Combination Axial and Radial Active Magnetic Bearing With Improved Axial Bandwidth

2012 ◽  
Author(s):  
Alexei V. Filatov ◽  
Lawrence A. Hawkins
Keyword(s):  
Structural Integrity ◽  
Electrical Current ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Phase Lag ◽  
Axial Loads ◽  
Electromagnetic Actuators ◽  
Current Path ◽  
Force Reduction ◽  
Actuator Design

Homopolar Permanent-Magnet-Biased Combination Axial and Radial Electromagnetic Actuators used in Active Magnetic Bearings (AMBs) have several advantages over arrangements of separate axial and radial actuators including shorter length, lower part count, lower cost and better rotordynamic response. However, these actuators may require higher-order compensators in applications with significant dynamic axial loads due to somewhat lower axial bandwidth. One of the reasons for a lower axial bandwidth is having the axial magnetic control flux flowing through an opening in a radial actuator assembled from insulated electrical-steel laminations stacked axially. Whenever this flux changes in time, it induces an electrical current in each lamination which is responsible for the dynamic axial force reduction and an additional phase lag. In an improved actuator design, a current path in each lamination is interrupted by a single slot located between two radial control poles. In order to maintain structural integrity of the stack and magnetic conductivity between the radial poles, the slot position is rotated by 90 degrees between each subsequent lamination in the stack. The solution has been evaluated in a test actuator with 3000N axial and 1200N radial load capacities. 7dB gain improvement and 15 degrees phase improvement at 30Hz have been demonstrated.

Vibration Mitigation of Rotors Suspended on Low-Cost Hybrid Gas Foil Bearing

2019 ◽  
Author(s):  
Kamal Kumar Basumatary ◽  
Karuna Kalita ◽  
Sashindra K. Kakoty ◽  
Seamus D. Garvey
Keyword(s):  
High Speed ◽  
Low Cost ◽  
Current Source ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Electromagnetic Actuators ◽  
Manufacturing Method ◽  
Foil Bearings ◽  
Foil Bearing ◽  
Small Series

Abstract The hybrid Gas Foil Bearings combining the Gas Foil Bearing and Active Magnetic Bearing is a possibility for application in high-speed turbomachinery and a few developments have been made in this context. As such, the cost of conventional Gas Foil Bearing increases due to its requirement of precise manufacturing method and the coating material for the top foil and bump foil. In case of Active Magnetic Bearing, the normal electrical arrangement includes a multiplicity of independently controlled current sources usually at least four drives per bearing which increases its cost. Therefore, the hybrid Gas Foil Bearing will have much higher cost. In this work, a new electrical arrangement for the electromagnetic actuators of the hybrid Gas Foil Bearing has been proposed. The new arrangement requires only two drives per bearing and the bias current has been provided (in the same set of windings) through a simple rectifier with small series choke and shunt capacitor. As the number of drives required is less, the proposed bearing will have low cost. Implementing the new approach, the force vectors are achieved using only two current-source drives whereas the usual conventional arrangement requires four such drives. Numerical simulations are performed to explore the capabilities of the low cost bearing.

Design and Testing of a Permanent Magnet Biased Active Magnetic Bearing

1999 ◽  
Author(s):  
Ross W. Overstreet ◽  
George T. Flowers ◽  
Gyorgy Szasz
Keyword(s):  
Permanent Magnet ◽  
Permanent Magnets ◽  
Experimental Testing ◽  
Control Strategies ◽  
Active Vibration Control ◽  
Electrical Current ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Active Magnetic Bearing ◽  
Flux Flow

Abstract Magnetic bearings provide rotor support without direct contact. There is a great deal of current interest in using magnetic bearings for active vibration control. Conventional designs use electrical current to provide the bias flux, which is an integral feature of most magnetic bearing control strategies. Permanent magnet biased systems are a relatively recent innovation in the field of magnetic bearings. The bias flux is supplied by permanent magnets (rather than electrically) allowing for significant decreases in resistance related energy losses. The use of permanent magnet biasing in homopolar designs results in a complex flux flow path, unlike conventional radial designs which are much simpler in this regard. In the current work, a design is developed for a homopolar permanent magnet biased magnetic bearing system. Specific features of the design and results from experimental testing are presented and discussed. Of particular interest is the issue of reduction of flux leakage and more efficient use of the permanent magnets.

Research About Eddy Effect and Dynamic Force of the Magnetic Thrust Bearing

2014 ◽  
Author(s):  
Xingnan Liu ◽  
Ni Mo ◽  
Guojun Yang ◽  
Zhengang Shi ◽  
Suyuan Yu
Keyword(s):  
Thrust Bearing ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Dynamic Force ◽  
Phase Lag ◽  
Direct Part ◽  
Element Analysis ◽  
Large Eddy ◽  
The Finite Element Analysis ◽  
Sinusoidal Current

The eddy effect of the magnetic thrust bearing (MTB) is researched by the finite element analysis (FEA). The active magnetic bearing (AMB) is an advanced bearing, used in HTR-PM. The alternating current in the bearing windings will decrease the electromagnetic force and cause phase lag, especially in the MTB which has no lamination structure. According to the calculation in this paper, simple sinusoidal current has large eddy effect. The force decreases obviously and the phase lag is large. However, the current containing direct part and sinusoidal part, which is closer to actual current, has less eddy effect. That is to say, because of the direct part in the current, the eddy effect of the sinusoidal part decreases.

scholarly journals Optimal Coil Design of an Electromagnetic Actuator Using Particle Swarm Optimization

2020 ◽  
Vol 53 (6) ◽  
pp. 755-761
Author(s):  
Eduardo Chiarello ◽  
Juliana Almansa Malagoli
Keyword(s):  
Particle Swarm Optimization ◽  
Particle Swarm ◽  
Electrical Current ◽  
Magnetic Bearing ◽  
Optimization Techniques ◽  
Design Parameters ◽  
Electromagnetic Actuator ◽  
Coil Design ◽  
Electromagnetic Actuators ◽  
Swarm Optimization

This paper aims to reduce the heating of the electromagnetic actuators of a magnetic bearing. The electrical current of the coils was above normal, so the need for a new coil design to reduce heating due to high currents. In this scenario, the proposed methodology allows minimizing copper losses using Particle Swarm Optimization, so that the best result of the design parameters will be used in the construction of the new coil for the actuator. For the development of this work, it was decided to use a computational tool for public use, FEMM (Finite Element Method Magnetics) to simulate the electromagnetic device. In the simulations, the densities of magnetic fluxes in the core and in the air gap are shown, as well as the energies, electromagnetic forces and losses in the copper of the electromagnetic actuator winding. Finally, an optimal model of the actuator is obtained through the use of optimization techniques. Therefore, the results obtained demonstrate that the proposed methodology is configured as an interesting strategy for the purpose of this work.

Improving Disturbance Rejection in Nonlinear Active Magnetic Bearing Systems: Using Lur'e Formulation

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Ali Gerami ◽  
Roger Fittro ◽  
Carl Knospe
Keyword(s):  
Disturbance Rejection ◽  
System Approach ◽  
Magnetic Bearing ◽  
Experimental Results ◽  
Active Magnetic Bearing ◽  
Electromagnetic Actuators ◽  
Lur’E System ◽  
Series Of Experiments ◽  
Magnetization Behavior ◽  
Good Agreement

Abstract The efficacy of magnetic bearing controllers designed to reject transient disturbances is evaluated via a series of experiments. The experiment consists of a rocking beam with opposing electromagnetic actuators for control as well as an actuator for applying a disturbance torque. Controller synthesis employed a generalized Lur'e system approach to accommodate the nonlinear magnetization behavior of the electromagnetic actuator iron. Experimental results demonstrate significant improvements in disturbance rejection with controllers based upon the Lur'e system approach. Good agreement between simulation and experimental results was obtained, providing confidence that similar benefits can be achieved in industrial machinery employing active magnetic bearings.

scholarly journals Application of the Dynamic Iterative Learning Control to the Heteroplanar Active Magnetic Bearing

2020 ◽  
Vol 53 (2) ◽  
pp. 1511-1516
Author(s):  
Lukasz Hladowski ◽  
Arkadiusz Mystkowski ◽  
Krzysztof Galkowski ◽  
Eric Rogers ◽  
Bing Chu
Keyword(s):  
Iterative Learning Control ◽  
Learning Control ◽  
Magnetic Bearing ◽  
Iterative Learning ◽  
Active Magnetic Bearing

Analysis of supercritical pitchfork bifurcation in active magnetic bearing-rotor system with current saturation

2021 ◽  
Vol 104 (1) ◽  
pp. 103-123
Author(s):  
Xiaoshen Zhang ◽  
Zhe Sun ◽  
Lei Zhao ◽  
Xunshi Yan ◽  
Jingjing Zhao ◽  
...  
Keyword(s):  
Pitchfork Bifurcation ◽  
Magnetic Bearing ◽  
Rotor System ◽  
Active Magnetic Bearing ◽  
Current Saturation
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