scholarly journals Dynamic Modeling and Parametric Analysis of the Magnetic Stiffness on a Radial Heteropolar Rotor Magnetic Bearing (RMB)

2021 ◽  
Vol 1 (1) ◽  
pp. 9-14
Author(s):  
Rodrigo Trentini ◽  
Daniel Dos Santos ◽  
Oscar Henrique Reichow ◽  
Rodrigo Piontkewicz
Keyword(s):  
Dynamic Modeling ◽  
Parametric Analysis ◽  
Equilibrium Points ◽  
Dynamic Modelling ◽  
Magnetic Bearing ◽  
Air Gap ◽  
Physical Parameters ◽  
Base Current ◽  
Magnetic Stiffness ◽  
Control Current

This paper presents both the dynamic modelling and the study of the variation of certain physical parameters (pole area, gap and base current) that change the magnetic stiffness of a radial heteropolar Rotor Magnetic Bearing (RMB) aiming at the analysis of the magnitude of its control current for three different equilibrium points. The RMB is modelled as a fully uncoupled symmetric active 8-pole magnetic bearing. The analysis is performed using spectral cubes for a better visualisation of the posed problem. The saturation analysis of the RMB is also performed. At last, it is shown that a control current with the same magnitude as the base current is reached with minimum pole area and air gap s0 = 528 um.

scholarly journals Three-Axis Inductive Displacement Sensor Using Phase-Sensitive Digital Signal Processing for Industrial Magnetic Bearing Applications

Actuators ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 115
Author(s):  
Teemu Sillanpää ◽  
Alexander Smirnov ◽  
Pekko Jaatinen ◽  
Jouni Vuojolainen ◽  
Niko Nevaranta ◽  
...  
Keyword(s):  
Signal Processing ◽  
Digital Signal Processing ◽  
Eddy Current ◽  
High Speed ◽  
Digital Signal ◽  
Magnetic Bearing ◽  
Air Gap ◽  
Sensor Design ◽  
Quadrature Demodulation ◽  
Displacement Sensors

Non-contact rotor position sensors are an essential part of control systems in magnetically suspended high-speed drives. In typical active magnetic bearing (AMB) levitated high-speed machine applications, the displacement of the rotor in the mechanical air gap is measured with commercially available eddy current-based displacement sensors. The aim of this paper is to propose a robust and compact three-dimensional position sensor that can measure the rotor displacement of an AMB system in both the radial and axial directions. The paper presents a sensor design utilizing only a single unified sensor stator and a single shared rotor mounted target piece surface to achieve the measurement of all three measurement axes. The sensor uses an inductive measuring principle to sense the air gap between the sensor stator and rotor piece, which makes it robust to surface variations of the sensing target. Combined with the sensor design, a state of the art fully digital signal processing chain utilizing synchronous in-phase and quadrature demodulation is presented. The feasibility of the proposed sensor design is verified in a closed-loop control application utilizing a 350-kW, 15,000-r/min high-speed industrial induction machine with magnetic bearing suspension. The inductive sensor provides an alternative solution to commercial eddy current displacement sensors. It meets the application requirements and has a robust construction utilizing conventional electrical steel lamination stacks and copper winding.

scholarly journals Dynamic Modelling and Response Characteristics of a Magnetic Bearing Rotor System With Auxiliary Bearings

1995 ◽  
Author(s):  
April M. Free ◽  
George T. Flowers ◽  
Victor S. Trent
Keyword(s):  
Dynamic Modelling ◽  
Magnetic Bearing ◽  
Rotor System ◽  
Rolling Element Bearing ◽  
Test Facility ◽  
Iron Core ◽  
Critical Feature ◽  
Response Characteristics ◽  
Rolling Element ◽  
Auxiliary Bearing

Abstract Auxiliary bearings are a critical feature of any magnetic bearing system. They protect the soft iron core of the magnetic bearing during an overload or failure. An auxiliary bearing typically consists of a rolling element bearing or bushing with a clearance gap between the rotor and the inner race of the support. The dynamics of such systems can be quite complex. It is desired to develop a rotordynamic model which describes the dynamic behavior of a flexible rotor system with magnetic bearings including auxiliary bearings. The model is based upon an experimental test facility. Some simulation studies are presented to illustrate the behavior of the model. In particular, the effects of introducing sideloading from the magnetic bearing when one coil fails is studied. These results are presented and discussed.

Dynamic Modeling and Analysis of Active Magnetic Bearings

2014 ◽  
Vol 494-495 ◽  
pp. 685-688
Author(s):  
Rong Gao ◽  
Gang Luo ◽  
Cong Xun Yan
Keyword(s):  
Dynamic Characteristic ◽  
Dynamic Modeling ◽  
Magnetic Bearing ◽  
Integrated System ◽  
Magnetic Bearings ◽  
Active Magnetic Bearing ◽  
Active Magnetic Bearings ◽  
Modeling And Analysis ◽  
Amb System ◽  
Mathematics Method

Active magnetic bearing (AMB) system is a complex integrated system including mechanics, electronic and magnetism. In order to research for the basic dynamic characteristic of rotor supported by AMB, it is necessary to present mathematics method. The dynamics formula of AMB is established using theory means of dynamics of rotator and mechanics of vibrations. At the same tine, the running stability of rotor is analyzed and the example is presented in detail.

scholarly journals Spectrum Analysis and Optimization of the Axial Magnetic Gear with Halbach Permanent Magnet Arrays

Energies ◽  
2019 ◽  
Vol 12 (10) ◽  
pp. 2003
Author(s):  
Fang Hu ◽  
Yilan Zhou ◽  
Hesong Cui ◽  
Xiao Liu
Keyword(s):  
Permanent Magnet ◽  
Axial Force ◽  
Spectrum Analysis ◽  
Parametric Analysis ◽  
Air Gap ◽  
Torque Density ◽  
Output Torque ◽  
Magnetic Gear ◽  
The Difference ◽  
Force Calculation

In order to study the contribution of each harmonic to the output torque and axial torque of the axial magnetic gear with Halbach permanent magnet arrays (HAMG), torque and axial force calculation formulas of the HAMG are proposed based on the air-gap flux density distribution of the HAMG. Because of the difference of the air-gap flux densities at different radii, two simplified torque and axial force calculation formulas are proposed and compared. To improve the torque capability of the HAMG, parametric analysis of eight dimensional parameters is firstly conducted. By parametric analysis, six parameters such as the inner radius have been found to have obvious impact on the output torque and output torque density of the HAMG. The optimization using Maxwell software is then executed for maximizing the output torque density of the HAMG. The output torque density of the optimized HAMG is improved from 78.1 kNm/m3 to 93.3 kNm/m3 with an increase of 19%. Furthermore, spectrum analysis is also presented to illustrate the significant output torque improvement based on the torque calculation formulas.

Magnetic Force Characteristics and Structure of a Novel Radial Hybrid Magnetic Bearing

2012 ◽  
Vol 150 ◽  
pp. 69-74
Author(s):  
Jun Hui Chen ◽  
Feng Yu Yang ◽  
Chao Rui Nie ◽  
Jun Yang ◽  
Peng Yan Wan
Keyword(s):  
Flux Density ◽  
Equilibrium Position ◽  
Magnetic Force ◽  
Magnetic Bearing ◽  
Air Gap ◽  
Magnetic Flux Density ◽  
Initial Current ◽  
Virtual Displacement ◽  
Self Stabilization ◽  
Radial Magnetic Bearing

There are some problems in the permanent magnetic circuit of the current permanent magnet biased magnetic bearings, such as small magnetic force, low magnetic flux density and lack of self-stabilization. To solve this problem, a new hybrid radial magnetic bearing structure has been proposed. The nonlinear model and linearization equation of the new hybrid radial magnetic bearing capacity has been established by current molecular method and virtual displacement theorem. It is found that the permanent magnetic bearing can achieve self-stabilization in the radial degrees of freedom and can reduce the total displacement of negative stiffness. The results show that the air gap flux density is greatly improved by the new hybrid magnetic bearing with Halbach array structure. Current stiffness and displacement rigidity is closely related to initial current and initial gap of the equilibrium position. Near the equilibrium position, current stiffness and displacement rigidity are linear relationship. With the increase of air gap, it remains a good linearity. While with the decrease of air gap, it presents nonlinear characteristics..

Dynamic modeling of dry-jet wet spinning of cellulose/[BMIM]Cl solution: complete deformation in the air-gap region

Cellulose ◽  
2015 ◽  
Vol 22 (3) ◽  
pp. 1963-1976 ◽  
Author(s):  
Xiaolin Xia ◽  
Mingfang Gong ◽  
Chaosheng Wang ◽  
Biao Wang ◽  
Yumei Zhang ◽  
...  
Keyword(s):  
Dynamic Modeling ◽  
Air Gap ◽  
Wet Spinning ◽  
Complete Deformation

Rotor Power Losses in Planar Radial Magnetic Bearings — Effects of Number of Stator Poles, Air Gap Thickness, and Magnetic Flux Density

1998 ◽  
Author(s):  
P. E. Allaire ◽  
M. E. F. Kasarda ◽  
L. K. Fujita
Keyword(s):  
Magnetic Flux ◽  
Flux Density ◽  
Eddy Current ◽  
Power Loss ◽  
Magnetic Bearing ◽  
Air Gap ◽  
Magnetic Bearings ◽  
Magnetic Flux Density ◽  
Power Losses ◽  
Loss Mechanism

Rotor power losses in magnetic bearings cannot be accurately calculated at this time because of the complexity of the magnetic field distribution and several other effects. The losses are due to eddy currents, hysteresis, and windage. This paper presents measured results in radial magnetic bearing configurations with 8 pole and 16 pole stators and two laminated rotors. Two different air gaps were tested. The rotor power losses were determined by measuring the rundown speed of the rotor after the rotor was spun up to speeds of approximately 30,000 rpm, DN = 2,670,000 mm-rpm, in atmospheric air. The kinetic energy of the rotor is converted to heat by magnetic and air drag power loss mechanisms during the run down. Given past publications and the opinions of researchers in the field, the results were quite unexpected. The measured power losses were found to be nearly independent of the number of poles in the bearing. Also, the overall measured rotor power loss increased significantly as the magnetic flux density increased and also increased significantly as the air gap thickness decreased. A method of separating the hysteresis, eddy current and windage losses is presented. Eddy current effects were found to be the most important loss mechanism in the data analysis, for large clearance bearings. Hysteresis and windage effects did not change much from one configuration to the other.

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.

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