rotor suspension eccentricity. In both figure (a) and figure (b) in

[0044] The method for self-optimizing compensation of rotor suspension eccentricity of the bearingless permanent magnet motor of the present application solves the problem of rotor suspension eccentricity of the bearingless permanent magnet motor under non-ideal factors. Please refer to Figure 2 , Figure 2 which is a flowchart of the method for self-optimizing compensation of rotor suspension eccentricity of the bearingless permanent magnet motor of the present application. The method for self-optimizing compensation of rotor suspension eccentricity of the bearingless permanent magnet motor of the present application includes: step S1 to step S6.

[0045] Step S1: Calculation of displacement harmonic amplitude: Obtain the amplitude of the double-frequency harmonic component of the radial displacement according to the rotor radial displacement signals D x , D y and the rotor angular velocity signal ω, and obtain the value function ξ at the current moment according to the calculation result of the displacement harmonic amplitudeCF (k); where D x represents the displacement signal of the rotor in the x-direction, and D y represents the displacement signal of the rotor in the y-direction;

[0046] Step S2: Eccentric vector iterative search start judgment: Determine whether the value function ξ CF (k) at the current moment is greater than the start threshold ξ th . If so, start the eccentric vector iterative search algorithm and proceed to Step S3; if not, stop the eccentric vector iterative search algorithm and proceed to Step S5;

[0047] Step S3: Determine the search direction based on the value function ξ CF (k) at the current moment;

[0048] Step S4: Update the search direction vector s(k) at the current moment according to the search direction judgment result;

[0049] Step S5: Update the eccentric vector P x / y (k) at the current moment;

[0050] Step S6: Use the eccentric vector P x / y (k) at the current moment as the eccentric compensation for radial suspension control, and return to Step S1.

[0051] As an example, the eccentric vector is the rotor suspension eccentricity coordinates in the two-dimensional coordinate system of the bearingless permanent magnet motor identified by the eccentric vector iterative search method at the radial displacement sensor 3.

[0052] In Step S1, please refer to Figure 2 Step S1 in, displacement harmonic amplitude calculation: According to the rotor radial displacement signals D x , D y and the rotor angular velocity signal ω, obtain the amplitude of the radial displacement second harmonic component, and obtain the value function ξ CF (k) at the current moment according to the displacement harmonic amplitude calculation result.

[0053] The rotor suspension eccentricity will cause the following eccentric disturbance magnetic pull force to act on the radial suspension system of the bearingless permanent magnet motor:

[0054]

[0055] In the formula, F n is the eccentric disturbance magnetic pull force, F nx,dc is the DC component of the eccentric magnetic pull force in the x-direction, F nx,ac is the AC component of the eccentric magnetic pull force in the x-direction, F ny,dc is the DC component of the eccentric magnetic pull force in the y-direction, F ny,acis the AC component of the eccentric magnetic pull force in the y direction, d p is the rotor suspension eccentric distance, θ p is the rotor suspension eccentric angle, κ s is the radial displacement stiffness of the motor, ω is the rotor angular velocity signal, and t represents time.

[0056] Please refer to Figure 3 , Figure 3 is a schematic diagram of the three-dimensional finite element simulation results of the rotor force under the condition of suspension eccentricity. When the rotor is suspended eccentrically and no excitation is applied to the stator winding, the only force on the rotor is the eccentric disturbance magnetic pull force F n , from Figure 3 the AC component of the eccentric disturbance magnetic pull force F nx,ac , F ny,ac has a frequency that is twice the fundamental rotational speed frequency, and the amplitude increases with the increase of the eccentric distance d p . In the radial displacement control loop, the AC components of the eccentric disturbance magnetic pull force F nx,ac , F ny,ac are difficult to be suppressed. Therefore, the rotor will form a radial pulsation of the same frequency under the action of this disturbing force, that is, it is manifested as a second-harmonic component of the radial displacement.

[0057] Furthermore, please refer to Figure 4 , Figure 4 Figure (a) in Figure 4 is a schematic diagram of the experimental results of the amplitude of the second-harmonic component of the radial displacement at different rotor suspension eccentric distances when the rotational speed is 500 rpm, Figure 4 Figure (b) in Figure 4 is a schematic diagram of the experimental results of the amplitude of the second-harmonic component of the radial displacement at different rotor suspension eccentric distances when the rotational speed is 1000 rpm. From the curves in nx,ac Figure (a) in ny,ac and Figure (b) in

[0058] it can be obtained that the amplitude of the second-harmonic component of the radial displacement is basically linearly positively correlated with the rotor suspension eccentric distance, that is, the larger the rotor suspension eccentric distance, the larger the amplitudes of the AC components of the eccentric disturbance magnetic pull force F p , F

[0059] As an example, before calculating the amplitude of the second-harmonic component of the radial displacement, it also includes: initializing the values of the eccentric vector P x / y and the search direction vector s.

[0060] In an embodiment of the present application, the initial value of the eccentric vector P x / y is set at the center of the radial displacement sensor 3, that is, P x / y (0) = (0, 0);

[0061] As an example, the search direction vector s is a unit vector with a constant amplitude of 1, and the direction of the initial value s(0) of the search direction vector s can be set to any direction between 0 and 360 degrees.

[0062] In an embodiment of the present application, the initial direction of the search direction vector s(0) is set to 0 degrees, that is, s(0) = (1, 0).

[0063] As an example, according to the radial displacement sensor 3, the radial displacement signal D x 、D y and the angular velocity signal ω of the rotor 1 are used to calculate the amplitude of the second harmonic component of the radial displacement.

[0064] As an example, the Fourier series discrete calculation method is used to calculate the amplitudes of the sine component and the cosine component of the second harmonic in the displacement in the x direction and the displacement in the y direction respectively, which are expressed as:

[0065]

[0066] In the formula, T is the discrete sampling period, N is the number of discrete integration periods, ω is the angular velocity signal of the rotor, D x is the displacement signal of the rotor in the x direction, D y is the displacement signal of the rotor in the y direction, a x is the amplitude of the sine component of the second harmonic in the x direction, b x represents the amplitude of the cosine component of the second harmonic in the x direction, a y is the amplitude of the sine component of the second harmonic in the y direction, b y is the amplitude of the cosine component of the second harmonic in the y direction, n is the discrete sampling signal count, D x (nT) is the discrete sampling signal obtained by the rotor in the x direction at the nth sampling period, D y (nT) is the discrete sampling signal obtained by the rotor in the y direction at the nth sampling period.

[0067] Furthermore, the positive and cosine two orthogonal components of the second harmonic displacement in the x-direction displacement and the second harmonic displacement in the y-direction displacement are superimposed on each other to obtain the amplitude A x of the second harmonic component of the x-direction displacement and the amplitude A y of the second harmonic component of the y-direction displacement, which are expressed as:

[0068]

[0069] Furthermore, the value function ξ is calculated by combining the amplitude A of the second - harmonic component in the x - direction x with the amplitude A of the second - harmonic component in the y - direction y The value function ξ CF , the expression of the value function ξ CF includes: and other combined forms that also have the amplitude A of the second - harmonic component of the displacement in the x - direction x and the amplitude A of the second - harmonic component of the displacement in the y - direction y and the two parts have the same weight.

[0070] In an embodiment of the present application, the expression of the value function ξ(k) at the current moment is: CF (k) is as follows:

[0071]

[0072] In step S2, refer to Figure 2 the S2 step in, for the start judgment of the eccentric vector iterative search: judge whether the value function ξ CF (k) at the current moment is greater than the start threshold ξ th . If so, start the eccentric vector iterative search algorithm and enter step S3; if not, stop the eccentric vector iterative search algorithm and enter step S5.

[0073] As an example, the start threshold ξ th is initially set as the value function under the condition that the rotor suspension eccentricity is 2%, that is, after reserving the margin, it is set as 2% of the maximum allowable eccentric distance on one side of the rotor, and is adjusted subsequently based on the system noise level.

[0074] In step S3, refer to Figure 2 the S3 step in, and judge the search direction according to the value function ξ CF (k) at the current moment.

[0075] As an example, compare the value function ξ CF (k) at the current moment with the value function ξ CF (k - 1) at the previous moment, and judge whether the value function ξ CF (k) at the current moment is less than or equal to the value function ξ CF (k - 1) at the previous moment. If so, judge that the search direction is correct; if not, judge that the search direction is wrong.

[0076] In step S4, refer to Figure 2 the S4 step in, and update the search - direction vector s(k) at the current moment according to the search - direction judgment result.

[0077] As an example, when the search direction is correct, the search direction vector s(k) at the current moment is the same as the search direction vector s(k-1) at the previous moment, that is, s(k) = s(k-1); when the search direction is incorrect, the search direction vector s(k) at the current moment is obtained by transforming the search direction vector s(k-1) at the previous moment according to the direction switching matrix R, that is, s T (k) = R · s T (k-1).

[0078] The direction switching matrix R is a 2×2 rotation transformation matrix in the radial two-dimensional plane, expressed as:

[0079]

[0080] where θ represents the rotation angle, which can be designed as any fixed angle between 0 and 360 degrees or a changing angle updated in real time. Through the direction switching matrix R, the search direction vector s at the previous moment can be rotated by θ degrees in the counterclockwise or clockwise direction.

[0081] In an embodiment of the present application, θ = π / 2, and the direction switching matrix R is expressed as:

[0082]

[0083] Specifically, in the case where the search direction is incorrect, the direction switching matrix R rotates the search direction vector s(k-1) at the previous moment by 90° in the counterclockwise direction to obtain the search direction vector s(k) at the current moment.

[0084] In step S5, please refer to Figure 2 step S5 in x / y (k) to update the eccentricity vector P at the current moment

[0085] As an example, when the eccentricity vector iterative search algorithm is started, the eccentricity vector P x / y (k) at the current moment is obtained by adding the product of the search direction vector s(k) at the current moment and the search step r to the eccentricity vector P x / y (k-1) at the previous moment, that is, P x / y (k) = P x / y (k-1) + r · s(k); when the eccentricity vector iterative search algorithm stops, the eccentricity vector P x / y (k) at the current moment is the same as the eccentricity vector P x / y (k-1) at the previous moment, that is, P x / y (k) = P x / y (k-1).

[0086] As an example, the search step r is the eccentricity vector P at the current moment in each iteration cycle x / y(k) The variable distance can be designed as a fixed value or a variable value that is updated in real time according to the iteration period.

[0087] In a specific embodiment of the present application, the search step size r is designed as a fixed value, which is 1% of the maximum allowable eccentric distance on one side of the rotor.

[0088] In step S6, please refer to Figure 2 step S6 in x / y The eccentric vector P(k) at the current moment is used as the eccentric compensation for radial suspension control, and then return to step S1.

[0089] As an example, the eccentric vector P(k) at the current moment is used as the eccentric compensation and input into the radial displacement control loop (not shown in x / y ) of the bearingless permanent magnet motor for radial suspension control. Figure 1

[0090] As an example, the radial displacement control loop will subtract the set reference displacements R x 、R y from the rotor radial displacement signals D x 、D y , and the feedback and the eccentric compensation P x / y obtained by iterative search, and then input the result into the radial displacement regulator (not shown in Figure 1 ). Then, the active control signal output by the radial displacement regulator is applied to the radial suspension system of the bearingless permanent magnet motor for radial suspension control.

[0091] As an example, please refer to Figure 5 Figure 5 .

[0092] x 、D y is the control block diagram of the radial displacement control loop, and the radial displacement control loop adopts closed-loop control. The eccentric disturbance magnetic pulling force caused by the rotor suspension eccentricity acts on the radial motion model of the radial suspension system of the bearingless permanent magnet motor. After obtaining the rotor radial displacement signals D CF , the displacement harmonic amplitude is calculated to obtain the value function ξ x 、R y is used to judge whether to perform eccentric vector iterative search. The set reference displacements R x 、D y are subtracted from the feedback and the eccentric compensation P x / y obtained by iterative search, and then input into the radial displacement regulator of the bearingless permanent magnet motor. The output active control signal is applied to the radial motion model of the radial suspension system of the bearingless permanent magnet motor for radial suspension control.

[0092] As an example, the radial displacement regulator adopts PID control.

[0093] As an example, the control method of the radial displacement regulator further includes other linear or non-linear control techniques.

[0094] As an example, the process of calculating the displacement harmonic amplitude and iteratively searching for the eccentricity vector in steps S1 to S6 is repeatedly executed to continuously identify and compensate the rotor suspension eccentricity coordinates in real time, so that the value function ξ CF (k) is reduced to the target threshold ξ th , and the self-optimizing compensation for the rotor suspension eccentricity of the bearingless permanent magnet motor is realized.

[0095] Please refer to Figure 6 , Figure 6 , which is a schematic diagram of the iterative search process of the eccentricity vector. At the current moment, the eccentricity vector P(k) starts from the origin and iteratively searches along the positive x-axis direction, approaching the suspension eccentricity coordinates step by step with a step size of r, and direction switching is performed at four points A, B, C, and D in the figure. After 17 iterations, the value function ξ CF is finally reduced to the starting threshold ξ th . Hereinafter, the iterative search of the eccentricity vector is completed.

[0096] Please refer to Figure 7 , Figure 7 , which is a schematic diagram of the experimental waveforms of the radial displacement pulsation and the value function before and after eccentricity compensation. The method described in this application is experimentally tested on a prototype of a bearingless permanent magnet motor. After starting the self-optimizing compensation for the rotor suspension eccentricity, the value function ξ CF continually decreases, and the displacement pulsations in the x and y directions also decrease significantly. It can be seen that the self-optimizing compensation method for the rotor suspension eccentricity of the bearingless permanent magnet motor proposed in this application can effectively suppress the rotor suspension eccentricity problem, reduce the radial displacement pulsation, and enable the rotor to accurately and stably suspend at the optimal position.

[0097] This application also provides a self-optimizing compensation system for the rotor suspension eccentricity of a bearingless permanent magnet motor, including: one or more processors; a storage device for storing one or more programs. When the one or more programs are executed by the one or more processors, the one or more processors implement the self-optimizing compensation method for the rotor suspension eccentricity of the bearingless permanent magnet motor as described above, and perform self-optimizing compensation for the rotor suspension eccentricity of the bearingless permanent magnet motor according to the self-optimizing compensation method for the rotor suspension eccentricity of the bearingless permanent magnet motor.

[0098] This application also provides a computer program product, including a computer program, which implements the self-optimizing compensation method for the rotor suspension eccentricity of the bearingless permanent magnet motor as described above when executed by a processor.

[0099] The rotor suspension eccentricity self-optimizing compensation method, system and computer program product proposed by this application can effectively solve the rotor suspension eccentricity problem caused by non-ideal factors such as sensor assembly errors and temperature drifts, self-optimize and compensate the center of the radial displacement sensor to the stator center position, and achieve the optimal position suspension of the rotor. This application identifies the suspension eccentricity information from the radial displacement signal itself and performs real-time compensation for the suspension eccentricity based on the iterative search method, which neither depends on an accurate mathematical model nor requires additional hardware devices, and has a simple implementation and good compensation effect. At the same time, this application reduces the rotor radial displacement pulsation, improves the radial suspension control accuracy of the bearingless permanent magnet motor, and also has the functions of suppressing the vibration of the motor housing and reducing the additional losses of the system.

[0100] Those skilled in the art of this technology can understand that, unless otherwise defined, all terms used herein (including technical terms and scientific terms) have the same meaning as the general understanding of those of ordinary skill in the field to which this invention belongs. It should also be understood that terms such as those defined in a general dictionary should be understood to have a meaning consistent with the meaning in the context of the prior art, and will not be interpreted with an idealized or overly formal meaning unless defined as such here.

[0101] The specific embodiments described above have further elaborated on the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only for the specific embodiments of the present invention and is not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A self-optimizing compensation method for the suspension eccentricity of a bearingless permanent magnet motor rotor, characterized in that: include, Step S1: Calculation of displacement harmonic amplitude: obtaining the amplitude of the radial displacement double frequency harmonic component according to the rotor radial displacement signal and the rotor angular velocity signal, and obtaining the value function according to the displacement harmonic amplitude calculation result; Step S2: Determine whether the value function is greater than the start threshold, if so, start the eccentricity vector iterative search algorithm and go to step S3; if not, stop the eccentricity vector iterative search algorithm and go to step S5; Step S3: Determine the search direction based on the value function; Step S4: updating the search direction vector according to the search direction determination result; Step S5: Update the eccentricity vector; Step S6: Use the current eccentricity vector as eccentricity compensation to perform radial suspension control, and return to step S1.

2. The bearingless permanent magnet motor rotor suspension eccentricity self-optimization compensation method according to claim 1 is characterized in that: The radial displacement signal of the rotor includes: a displacement signal of the rotor in the x direction and a displacement signal of the rotor in the y direction; The Fourier series discrete calculation method is used to calculate the amplitude of the sine component and the cosine component of the double frequency harmonic in the displacement in the x direction and the displacement in the y direction, respectively, which can be expressed as: Where T is the discrete sampling period, N is the number of discrete integration periods, ω is the rotor angular velocity signal, and D x is the displacement signal of the rotor in the x direction, D y is the displacement signal of the rotor in the y direction, a x is the amplitude of the sinusoidal component of the double frequency harmonic in the x direction, b x represents the amplitude of the cosine component of the double harmonic in the x direction, a y is the amplitude of the sinusoidal component of the double frequency harmonic in the y direction, b y is the amplitude of the cosine component of the double frequency harmonic in the y direction, n represents the discrete sampling signal count, D x (nT) is the discrete sampling signal obtained by the rotor in the nth sampling period in the x direction, D y (nT) is the discrete sampling signal obtained by the rotor in the nth sampling period in the y direction; The amplitude of the second harmonic component of radial displacement is expressed as: Among them, A x A represents the amplitude of the double harmonic component of the x-direction displacement. y Represents the amplitude of the second harmonic component of the displacement in the y direction.

3. The bearingless permanent magnet motor rotor suspension eccentricity self-optimization compensation method according to claim 2, characterized in that: The value function expression includes: a combination of the amplitude of the double frequency harmonic component of the x-direction displacement and the amplitude of the double frequency harmonic component of the y-direction displacement, and the two parts have the same weight.

4. The bearingless permanent magnet motor rotor suspension eccentricity self-optimization compensation method according to claim 1, characterized in that: The start threshold is initially set as the value function of the rotor suspension eccentricity of 2%.

5. The bearingless permanent magnet motor rotor suspension eccentricity self-optimization compensation method according to claim 1, characterized in that: Determine whether the current moment value function is less than or equal to the previous moment value function. If so, the search direction is correct; if not, the search direction is wrong.

6. The bearingless permanent magnet motor rotor suspension eccentricity self-optimization compensation method according to claim 5, characterized in that: When the search direction is correct, the current search direction vector remains the same as the previous search direction vector; when the search direction is wrong, the current search direction vector is obtained by transforming the previous search direction vector according to the direction switching matrix.

7. The bearingless permanent magnet motor rotor suspension eccentricity self-optimization compensation method according to claim 6, characterized in that: When the eccentricity vector iterative search algorithm is started, the eccentricity vector at the current moment is obtained by adding the eccentricity vector at the previous moment to the product of the search direction vector at the current moment and the search step length r; When the eccentricity vector iterative search algorithm stops, the eccentricity vector at the current moment remains the same as the eccentricity vector at the previous moment.

8. The bearingless permanent magnet motor rotor suspension eccentricity self-optimization compensation method according to claim 1, characterized in that: The eccentricity vector at the current moment is used as the eccentricity compensation for radial suspension control, including: subtracting the set reference displacement from the rotor radial displacement signal feedback and the eccentricity compensation obtained by iterative search, adjusting through PID control, and outputting an active control signal for radial suspension control.

9. The bearingless permanent magnet motor rotor suspension eccentricity self-optimization compensation method according to claim 1, characterized in that: Before calculating the amplitude of the second harmonic component of the radial displacement, it also includes: initializing the values ​​of the eccentricity vector and the search direction vector; the search direction vector is a unit vector with a constant amplitude of 1, and the direction of the initial value of the search direction vector includes any direction between 0 and 360 degrees.

10. A bearingless permanent magnet motor rotor suspension eccentricity self-optimizing compensation system, characterized in that: include: one or more processors; A storage device for storing one or more programs. When the one or more programs are executed by the one or more processors, the one or more processors implement the bearingless permanent magnet motor rotor suspension eccentricity self-optimizing compensation method as described in any one of claims 1 to 9, and perform suspension eccentricity self-optimizing compensation on the bearingless permanent magnet motor rotor according to the bearingless permanent magnet motor rotor suspension eccentricity self-optimizing compensation method.

11. A computer program product, comprising a computer program, characterized in that When the computer program is executed by a processor, the bearingless permanent magnet motor rotor suspension eccentricity self-optimization compensation method as described in any one of claims 1 to 9 is implemented.

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