503 Vibration Characteristics of a Rotor System Supported by a Magnetic Bearing : Influence of Rotational Speed on Major Critical Speed

2007 ◽  
Vol 2007 (0) ◽  
pp. _503-1_-_503-5_
Author(s):  
Shin MURAKAMI ◽  
Takashi IKEDA ◽  
Tsubasa Watanabe
Keyword(s):  
Rotational Speed ◽  
Critical Speed ◽  
Magnetic Bearing ◽  
Vibration Characteristics ◽  
Rotor System

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.

Experimental research on suppressing unbalanced vibration of rotor by integral squeeze film damper

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Wei Yan ◽  
Lidong He ◽  
Zhe Deng ◽  
Xingyun Jia
Keyword(s):  
Rotational Speed ◽  
Critical Speed ◽  
Structural Characteristics ◽  
Experimental Studies ◽  
Rotor System ◽  
Squeeze Film ◽  
Rigid Rotor ◽  
Flexible Rotor ◽  
Test Rig ◽  
Squeeze Film Damper

Abstract As a novel structural damper, the unique structural characteristics of the integral squeeze film damper (ISFD) solve the nonlinear problem of the traditional squeeze film damper (SFD), and it has good linear damping characteristics. In this research, the experimental studies of ISFD vibration reduction performance are carried out for various working conditions of unbalanced rotors. Two ball bearing-rotor system test rigs are built based on ISFD: a rigid rotor test rig and a flexible rotor test rig. When the rotational speed of rigid rotor is 1500 rpm, ISFD can reduce the amplitude of the rotor by 41.79%. Under different unbalance conditions, ISFD can effectively improve the different degrees of unbalanced faults in the rotor system, reduce the amplitude by 43.21%, and reduce the sensitivity of the rotor to unbalance. Under different rotational speed conditions, ISFD can effectively suppress the unbalanced vibration of rigid rotor, and the amplitude can be reduced by 53.51%. In the experiment of the unbalanced response of the flexible rotor, it is found that ISFD can improve the damping of the rotor system, effectively suppress the resonance of the rotor at the critical speed, and the amplitude at the first-order critical speed can be reduced by 31.72%.

Blade-Shaft Coupled Resonance Vibration by Using Active Magnetic Bearing Excitation

2008 ◽  
Author(s):  
Norihisa Anegawa ◽  
Hiroyuki Fujiwara ◽  
Osami Matsushita
Keyword(s):  
Natural Frequency ◽  
Rotational Speed ◽  
Critical Speed ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Dynamic Vibration Absorber ◽  
Blade Vibration ◽  
Lower Natural Frequency ◽  
Damped System ◽  
Spring System

The turbine generator requires sufficient reliability as a major component of the power plant. The rotor dynamics calculates the critical speed of the shaft-bearing system for design to avoid appearance of the critical speed, while the blade dynamics calculates the natural frequency of the blade to avoid nX resonance. For longer blades, however, the lower natural frequency requires that the design of the shaft and blade takes into account the coupling of the blade vibration mode with nodal diameter k = 0 and k = 1 with the vibration of the shaft. The present work analyzes the coupling of the parallel motion of the shaft with the in-plane vibration of the blade within k = 1 modes. More specifically, the existence of an unstable region due to coupling and the coupled resonance in an eight-blade (N = 8) where each blade is assumed to be a 1-DOF mass-spring system were analyzed in detail. Analysis was also made on the forced vibration of a stable damped system. At a rotational speed Ω = |ωs − ωb|, the vibration of the shaft was limited to a relatively small amplitude due to anti-resonance points resulting from the dynamic vibration absorber effect, while the resonance of the blades was relatively big amplitude. A violent coupled resonance resulting from the dynamic absorber effect of the blades and shaft was observed at a rotational speed Ω = ωs + ωb. The resonance in blade vibration at Ω = |ωb − ωs| was experimentally confirmed.

Research on Dynamic Characteristic of Rotor System for Small Maglev Wind Turbine Generator

2014 ◽  
Vol 953-954 ◽  
pp. 437-442
Author(s):  
Shi Min Peng ◽  
Ru Hao Dong ◽  
Bo Yu Li ◽  
Ming Xue Liu
Keyword(s):  
Wind Turbine ◽  
Critical Speed ◽  
Simulation Analysis ◽  
Magnetic Bearing ◽  
Rotor System ◽  
Characteristic Analysis ◽  
Turbine Generator ◽  
Wind Turbine Generator ◽  
Finite Element Software ◽  
Vibration Measuring

Aiming at the small magnetic wind turbine, finite element software ANSYS is used to establish the model of rotor system with passive magnetic bearing, and obtain the vibration mode and critical speed of rotor system in situations: free-free, rigid bearing, hybrid combination of elastic and rigid bearing. Experimental analysis of critical speed of the rotor system can be conducted with the testing platform built by the B&K Vibration Measuring System.The result shows that the simulation analysis are approximately agreed with the experiment result. The simulation analysis has instructive significance in the structure optimization of magnetic bearing and rotor system and provides basis for vibration characteristic analysis of permanent maglev wind turbine generator and dynamic characteristics of structure.

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