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Title: ACES Journal August 2017 Cover
Abstract: ACES
Author(s):
File Type: Journal Paper
Issue:Volume: 32      Number: 8      Year: 2017
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Title: ACES Journal August 2017 Front/Back Matter
Abstract: ACES
Author(s):
File Type: Journal Paper
Issue:Volume: 32      Number: 8      Year: 2017
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Title: ACES Journal August 2017 Full
Abstract: ACES
Author(s):
File Type: Journal Paper
Issue:Volume: 32      Number: 8      Year: 2017
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Title: Stability Analysis for a Flywheel Supported on Magnetic Bearings with Delayed Feedback Control
Abstract: In this paper, the model of the rotor dynamics of the flywheel is given using a rigid rotor supported on magnetic bearings. The phase lag of the control loop is modeled by a simple time delay. Limits of stability and the associated vibration frequencies are described in terms of nondimensional magnetic bearing stiffness and damping and nondimensional parameters of flywheel speed and time delay. Compared to the theoretical values, the simulation results and experimental measurements show the stability boundaries of the PD controller have the same qualitative tendencies.
Author(s): L. L. Zhang, J. H. Huang
File Type: Journal Paper
Issue:Volume: 32      Number: 8      Year: 2017
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Title: Nonlinear Position-Flux Zero-Bias Control for AMB System with Disturbance
Abstract: This study presents two novel nonlinear controllers for a single one-degree-of-freedom (1–DOF) active magnetic bearing (AMB) system operated in zero-bias mode with externally bounded disturbance. Recently developed controllers are complicated and inherently difficult to implement. The simple and low-order controllers proposed in this paper are designed using nonlinear feedback tools, including Lyapunov-based techniques and control Lyapunov functions (CLFs). The control objective is to globally stabilize the mass position of the nonlinear flux-controlled AMB system with control voltage saturation. The zero-bias AMB control model is derived from the voltage switching strategy. The developed CLF-based controllers are verified by numerical calculations.
Author(s): A. Mystkowski, E. Pawluszewicz
File Type: Journal Paper
Issue:Volume: 32      Number: 8      Year: 2017
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Title: Six-Axis Rotor Magnetic Suspension Principle for Permanent Magnet Synchronous Motor with Control of the Positive, Negative and Zero-Sequence Current Components
Abstract: A novel magnetic levitation principle, applicable for two- and four-pole high-speed permanent magnet synchronous motors, is presented. The drive consists of two half-motors, in which two asymmetric star-connected windings are arranged. An additional active magnetic bearing part is inserted to control the axial displacement. The two coils of the axial magnetic bearing are fed by the zero-sequence current components of the star-connected windings. The proper control of the positive, the negative, and the zero-sequence currents permits to set the torque, the radial levitation forces and the axial levitation force, respectively.
Author(s): G. Messager, A. Binder
File Type: Journal Paper
Issue:Volume: 32      Number: 8      Year: 2017
Download Link:Click here to download PDF     File Size: 1788 KB

Title: Magnetic Propulsion Force Calculation of a 2-DoF Large Stroke Actuator for High-Precision Magnetic Levitation System
Abstract: The design of high-precision magnetic levitation positioning systems requires fast electromagnetic models. Since three-dimensional finite element method (3D-FEM) is very time-consuming, in order to calculate magnetic forces, an interesting alternative is to determine the forces semi-analytically due to the high accuracy with a short calculation time. In this paper, a new compact semi-analytical equation for determining the magnetic propulsion forces of a new ironless two degrees of freedom (2-DoF) actuator for a high-precision magnetic levitation system is presented. The derived equation is based on the magnetic scalar potential and the Lorentz force law. An important result is that this new expression takes also the position dependence of the propulsion forces over the whole planar stroke into account. The calculated propulsion forces from the derived equations and the verification by 3D-FEM (Maxwell 3D) are presented in this paper as well.
Author(s): M. Lahdo, T. Ströhla, S. Kovalev
File Type: Journal Paper
Issue:Volume: 32      Number: 8      Year: 2017
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Title: Magneto-Mechanical Model of Passive Magnetic Axial Bearings versus the Eccentricity Error, Part I: Physical Mathematical Model
Abstract: In this paper we illustrate a particular analytical numerical model of passive magnetic bearings with axial magnetization. The approach is based on the magnetic charges method. This method avoids the utilization of the finite element analysis. In relation to the system geometry, we find explicit formulations for computing magnetic fields by simple numerical integrations. A detailed magnetostatic model is developed and the nonlinearity of the magnetization vector M of the ring magnets can be considered by a very simple modification of the equations illustrated. The equations can be immediately implemented in a mathematical software and only few minutes are sufficient to obtain the results.
Author(s): R. Muscia
File Type: Journal Paper
Issue:Volume: 32      Number: 8      Year: 2017
Download Link:Click here to download PDF     File Size: 1965 KB

Title: Magneto-Mechanical Model of Passive Magnetic Axial Bearings versus the Eccentricity Error, Part II: Application and Results
Abstract: In this paper we apply the physical mathematical model described in Part I [1]. The study shows: i) the influence of the eccentricity of two polarized rings of the bearing on the stiffness; ii) the numerical efficiency of the response surfaces for evaluating the magnetic field in any point of the domain fixed; iii), in relation to a demanding application example (possible replacement of a big axial oleodynamic bearing with a thrust magnetic passive bearing), the danger arising from possible resonances (the natural frequencies of the device are near to the excitation frequencies).
Author(s): R. Muscia
File Type: Journal Paper
Issue:Volume: 32      Number: 8      Year: 2017
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Title: Performance of Yokeless Heteropolar Electrodynamic Bearings
Abstract: Electrodynamic bearings (EDBs) are a promising way to support rotors passively with no friction. In particular, heteropolar EDBs could allow for combining the motor and guiding functions, thereby optimizing the use of permanent magnets. Despite this advantage, few efforts have been dedicated to the evaluation and optimization of the performance of heteropolar EDBs. In this paper, the performance of a yokeless topology of heteropolar EDB is evaluated and optimized. This is done by evaluating the parameters of a parametric dynamical model of the EDB using a two-dimensional analytical model of the field distribution in the bearing. Compared to existing EDBs, the present one is shown to achieve a reasonable stiffness to permanent magnet volume ratio at high speeds.
Author(s): C. Dumont, V. Kluyskens, B. Dehez
File Type: Journal Paper
Issue:Volume: 32      Number: 8      Year: 2017
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Title: Modeling and Discussing an Interconnected Flux Magnetic Bearing
Abstract: An alternative idea for the construction of active magnetic bearings, adapted from a successful structure used in split-winding self-bearing motors, has been recently discussed in the literature. A mathematical model for this bearing configuration is developed in this paper. Preliminary theoretical results predict a greater equivalent stiffness for this model, when compared with traditional active magnetic bearings. The use of recently built prototypes for testing if these expectations hold true is also discussed.
Author(s): D. F. B. David, J. A. Santisteban, A. C. Del Nero Gomes
File Type: Journal Paper
Issue:Volume: 32      Number: 8      Year: 2017
Download Link:Click here to download PDF     File Size: 1994 KB

Title: Crucial Parameters and Optimization of High-Speed Bearingless Drives
Abstract: Bearingless drives integrate the functionality of magnetic bearings and an electric machine into a single device. While this integration allows very compact drives offering all advantages of magnetic levitation, the design process becomes significantly more complex. This work deals with the numerous topological and geometric design decisions which need to be taken for such a bearingless drive. Additionally, the definition of suitable optimization targets for the electromagnetic simulation process is outlined. The proposed guidelines generate a complex relationship of different dependencies which is then fed into the MagOpt optimizer for the design of a high speed bearingless disk drive, which allows verifying the optimization results through measurement results from two prototype drives.
Author(s): H. Mitterhofer, S. Silber
File Type: Journal Paper
Issue:Volume: 32      Number: 8      Year: 2017
Download Link:Click here to download PDF     File Size: 1876 KB

Title: Performance Tests of a Permanent Magnet Thrust Bearing for a Hydropower Synchronous Generator Test-Rig
Abstract: Permanent magnets are an attractive material to be utilized in thrust bearings as they offer relatively low losses. If utilized properly, they have a long service lifetime and are virtually maintenance free. In this contribution, we communicate the results of the tests performed on a permanent magnet thrust bearing that was custom built and installed in a hydropower synchronous generator test-rig. Tridimensional finite element simulations were performed and compared with measurements of axial force. Spin down times and axial force ripple have also been measured. We found good correspondence between the measurements and the simulations.
Author(s): J. J. Pérez-Loya, C. J. D. Abrahamsson, F. Evestedt, U. Lundin
File Type: Journal Paper
Issue:Volume: 32      Number: 8      Year: 2017
Download Link:Click here to download PDF     File Size: 1821 KB

Title: Vibration Isolation of Magnetic Suspended Platform with Double Closed-loop PID Control
Abstract: In magnetic vibration isolation field, magnetic force is used for the isolation, while the whole isolation system is always supported passively, which have non-control shortcomings. Aimed at this problem, a novel active control strategy with a double closed-loop PID algorithm was designed in this paper. The double closed-loop strategy includes an internal and external loop control, which was designed to fulfill the magnetic levitation and isolation, respectively. Firstly, the vibration isolation strategy proposed in this paper was simulated in both time and frequency domain. The simulation results showed that this method possesses good performance of vibration isolation. Then, an active levitation and vibration isolation control experiment was designed. The experimental results showed that the control algorithm has a good vibration control effect under periodic vibration and random vibration conditions.
Author(s): M. Tang, J. Zhou, C. Jin, Y. Xu
File Type: Journal Paper
Issue:Volume: 32      Number: 8      Year: 2017
Download Link:Click here to download PDF     File Size: 2261 KB

Title: Sensorless Control for a Three-pole Active Magnetic Bearing System
Abstract: This study proposes a novel sensorless control of a current-controlled three-pole active magnetic bearing (AMB) system. It is based on the smooth current controller incorporated with the estimated rotor displacements. The rotor position information is extracted from additional sensing coil currents. The sensing coil currents are generated from three phase voltages injected to the additional coils on each magnetic pole. The dynamic model of the 3-pole AMB with the additional high frequency input is derived for levitation control and for position estimation. The results are verified through simulation analysis.
Author(s): S.-L. Chen, K.-Y. Liu
File Type: Journal Paper
Issue:Volume: 32      Number: 8      Year: 2017
Download Link:Click here to download PDF     File Size: 1642 KB

Title: Algorithm for Accounting for Inner Damping in a Computer Model of Dynamics of a Flexible Rotor on Active Magnetic Bearings
Abstract: An algorithm for accounting for inner damping in an actively developed computer model of dynamics of a flexible rotor on active magnetic bearings is presented. The algorithm is illustrated by applying it for analyzing the effects of amplitude-independent inner damping on rotor dynamics when residual imbalance is present.
Author(s): V. F. Ovchinnikov, M. Y. Nikolaev, V. N. Litvinov
File Type: Journal Paper
Issue:Volume: 32      Number: 8      Year: 2017
Download Link:Click here to download PDF     File Size: 1849 KB

Title: A Stepped Magnetic Suspension System (SMSS)
Abstract: In this article, the vertical and horizontal forces of interaction of permanent magnets in a magnetic support system (magnetic suspension, MS) are considered. Permanent magnets have a stepped structure and uniform magnetization M throughout their entire volume (M = const ). The magnetic support system contains multi-row magnetic strips. The results of the comparison of the vertical and lateral forces for the classic horizontal magnetic system (HMS) are presented too. A stability factor index, the ratio of vertical to lateral force of interaction gamma= fZ/ fY, and an effectiveness factor mu eff=f Z/(mg) are defined (where mg is the weight of the magnets per unit length). A prototype of the proposed magnetic support system was built, and measurements were performed. Analysis of the obtained data indicates that the investigated magnetic suspension system performs better than the classical horizontal MS system.
Author(s): E. Frishman
File Type: Journal Paper
Issue:Volume: 32      Number: 8      Year: 2017
Download Link:Click here to download PDF     File Size: 1727 KB

Title: Coupled Electromechanical Analysis of a Permanent-Magnet Bearing
Abstract: In this paper we present a new Permanent Magnets (PMs) bearing, which is composed of a rotor capable to levitate at a short distance from a dedicated stator. Proper configurations of PMs arranged on both the stator and the rotor allows having the magnetic suspension. Intrinsic mechanical instability characterizes the device; a passive stabilization is attempted exploiting eddy currents on a conducting sheet that surrounds the magnets on the stator. The system has been simulated by means of a dedicated numerical code that takes into account the effects of magneto-mechanical coupling. The coupled problem has been integrated by means of a prediction-correction nested scheme. Some interesting results, extensively discussed here, has been produced by simulation activity. In particular the stability of to the center of mass with respect to the translations has been passively obtained, if the rotations are actively prevented.
Author(s): V. Di Dio, L. Sani
File Type: Journal Paper
Issue:Volume: 32      Number: 8      Year: 2017
Download Link:Click here to download PDF     File Size: 2100 KB