Vibration suppression method, device and system for rotor in magnetic suspension bearing system

Abstract

The invention relates to a vibration suppression method, device and system for a rotor in a magnetic suspension bearing system, and belongs to the technical field of magnetic suspension bearing control. Predicting to obtain a second displacement signal of the rotor at the current moment; determining a current compensation signal based on the rotating speed frequency of the rotor determined by the current signal of the winding at the current moment and the second displacement signal; and superposing the current compensation signal and the original current instruction to obtain a target current instruction. According to the method provided by the invention, the rotation frequency and the rotor position can be extracted without installing a position sensor in the motor, the structural design of the motor can be optimized to a great extent, and unstable work and maintenance and repair cost caused by damage of the sensor are avoided; a vibration suppression algorithm can be effectively realized in a magnetic bearing system without or without a sensor, and rotor vibration is effectively suppressed.

Description

Technical Field

[0001] The present invention relates to the field of magnetic bearing control technology, and in particular to a vibration suppression method, device and system for a rotor in a magnetic bearing system. Background Art

[0002] Active Magnetic Bearing (AMB), also known as active magnetic bearing, is the most widely used type of magnetic bearing. Magnetic bearings have the characteristics of no mechanical contact and dynamic controllability. Compared with traditional mechanical bearings, they have the advantages of long life, simple structure, and low noise. In many application scenarios that require high-speed motors, active magnetic bearings have been used to support the rotation of the rotor to eliminate friction and active control. Vibration is a common problem in rotating machinery. Due to its mechanical characteristics, traditional bearings are difficult to solve the vibration caused by stiffness, while active magnetic bearings have controllable stiffness, which makes it possible to suppress vibration. In addition, due to the special structure of some high-speed motors, sensors such as rotary encoders or displacement sensors cannot be installed. Therefore, it is necessary to observe the speed and rotor position in real time while implementing the control algorithm of the magnetic suspension system.

[0003] The radial displacement vibration of the magnetic bearing rotor during the rotation of the motor is a common problem in the magnetic bearing system. Due to the machining error, the geometric center and the center of gravity of the rotor are not coincident, so centrifugal force is generated when the rotor rotates. In the magnetic bearing system, the centrifugal force causes the centrifugal displacement of the rotor and causes current fluctuations through the sensor and controller. There are resonant frequencies in the first and second order modes of the rotor, which makes the system more prone to instability at a specific speed, resulting in mechanical collision.

[0004] Existing magnetic bearing control methods and vibration suppression algorithms often require the use of speed sensors or displacement sensors. However, in actual use, some high-speed motors are difficult to install due to their special structures, and the vibration suppression function of these magnetic bearing systems is often difficult to achieve. Summary of the invention

[0005] In view of this, it is necessary to provide a vibration suppression method, device and system for a rotor in a magnetic bearing system, so as to solve the problem of how to suppress the vibration of the rotor without using a position sensor.

[0006] In order to solve the above problems, in a first aspect, the present invention provides a vibration suppression method for a rotor in a magnetic bearing system, comprising: Based on the current signal of the winding of the magnetic bearing at the current moment and the first displacement signal of the rotor at the previous moment, a second displacement signal of the rotor at the current moment is predicted; Determine a current compensation signal based on the rotational speed frequency of the rotor determined by the current signal of the winding at the current moment and the second displacement signal; determine a current compensation signal based on the second displacement signal and the rotational speed frequency of the rotor; The current compensation signal and the original current command are superimposed to obtain a target current command; the target current command is used to indicate the generation of a target current signal in the winding; the target current signal is used to suppress the vibration of the rotor.

[0007] In a possible implementation, the current signal of the winding of the magnetic bearing at the current moment and the first displacement signal of the rotor at the previous moment are used to predict the second displacement signal of the rotor at the current moment, including: Inputting the current signal and the first displacement signal into a trained prediction model to obtain the second displacement signal output by the prediction model; The prediction model is obtained by training the RNN algorithm based on historical current signals and historical displacement signals.

[0008] In a possible implementation, before determining the current compensation signal based on the rotational speed frequency of the rotor determined by the current signal of the winding at the current moment and the second displacement signal, the method further includes: Using a high-pass filter to filter out a DC component in the current signal to obtain a filtered current signal; A phase-locked loop is used to extract the frequency of the filtered current signal to obtain the rotation speed frequency.

[0009] In a possible implementation, determining the current compensation signal based on the rotational speed frequency of the rotor determined by the current signal of the winding at the current moment and the second displacement signal includes: The second displacement signal and the rotation speed frequency are input into a quasi-proportional resonator to obtain the current compensation signal.

[0010] In a possible implementation, before superimposing the current compensation signal and the original current command to obtain the target current command, the method further includes: The original current command is determined based on the second displacement signal and a preset reference displacement command.

[0011] In a possible implementation, before predicting the second displacement signal of the rotor at the current moment based on the current signal of the winding of the magnetic bearing at the current moment and the first displacement signal of the rotor at the previous moment, the method further includes: The current sensor is used to collect the current signal of the winding on any radial degree of freedom of the magnetic bearing.

[0012] In a second aspect, the present invention further provides a vibration suppression device for a rotor in a magnetic bearing system, comprising: A displacement prediction model, used to predict a second displacement signal of the rotor at a current moment based on a current signal of a winding of the magnetic bearing at a current moment and a first displacement signal of the rotor at a previous moment; A quasi-proportional resonator, used to determine a current compensation signal based on the rotational speed frequency of the rotor determined by the current signal of the winding at a current moment and the second displacement signal; A power amplifier is used to superimpose the current compensation signal and the original current instruction to obtain a target current instruction; the target current instruction is used to indicate the generation of a target current signal in the winding; the target current signal is used to suppress the vibration of the rotor.

[0013] In a possible implementation, the method further includes: A high-pass filter, used to filter out a DC component in the current signal to obtain a filtered current signal; A phase-locked loop is used to extract the frequency of the filtered current signal to obtain the rotational speed frequency.

[0014] In a possible implementation, the method further includes: The controller is used to determine the original current instruction based on the second displacement signal and a preset reference displacement instruction.

[0015] In a third aspect, the present invention further provides a magnetic bearing system, comprising the vibration suppression device for a rotor in the magnetic bearing system described in any of the above implementations.

[0016] The beneficial effects of the present invention are as follows: the vibration suppression method, device and system of the rotor in the magnetic suspension bearing system provided by the present invention predicts the second displacement signal of the rotor at the current moment according to the current signal of the winding at the current moment and the first displacement signal of the rotor at the previous moment by using a neural network algorithm, and determines the rotational speed frequency according to the current signal, and can extract the rotational frequency and the rotor position without installing a position sensor inside the motor, which can greatly optimize the structural design of the motor, simplify the system architecture, avoid the working instability and maintenance and repair costs caused by sensor damage, and determine the current compensation signal according to the second displacement signal and the rotational speed frequency of the rotor, and superimpose the current compensation signal and the original current instruction to obtain the target current instruction, thereby generating a target current signal in the winding to suppress the vibration of the rotor, and introducing the current compensation signal through radial displacement and the winding current signal, which can effectively implement the vibration suppression algorithm in the magnetic bearing system where the sensor is not installed or cannot be installed, and effectively suppress the vibration of the rotor. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0018] Figure 1 One of the flow charts of an embodiment of a method for suppressing vibration of a rotor in a magnetic bearing system provided by the present invention; Figure 2 One of the trajectory tracking schematic diagrams of the prediction model provided by the present invention; Figure 3 The second schematic diagram of trajectory tracking of the prediction model provided by the present invention; Figure 4 A schematic diagram of the structure of a quasi-proportional resonator provided by the present invention; Figure 5 A schematic structural diagram of an embodiment of a vibration suppression device for a rotor in a magnetic bearing system provided by the present invention; Figure 6 A second flow chart of an embodiment of a method for suppressing vibration of a rotor in a magnetic bearing system provided by the present invention; Figure 7 This is a diagram of the simulation results of single-degree-of-freedom displacement vibration suppression of the magnetic bearing control system provided by the present invention. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative work are within the scope of protection of the present invention.

[0020] In the description of the embodiments of the present invention, unless otherwise specified, "multiple" means two or more than two. "And / or" describes the association relationship of associated objects, indicating that three relationships may exist. For example, "A and / or B" may mean: A exists alone, A and B exist at the same time, and B exists alone.

[0021] The descriptions of "first", "second", etc. involved in the embodiments of the present invention are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the technical features defined as "first" or "second" may explicitly or implicitly include at least one of the features.

[0022] Reference to "embodiments" herein means that a particular feature, structure, or characteristic described in conjunction with the embodiments may be included in at least one embodiment of the present invention. The appearance of the phrase in various places in the specification does not necessarily refer to the same embodiment, nor is it an independent or alternative embodiment that is mutually exclusive with other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0023] The present invention provides a vibration suppression method, device and system for a rotor in a magnetic bearing system, which are described below respectively.

[0024] Figure 1 One of the flow charts of an embodiment of a method for suppressing vibration of a rotor in a magnetic bearing system provided by the present invention is as follows: Figure 1 As shown, the vibration suppression method of the rotor in the magnetic bearing system includes: S101. Predicting a second displacement signal of the rotor at a current moment based on a current signal of a winding of a magnetic bearing at a current moment and a first displacement signal of a rotor at a previous moment.

[0025] In step S101 , the current signal may be a current signal of a winding corresponding to any radial degree of freedom of the magnetic bearing at the current moment.

[0026] Based on the current current signal and the displacement signal at the previous moment, the neural network algorithm can accurately predict the second displacement signal of the rotor at the current moment. That is, the rotor displacement signal can be obtained without installing a position sensor inside the motor, which can greatly optimize the motor's structural design, simplify the system architecture, and avoid unstable operation and maintenance costs caused by sensor damage.

[0027] The neural network algorithm can learn and capture complex input-output relationships. By training the neural network model, it can learn the potential correlation between the current signal and the displacement signal, so that the second displacement signal of the rotor at the current moment can be accurately predicted based on the current current signal and the displacement signal at the previous moment. The neural network algorithm can be a recurrent neural network algorithm, a decision tree algorithm, or a support vector regression algorithm.

[0028] It is understandable that after the second displacement signal at the current moment is predicted, the second displacement signal and the current signal at the next moment can be used at the next moment to predict the displacement signal at the next moment.

[0029] S102: Determine a current compensation signal based on the rotational speed frequency of the rotor determined by the current signal of the winding at the current moment and the second displacement signal.

[0030] In step S102, the rotational frequency of the magnetic bearing rotor can be observed through a phase-locked loop using the winding current signal collected by the radial degree of freedom.

[0031] By using the rotational speed frequency and the second displacement signal, a current compensation signal for suppressing vibration can be calculated.

[0032] S103, superimposing the current compensation signal and the original current command to obtain a target current command; the target current command is used to indicate the generation of a target current signal in the winding; the target current signal is used to suppress the vibration of the rotor.

[0033] In step S103, the original current command can be determined according to the second displacement signal and the preset reference displacement command. The calculated current compensation signal is superimposed on the original current command to obtain a target current command.

[0034] The target current instruction is input into the winding of the magnetic bearing system. The winding can generate a target current signal according to the target current instruction. The target current signal can change the magnetic field distribution around the winding, thereby applying a specific electromagnetic force to the rotor to suppress the vibration of the rotor.

[0035] By precisely controlling the target current signal, the electromagnetic force acting on the rotor can be adjusted in real time to offset or reduce the various disturbance forces that cause rotor vibration. This can effectively suppress rotor vibration and improve the stability and performance of the magnetic bearing system.

[0036] The vibration suppression method of the rotor in the magnetic bearing system provided by the embodiment of the present invention predicts the second displacement signal of the rotor at the current moment by using a neural network algorithm according to the current signal of the winding at the current moment and the first displacement signal of the rotor at the previous moment, and determines the rotational speed frequency according to the current signal. The rotational frequency and the rotor position can be extracted without installing a position sensor inside the motor, which can greatly optimize the structural design of the motor, simplify the system architecture, avoid working instability and maintenance and repair costs caused by sensor damage, and determine the current compensation signal according to the second displacement signal and the rotational speed frequency of the rotor, superimpose the current compensation signal and the original current command to obtain the target current command, thereby generating a target current signal in the winding to suppress the vibration of the rotor, and introduce the current compensation signal through the radial displacement and the winding current signal, which can effectively implement the vibration suppression algorithm in the magnetic bearing system where the sensor is not installed or cannot be installed, and effectively suppress the vibration of the rotor.

[0037] In some embodiments of the present invention, the method further includes: The current sensor is used to collect the current signal of the winding on any radial degree of freedom of the magnetic bearing.

[0038] The magnetic bearing has multiple radial degrees of freedom, and the winding on each degree of freedom can control the movement of the rotor in that direction. By sampling with the current sensor, the current signal of the winding corresponding to a certain radial degree of freedom of the magnetic bearing in the current state can be obtained.

[0039] In some embodiments of the present invention, the current signal of the winding of the magnetic bearing at the current moment and the first displacement signal of the rotor at the previous moment are used to predict the second displacement signal of the rotor at the current moment, including: Inputting the current signal and the first displacement signal into a trained prediction model to obtain the second displacement signal output by the prediction model; The prediction model is obtained by training the RNN algorithm based on historical current signals and historical displacement signals.

[0040] The position at the current moment is predicted using a neural network algorithm through the acquired current signal and the displacement signal of the magnetic bearing at the previous moment.

[0041] In an embodiment of the present invention, the prediction model is obtained by training the RNN algorithm, and the prediction model is trained and verified by a collected data set, the data set includes historical current signals and historical displacement signals, and the displacement observation of the magnetic bearing rotor is completed by adjusting the structural parameters and sequence length.

[0042] For example, Figure 2 and Figure 3 A schematic diagram of the trajectory tracking of the prediction model provided by the present invention, such as Figure 2 and Figure 3 As shown, the prediction model can accurately predict the rotor displacement signal by making full use of historical data for training, and has high accuracy when processing the complex dynamic characteristics of the magnetic bearing system.

[0043] The vibration suppression method of the rotor in the magnetic bearing system provided by the embodiment of the present invention selects the RNN algorithm for model training, and utilizes the RNN's processing ability for sequence data to effectively capture the previous and next dependencies in the time series information. By continuously iteratively updating the weight parameters of the network, the model gradually learns the mapping relationship between the current signal and the previous displacement signal and the subsequent displacement signal.

[0044] In some embodiments of the present invention, before determining the current compensation signal based on the rotor speed frequency determined by the current signal of the winding at the current moment and the second displacement signal, the method further includes: Using a high-pass filter to filter out a DC component in the current signal to obtain a filtered current signal; A phase-locked loop is used to extract the frequency of the filtered current signal to obtain the rotation speed frequency.

[0045] The magnetic bearing winding current signal first passes through a high-pass filter and then enters the phase-locked loop to obtain the rotation frequency of the magnetic bearing rotor, thereby inputting the predicted second displacement signal and speed frequency signal into the quasi-proportional resonator control link, and outputting a vibration suppression compensation signal of the current command.

[0046] The motor rotation frequency can be obtained from the current signal using a phase-locked loop. Since the phase-locked loop is more sensitive to DC components, a high-pass filter is added to the front end of the phase-locked loop to filter out the DC component in the current signal.

[0047] In some embodiments of the present invention, the current compensation signal is determined based on the rotational speed frequency of the rotor determined by the current signal of the winding at the current moment and the second displacement signal, including: The second displacement signal and the rotation speed frequency are input into a quasi-proportional resonator to obtain the current compensation signal.

[0048] Figure 4 The schematic diagram of the structure of the quasi-proportional resonator provided by the present invention is as follows: Figure 4 As shown, by inputting the second displacement signal and the rotation speed frequency into a quasi-proportional resonator (Quasi Proportional Resonance, QPR), a vibration suppression compensation signal of the current command can be obtained.

[0049] The quasi-proportional resonator has a large gain at the resonant frequency and also has a certain gain bandwidth, which can ensure the stability of the system while suppressing vibration.

[0050] The vibration suppression method of the rotor in the magnetic bearing system provided in the embodiment of the present invention inputs the second displacement signal and the rotational speed frequency into the quasi-proportional resonator to obtain a current compensation signal. The quasi-proportional resonator has a large gain at the resonant frequency and also has a certain gain bandwidth, so that the stability of the system can be ensured while suppressing the vibration.

[0051] In some embodiments of the present invention, before superimposing the current compensation signal and the original current instruction to obtain the target current instruction, the method further includes: The original current command is determined based on the second displacement signal and a preset reference displacement command.

[0052] Through the predicted second displacement signal and according to the preset reference displacement instruction of the system, the original current instruction can be obtained through the position outer loop calculation.

[0053] Exemplarily, the second displacement signal is converted into an electrical signal to obtain the original radial displacement, and the displacement difference signal between the original radial displacement and the preset reference displacement instruction is input into the displacement controller. The displacement controller processes the displacement difference signal using the control algorithm to obtain the corresponding original current instruction.

[0054] The present invention uses an observation algorithm to obtain a speed frequency and a displacement signal through a current signal to realize a vibration suppression algorithm for a magnetic bearing. Its basic control algorithm includes a position outer loop, a current inner loop, a frequency observer, a displacement observer, and a vibration suppression feedforward compensation algorithm. The algorithm reduces the radial displacement vibration of the magnetic bearing rotor and avoids damage such as system instability and mechanical collision caused by vibration. Unlike the current mainstream method, the displacement information and speed frequency of the present invention can be obtained through current signal observation, which increases the use scenarios of the control algorithm.

[0055] Figure 5 A schematic structural diagram of an embodiment of a vibration suppression device for a rotor in a magnetic bearing system provided by the present invention is shown in FIG. Figure 5 As shown, the vibration suppression device 500 of the rotor in the magnetic bearing system provided by the embodiment of the present invention includes: A displacement prediction model 501, used to predict a second displacement signal of the rotor at a current moment based on a current signal of a winding of a magnetic bearing at a current moment and a first displacement signal of the rotor at a previous moment; A quasi-proportional resonator 502, configured to determine a current compensation signal based on the rotational speed frequency of the rotor determined by the current signal of the winding at a current moment and the second displacement signal; The power amplifier 503 is used to superimpose the current compensation signal and the original current instruction to obtain a target current instruction; the target current instruction is used to indicate the generation of a target current signal in the winding; the target current signal is used to suppress the vibration of the rotor.

[0056] The vibration suppression device for the rotor in the magnetic bearing system provided by the embodiment of the present invention uses a displacement prediction model to predict the second displacement signal of the rotor at the current moment according to the current signal of the winding at the current moment and the first displacement signal of the rotor at the previous moment, and uses a neural network algorithm to determine the rotational speed frequency according to the current signal. The rotational frequency and the rotor position can be extracted without installing a sensor inside the motor, which can greatly optimize the structural design of the motor, simplify the system architecture, avoid working instability and maintenance and repair costs caused by sensor damage, and use a quasi-proportional resonator to determine the current compensation signal according to the second displacement signal and the rotational speed frequency of the rotor, and use a power amplifier to superimpose the current compensation signal and the original current instruction to obtain a target current instruction, thereby generating a target current signal in the winding to suppress the vibration of the rotor, and introducing the current compensation signal through radial displacement and the winding current signal, which can effectively implement the vibration suppression algorithm in the magnetic bearing system where the sensor is not installed or cannot be installed, adjust the system stiffness, and solve the problem of mechanical device damage caused by excessive radial displacement at different speeds.

[0057] In some embodiments of the present invention, it further includes: A high pass filter 504, used to filter out the DC component in the current signal to obtain a filtered current signal; The phase-locked loop 505 is used to extract the frequency of the filtered current signal to obtain the rotation speed frequency.

[0058] The magnetic bearing winding current signal first passes through a high-pass filter and then enters the phase-locked loop to obtain the rotation frequency of the magnetic bearing rotor, thereby inputting the predicted second displacement signal and speed frequency signal into the quasi-proportional resonator control link, and outputting a vibration suppression compensation signal of the current command.

[0059] The motor rotation frequency can be obtained from the current signal using a phase-locked loop. Since the phase-locked loop is more sensitive to DC components, a high-pass filter is added to the front end of the phase-locked loop to filter out the DC component in the current signal.

[0060] In some embodiments of the present invention, it further includes: The controller 506 is configured to determine the original current instruction based on the second displacement signal and a preset reference displacement instruction.

[0061] Through the predicted second displacement signal and according to the preset reference displacement instruction of the system, the original current instruction can be obtained through the position outer loop calculation.

[0062] Exemplarily, the second displacement signal is converted into an electrical signal to obtain the original radial displacement, and the displacement difference signal between the original radial displacement and the preset reference displacement instruction is input into the displacement controller. The displacement controller processes the displacement difference signal using the control algorithm to obtain the corresponding original current instruction.

[0063] The present invention obtains the current signal of the radial degree of freedom of the magnetic bearing, obtains the speed frequency signal by observing the phase-locked loop, obtains the displacement signal by using the machine learning model, calculates the original current command signal by using the displacement signal, obtains the current compensation signal according to the speed frequency and the radial displacement signal, feed-forwards and superimposes the original current command and the current compensation signal to obtain the actual target current command, and enables the magnetic bearing to achieve more stable suspension at the speed through the actual current generated. The present invention can effectively suppress the radial vibration of the magnetic bearing rotor and improve the stability of the magnetic bearing during the speed increase process. The corresponding observation algorithm solves the problem that the current sensors such as rotary encoders or position sensors cannot be installed due to the special structure of high-speed motors.

[0064] Based on the vibration suppression device for a rotor in a magnetic bearing system in the above embodiments, the present invention also provides a magnetic bearing system, including the vibration suppression device for a rotor in a magnetic bearing system described in any of the above implementations.

[0065] The magnetic bearing system only needs a current signal to achieve displacement vibration suppression of the magnetic bearing, thereby solving the collision and damage of mechanical components caused by radial displacement of the magnetic bearing rotor at different speeds and improving the reliability and stability of the system.

[0066] That is, the present invention proposes a vibration suppression control method for a magnetic bearing system based on a position sensorless system, which has the advantage that only a current signal is required to achieve displacement vibration suppression of the magnetic bearing, thereby solving the collision and damage of mechanical components caused by radial displacement of the magnetic bearing rotor at different speeds, and improving the reliability and stability of the system.

[0067] By using the winding current signal collected by the radial degree of freedom, the speed frequency of the magnetic bearing is observed through the phase-locked loop, and the current position of the magnetic bearing is predicted using the position signal and current signal at the previous moment. At the same time, the vibration suppression current compensation signal is calculated using the speed frequency and displacement signal, and the current command signal is fed forward to achieve position sensorless vibration suppression of the magnetic bearing at different speeds.

[0068] For example, Figure 6 The second flow chart of an embodiment of the method for suppressing vibration of a rotor in a magnetic bearing system provided by the present invention is as follows: Figure 6 As shown, the vibration suppression method of the rotor in the magnetic bearing system includes: S601. Acquire a winding current signal corresponding to a certain radial degree of freedom of the magnetic bearing in the current state through sampling by a current sensor.

[0069] S602, using the acquired current signal and the displacement signal of the magnetic bearing at the previous moment, using a neural network algorithm to complete the prediction of the current position.

[0070] Among them, the location prediction algorithm uses the RNN algorithm for model training.

[0071] S603, using the predicted displacement signal and the reference displacement instruction preset by the system, an original current instruction is calculated through a position outer loop.

[0072] S604: Obtain a rotation speed frequency observation signal from the collected current signal through a phase-locked loop, and calculate a current compensation signal for vibration suppression based on the predicted displacement signal and the rotation speed frequency observation signal.

[0073] Among them, the magnetic bearing winding current signal first passes through a high-pass filter and then enters the phase-locked loop to obtain the rotation frequency of the magnetic bearing rotor. The predicted displacement signal and speed frequency signal are input into the quasi-proportional resonator control link to output the vibration suppression compensation signal of the current command.

[0074] S605 , feed-forward the current compensation signal and add it to the original current signal to obtain a system target current command.

[0075] S606: Generate a corresponding current signal in the magnetic bearing winding using the system target current instruction through the current loop to adjust the suspension state of the magnetic bearing system.

[0076] The magnetic bearing system is a typical high-order nonlinear system. Its nonlinear characteristics are mainly caused by the nonlinearity of force-current-displacement. When the shaft deviates from the center within a small range, the electromagnetic force can be expressed as a linear combination of the eccentric displacement of the shaft and the control current, which realizes the linearization of the electromagnetic force. Two adjacent magnetic poles form a pair of poles, which can generate attraction to the rotor, and the other pair of poles opposite to it can also generate electromagnetic attraction. The differential action of the two pairs of poles realizes the control of one degree of freedom of the rotor.

[0077] The power amplifier can usually be approximated as linear, so the transfer function from centrifugal force to displacement in the system can be expressed as: (1) in, The dynamic equation representing the single degree of freedom of the rotor under the influence of electromagnetic force, represents the controller transfer function, represents the current stiffness of the magnetic bearing, Indicates the sensor sampling gain.

[0078] make , and substitute it into formula (1) to get: (2) (3) in, , , Respectively represent PID control parameters, represents the displacement stiffness of the magnetic bearing, represents the mass of the magnetic bearing rotor, Indicates the angular velocity of rotation.

[0079] In the steady state, the centrifugal force can be expressed as: (4) in, represents the eccentricity, is the angular velocity of rotation, is the initial phase value of the centrifugal force.

[0080] Therefore, the vibration amplitude of the displacement can be expressed as: (5) According to the expression of vibration amplitude, when the PID parameters remain unchanged, increasing Can effectively suppress vibration, however, with As the gain of increases, the introduced noise gain will also increase, affecting the stability of the system. To reduce vibration, it is only necessary to increase the controller gain. The proportional resonant controller has infinite gain at its resonant frequency. Applying the proportional resonant controller in the displacement control loop can effectively suppress the vibration in the displacement.

[0081] However, in practical applications, the proportional resonator cannot effectively suppress the vibration caused by the rotation frequency due to the fluctuation of the rotation speed. Therefore, the quasi-proportional resonator is often used more widely. QPR has a large gain at the resonant frequency and also has a certain gain bandwidth, which can ensure the stability of the system while suppressing vibration.

[0082] The phase-locked loop is used to obtain the motor rotation frequency from the current signal. Since the phase-locked loop is more sensitive to the DC component, a high-pass filter is added at the front end to filter out the DC component. The specific control block diagram is as follows: Figure 4 shown.

[0083] When QPR is applied to the control loop, the transfer function of the system centrifugal force to displacement is: (6) in, , They represent the quasi-proportional resonator control parameters, represents the quasi-proportional resonator cut-off frequency, represents the resonant frequency of the quasi-proportional resonator, Represents the cutoff frequency of the power amplifier transfer function.

[0084] Figure 7 The simulation result diagram of the single-degree-of-freedom displacement vibration suppression of the magnetic bearing control system provided by the present invention is shown in Figure 6. The Bode diagram of the transfer function corresponding to formula (6) is as follows: Figure 7 As shown in the figure, the gain of the QPR controller at the set resonant frequency is significantly lower than that of the traditional PID control. If the resonant frequency parameter always follows the rotation frequency, the displacement of the magnetic bearing system will not be affected by the centrifugal force, so the displacement vibration caused by the motor rotation will be suppressed.

[0085] The vibration suppression method of the rotor in the magnetic bearing system provided by the present invention has the following advantages: (1) By collecting the winding current signal, the rotor displacement and rotation frequency at the corresponding degree of freedom are obtained. The rotation frequency and rotor position can be extracted without installing sensors inside the motor. This can greatly optimize the motor's structural design, simplify the system architecture, and avoid unstable operation and maintenance costs caused by sensor damage.

[0086] (2) By introducing the current compensation signal through the radial displacement and winding current signal, the vibration suppression algorithm can be effectively implemented in the magnetic bearing system where the sensor is not installed or cannot be installed, and the system stiffness can be adjusted, thereby solving the problem of mechanical device damage caused by excessive radial displacement at different speeds.

[0087] Those skilled in the art will appreciate that all or part of the processes of the above-mentioned embodiments can be implemented by instructing related hardware (such as a processor, a controller, etc.) through a computer program, and the computer program can be stored in a computer-readable storage medium, wherein the computer-readable storage medium is a disk, an optical disk, a read-only storage memory, or a random access memory, etc.

[0088] The vibration suppression method, device and system of the rotor in the magnetic bearing system provided by the present invention are introduced in detail above. Specific examples are used in this article to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea; at the same time, for technical personnel in this field, according to the idea of ​​the present invention, there will be changes in the specific implementation method and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

Claims

1. A method for suppressing vibration of a rotor in a magnetic bearing system, characterized in that: include: Based on the current signal of the winding of the magnetic bearing at the current moment and the first displacement signal of the rotor at the previous moment, a second displacement signal of the rotor at the current moment is predicted; Determine a current compensation signal based on the rotational speed frequency of the rotor determined by the current signal of the winding at the current moment and the second displacement signal; Superimposing the current compensation signal and the original current command to obtain a target current command; The target current instruction is used to instruct the generation of a target current signal in the winding; the target current signal is used to suppress the vibration of the rotor.

2. The vibration suppression method of the rotor in the magnetic bearing system according to claim 1, characterized in that: The method predicts a second displacement signal of the rotor at the current moment based on the current signal of the winding of the magnetic bearing at the current moment and the first displacement signal of the rotor at the previous moment, including: Inputting the current signal and the first displacement signal into a trained neural network prediction model to obtain the second displacement signal output by the neural network prediction model; The neural network prediction model is obtained by training the RNN algorithm based on historical current signals and historical displacement signals.

3. The vibration suppression method of a rotor in a magnetic bearing system according to claim 1, characterized in that: Before determining the current compensation signal based on the rotor speed frequency determined by the current signal of the winding at the current moment and the second displacement signal, the method further includes: Using a high-pass filter to filter out a DC component in the current signal to obtain a filtered current signal; A phase-locked loop is used to extract the frequency of the filtered current signal to obtain the rotation speed frequency.

4. The vibration suppression method of a rotor in a magnetic bearing system according to claim 1, characterized in that: The step of determining the current compensation signal based on the rotational speed frequency of the rotor determined by the current signal of the winding at the current moment and the second displacement signal comprises: The second displacement signal and the rotation speed frequency are input into a quasi-proportional resonator to obtain the current compensation signal.

5. The vibration suppression method of a rotor in a magnetic bearing system according to claim 1, characterized in that: Before superimposing the current compensation signal and the original current command to obtain the target current command, the method further includes: The original current command is determined based on the second displacement signal and a preset reference displacement command.

6. The method for suppressing vibration of a rotor in a magnetic bearing system according to claim 1, characterized in that: Before predicting the second displacement signal of the rotor at the current moment based on the current signal of the winding of the magnetic bearing at the current moment and the first displacement signal of the rotor at the previous moment, the method further includes: The current sensor is used to collect the current signal of the winding on any radial degree of freedom of the magnetic bearing.

7. A vibration suppression device for a rotor in a magnetic bearing system, characterized in that: include: A displacement prediction model, used to predict a second displacement signal of the rotor at a current moment based on a current signal of a winding of the magnetic bearing at a current moment and a first displacement signal of the rotor at a previous moment; A quasi-proportional resonator, used to determine a current compensation signal based on the rotational speed frequency of the rotor determined by the current signal of the winding at a current moment and the second displacement signal; A power amplifier, used for superimposing the current compensation signal and the original current instruction to obtain a target current instruction; The target current instruction is used to instruct the generation of a target current signal in the winding; the target current signal is used to suppress the vibration of the rotor.

8. The vibration suppression device for a rotor in a magnetic bearing system according to claim 7, characterized in that: Also includes: A high-pass filter, used to filter out a DC component in the current signal to obtain a filtered current signal; A phase-locked loop is used to extract the frequency of the filtered current signal to obtain the rotational speed frequency.

9. The vibration suppression device for a rotor in a magnetic bearing system according to claim 7, characterized in that: Also includes: The controller is used to determine the original current instruction based on the second displacement signal and a preset reference displacement instruction.

10. A magnetic bearing system, characterized in that: A vibration suppression device for a rotor in a magnetic bearing system comprising any one of claims 7 to 9.

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