CN102392828B - Magnetic molecular pump rotor nutation peak vibration control method - Google Patents
Magnetic molecular pump rotor nutation peak vibration control method Download PDFInfo
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Abstract
The invention relates to a magnetic molecular pump rotor nutation peak vibration control method. When a magnetic molecular pump rotor is accelerated, a magnetic molecular pump controller controls a rotor displacement detector to acquire rotor displacement signals, and the displacement signals receive fast Fourier transform, so that a rotor vibration frequency spectrum is obtained. According to the obtained rotor vibration frequency spectrum, the frequency and amplitude of a rotor nutation peak are obtained, and whether the amplitude of the rotor nutation peak exceeds a preset stable operation threshold or not is judged. If the amplitude of the rotor nutation peak exceeds the preset stable operation threshold, then a nutation peak inhibition method is adopted to inhibit the nutation peak, and thereby the self-adaptive control of the rotor nutation peak of a magnetic molecular pump within the whole operating frequency range is realized. In the process, if rotor vibration exceeds a safe threshold, then a motor is controlled to be shut down in order to guarantee the operating safety of the magnetic molecular pump. The control method provided by the invention solves the technical problem that the inhibiting effect is limited in the prior art presetting fixed parameters to inhibit the magnetic molecular pump rotor nutation peak, and realizes the self-adaptive control of the magnetic molecular pump rotor nutation peak.
Description
Technical field
The present invention relates to a kind of maglev molecular pump controlling method, specifically a kind of rotor nutating peak vibration control method of maglev molecular pump.
Background technique
Molecular pump be utilize High Rotation Speed rotor MOMENTUM TRANSMISSION to gas molecule, make it to obtain directed velocity, thus compressed, be driven to a kind of vacuum pump of taking away for prime after relief opening.Maglev molecular pump is to utilize magnetic bearing to produce electromagnetic force to make rotor suspension aloft, realizes a kind of novel high-performance molecular pump that machinery-free contact between rotor and stator and rotor-position can ACTIVE CONTROL.Because maglev molecular pump has without friction, without advantages such as lubricated, pollution-free, high-speed, life-span are long, so maglev molecular pump is widely used in the vacuum acquisition field of condition of high vacuum degree, high-cleanness, high.
Maglev molecular pump is a kind of machinery of High Rotation Speed, and it relies on magnetic bearing by its rotor suspension aloft.Maglev molecular pump rotor is in boosting velocity procedure, and rotor is because gyroscopic effect produces nutating.The nutating of maglev molecular pump rotor refers to that the rotor axis of rotation is around the positive precession of hollow shaft.The nutating peak of maglev molecular pump rotor refers to the vibration displacement spectral peak that rotor nutating causes, and nutating peak amplitude refers to the numerical values recited of this spectral peak, and nutating peak frequency refers to the frequency of rotor nutating.Amplitude and the frequency at the nutating peak of maglev molecular pump rotor can change along with the variation of rotor speed.If when intrinsic certain model frequency of the nutating peak frequency of maglev molecular pump rotor and maglev molecular pump stator structure or rotor blade is identical and amplitude is enough large, can cause that resonance causes rotor unstability, therefore must suppress the nutating peak of rotor.Common rotor nutating peak inhibition method is to suppress by rotor being applied to the moment reverse with gyrostatic moment the vibration that rotor nutating peak causes, moment is herein generally predefined based on experience value.Wherein, gyrostatic moment refers to the resistance moment that the rotor of High Rotation Speed shows when running shaft changes orientation in space, and its size is directly proportional to the angular velocity of precession of rotor moment of inertia, rotating speed and the axis of rotation.Because amplitude and the frequency at rotor nutating peak changes with rotor speed, if adopt preset parameter to suppress nutating peak, cannot realize good control to the rotor oscillation of whole working rotor speed range; When if the structure of system or characteristic change, rotor nutating peak also can change thereupon, and predefined control parameter possibly cannot realize the inhibition to rotor nutating peak.
For addressing the above problem, the present invention proposes a kind of magnetic molecular pump rotor nutation peak vibration control method, the method can realize in whole working rotor speed range rotor nutating is realized to good inhibition automatically, guarantees maglev molecular pump stable operation.
Summary of the invention
For this reason, technical problem to be solved by this invention is in prior art in maglev molecular pump rotor nutating peak inhibition method, it is controlled parameter and fixes, inhibition is restricted, thereby propose a kind of situation of change that can automatically detect maglev molecular pump rotor nutating peak, and automatically revise the corresponding magnetic molecular pump rotor nutation peak vibration control method of controlling parameter.
For solving the problems of the technologies described above, the magnetic molecular pump rotor nutation peak vibration control method that the present invention proposes, comprises the steps:
(1), during maglev molecular pump rotor raising speed, maglev molecular pump controller is controlled rotor displacement detection device and is gathered the displacement signal of described maglev molecular pump rotor, and described displacement signal is transferred to rotor oscillation detection device;
(2) in described rotor oscillation detection device, be provided with digital signal processing unit, described digital signal processing unit carries out FFT by described displacement signal and obtains rotor oscillation frequency spectrum, according to described rotor oscillation frequency spectrum, obtain frequency and the amplitude at rotor nutating peak, then the frequency at described rotor nutating peak and amplitude are transferred in described maglev molecular pump controller;
(3) described maglev molecular pump controller comprises vibration control unit, rotor nutating peak, in described nutating peak control unit, set in advance control parameter, in described maglev molecular pump controller, set in advance default stable operation threshold value and the default secure threshold at rotor nutating peak, whether the amplitude at the rotor nutating peak obtaining in described maglev molecular pump controller determining step (2) surpasses described default stable operation threshold value, if the amplitude at described rotor nutating peak surpasses described default stable operation threshold value, the control parameter of revising vibration control unit, described rotor nutating peak suppresses nutating peak,
(4) when rotor speed changes, repeating step (1)-(3), thereby obtain being applicable to the control parameter of the vibration control unit, a series of rotor nutatings peak of every speed section, by the control reference record of vibration control unit, described rotor nutating peak in pump internal memory;
The control parameter of vibration control unit, described rotor nutating peak comprises a series of nutatings peak inhibitory control parameter and corresponding velocity range thereof;
In said process, if detecting rotor oscillation, described rotor oscillation detection device surpasses described default secure threshold, described maglev molecular pump controller is controlled motor stopping, guarantees the security of operation of maglev molecular pump;
(5) described maglev molecular pump controller control rate detection device detection rotor rotating speed, and control according to control parameter corresponding to this speed stage described in rotor speed invocation step (4), thereby maglev molecular pump stable operation guaranteed.
In described step (2), described digital signal processing unit comprises high-speed figure process chip.
In described step (3), the default stable operation threshold value at the described rotor nutating peak of setting is 30% of this frequency vibration of rotor amplitude, and the default secure threshold at the described rotor nutating peak of setting is 60% of this frequency vibration of rotor amplitude.
Technique scheme of the present invention has the following advantages compared to existing technology,
(1) magnetic molecular pump rotor nutation peak vibration control method of the present invention can detect the situation of change at maglev molecular pump rotor nutating peak automatically, and the corresponding parameter of controlling is revised in variation automatically accordingly, the self adaptive control of realization to the rotor nutating peak of whole working rotor frequency range, thus system stability work guaranteed.
(2) magnetic molecular pump rotor nutation peak vibration control method of the present invention; in said process; if described rotor oscillation detection device detects the vibration of rotor, surpass default secure threshold, control motor stopping, guarantee maglev molecular pump security of operation.That is to say, when maglev molecular pump controller cannot be realized the inhibition to rotor nutating peak, when unstability tendency appears in rotor, program can be controlled molecular pump motor stopping reduction of speed automatically, thereby plays the object of protection maglev molecular pump.
(3) magnetic molecular pump rotor nutation peak vibration control method of the present invention, in described step (2), described digital signal processing unit comprises high-speed figure process chip, for example adopt fpga chip, improve the speed of Digital Signal Processing, guarantee the real-time of data processing, contributed to realize fast the inhibition to rotor nutating peak.
(4) magnetic molecular pump rotor nutation peak vibration control method of the present invention, in described step (3), the stable operation threshold value at default described rotor nutating peak is 30% of this frequency vibration of rotor amplitude, the secure threshold at default described rotor nutating peak is 60% of this frequency vibration of rotor amplitude, guarantee that described maglev molecular pump can stable operation in described stable operation threshold value, can safe operation in described secure threshold, thus described maglev molecular pump stability and safety operation guaranteed.
Accompanying drawing explanation
For content of the present invention is more likely to be clearly understood, below according to a particular embodiment of the invention and by reference to the accompanying drawings, the present invention is further detailed explanation, wherein
Fig. 1 is the structural representation of maglev molecular pump;
Fig. 2 is the front rotor rumble spectrum figure of the rotor nutating peak vibration control unit effect of maglev molecular pump;
Fig. 3 is rotor oscillation spectrogram after the rotor nutating peak vibration control unit effect of maglev molecular pump.
In figure, reference character is: 1-maglev molecular pump body, 2-maglev molecular pump rotor, 3-maglev molecular pump impeller, 4-thrust disc, 5-maglev molecular pump motor, the upper radial direction magnetic bearing of 6-, radial direction magnetic bearing under 7-, 8-axial magnetic bearing, on 9-, radially protect bearing, under 10-, radially protect bearing, 11-axially protects bearing, the upper radial displacement transducer of 12-, radial displacement transducer under 13-, 14-shaft position sensor, 15-rotor speed detection device, 16-rotor displacement testing circuit, 17-maglev molecular pump controller, 18-rotor oscillation detection device.
Embodiment
The general structure of maglev molecular pump as shown in Figure 1, by following part, formed: maglev molecular pump body 1, maglev molecular pump rotor 2, maglev molecular pump impeller 3, thrust disc 4, maglev molecular pump motor 5, upper radial direction magnetic bearing 6, lower radial direction magnetic bearing 7, axial magnetic bearing 8, on radially protect bearing 9, under radially protect bearing 10, axially protect bearing 11, upper radial displacement transducer 12, lower radial displacement transducer 13, shaft position sensor 14, rotor speed detection device 15, rotor displacement detection device 16, maglev molecular pump controller 17 and rotor oscillation detection device 18.
The embodiment that provides magnetic molecular pump rotor nutation peak vibration control method of the present invention below, comprises the following steps:
(1) during maglev molecular pump rotor 2 raising speed, maglev molecular pump controller 17 is controlled rotor displacement detection device 16 and is gathered rotor displacement signal, rotor displacement detection device 16 is herein collected the displacement signal that above radial displacement transducer 12, lower radial displacement transducer 13, shaft position sensor 14 detect, and described displacement signal is transferred to rotor oscillation detection device 18;
(2) in described rotor oscillation detection device 18, be provided with digital signal processing unit, described digital signal processing unit comprises high-speed figure process chip, adopts fpga chip in the present embodiment.Described digital signal processing unit carries out fast Fourier transform (FFT) by the displacement signal of described rotor and obtains rotor oscillation frequency spectrum, according to described rotor oscillation frequency spectrum, obtain frequency and the amplitude at rotor nutating peak, then the frequency at described rotor nutating peak and amplitude are transferred in described maglev molecular pump controller 17;
(3) described maglev molecular pump controller 17 comprises vibration control unit, rotor nutating peak, and described rotor nutating peak has set in advance control parameter in vibration control unit, and control parameter herein presets based on experience value, in subsequent process, revises.In described maglev molecular pump controller 17, set in advance default stable operation threshold value and the default secure threshold at rotor nutating peak, default stable operation threshold value described herein can be set to 30% of this frequency vibration of rotor amplitude, described default secure threshold can be set to 60% of this frequency vibration of rotor amplitude, its concrete numerical value can arrange according to concrete working environment, guarantee that described maglev molecular pump can stable operation in described default stable operation threshold value, can safe operation in described default secure threshold, thereby guarantee described maglev molecular pump stability and safety operation.Whether the amplitude at the rotor nutating peak in described maglev molecular pump controller 17 determining steps (2) surpasses described default stable operation threshold value, if the amplitude at described rotor nutating peak surpasses described default stable operation threshold value, the control parameter of revising vibration control unit, described rotor nutating peak suppresses nutating peak, in the present embodiment, the method of operating speed cross feedback suppresses nutating peak, automatically the speed cross feedback of adjusting corresponding speed section over the degree of stable operation threshold value according to the amplitude at nutating peak is controlled parameter, thereby automatically rotor nutating peak is suppressed, speed cross feedback controlling method is herein a kind of control mode conventional in prior art,
(4) when rotor speed changes, repeating step (1)-(3), thereby obtain being applicable to the vibration control unit, a series of rotor nutatings peak of every speed section, by the reference record of described rotor nutating peak vibration control unit controls, in pump internal memory, the control parameter of vibration control unit, described rotor nutating peak comprises a series of speed cross feedbacks control parameters and corresponding velocity range thereof.
In said process, if detecting the vibration of rotor, described rotor oscillation detection device 18 surpasses described default secure threshold, control motor stopping, guarantee the safety of maglev molecular pump operation.
In addition, in described step (3), speed cross feedback method is one of the inhibition method at nutating peak, can also select to suppress the additive method at nutating peak herein, as methods such as control, μ analyses.
(5) described maglev molecular pump controller 17 control rate detection device detection rotor rotating speeds, vibration control unit, described rotor nutating peak is controlled parameter according to speed cross feedback corresponding to this speed stage obtaining in rotor speed invocation step (4) and is controlled, thereby guarantees maglev molecular pump stable operation.
Before the rotor nutating peak vibration control unit effect of maglev molecular pump, as shown in Figure 2, after the rotor nutating peak vibration control unit effect of maglev molecular pump, rotor oscillation frequency spectrum as shown in Figure 3 for rotor rumble spectrum.Comparison diagram 2 and Fig. 3 are known, use after the magnetic molecular pump rotor nutation peak vibration control method of this patent proposition, and rotor nutating peak has reduced 75% left and right, has realized the effective inhibition to rotor nutating peak.
Obviously, above-described embodiment is only for example is clearly described, and the not restriction to mode of execution.For those of ordinary skill in the field, can also make other changes in different forms on the basis of the above description.Here exhaustive without also giving all mode of executions.And the apparent variation of being extended out thus or change are still among the protection domain in the invention.
Claims (1)
1. a magnetic molecular pump rotor nutation peak vibration control method, is characterized in that, comprises the steps:
(1), during maglev molecular pump rotor raising speed, maglev molecular pump controller is controlled rotor displacement detection device and is gathered the displacement signal of described maglev molecular pump rotor, and described displacement signal is transferred to rotor oscillation detection device;
(2) in described rotor oscillation detection device, be provided with digital signal processing unit, described digital signal processing unit carries out FFT by described displacement signal and obtains rotor oscillation frequency spectrum, according to described rotor oscillation frequency spectrum, obtain frequency and the amplitude at rotor nutating peak, then the frequency at described rotor nutating peak and amplitude are transferred in described maglev molecular pump controller;
(3) described maglev molecular pump controller comprises vibration control unit, rotor nutating peak, described rotor nutating peak has set in advance control parameter in vibration control unit, in described maglev molecular pump controller, set in advance default stable operation threshold value and the default secure threshold at rotor nutating peak, whether the amplitude at the rotor nutating peak obtaining in described maglev molecular pump controller determining step (2) surpasses described default stable operation threshold value, if the amplitude at described rotor nutating peak surpasses described default stable operation threshold value, the control parameter of revising vibration control unit, described rotor nutating peak suppresses nutating peak,
(4) when rotor speed changes, repeating step (1)-(3), thereby obtain being applicable to the control parameter of the vibration control unit, a series of described rotor nutating peak of every speed section, by the control reference record of vibration control unit, described rotor nutating peak in pump internal memory;
In said process, if detecting rotor oscillation, described rotor oscillation detection device surpasses described default secure threshold, described maglev molecular pump controller is controlled motor stopping, guarantees the security of operation of maglev molecular pump;
(5) described maglev molecular pump controller control rate detection device detection rotor rotating speed, and control according to control parameter corresponding to this speed stage described in rotor speed invocation step (4), thereby maglev molecular pump stable operation guaranteed.
2. controlling method according to claim 1, is characterized in that: the control parameter of vibration control unit, described rotor nutating peak comprises a series of nutatings peak inhibitory control parameter and corresponding velocity range thereof.
3. controlling method according to claim 1 and 2, is characterized in that: in described step (2), described digital signal processing unit comprises high-speed figure process chip.
4. controlling method according to claim 3, it is characterized in that: in described step (3), the default stable operation threshold value at the described rotor nutating peak arranging is 30% of this frequency vibration of rotor amplitude, and the default secure threshold at the described rotor nutating peak of setting is 60% of this frequency vibration of rotor amplitude.
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| CN104344535B (en) * | 2013-08-02 | 2017-01-25 | 广东美的制冷设备有限公司 | Method and device for adaptively adjusting frequency of conditioner motor and air conditioner |
| CN108919713A (en) * | 2018-07-12 | 2018-11-30 | 珠海格力电器股份有限公司 | Magnetic suspension bearing monitoring method and monitoring device, magnetic suspension bearing monitoring host computer and computer readable storage medium |
| CN112128108B (en) * | 2019-06-24 | 2022-10-18 | 长鑫存储技术有限公司 | Molecular pump monitoring system and molecular pump monitoring method |
| CN115628224B (en) * | 2022-10-14 | 2024-05-21 | 北方工业大学 | Magnetic suspension molecular pump blade peak online monitoring system and method |
| CN115978088B (en) * | 2023-03-20 | 2023-09-26 | 南昌航空大学 | Magnetic suspension rotor vibration control method based on self-adaptive bias and speed observer |
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