Detailed modelling and LQG\LTR control of a 2-DOF radial active magnetic bearing for rigid rotor

2021 ◽  
Vol 43 (5) ◽  
Author(s):  
Muhammad Abdul Ahad ◽  
Nadeem Iqbal ◽  
Sarvat M. Ahmad ◽  
Masroor Khan
Keyword(s):  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Rigid Rotor ◽  
Detailed Modelling

scholarly journals Research on Automatic Balance Control of Active Magnetic Bearing-Rigid Rotor System

2019 ◽  
Vol 2019 ◽  
pp. 1-13 ◽  
Author(s):  
Yang Liu ◽  
Shuaishuai Ming ◽  
Siyao Zhao ◽  
Jiyuan Han ◽  
Yaxin Ma
Keyword(s):  
Vibration Control ◽  
Rotational Speed ◽  
Notch Filter ◽  
Magnetic Bearing ◽  
Rotor System ◽  
Vibration Response ◽  
Active Magnetic Bearing ◽  
Rigid Rotor ◽  
Phase Compensation ◽  
Synchronous Control

In this paper, in order to solve the problem of unbalance vibration of rigid rotor system supported by the active magnetic bearing (AMB), automatic balancing method is applied to suppress the unbalance vibration of the rotor system. Firstly, considering the dynamic and static imbalance of the rotor, the detailed dynamic equations of the AMB-rigid rotor system are established according to Newton’s second law. Then, in order to rotate the rotor around the inertia axis, the notch filter with phase compensation is used to eliminate the synchronous control current. Finally, the variable-step fourth-order Runge–Kutta iteration method is used to solve the unbalanced vibration response of the rotor system in MATLAB simulation. The effects of the rotational speed and phase compensation angle on the unbalanced vibration control are analysed in detail. It is found that the synchronous control currents would increase rapidly with the increase of rotational speed if the unbalance vibration cannot be controlled. When the notch filter with phase shift is used to balance the rotor system automatically, the control current is reduced significantly. It avoids the saturation of the power amplifier and reduces the vibration response of the rotor system. The rotor system can be stabilized over the entire operating speed range by adjusting the compensation phase of the notch filter. The method in the paper is easy to implement, and the research result can provide theoretical support for the unbalance vibration control of AMB-rotor systems.

Nonlinear Vibration in a Vertical Rigid Rotor Supported by the Magnetic Bearing: Case Considering the Delays of Both Electric Current and Magnetic Flux

2007 ◽  
Author(s):  
Tsuyoshi Inoue ◽  
Motoki Sugiyama ◽  
Yasuhiko Sugawara ◽  
Yukio Ishida
Keyword(s):  
Magnetic Flux ◽  
Electric Current ◽  
Magnetic Force ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Nonlinear Phenomena ◽  
Control Force ◽  
Rigid Rotor ◽  
Rotating Speed ◽  
First Order

Active magnetic bearing (AMB) becomes to be widely used in various kinds of rotating machinery. However, as the magnetic force is nonlinear, nonlinear phenomena may occur when the rotating speed becomes higher and delay of control force increases. In this paper, the magnetic force is modeled by considering both the second order delay of the electric current and the first order delay of the magnetic flux, and the AMB force is represented by a power series function of the electric current and shaft displacement. The nonlinear theoretical analysis of the vertical rigid rotor supported by AMB is demonstrated. The effects of the delays and other AMB parameters on the nonlinear phenomena are clarified theoretically and experimentally.

A Numerical Study on Effect of Electromagnetic Actuator on Rigid Rotor Supported on Gas Foil Bearing

2017 ◽  
Author(s):  
Kamal Kumar Basumatary ◽  
Gaurav Kumar ◽  
Karuna Kalita ◽  
Sashindra Kumar Kakoty
Keyword(s):  
Numerical Study ◽  
Load Capacity ◽  
Current Trend ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Normal Operation ◽  
Electromagnetic Actuator ◽  
Rigid Rotor ◽  
Magnetic Actuator ◽  
The Stability

Generally, Gas Foil Bearings (GFBs) are used in high speed machineries which are quite prone to instability or wear and tear. The current trend is to develop hybrid bearings which has conventional bearing (GFB) along with active magnetic bearing as an electromagnetic actuator (EMA). The GFBs are used for normal operation and the magnetic actuator can be used for the improvement of the stability and the load capacity of the bearing. In the present work a numerical study has been carried out to study the effects of magnetic actuator on the stability of bump type GFB supported rigid rotor. A rigid rotor supported on two identical GFBs with and without EMA has been investigated. The electromagnetic forces are incorporated in the equation of motion to provide the active control. A PD controller has been used as a controller for the magnetic actuator. It has been observed that the incorporation of EMA to the GFB reduces the sub synchronous vibrations and hence increases the stability.

Modeling and Nonlinear Vibration Analysis of a Rigid Rotor System Supported by the Magnetic Bearing (Effects of Delays of Both Electric Current and Magnetic Flux)

2009 ◽  
Vol 77 (1) ◽  
Author(s):  
Tsuyoshi Inoue ◽  
Yasuhiko Sugawara ◽  
Motoki Sugiyama
Keyword(s):  
Magnetic Flux ◽  
Electric Current ◽  
Magnetic Force ◽  
Magnetic Bearing ◽  
Rotor System ◽  
Active Magnetic Bearing ◽  
Nonlinear Phenomena ◽  
Rigid Rotor ◽  
Rotating Speed ◽  
First Order

Active magnetic bearing (AMB) becomes widely used in various kinds of rotating machinery. However, as the magnetic force is nonlinear, nonlinear phenomena may occur when the rotating speed becomes high and delays of electric current or magnetic flux in the AMB relatively increase. In this paper, the magnetic force in the AMB is modeled by considering both the second-order delay of the electric current and the first-order delay of the magnetic flux. The magnetic flux in the AMB is represented by a power series function of the electric current and shaft displacement, and its appropriate representation for AMB is discussed. Furthermore, by using them, the nonlinear theoretical analysis of the rigid rotor system supported by the AMB is demonstrated. The effects of the delays and other AMB parameters on the nonlinear phenomena are clarified theoretically, and they are confirmed experimentally.

Effects of eccentricity and vibration response on high-speed rigid rotor supported by hybrid foil-magnetic bearing

2015 ◽  
Vol 230 (6) ◽  
pp. 994-1006 ◽  
Author(s):  
Sena Jeong ◽  
Yong Bok Lee
Keyword(s):  
Load Distribution ◽  
High Speed ◽  
Control Algorithm ◽  
Initial Position ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Control Force ◽  
Rigid Rotor ◽  
Reliability Parameters ◽  
Derivative Control

A hybrid foil-magnetic bearing (HFMB) consists of an air foil bearing (AFB) and an active magnetic bearing (AMB). The HFMB, inherently proposed as a backup bearing for an AMB, has many advantages, such as good controllability and the ability to exhibit preload sharing with the two types of bearings (i.e., the AFB and AMB) in high-speed turbomachinery. However, because the bearing has a limited clearance, the eccentric position of the rotor affects its stability and the reliability parameters of the AFBs such as the initial preload rub. In this study, a rigid rotor supported by an HFMB was operated at speeds of up to 18 kr/min and was tested using a proportional-derivative control algorithm, in order to reduce the vibration amplitude. In addition, to elucidate the effect of the initial eccentric position of the rotor, the control algorithm was started from the initial position of the rotor (X: from –100 to 100 µm and Y: from –80 to 200 µm) using a constant gain value. When the HFMB was active, the magnetic control force was remarkably effective in reducing the subsynchronous vibration of the rotor supported by the HFMB. Eccentricities of 0.2–0.5 corresponded to appropriate rotor positions for the hybrid bearing, and the corresponding load distribution of the AFB was found to be the optimal one. In addition, the proportional-derivative control gain was not very high. The performance of the bearing could be improved further by controlling the eccentricity. An HFMB was tested experimentally, and it was verified that it is possible to determine the effective load carrying capacity for a specific load distribution of the AFB.

On the Stability Analysis of Active Magnetic Bearing With Parametric Uncertainty and Position Tracking Control

2016 ◽  
Author(s):  
Junya Kato ◽  
Kentaro Takagi ◽  
Tsuyoshi Inoue
Keyword(s):  
Tracking Control ◽  
Feedback Linearization ◽  
Disturbance Observer ◽  
Parametric Uncertainty ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Uncertain Parameters ◽  
Rigid Rotor ◽  
Pd Control ◽  
The Stability

This paper considers effect of the parametric uncertainty of an active magnetic bearing which is used to control a rigid rotor. In the feedback control law, PD control and feedback linearization is used. Firstly, this paper shows that one of the two uncertain parameters in the electromagnet model significantly affects the stability of the system. Moreover, this paper analytically shows a method to select the nominal value of the critical parameter affecting the stability. Next, while the shaft is rotating, this paper considers reducing vibration due to rotating unbalance by inversion-based disturbance observer and controlling position by feedforward control, besides PD control and feedback linearization. Based on the linearized model, this paper shows the performance degradation caused by the parametric error and investigates the tracking error experimentally. Finally, in order to improve the tracking performance under the existence of the uncertain parameters, this paper proposes to employ an inversion-based feedforward controller designed from the augmented control object, which includes the controlled object (rigid rotor and magnetic bearing), the disturbance observer and the feedback linearization. The experiment of tracking control of the rotor position is carried out to demonstrate the effectiveness of the proposed method.

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