scholarly journals A System Identification Technique Using Bias Current Perturbation for the Determination of the Magnetic Axes of an Active Magnetic Bearing

Actuators ◽  
2017 ◽  
Vol 6 (2) ◽  
pp. 13 ◽  
Author(s):  
Dewey Spangler ◽  
Robert Prins ◽  
Mary Kasarda
Keyword(s):  
System Identification ◽  
Magnetic Bearing ◽  
Bias Current ◽  
Active Magnetic Bearing ◽  
Identification Technique

scholarly journals A System Identification Technique Using Bias Current Perturbation for the Determination of the Magnetic Axes of an Active Magnetic Bearing

2017 ◽  
Author(s):  
Dewey Spangler Jr. ◽  
Robert Prins ◽  
Mary Kasarda
Keyword(s):  
Force Measurement ◽  
Measurement Techniques ◽  
Magnetic Bearing ◽  
Bias Current ◽  
Active Magnetic Bearing ◽  
Mechanical Assembly ◽  
Identification Technique ◽  
Potential Improvement

Inherent in every Active Magnetic Bearing (AMB) are differences between the expected geometric axes and the actual magnetic axes due to a combination of discrepancies, including physical variation from manufacturing tolerances and misalignment from mechanical assembly, fringing and leakage effects, as well as variations in magnetic material properties within a single AMB. A method is presented here for locating the magnetic axes of an AMB that will facilitate the accurate characterization of the bearing air gaps for potential improvement in field tuning, performance analyses and certain shaft force measurement techniques. This paper presents an extension of the application of the bias current perturbation method for the determination of the magnetic center [4] to the determination of magnetic axes for the further development of accurate current-based force measurement techniques [1].

A System Identification Technique Using Bias Current Perturbation for Determining the Effective Rotor Origin of Active Magnetic Bearings

2006 ◽  
Vol 129 (3) ◽  
pp. 317-322 ◽  
Author(s):  
Robert J. Prins ◽  
Mary E. F. Kasarda ◽  
Samantha C. Bates Prins
Keyword(s):  
System Identification ◽  
Magnetic Circuit ◽  
Force Measurement ◽  
Measurement Techniques ◽  
Magnetic Bearing ◽  
Bias Current ◽  
Active Magnetic Bearing ◽  
Force Model ◽  
Air Gaps ◽  
Identification Technique

Locating the effective rotor origin of an active magnetic bearing (AMB) is an important step toward accurate characterization of the bearing air gaps for field tuning, performance analyses, and some shaft force measurement techniques. Specifically, application of current-based force measurement techniques to AMBs requires accurate modeling of air gaps in order to predict dynamic forces with accuracy. This paper discusses the application of a system identification technique that employs perturbation of the bias current and allows the user to establish the location of the effective rotor origin, an important step in characterizing the actual bearing gap. The technique analyzes the AMB system’s response to the perturbation of bias currents in conjunction with a magnetic circuit model to infer the center position. The effective rotor origin identification technique developed here does not require additional hardware and is suitable for use in the general class of AMBs in field applications. For our purposes, the effective rotor origin of an electro-magnet biased magnetic bearing is defined as the unique rotor location for which a magnetic circuit based force model of the bearing is satisfied for zero position offset of the rotor along each control axis. Note that the effective rotor origin referred to here is the radial origin.

Calculation and Verification of Magnetic Field Parameters in Axial Active Magnetic Bearing

2014 ◽  
Vol 214 ◽  
pp. 143-150
Author(s):  
Piotr Graca
Keyword(s):  
Magnetic Field ◽  
Finite Element Method ◽  
Magnetic Force ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Magnetic Flux Density ◽  
Two Dimensional ◽  
The Finite Element Method ◽  
Magnetic Field Computation

The paper presents numerical modeling of an Axial Active Magnetic Bearing (AAMB) based on two-dimensional (2D) magnetic field computation. The calculations, assisted by the Finite Element Method (FEM), have focused on the determination of the magnetic flux density and the magnetic force. Obtained magnetic field parameters were then measured and verified on a physical model.

scholarly journals System Identification and Robust Control of Multi-Input Multi-Output Active Magnetic Bearing Systems

2016 ◽  
Vol 24 (4) ◽  
pp. 1227-1239 ◽  
Author(s):  
Amin Noshadi ◽  
Juan Shi ◽  
Wee Sit Lee ◽  
Peng Shi ◽  
Akhtar Kalam
Keyword(s):  
Robust Control ◽  
System Identification ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing

scholarly journals Modelling and system identification of active magnetic bearing systems

2007 ◽  
Vol 13 (2) ◽  
pp. 125-142 ◽  
Author(s):  
Young Man Cho ◽  
Sriram Srinavasan ◽  
Jae-Hyuk Oh ◽  
Hwa Soo Kim
Keyword(s):  
System Identification ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing

Residual Unbalanced Mass Determination of an AMBs Controlled Rotor Based on Control Current Analysis of the Feedback Loop

2018 ◽  
Author(s):  
Tianpeng Fan ◽  
Zhe Sun ◽  
Xiaoshen Zhang ◽  
Xunshi Yan ◽  
Jingjing Zhao ◽  
...  
Keyword(s):  
High Speed ◽  
High Performance ◽  
Feedback Loop ◽  
Image Data ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Current Analysis ◽  
Unbalanced Mass ◽  
Control Current

Active magnetic bearing technology is used more and more for its high performance, such as high speed and frictionless operation. But the rotor vibrates sometimes during operation due to the existence of residual unbalanced mass, which may affect the security of the whole system. In order to determine the distribution of residual unbalanced mass, this paper proposes a method based on frequency response, control current analysis, and image data processing. The theoretical and calculated results show the validity of the method.

Adaptive Bias Current Control in Active Magnetic Bearings for Energy Optimization

2011 ◽  
Author(s):  
Satoshi Ueno ◽  
M. Necip Sahinkaya
Keyword(s):  
Power Consumption ◽  
Control Method ◽  
Optimization Method ◽  
Magnetic Bearing ◽  
Descent Method ◽  
Bias Current ◽  
Current Control ◽  
Experimental Results ◽  
Active Magnetic Bearing ◽  
Steepest Descent Method

This paper introduces an adaptive bias current control method for an active magnetic bearing (AMB). The bearing force is analyzed theoretically, and the dynamic performance of the magnetic bearing for various bias currents is discussed. Then power consumption is analyzed and the optimum bias current that minimizes power consumption is derived. A novel optimization method using a steepest descent method is proposed. This requires less computing power than the former optimization method using a recursive Fourier transform algorithm. Experimental results show that the optimized bias current can be achieved by the proposed method. However, the dynamics of the rotor is affected by the bias current variation. In order to overcome this problem, the effects of parameter errors are investigated and correction methods are introduced. Experimental results show that the rotor dynamics are not affected by the variable bias current if the parameters are corrected. Results are also presented for machine run-up and run-down.

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