Evaluation of inductive displacement sensors for a basic active magnetic bearing test rig

2011 ◽  
Author(s):  
M. Recheis ◽  
J. Nicolics ◽  
H. Wegleiter ◽  
B. Schweighofer ◽  
P. Fulmek
Keyword(s):  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Test Rig ◽  
Displacement Sensors

Design and Implementation of Redundant Sensors in Active Magnetic Bearing

2017 ◽  
Author(s):  
Zhengang Shi ◽  
Jiaji Yang ◽  
Ni Mo ◽  
Xingnan Liu ◽  
Yan Zhou
Keyword(s):  
High Reliability ◽  
Short Circuit ◽  
Stability Control ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Displacement Sensor ◽  
Special Equipment ◽  
Design And Implementation ◽  
Displacement Sensors ◽  
Redundancy Design

With the advantages of frictionless, no need of lubrication, no pollution, low consuming and long life, active magnetic bearing (AMB) is applied in the primary helium circulator of the High Temperature Gas-Cooled Reactor-Pebble bed Module (HTR-PM), which is under construction in Shidao Bay Nuclear Power Plant. Active magnetic bearing is a typical mechatronic system with interconnection of mechanical and electronic components with the function of picking up signals, processing and producing. Displacement sensor is an important component to pick up signals for stability control, and also the most susceptible part to fail due to variation of air temperature and vibration of high rotation speed. However, rotating system can’t run normally if a single sensor fails in AMB without redundancy design. For security considerations, higher reliability is required in some special equipment, especially in primary helium circulator of HTR-PM. Design and implementation of redundant sensors is an effective method. This paper reviewed the present research of fault diagnosis and redundant control of displacement sensors, simulation of coil’s short-circuit and open-circuit fault was made with MATLAB/SIMULINK. Parameters were optimized for fault diagnostic circuit by Multisim. Based on the high reliability demand, redundancy design was applied both on structure and control system in AMB. Schematic drawing and PCB board were finished by Altium Design, and experiments were carried out. The result showed that if the coils of sensor failed, AMB system could still work normally by switching to the redundant sensors automatically.

Harmonic disturbance attenuation in a three-pole active magnetic bearing test rig using a modified notch filter

2016 ◽  
Vol 23 (5) ◽  
pp. 770-781 ◽  
Author(s):  
S Mahdi Darbandi ◽  
Mehdi Behzad ◽  
Hassan Salarieh ◽  
Hamid Mehdigholi
Keyword(s):  
Notch Filter ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Disturbance Attenuation ◽  
Test Rig ◽  
Stability Margins ◽  
Periodic Disturbances ◽  
Mass Unbalance ◽  
Gain Margin ◽  
The Stability

This study is concerned with the problem of harmonic disturbance rejection in active magnetic bearing systems. A modified notch filter is presented to identify both constant and harmonic disturbances caused by sensor runout and mass unbalance. The proposed method can attenuate harmonic displacement and currents at the synchronous frequency and its integer multiples. The reduction of stability is a common problem in adaptive techniques because they alter the original closed-loop system. The main advantage of the proposed method is that it is possible to determine the stability margins of the system by few parameters. The negative phase shift of the modified notch filter can be tuned to achieve a desired phase margin, while the gain margin can also be adjusted separately. It is shown that the modified notch filter can be designed to suppress multiple harmonics at the same time. It is implemented on a three-pole magnetic bearing test rig to evaluate its performance. Simulation and experimental results indicate that the presented method can be successfully applied to compensate the periodic disturbances such as sensor runout and mass unbalance in active magnetic bearing systems.

Dynamic Characteristics of Sealed Squeeze Film Damper With a Central Feeding Groove

2005 ◽  
Vol 127 (1) ◽  
pp. 103-111 ◽  
Author(s):  
Keun-Joo Kim ◽  
Chong-Won Lee
Keyword(s):  
Dynamic Characteristics ◽  
Pressure Field ◽  
Dynamic Pressure ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Field Analysis ◽  
Squeeze Film ◽  
Test Rig ◽  
Squeeze Film Damper ◽  
Dynamic Coefficients

In this paper, the dynamic characteristics of an oil-lubricated, sealed squeeze film damper (SFD) with a central feeding groove are analytically derived based on an enhanced dynamic pressure field analysis, accounting for the effect of the seal and feeding grooves, and its validity is experimentally verified. A test rig using an active magnetic bearing system as an exciter is introduced to identify the dynamic characteristics of SFDs with high accuracy and efficiency. Experiments are conducted with the seal gap varied, in order to investigate its effect on the dynamic characteristics of the SFD. The estimated and analytical damping and inertia coefficients for the sealed SFD with a groove are compared and it is found that the pressure field analysis, when neglecting the effect of the seal groove, tends to far underestimate the SFD dynamic coefficients.

scholarly journals Inductive Displacement Sensors with a Notch Filter for an Active Magnetic Bearing System

Sensors ◽  
2014 ◽  
Vol 14 (7) ◽  
pp. 12640-12657 ◽  
Author(s):  
Seng-Chi Chen ◽  
Dinh-Kha Le ◽  
Van-Sum Nguyen
Keyword(s):  
Notch Filter ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Displacement Sensors ◽  
Bearing System

Evaluation of Q-Values of a Rotor-Bearing System Using a Modal Open Loop Transfer Function

2009 ◽  
Author(s):  
Hiroyuki Fujiwara ◽  
Yasuo Fukushima ◽  
Naohiko Takahashi ◽  
Hiroto Oyama ◽  
Osami Matsushita
Keyword(s):  
Transfer Function ◽  
Damping Ratio ◽  
Magnetic Bearing ◽  
Open Loop ◽  
Active Magnetic Bearing ◽  
Q Value ◽  
Oil Whip ◽  
Displacement Sensors ◽  
Loop Transfer Function ◽  
Value Estimation

As indicated by ISO standard 10816, Q-value estimation is very important for rotating machinery commission and/or machine safety operation. Impulse tests and resonance curve measurements are commonly contributed to Q-value estimation. Instead of two methods, we are developing a new method using open-loop transfer function (Go) at real operational condition. In this paper, we present a theoretical background on how to measure the open loop transfer function. Our key technique is the measurement of the modal coordinates with a combination of several displacement sensors. Concerning the experimental measurement of Go, we use multiple sensors and only one active magnetic bearing (AMB) in a rotor system supported by oil-film/ball bearing. This Go is converted to damping ratio. In fact, a smaller damping ratio is recognized just before oil-whip instability by our open loop measurement. In addition, we set a dynamic damper which has been developed for suppression of oil whip instability, and an increasing damping ratio is also recognized by our method.

Stabilizing Hydrodynamic Bearing Oil Whip With μ-Synthesis Control of an Active Magnetic Bearing

2015 ◽  
Author(s):  
Alexander H. Pesch ◽  
Jerzy T. Sawicki
Keyword(s):  
Rotation Speed ◽  
Stability Limit ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Related Phenomenon ◽  
Test Rig ◽  
Hydrodynamic Bearing ◽  
Oil Whip ◽  
Oil Whirl ◽  
Excited Vibration

Oil whip is a self-excited vibration in a hydrodynamic bearing which occurs when the rotation speed is above approximately twice the first natural frequency. Because of this, the oil whip phenomenon limits the operational speed of a rotor system on hydrodynamic bearings. Below the oil whip threshold, the related phenomenon of oil whirl can cause large vibrations at frequencies below half the rotation speed. A method is presented for stabilizing oil whip and oil whirl in a hydrodynamic bearing with an active magnetic bearing (AMB). The AMB controller is designed with μ-synthesis model-based robust control utilizing the Bently-Muszynska fluid film bearing model, which predicts the unstable phenomena. Therefore, the resulting AMB controller stabilizes the natural instability in the hydrodynamic bearing. Rotor speed is taken into account by use of a parametric uncertainty such that the method is robust to changes in running speed. The proposed method is demonstrated on an experimental hydrodynamic bearing test rig. Details of the test rig and implementation of the AMB controller design are presented. Waterfall plots for the controlled and uncontrolled system are presented which demonstrate the improved stability limit.

Circularity Error Analysis of Axial Displacement Sensor Detecting Surface for Active Magnetic Bearings of 10MW High Temperature Gas-Cooled Reactor (HTR-10GT)

2013 ◽  
Author(s):  
Jingjing Zhao ◽  
Yan Zhou ◽  
Zhe Sun ◽  
Suyuan Yu
Keyword(s):  
High Temperature ◽  
Degrees Of Freedom ◽  
Magnetic Bearing ◽  
Axial Displacement ◽  
Working Environment ◽  
Active Magnetic Bearing ◽  
Displacement Sensor ◽  
Displacement Sensors ◽  
Circularity Error ◽  
High Temperature Gas

The 10MW high temperature gas-cooled test module reactor (HTR-10GT) with the core made of spherical fuel elements was designed and constructed by the Institute of Nuclear and New Energy Technology of Tsinghua University in China. In the HTR-10GT, turbo-compressor and generator rotors are connected by a flexible coupling and a decelerator. The rotors, restricted by actual instruments and working environment, must be supported without any contact and lubrication. Active magnetic bearing (AMB), is the best way to suspend and stabilize the position of rotors of HTR-10GT. In AMB system, the displacement sensors are designed for converting measured physical value into proportional electric signals and transferring it into the control and monitoring system. The characteristics and influence of circularity error of the axial displacement sensor detecting surface is analyzed according to AMB with five degrees of freedom. In order to reduce the circularity error of the magnetic bearing system, the sensor detecting surface requires high-precision machining.

A New Fluid Film Bearing Test Rig for Oil and Water Bearings

2008 ◽  
Author(s):  
Tim Dimond ◽  
Robert D. Rockwell ◽  
Pradip N. Sheth ◽  
Paul E. Allaire
Keyword(s):  
Experimental Data ◽  
Pressure Profile ◽  
Added Mass ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Fluid Film ◽  
Turbulent Regime ◽  
Test Rig ◽  
Tilting Pad ◽  
Displacement Measurements

Ever-increasing demands on the turbomachinery industry result in faster, lighter machines with higher rotational speeds and power densities. Modern, well-established thermoelastohydrodynamic (TEHD) analyses predict static and dynamic bearing characteristics in the presence of a turbulent lubricant and reduced lubricant flows. Proper design of tilting-pad journal bearings (TPJB) is required for successful operation of rotating machinery. Bearing static effects include pad temperature, bearing pressure profile, and static operating position. Bearing dynamic effects include stiffness, damping, and added mass coefficients. The current body of experimental data does not include the entire range of speed and load for which TEHD analyses are thought to be valid or where industrial machines operate. Experimental data for both oil-lubricated and water-lubricated bearings is desired. Oil lubricated bearings are used in high-speed turbomachinery. Water bearing data are of interest for applications that use the process fluid as the bearing lubricant. This paper describes a new Fluid Film Bearing Test Rig (FFBTR) which is being designed to experimentally verify the TEHD analyses, both in the laminar and in the turbulent regime, and support industrial needs. Static bearing characteristics will be measured with temperature probes, pressure probes, and displacement measurements. The dynamic bearing coefficients will be identified by rotor perturbation with active magnetic bearing force actuators. The rotational speed range of the FFBTR will be 9000–22000 rpm. The test bearing size is 127 mm, giving a range of surface speeds of 60–146 m/s. The range of bearing length-to-diameter (L/D) ratios that can be tested will be 0.5–0.75. Separate lubrication systems for water-lubricated and oil-lubricated bearings will be provided. Two magnetic bearings will be used as non-contact force actuators for rotorbearing system perturbation. The designed capacity for the magnetic force actuators is 13 kN/exciter, for a total static plus dynamic load of 26 kN that can be applied to the test bearing. The actuators are designed to apply forces to the test rotor at non-synchronous frequencies up to 560 Hz. Bearing static characteristics will be measured. Static measurements will include lubricant pressure profile, lubricant and pad temperatures, and static eccentricity. During dynamic testing, test shaft and bearing tilting pad motion will be measured. Dynamic bearing stiffness, damping, and added mass coefficients will be identified from force and displacement measurements. The frequency dependence in tilting-pad journal bearing coefficients will be investigated. The combination of static and dynamic measurements will be used to validate the TEHD analyses and provide design information to industry.

Preliminary Research of Auxiliary Bearing in HTR-10GT Project

2008 ◽  
Author(s):  
Qingquan Qin ◽  
Guojun Yang ◽  
Zhengang Shi ◽  
Suyuan Yu
Keyword(s):  
Reference Value ◽  
Free Fall ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Main Function ◽  
Test Results ◽  
Test Rig ◽  
Advantages And Disadvantages ◽  
Auxiliary Bearing ◽  
Amb System

Active Magnetic Bearing (AMB) was used in the project of 10MW high temperature gas-cooled reactor (HTR-10GT) for the advantages over conventional mechanical bearings: without any mechanical friction and lubrication, etc. Auxiliary Bearings (ABs) is one of the most important parts in the AMB system, and its main function is to support the rotor at rest and provide protection for the rotor system during an overload or magnetic bearings failure situation. This paper introduced auxiliary bearings used in the HTR-10GT project and compared its advantages and disadvantages with other types of auxiliary bearings. The dynamic behaviors and temperature variation are the most important factors that may affect the performance of auxiliary bearings in a rotor drop event, this paper also analyzed the touching down course and dynamics in detail, divided the drop down process into four distinct stages of motion: free fall, impact, sliding-whirling and rolling. Finally, a test rig built up for the following rotor drop test is presented in the article. Test results at lower drop down speed were discussed. The result of the theory and experiment research has important reference value for the auxiliary bearings design of HTR-10GT.

A Gas Turbine Engine Backup Bearing Operating Beyond 2.5 Million DN

2000 ◽  
Author(s):  
Erik Swanson ◽  
James F. Walton ◽  
Hooshang Heshmat
Keyword(s):  
Gas Turbine ◽  
High Speed ◽  
Gas Turbine Engine ◽  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Test Rig ◽  
Turbine Engine ◽  
Post Test ◽  
Rotor Support ◽  
Auxiliary Bearing

Gas turbine engines and high speed rotating machinery using magnetic bearings require auxiliary and backup bearings for reliability and safety of operation. A 140 mm diameter Zero Clearance Auxiliary Bearing (ZCAB) capable of supporting radial and/or thrust loads of up to 4500 N was designed for an advanced gas turbine engine. The ZCAB was fabricated and tested successfully up to the expected maximum operating speed of 18,000 rpm in a specially configured test rig. The test rig included a 36,000 rpm capable drive motor, a 64 kg rotor which simulates a gas turbine engine shaft dynamics, a damped ball bearing at the drive end and an active magnetic bearing next to the ZCAB. Operation in excess of 240 minutes and 20 transient engagements simulating magnetic bearing failures were completed in the initial tests. Post test inspection revealed minimal wear to the shaft and the ZCAB rollers, whereupon the ZCAB was reassembled for shipment. These preliminary tests confirm the operation and durability of the ZCAB in maintaining rotor support and continued operation even if the primary magnetic bearing support is overloaded or encounters a failure.

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