scholarly journals Gain-Scheduled Control of Asymmetric Thrust Magnetic Bearing

Actuators ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 329
Author(s):  
Shuyue Zhang ◽  
Jihao Wu
Keyword(s):  
Control Method ◽  
Magnetic Levitation ◽  
Structural Parameters ◽  
Response Speed ◽  
Magnetic Bearing ◽  
Structure Design ◽  
Magnetic Bearings ◽  
And Performance ◽  
The Cost ◽  
Gain Scheduled

The thrust position of the magnetic levitation rotor can be changed, bringing convenience to the practical application of cold compressors. This paper derives the mathematical model of asymmetric thrust magnetic bearings for a cold compressor and analyzes the changes in the system characteristics with the equilibrium position. By constructing PID controllers associated with the structural parameters of the magnetic bearing, the adaptive adjustment of the control parameters under different balanced position commands is realized. The simulation and experimental results prove that the gain-scheduled control method proposed in this paper can achieve a robust stability of the rotor in the range of 50 to 350 μm, and not at the cost of the response speed, adjustment time, and overshoot. The research results have reference significance for the structure design of asymmetric thrust magnetic bearings and play an important role in the commissioning and performance improvement of cold compressors.

Analysis of a New Magnetic Bearing for Magnetic Levitation Stages

2011 ◽  
Vol 295-297 ◽  
pp. 2106-2111
Author(s):  
Yu Zhu ◽  
Yu Liu ◽  
Ming Zhang
Keyword(s):  
Current Sheet ◽  
Calculation Method ◽  
Magnetic Levitation ◽  
Levitation Force ◽  
Structural Parameters ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Axial Stiffness ◽  
Equivalent Current ◽  
Ultra Precision

This paper proposed a new configuration of magnetic bearings used in magnetic levitation stages. The equivalent current sheet model is introduced to calculate the levitation force of the proposed magnetic bearing, and the experiment result validates the correctness of the calculation method. The relationships of structural parameters to the levitation force and axial stiffness are studied, which prove that the new magnetic bearing has larger levitation force with lower axial stiffness over the working stroke and could be applied in ultra-precision magnetic levitation stages.

The Nonlinear PID Control for Beam Magnetic Suspension System of Gantry-Moving Type Numerically Controlled Machine Tool

2012 ◽  
Vol 546-547 ◽  
pp. 992-996
Author(s):  
Chun Fang Liu ◽  
Bin Zang ◽  
Tong Wang
Keyword(s):  
Pid Control ◽  
Pid Controller ◽  
Control Method ◽  
Magnetic Levitation ◽  
Response Speed ◽  
Fast Response ◽  
Magnetic Suspension ◽  
Control Effect ◽  
Maglev System ◽  
Nonlinear Tracking

The maglev system is a typical nonlinear system, it is difficult to get the best control effect only by nonlinear control method. At first, the maglev system is linearized in this paper, for the classic PID control magnetic levitation system which exists the contradiction between fast and overshoot .This paper adopts the nonlinear tracking-differentiator-based PID controller to control the maglev system. Finally simulation results show that the nonlinear PID controller has fast response speed, no overshoot, and strong robustness in controlling the maglev system.

Research on method for adaptive imbalance vibration control for rotor of variable-speed mscmg with active-passive magnetic bearings

2016 ◽  
Vol 23 (2) ◽  
pp. 167-180 ◽  
Author(s):  
Peiling Cui ◽  
Jingxian He ◽  
Jiancheng Fang ◽  
Xiangbo Xu ◽  
Jian Cui ◽  
...  
Keyword(s):  
Vibration Control ◽  
Attitude Control ◽  
Control Method ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
System Stability ◽  
Variable Speed ◽  
Control Moment ◽  
Vibration Compensation ◽  
Main Factor

Imbalance vibration control for rotor is the main factor affecting attitude control performance for satellite using magnetically suspended control moment gyro (MSCMG). The method for adaptive imbalance vibration control for the rotor of variable-speed MSCMG with active-passive magnetic bearings is investigated in this paper. Firstly, on the basis of feedforward compensation, a rotor model for the imbalance vibration of variable-speed MSCMG with active-passive magnetic bearings is built, and the main factor affecting imbalance vibration compensation is also analyzed. Then, power amplifier parameter modifier with control switches is designed to eliminate the effects of time-varying parameters on the imbalance vibration compensation precision. The adaptive imbalance vibration control based on this modifier not only has high compensation precision, but also can control the frequency of parameter adjustment according to the compensation precision. Besides, since the passive magnetic bearing displacement stiffness of the rotor of variable-speed MSCMG with active-passive magnetic bearings cannot be obtained accurately, displacement stiffness modifier is employed. Finally, stability analysis is made on the imbalance vibration control system, and the range of rotation speed to ensure system stability is derived. Simulation results show that, imbalance vibration control method proposed in this paper can suppress the imbalance vibration of the rotor of variable-speed MSCMG with active-passive magnetic bearings effectively and has high precision.

Force Measurements in Magnetic Bearings Using Fiber Optic Strain Gauges

2001 ◽  
Author(s):  
Stephen G. Raymer ◽  
Dara W. Childs
Keyword(s):  
Fiber Optic ◽  
Reaction Force ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Strain Gauges ◽  
Rotordynamic Coefficients ◽  
Precise Knowledge ◽  
Accuracy And Precision ◽  
Force Components ◽  
And Performance

A new method for measuring forces in magnetic bearings is presented. Fiber-optic strain gauges (FOSGs) mounted to the side of the magnet poles are used to detect the small levels of strain that the metal experiences as the bearing exerts a force. These strains can be converted into force components, providing measurements with a previously unattainable level of accuracy and precision. Tests were done using the Magnetic Bearing Test Rig at the Texas A&M University Turbomachinery Laboratory. Two FOSGs were placed approximately 90° apart on two separate poles of one of the bearings, and the strain levels for different load magnitudes and directions were measured. The raw signal has several undesirable attributes that prevent an accurate static measurement. However, dynamic measurements proved to be very effective in the frequency domain, as most of the noise in the signal is confined to frequencies below 1 Hz. Due to the raw signal characteristics, new techniques for load application and calibration were developed. By using these new approaches, an equation relating reaction force components and strain was generated. This equation provides precise knowledge of any force vector in the bearing. An uncertainty analysis was performed on the resulting equation, providing a measure of resolution and a reduction in error several times more precise than any previous result. As a result of these findings, magnetic bearings can now be used to perform precise diagnostic analysis, determine rotordynamic coefficients, and improve magnetic bearing design and performance.

Structural Redundancy Design and Reliability Analysis of Magnetic Bearing for HTGR Primary Helium Circulator

2018 ◽  
Author(s):  
Yangbo Zheng ◽  
Zhengang Shi ◽  
Xingnan Liu ◽  
Ni Mo ◽  
Guojun Yang
Keyword(s):  
Reliability Analysis ◽  
Reactor Core ◽  
Magnetic Bearing ◽  
Structure Design ◽  
Magnetic Bearings ◽  
Structural Redundancy ◽  
New Approach ◽  
Safety And Reliability ◽  
Redundant Structure ◽  
Redundancy Design

As primary pump of High Temperature Gas-cooled Rector (HTGR), the safety and reliability of primary helium circulator has a direct relationship with heat export in the reactor core. This paper proposed two conceptual design methods, which are structural redundancy design in the axial and radial magnetic bearings (coils), and crossing redundancy design between amplifiers and the redundant bearings (coils), combined with the characteristics of magnetic bearing in the primary helium circulator. Then we built Markov model for the magnetic bearing with redundant structure, which was used to reliability analysis and calculation. Finally, we performed simulation of the redundant magnetic bearings in Matlab/Simulink. The results show that the redundant structure design can greatly improve the reliability of the magnetic bearing system. Therefore, these methods would provide a new approach for further improving the safety and reliability of primary helium circulator.

Disturbance suppression in active magnetic bearings with adaptive control and extended state observer

2019 ◽  
Vol 234 (2) ◽  
pp. 272-284
Author(s):  
Xudong Guan ◽  
Jin Zhou ◽  
Chaowu Jin ◽  
Yuanping Xu
Keyword(s):  
Adaptive Control ◽  
Control Method ◽  
State Observer ◽  
Magnetic Bearing ◽  
Extended State Observer ◽  
Magnetic Bearings ◽  
Active Magnetic Bearings ◽  
Extended State ◽  
Disturbance Suppression ◽  
Bearing System

Some sources of disturbance inevitably exist in magnetic bearings systems in the process of operation. This article proposes a disturbance suppression scheme for active magnetic bearings systems using an improved characteristic model-based all-coefficient adaptive control algorithm. First, the mathematical model of the magnetic bearing system is established. Then, by introducing the extended state observer into the adaptive control, the adaptive control method is improved. And the simulation of the combined control of the adaptive control and extended state observer is carried out based on mathematical model of controlled object. Simulation results demonstrate that this control method can not only adjust the control parameters online, but also estimate and compensate the disturbance in real time, which improves the control performance of the controller. Finally, the feasibility of adaptive control method with extended state observer is verified by experiments. When the sinusoidal disturbance signal is introduced at the 9000 r/min, the vibration displacement of the magnetic bearing system with the improved adaptive controller is reduced around 43%, which is in accordance with the theoretical results.

Harmonic vibration moment suppression using hybrid repetitive control for active magnetic bearing system

2021 ◽  
pp. 107754632110109
Author(s):  
Peiling Cui ◽  
Liang Du ◽  
Xinxiu Zhou ◽  
Jinlei Li ◽  
Yanbin Li ◽  
...  
Keyword(s):  
Control Method ◽  
Hybrid Control ◽  
Repetitive Control ◽  
Control Object ◽  
Sampling Period ◽  
Response Speed ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Harmonic Vibration ◽  
Bearing System

The active magnetic bearing system exhibits mass imbalance and sensor runout which cause the system to generate harmonic vibration force and moment. Repetitive control is an effective method to eliminate such harmonic vibration. Traditional repetitive control will eliminate all of the harmonic frequency components. However, in a practical system, the odd harmonic components usually dominate. Meanwhile, the existing method only suppresses the vibration force in the magnetic bearing system, and there is little research on the suppression of moment. Aiming at these problems, the harmonic vibration moment of the active magnetic bearing system is taken as the control object. This study investigates a hybrid control method that combines a second-order odd harmonic repetitive control with finite-dimensional repetitive control. And the virtual variable sampling is applied to construct any virtual sampling period in the proposed method, which effectively solves the problem of non-integer delay of digital repetitive control. The stability of the active magnetic bearing system is analyzed. The experimental results show that this method has faster response speed and better robustness when the frequency fluctuates.

Development of an axial-flux self-bearing motor using two permanent magnet attractive type passive magnetic bearings

2020 ◽  
Vol 64 (1-4) ◽  
pp. 827-833
Author(s):  
Satoshi Ueno ◽  
Masaya Tomoda ◽  
Changan Jiang
Keyword(s):  
Control System ◽  
Permanent Magnet ◽  
Simple Structure ◽  
Control Method ◽  
Rotation Speed ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Axial Flux ◽  
And Control ◽  
Thrust Magnetic Bearing

This paper introduces an axial-flux self-bearing motor (ASBM) using two permanent magnet attractive type passive magnetic bearings (PMBs). The ASBM provides both functions of a disc motor and thrust magnetic bearing, and controls motor torque and axial force by single rotational magnetic flux. The PMB consists of a cylindrical permanent magnet and an iron shaft with conical edge, and it supports the rotor in radial directions. This motor has a simple structure and control system, and it is possible to reduce the size and cost. In this paper, the structure and control method are introduced, and the results of levitation and rotation tests whose non-contact rotation speed was achieved up to 1,500 rpm are shown.

Sign in / Sign up

Export Citation Format

Share Document