3 edition of A magnetic bearing control approach using flux feedback found in the catalog.
A magnetic bearing control approach using flux feedback
by National Aeronautics and Space Administration, Langley Research Center, For sale by the National Technical Information Service in Hampton, Va, [Springfield, Va
Written in English
|Statement||Nelson J. Groom.|
|Series||NASA technical memorandum -- 100672.|
|Contributions||Langley Research Center.|
|The Physical Object|
The present work extends a method of unbiased control originally developed for three-pole radial magnetic bearings into a generalized unbiased control strategy that encompasses bearings with an arbitrary number of poles. By allowing the control of bearings with more than three poles, the applicability of the approach is broadened to the case of large rotors. A magnetic bearing is a type of bearing that supports a load using magnetic ic bearings support moving parts without physical contact. For instance, they are able to levitate a rotating shaft and permit relative motion with very low friction and no mechanical wear. Magnetic bearings support the highest speeds of all kinds of bearing and have no maximum relative speed.
A nonlinear control scheme for active magnetic bearings is presented in this work. Magnet winding currents are chosen as control inputs for the electromechanical dynamics, which are linearized using feedback linearization. Then, the desired magnet currents are enforced by sliding mode control design of the electromagnetic dynamics. A passive magnetic bearing is composed of permanent magnets and the output flux can not be controlled while an active magnetic bearing (AMB) is made of electromagnets and the output flux can be adjusted by changing the current on the coil. Therefore, AMB is more popular in FESS than passive magnetic bearings.
With this approach, important parameters used for optimal MB designing, such as magnetic leakage coefficient, as well as the flux density of main flux and fringing flux are given as simple formulas, which educe the axial restoring magnetic force and the axial passive stiffness. The coupling effect of these two units of the HMB is analyzed. Using signal generator to generate a signal with frequency and amplitude 1 V, put this signal to the input of the power amplifier 1 corresponding to the 1+ magnetic pole. At this time, the coil current of 1+ magnetic pole includes bias current, feedback control current, and external excitation rotor displacement signal and the control current of 1− pole coil will be collected.
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Successful implementation of the flux feedback algorithm simplifies the control system design of magnetic bearing systems by providing a more accurate, well characterized actuator model, and, by overcoming such effects as hysteresis, saturation, eddy currents and gap dependence, this approach provides magnetic bearings which exhibit Cited by: 9.
A magnetic bearing control approach using flux feedback is described and test results for a laboratory model magnetic bearing actuator are presented. Test results were obtained using a magnetic bearing test fixture, which is also described.
The magnetic bearing actuator consists of elements similar to those used in a laboratory test model Annular Momentum Control Device Cited by: Get this from a library. A magnetic bearing control approach using flux feedback. [Nelson J Groom; Langley Research Center.].
A magnetic bearing system like that of Fig. 2 is composed of the object to be levitated, core, electromagnet including the coil, amplifier to operate the electromagnet, displacement measurement system to measure the distance between the levitating object and the electromagnet, control law to calculate the control signal from the feedback signal Author: Hwang Hun Jeong, So Nam Yun, Joo Ho Yang.
Additionally, this approach can be exploited for academic purposes and may serve as a reference to implement simple but accurate active magnetic levitation control using low-cost, off-the-shelf.
Graham Foster, in Mechanical Circulatory and Respiratory Support, Magnetic Bearings. Magnetic bearings use magnetic forces to partially or fully suspend the rotor without contact with the casing. Both permanent and actively controlled electromagnets, often in combination, can be used to achieve magnetic levitation, though it should be noted that a solely permanently suspended rotor is.
Power lost due to bearing friction is extremely low, especially when compared to hydrodynamic rotor support systems. Most active magnetic-bearing supported pumps use a magnetic-bearing system with five active axes (one axial, two radial, and two tilt) to provide complete control.
CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): this paper, optimal control of a magnetic bearing without bias is investigated. A single degree-of-freedom system consisting of a mass and two opposing electromagnets is considered. The optimal control problem is examined for a cost function that penalizes both poor regulation and rotational energy lost.
CiteSeerX - Document Details (Isaac Councill, Lee Giles, Pradeep Teregowda): Conventional Active Magnetic Bearings (AMB) are operated using a bias current (or flux) to achieve greater linearity and dynamic capability.
Bias, however, results in undesirable rotating losses and consequent rotor heating. While control without bias flux is an attractive alternative, it is considerably more complex. An exhaustive, self-contained text on active magnetic bearing technology, this book should be a core reference for anyone seeking to understand or develop systems using magnetic bearings.
Show all. Table of contents Dynamics and Control Issues for Fault Tolerance. Pages Implicit flux feedback control for magnetic bearings / viabil ity of the control approach, but its use has been limited because three-pole bearings are primarily applicable to the suspension.
Jump to Content Jump to Main Navigation Jump to Main Navigation. transverse inertia ratio, Ip/It. At that time the magnetic bearing control algorithms will require additional refinement for the reconfigured rotor.
In order to achieve the target operating speed, a gain scheduled MIMO control approach was developed. Similar approaches have been applied to magnetic bearings for other applications [4,5]. This paper presents the study of magnetic bearings regarding a linear model.
Initially, the advantages of magnetic bearings are referenced, in relation to the existing technology. Subsequently, the linearized model of the system is presented and the need for closed loop and control of the system is clarified.
This need leads to further analysis of linear controllers like P, I, D, PI, PD, and PID. A magnetic bearing control approach using flux feedback is described and test The results for a laboratory model magnetic bearing actuator are presented.
were obtained using a magnetic bearing test fixture, which is also described. magnetic bearing actuator consists of elements similar to those used in a laboratory. Magnetic bearings without position measurement Flux density measurement instead of position feedback Pumping systems: cost reduction and miniaturization l ch Leybold Magnetic flux based control approach Envisioned applications of ultra-thin flexible Hall sensors providing flux feedback Requirement: Magnetic field sensors have to be mounted on.
A new approach for magnetic bearing rotor dis-placement estimation using on-line recursive least squares support vector machine (O-RLS-SVM) is proposed.
The basic premise of the method is that an O-RLS-SVM forms a very efficient mapping structure for the non-linear magnetic bearing. Through measurement of the phase flux linkages and phase currents the O-RLS-SVM is able to estimate the.
This company has made major improvements to the AMB fundamental technology in order to meet industrial requirements. Each component of the AMB system has been improved through a simple, robust, and patented solution.
Among others, inductive sensors, flux feedback control, control loops (automatic balancing system), auxiliary bearings. New Approach Calculation of the Tangential Components of the Magnetic Field.
Integration of Feedback Control in a Field Circuit Coupled Model G Manot. Analysis of the Laboratory Implementation of a Radial Active Magnetic Bearing.
/5(1). • Design of Active Magnetic Bearings • Control Engineering of Magnetic Bearings • Control of Rotor by using Magnetic Bearings • Conclusions Introduction • An active magnetic bearing (AMB) system supports a rotating shaft, without any physical contact by suspending the rotor in.
Active Magnetic Bearings (AMBs) are already widely used in rotating machinery and continue to gain popularity due to the ever-present push to higher rotational speeds and decreasing prices of associated electronic components. They offer several advantages over conventional mechanical bearings including non-contact rotor support (thus eliminating mechanical wear and the need for lubricants.magnetic bearing desJgner can manipulate several parameters (bus voltage, airgap, number of turns, control class) to optimize dynamic load capability, but ultimately bearing active area and the magnetic material saturation flux density will limit the bear ing load capability.
For this reason, it is desirable to select a bear ing with.First a nonlinear model for the magnetic bearing is set in state-variable form using airgap flux, gap displacement, and velocity as state variables.
The system, which is unstable in nature, is stabilized locally around the equilibrium point of zero speed using an optimal robust servo controller.