4-Factor Polarity Switching Control for Synchronous Vibration Suppression of Active Magnetic Bearings Rigid Rotors System in the Full Rotational Speed Range

2020 ◽  
pp. 1-1
Author(s):  
Lei Gong ◽  
Changsheng Zhu
Keyword(s):  
Rotational Speed ◽  
Vibration Suppression ◽  
Switching Control ◽  
Magnetic Bearings ◽  
Active Magnetic Bearings ◽  
Polarity Switching ◽  
Speed Range ◽  
Rigid Rotors

Vibration Analysis of a Self-Excited Vibration in a Rotor System Caused by a Ball Balancer

2012 ◽  
Vol 134 (2) ◽  
Author(s):  
Tsuyoshi Inoue ◽  
Yukiko Ishida ◽  
Hideaki Niimi
Keyword(s):  
Rotational Speed ◽  
Critical Speed ◽  
Vibration Suppression ◽  
The Self ◽  
Rotor Systems ◽  
Excited Vibration ◽  
Amplitude Vibration ◽  
Speed Range ◽  
Large Amplitude Vibration ◽  
Fundamental Equations

The ball balancer has been used as a vibration suppression device in rotor systems. It has a superior characteristic that the vibration amplitude is reduced to zero theoretically at a rotational speed range higher than the critical speed. However, the ball balancer causes a self-excited vibration near the critical speed when the balls rotate in the balancer. This self-excited vibration may occur in the wide rotational speed range with a large amplitude vibration, and in such a case, escaping from it becomes difficult. In this paper, the occurrence region and the vibration characteristics of the self-excited vibration caused by the ball balancer are investigated. The nonlinear theoretical analysis is performed and a set of the fundamental equations governing the self-excited vibration is obtained. The influences of the parameters of the ball balancer, such as, the damping of the ball’s motion, the ball’s mass, and radius of the balls’ path, are explained and they are also validated experimentally.

Active Magnetic Bearings: Robust performance against uncertainty in rotational speed

2010 ◽  
Vol 43 (18) ◽  
pp. 355-362
Author(s):  
H.M.N.K. Balini ◽  
Jasper Witte ◽  
Carsten W. Scherer ◽  
Sjoerd Dietz
Keyword(s):  
Rotational Speed ◽  
Magnetic Bearings ◽  
Active Magnetic Bearings ◽  
Robust Performance

Vibration Suppression of Rotating Machinery Utilizing an Automatic Ball Balancer and Discontinuous Spring Characteristics

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
Jun Liu ◽  
Yukio Ishida
Keyword(s):  
Rotational Speed ◽  
Large Amplitude ◽  
Small Amplitude ◽  
Critical Speed ◽  
Vibration Suppression ◽  
Rotating Machinery ◽  
Almost Periodic ◽  
Periodic Motions ◽  
Speed Range ◽  
Suppression Method

Automatic ball balancer is a balancing device where two balls inside a hollow rotor move to optimal rest positions automatically to eliminate unbalance. As a result, vibrations are suppressed to the zero amplitude in the rotational speed range higher than the major critical speed. However, it has the following defects. The amplitude of vibration increases in the rotational speed range lower than the major critical speed. In addition, almost periodic motions with large amplitude occur in the vicinity of the major critical speed due to the rolling of balls inside the rotor. Because of these defects, an automatic ball balancer has not been used widely. This paper proposes the vibration suppression method utilizing the discontinuous spring characteristics together with an automatic ball balancer to overcome these defects and to suppress vibration. The validity of the proposed method is confirmed theoretically, numerically, and experimentally. The results show that amplitude of vibration can be suppressed to a small amplitude in the vicinity of the major critical speed and the zero amplitude in the range higher than the major critical speed.

Elliptic Motions and Control of Rotors Suspending in Active Magnetic Bearings

2016 ◽  
Vol 11 (5) ◽  
Author(s):  
Xiao-Dong Yang ◽  
Hua-Zhen An ◽  
Ying-Jing Qian ◽  
Wei Zhang ◽  
Ming-Hui Yao
Keyword(s):  
Phase Portrait ◽  
Vibration Suppression ◽  
Multiple Scales ◽  
Free Vibrations ◽  
Magnetic Bearings ◽  
Pd Controller ◽  
Active Magnetic Bearings ◽  
Energy Ratios ◽  
And Control ◽  
Two Degree Of Freedom

The nonlinear dynamics of rotors suspending in the active magnetic bearings (AMBs) with eight pole pairs are investigated. The nonlinear governing equations of two degree-of-freedom (2DOF) are obtained considering the rotor with proportional–derivative (PD) controller. By studying the conservative free vibrations of the general 2DOF nonlinear systems, three types of motions are found, namely, in-unison modal motions, elliptic modal motions, and quasi-periodic motions. The method of multiple scales is used to obtain the amplitude-phase portrait to demonstrate the three types of motions by introducing the energy ratios and phase differences. It is found that in-unison modal motions do not exist due to the symmetry feature of the rotors in the AMBs. The effect of the PD controller and damping to the vibration suppression is discussed by the idea of the rolled-up amplitude-phase portrait.

Vibration Suppression of Rotating Machinery Utilizing an Automatic Ball Balancer and Discontinuous Spring Characteristics

2007 ◽  
Author(s):  
Jun Liu ◽  
Yukio Ishida
Keyword(s):  
Rotational Speed ◽  
Large Amplitude ◽  
Small Amplitude ◽  
Critical Speed ◽  
Vibration Suppression ◽  
Rotating Machinery ◽  
Almost Periodic ◽  
Periodic Motions ◽  
Speed Range ◽  
Suppression Method

Automatic ball balancer is a balancing device where two balls inside a hollow rotor move to optimal rest positions automatically to eliminate unbalance. As the result, vibrations are suppressed to a small amplitude or a zero amplitude in the rotational speed range higher than the major critical speed. However, it has the following defects. The amplitude of vibration increases in the rotational speed range lower than the major critical speed. In addition, almost periodic motions with large amplitude occur due to the rolling of balls inside the rotor in the vicinity of the major critical speed. Due to those defects, the automatic ball balancer has not been used widely. This paper proposes the vibration suppression method utilizing the discontinuous spring characteristics together with an automatic ball balancer to suppress vibration and to overcome these defects of the automatic ball balancer. The validity of proposed method is confirmed theoretically, numerically and experimentally. The results show that amplitude of vibration can be suppressed to a small amplitude in the vicinity of the major critical speed and the zero amplitude in the range higher than the major critical speed.

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