Test and Theory Correlation Study for a Flexible Rotor on Fault-Tolerant Magnetic Bearings

2002 ◽  
Vol 124 (3) ◽  
pp. 359-366 ◽  
Author(s):  
Uhn Joo Na ◽  
Alan B. Palazzolo ◽  
Andrew Provenza
Keyword(s):  
Fault Tolerant ◽  
Correlation Study ◽  
Magnetic Bearing ◽  
Test Results ◽  
Flexible Rotor ◽  
Magnetic Forces ◽  
Failure State ◽  
Simulation Results ◽  
Test Verification ◽  
Good Agreement

This paper provides a new algorithm and test verification for implementing fault-tolerant operation of magnetically suspended, flexible shaft, rotating machinery. The currents to the magnetic bearing are redistributed in a manner so that the bearing actuator preserves the same linearized magnetic forces after some of its coils experience failure. The algorithm that searches a database for the appropriate failure compensation matrix utilizes a Boolean description of the failure state to quickly locate and download its target. The test results are shown to have good agreement with the system simulation results presented.

Fault Tolerant Control of Magnetic Bearings

2001 ◽  
Author(s):  
Uhn Joo Na ◽  
Andrew Provenza ◽  
Alan B. Palazzolo ◽  
Benjamin Choi ◽  
Gerald Montague ◽  
...  
Keyword(s):  
Fault Tolerant ◽  
System Simulation ◽  
Magnetic Bearing ◽  
Rotating Machinery ◽  
Test Results ◽  
Magnetic Forces ◽  
Failure State ◽  
Simulation Results ◽  
Test Verification ◽  
Good Agreement

Abstract This paper provides a new algorithm and test verification for implementing fault-tolerant operation of magnetically suspended, flexible shaft, rotating machinery. The currents to the magnetic bearing are redistributed in a manner so that the bearing actuator preserves the same linearized magnetic forces after some of its coils experience failure. The algorithm that searches a database for the appropriate failure compensation matrix utilizes a Boolean description of the failure state to quickly locate and download its target. The test results are shown to have good agreement with the system simulation results presented.

scholarly journals High Temperature, Permanent Magnet Biased, Fault Tolerant, Homopolar Magnetic Bearing Development

2008 ◽  
Author(s):  
Alan Palazzolo ◽  
Randall Tucker ◽  
Andrew Kenny ◽  
Kyung-Dae Kang ◽  
Varun Ghandi ◽  
...  
Keyword(s):  
High Temperature ◽  
Design Methodology ◽  
Permanent Magnets ◽  
Fault Tolerant ◽  
State Of The Art ◽  
Magnetic Bearing ◽  
Test Results ◽  
Test Rig ◽  
Control Forces ◽  
Good Agreement

This paper summarizes the development of a magnetic bearing designed to operate at 1,000F. A novel feature of this high temperature magnetic bearing is its homopolar construction which incorporates state of the art high temperature, 1,000F, permanent magnets. A second feature is its fault tolerance capability which provides the desired control forces with over one-half of the coils failed. The construction and design methodology of the bearing is outlined and test results are shown. The agreement between a 3D finite element, magnetic field based prediction for force is shown to be in good agreement with predictions at room and high temperature. A 5 axis test rig will be complete soon to provide a means to test the magnetic bearings at high temperature and speed.

Fault Tolerant Magnetic Bearings

1999 ◽  
Vol 121 (3) ◽  
pp. 504-508 ◽  
Author(s):  
E. H. Maslen ◽  
C. K. Sortore ◽  
G. T. Gillies ◽  
R. D. Williams ◽  
S. J. Fedigan ◽  
...  
Keyword(s):  
Fault Tolerance ◽  
High Speed ◽  
Fault Tolerant ◽  
High Capacity ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Flexible Rotor ◽  
Variable Reluctance ◽  
Modular Redundancy ◽  
Bearing System

A fault tolerant magnetic bearing system was developed and demonstrated on a large flexible-rotor test rig. The bearing system comprises a high speed, fault tolerant digital controller, three high capacity radial magnetic bearings, one thrust bearing, conventional variable reluctance position sensors, and an array of commercial switching amplifiers. Controller fault tolerance is achieved through a very high speed voting mechanism which implements triple modular redundancy with a powered spare CPU, thereby permitting failure of up to three CPU modules without system failure. Amplifier/cabling/coil fault tolerance is achieved by using a separate power amplifier for each bearing coil and permitting amplifier reconfiguration by the controller upon detection of faults. This allows hot replacement of failed amplifiers without any system degradation and without providing any excess amplifier kVA capacity over the nominal system requirement. Implemented on a large (2440 mm in length) flexible rotor, the system shows excellent rejection of faults including the failure of three CPUs as well as failure of two adjacent amplifiers (or cabling) controlling an entire stator quadrant.

Eddy Current Effects on the Design of Rotor-Magnetic Bearing Systems

1995 ◽  
Vol 117 (B) ◽  
pp. 162-170 ◽  
Author(s):  
C. Kim ◽  
A. B. Palazzolo ◽  
A. Kascak ◽  
G. Brown
Keyword(s):  
Eddy Current ◽  
Magnetic Bearing ◽  
System Stability ◽  
Design Tools ◽  
Test Results ◽  
Flexible Rotor ◽  
New Methods ◽  
Novel Approach ◽  
Accurate Design ◽  
Effective Operation

The recent growth of magnetic bearing applications in the chemical, utility and aerospace industries requires more accurate design tools to insure reliable and effective operation as components of the overall rotor bearing system. This paper provides a novel approach for simulating a flexible rotor suspended in magnetic bearings, accounting for eddy current effects. The manuscript discusses some magnetic bearing fundamentals, leading up to the new methods for modeling. Test results show very good correlation with theory and confirm the importance of considering eddy current effects. Surface conductivity and frequency dependent permeability effects on the B field in the magnet gaps are shown to be very significant on overall system stability. The results in the manuscript should be very useful to the design or test rotor dynamicist.

Numerical Modeling of Composite Concrete Walls

2008 ◽  
Author(s):  
Eytan Kochavi ◽  
Yosef Kivity ◽  
Ido Anteby ◽  
Oren Sadot ◽  
Gabi Ben-Dor
Keyword(s):  
University Of California ◽  
Test Results ◽  
Dynamic Tests ◽  
Material Models ◽  
Concrete Walls ◽  
Beer Sheva ◽  
Simulation Results ◽  
The University ◽  
Development Center ◽  
Good Agreement

Dynamic tests of three reinforced concrete samples and six Dynablok samples were performed in the blast simulator facility at the University of California San-Diego (UCSD). The purpose of these tests was to evaluate the performance of a novel protective wall design. These tests were numerically simulated at the Protective Technologies Research and Development Center (PTR&DC) of the Ben-Gurion University (BGU) in Beer-Sheva, Israel. The simulations were carried out using two commercial hydro-codes: LS-Dyna and Dytran. The purpose of these simulations was to calibrate the parameters of the material models available in the above codes. Once calibrated, the simulation results showed good agreement with the test results for largely deflected yet moderately damaged specimens.

A Study on Semi-Active Magnetic Bearing Position-Controlled by Piezoelectric Actuators

2011 ◽  
Vol 5 (4) ◽  
pp. 594-600
Author(s):  
Jung-Ho Park ◽  
◽  
Hu-Seung Lee ◽  
Young-Bog Ham ◽  
So-Nam Yun
Keyword(s):  
Permanent Magnets ◽  
Position Control ◽  
Control Method ◽  
Piezoelectric Actuators ◽  
Magnetic Bearing ◽  
Repulsive Force ◽  
Active Magnetic Bearing ◽  
Test Results ◽  
Magnetic Forces ◽  
Hybrid Bearing

This paper investigates non-contact hybrid bearings that use permanent magnets for repulsive force and piezoelectric actuators for position-control. A structurally-improved hybrid bearing is presented. First, the concept of the hybrid bearing is briefly introduced along with previous test results. Then, the newly devised bearing with a decreased gap between rotor and stator is designed and analyzed with FEM to optimize the magnetic forces. Finally, a prototype bearing using the proposed mechanism is fabricated and a control method is discussed.

Eddy Current Effects on the Design of Rotor-Magnetic Bearing Systems

1995 ◽  
Vol 117 (B) ◽  
pp. 162-170 ◽  
Author(s):  
C. Kim ◽  
A. B. Palazzolo ◽  
A. Kascak ◽  
G. Brown
Keyword(s):  
Eddy Current ◽  
Magnetic Bearing ◽  
System Stability ◽  
Design Tools ◽  
Test Results ◽  
Flexible Rotor ◽  
New Methods ◽  
Novel Approach ◽  
Accurate Design ◽  
Effective Operation

The recent growth of magnetic bearing applications in the chemical, utility and aerospace industries requires more accurate design tools to insure reliable and effective operation as components of the overall rotor bearing system. This paper provides a novel approach for simulating a flexible rotor suspended in magnetic bearings, accounting for eddy current effects. The manuscript discusses some magnetic bearing fundamentals, leading up to the new methods for modeling. Test results show very good correlation with theory and confirm the importance of considering eddy current effects. Surface conductivity and frequency dependent permeability effects on the B field in the magnet gaps are shown to be very significant on overall system stability. The results in the manuscript should be very useful to the design or test rotor dynamicist.

Design of All-Dielectric Ultra-Wideband Transparent Water-Based Absorber

2021 ◽  
Author(s):  
Yi Lu ◽  
Juan Chen ◽  
Jianxing Li
Keyword(s):  
Thermal Stability ◽  
Energy Harvesting ◽  
Frequency Band ◽  
Oblique Incidence ◽  
Ultra Wideband ◽  
Test Results ◽  
Good Thermal Stability ◽  
Water Based ◽  
Simulation Results ◽  
Good Agreement

Abstract In this paper, an all-dielectric water-based transparent absorber is proposed. It is composed of transparent resin material filled with water, thus achieving the characteristics of all-dielectric and transparency. The simulation results show that the proposed absorber can achieve the absorptivity of more than 90% in the frequency band of 7.28-28.22GHz, and has good thermal stability and oblique incidence angular stability. The thickness of the absorber is only 6.5mm, corresponding to 0.16λmax~0.61λmin. The test results are in good agreement with the simulation results, which proves that the water-based absorber has good performance. It can be applied in the field of electromagnetic(EM) stealth, EM energy harvesting and EM shielding.

Ultra-Deepwater Model Testing of a Semisubmersible and Hybrid Verification

2008 ◽  
Author(s):  
Timothy E. Kendon ◽  
Ola Oritsland ◽  
Rolf J. Baarholm ◽  
Svein I. Karlsen ◽  
Carl-Trygve Stansberg ◽  
...  
Keyword(s):  
Model Test ◽  
Water Depth ◽  
Deep Water ◽  
Low Frequency ◽  
Line Tension ◽  
Model Tests ◽  
Test Results ◽  
Test Verification ◽  
Good Agreement

Model test verification of floater systems in ultra-deep water meets limitations when it comes to available laboratory sizes. Systems in depths beyond 1000–1500 m cannot be tested at reasonable scales without the truncation of the mooring and riser system. The development of methods and procedures to overcome this problem has been addressed through extensive research programs at MARINTEK (VERIDEEP, VERIDEEP Extension, NDP, DEMO2000). This led to a hybrid verification procedure which combines reasonable truncation principles, model tests of the truncated system, and numerical simulations, to estimate the system’s response at full depth. There is, however, still a need to address the actual influence from the truncation procedure, and from the integration with simulations, on the final extrapolated full depth results. This paper presents a case study for the validation of the procedure, that compares full depth model test results of a semisubmersible in water depth 1250m against the extrapolated full depth results obtained from a truncated system of 500m. Results are presented for line tension and vessel responses in 3 seastates. In general the extrapolated full depth results were found to be in good agreement with the full depth model tests. However, the results confirmed expectation that the low frequency response has the greater uncertainties and presents the greatest challenge for the procedure.

Parameter Design and Result Analysis for Radial AC Hybrid Magnetic Bearing

2011 ◽  
Vol 189-193 ◽  
pp. 484-488
Author(s):  
Wei Yu Zhang ◽  
Huang Qiu Zhu ◽  
Ze Bin Yang
Keyword(s):  
Finite Element Method ◽  
Finite Element ◽  
Power Converter ◽  
Magnetic Bearing ◽  
Parameter Design ◽  
Test Results ◽  
Static Performance ◽  
Simulation Results ◽  
Result Analysis ◽  
Design Result

In this paper, a novel radial hybrid magnetic bearing is proposed, which is driven by an AC 3-phase power converter, and biased magnetic fluxes are provided by an axial magnetized permanent magnet ring. Based on the introduction of the configuration and principle of the radial AC hybrid magnetic bearing (AC HMB), the methods in parameter design and design results for the prototype are presented. The parameter design results for the prototype of the radial AC HMB are simulated by 3D electromagnetic finite element method and the simulation results show that the obtained parameter is reasonable. The manufactured prototype applying to the parameter is operated and the test results also show that the design result for the prototype is available, and the AC HMB has good dynamic and static performance.

Sign in / Sign up

Export Citation Format

Share Document