scholarly journals CALCULATION OF PASSIVE MAGNETIC FORCE IN A RADIAL MAGNETIC BEARING USING GENERAL DIVISION APPROACH

2017 ◽  
Vol 54 ◽  
pp. 91-102 ◽  
Author(s):  
Tapan Santra ◽  
Debabrata Roy ◽  
Amalendu Bikash Choudhury
Keyword(s):  
Magnetic Force ◽  
Magnetic Bearing ◽  
Radial Magnetic Bearing

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..

The influence of the stator geometry on magnetic bearing parameters

2013 ◽  
Vol 62 (2) ◽  
pp. 209-215 ◽  
Author(s):  
Bronisław Tomczuk ◽  
Dawid Wajnert
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Magnetic Force ◽  
Magnetic Bearing ◽  
Current Gain ◽  
Maxwell Stress ◽  
The Finite Element Method ◽  
Tensor Method ◽  
Maxwell Stress Tensor ◽  
Radial Magnetic Bearing

Abstract This paper presents an analysis of the stator teeth geometry impact on the parameters of the 8-pole radial magnetic bearing. In this paper, such parameters as current gain and position stiffness have been analysed. Additionally, we have proposed criteria for evaluating the characteristics of these parameters by calculating the variability of current gain and position stiffness. The research has been performed by solving the magnetic bearing actuator boundary problem using the finite element method. Magnetic force has been calculated using the Maxwell stress tensor method. Other parameters, such as current gain and position stiffness have been calculated as partial derivate of the force with respect to control current and position of the rotor.

High Temperature Characterization of a Radial Magnetic Bearing for Turbomachinery

2003 ◽  
Author(s):  
Andrew J. Provenza ◽  
Gerald T. Montague ◽  
Mark J. Jansen ◽  
Alan B. Palazzolo ◽  
Ralph H. Jansen
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Magnetic Force ◽  
Magnetic Bearing ◽  
Open Loop ◽  
Core Permeability ◽  
Radial Gap ◽  
Radial Magnetic Bearing ◽  
Power Measurements

Open loop, experimental force and power measurements of a radial, redundant-axis, magnetic bearing at temperatures to 1000°F (538°C) and rotor speeds to 15,000 RPM along with theoretical temperature and force models are presented in this paper. The experimentally measured force produced by a single C-core circuit using 22 A was 600 lb. (2.67 kN) at room temperature and 380 lb. (1.69 kN) at 538°C. These values were compared with force predictions based on a 1D magnetic circuit analysis and a thermal analysis of gap growth as a function of temperature. The analysis showed that the reduction of force at high temperature is mostly due to an increase in radial gap due to test conditions, rather that to reduced core permeability. Tests under rotating conditions showed that rotor speed has a negligible effect on the bearing’s static force capacity. One C-core required approximately 340 W of power to generate 190 lb. (845 N) of magnetic force at 538°C, however the magnetic air gap was much larger than at room temperature. The data presented is after bearing operation for eleven total hours at 538°C and six thermal cycles.

High Temperature Characterization of a Radial Magnetic Bearing for Turbomachinery

2005 ◽  
Vol 127 (2) ◽  
pp. 437-444 ◽  
Author(s):  
Andrew J. Provenza ◽  
Gerald T. Montague ◽  
Mark J. Jansen ◽  
Alan B. Palazzolo ◽  
Ralph H. Jansen
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Magnetic Force ◽  
Magnetic Bearing ◽  
Open Loop ◽  
Core Permeability ◽  
Radial Gap ◽  
Radial Magnetic Bearing ◽  
Power Measurements

Open loop, experimental force and power measurements of a radial, redundant-axis, magnetic bearing at temperatures to 1000°F (538°C) and rotor speeds to 15,000 rpm along with theoretical temperature and force models are presented in this paper. The experimentally measured force produced by a single C-core circuit using 22A was 600 lb (2.67 kN) at room temperature and 380 lb (1.69 kN) at 538°C. These values were compared with force predictions based on a one-dimensional magnetic circuit analysis and a thermal analysis of gap growth as a function of temperature. The analysis showed that the reduction of force at high temperature is mostly due to an increase in radial gap due to test conditions, rather than to reduced core permeability. Tests under rotating conditions showed that rotor speed has a negligible effect on the bearing’s static force capacity. One C-core required approximately 340 W of power to generate 190 lb (845 N) of magnetic force at 538°C, however the magnetic air gap was much larger than at room temperature. The data presented are after bearing operation for eleven total hours at 538°C and six thermal cycles.

PIDNN control for Vernier-gimballing magnetically suspended flywheel under nonlinear change of stiffness and disturbance

2020 ◽  
pp. 095965182097757
Author(s):  
Jiqiang Tang ◽  
Mengyue Ning ◽  
Xu Cui ◽  
Tongkun Wei ◽  
Xiaofeng Zhao
Keyword(s):  
Neural Network ◽  
Attitude Control ◽  
Magnetic Force ◽  
Magnetic Bearing ◽  
Network Control ◽  
Gradient Descent Method ◽  
Neural Network Control ◽  
Proportional Integral Derivative ◽  
Tracking Accuracy ◽  
Proportional Integral

Vernier-gimballing magnetically suspended flywheel is often used for attitude control and interference suppression of spacecrafts. Due to the special structure of the conical magnetic bearing, the radial component generated by the axial magnetic force and the change of the magnetic air gap will cause the nonlinearity of stiffness and disturbance. That will lead to not only poor stability of the suspension control system but also unsatisfactory tracking accuracy of the rotor position. To solve the nonlinear problem of the system, this article proposes a proportional–integral–derivative neural network control scheme. First, the rotor model considering the nonlinear variation of disturbance and stiffness parameters is established. Then, the weight of neural network is adjusted by the gradient descent method online to ensure the accurate output of magnetic force. Finally, the convergence analysis is carried out based on the Lyapunov stability theory. Compared with the general proportional–integral–derivative control and the radial basis function neural network control, the simulation results demonstrate that the proposed method has the highest tracking accuracy and excellent performance in improving stability. The experimental results prove the correctness of the theoretical analysis and the validity of the proposed method.

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.

Sign in / Sign up

Export Citation Format

Share Document