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Title: ACES Journal April 2019 Cover
File Type: Journal Paper
Issue:Volume: 34      Number: 4      Year: 2019
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Title: ACES Journal April 2019 Front/Back Matter
File Type: Journal Paper
Issue:Volume: 34      Number: 4      Year: 2019
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Title: ACES Journal April 2019 Full
File Type: Journal Paper
Issue:Volume: 34      Number: 4      Year: 2019
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Title: Numerical Analysis and Preliminary Experimental Validation of a Heteropolar Electrodynamic Bearing
Abstract: In this paper we describe the numerical simulations of a Heteropolar Electrodynamic Bearing and compare them with some experimental data taken on a prototype in quasi-static state. The device is composed of a cylindrical permanent magnet rotor and six coils fixed onto the stator. The system has been simulated by means of a dedicated numerical code (“EN4EM” - Electric Network for Electromagnetics), previously developed for research purposes. The software is based on a 3D integral formulation and it is able to numerically simulate coupled multi-degree of freedom electro/mechanical problems. The comparison between computed and measured data are fully satisfactory.
Author(s): V. Kluyskens, B. Dehez, C. Dumont, A. Musolino, R. Rizzo
File Type: Journal Paper
Issue:Volume: 34      Number: 4      Year: 2019
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Title: Analysis of Unbalanced Response of Rigid Rotor Supported by AMBs under Coupling Dynamic and Control Methods
Abstract: The main helium circulator is the core component of the High Temperature Reactor (HTR). Mechanical machining errors and assembly errors can cause uneven distribution of rotor mass. When the rotor rotates, the unbalanced mass will generate unbalanced force which will change the rotor's axis trajectory. By coupling the rotor dynamics method and the electromagnetic bearing system control theory, the motion of the rotor is modeled. Three representative unbalanced conditions of the impeller position, the bearing position and the centroid position are assumed to simulate the unbalance response of the rotor, and the influence of changes in the stiffness and damping on the unbalance response of the rotor is analyzed by adjusting the stiffness and the damping of the rotor. The results of the analysis show that the bearings farther from the unbalanced position (UBP) have larger rotor displacements and bearing loads. Increasing Active Magnetic Bearings (AMBs) stiffness and damping will increase the bearing load and reduce the response displacement of the rotor. Therefore, the stiffness and damping of AMBs must be designed by considering the bearing capacity and the displacement limit of the rotor.
Author(s): G. Du, Z. Shi, H. Zuo, L. Zhao, Z. Sun
File Type: Journal Paper
Issue:Volume: 34      Number: 4      Year: 2019
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Title: Semi-Analytical 3D Force Calculation of an Ironless Cylindrical Permanent Magnet Actuator for Magnetic Levitation Systems
Abstract: The semi-analytical calculation of magnetic forces is currently an interesting alternative to the timeconsuming three-dimensional finite-element modeling (3D-FEM) due to its high accuracy and low computational cost. This paper presents novel equations for determining the magnetic forces of a cylindrical permanent magnet actuator used in high precision magnetic levitation positioning systems. Compared to the already available equations in literature, these equations consider the magnetic forces as a function of the current magnet position. Moreover, these equations are also suitable for designing and analyzing the cylindrical permanent magnet actuator. The results of our force equations and the verification by 3D-FEM and measurements are presented in this paper.
Author(s): M. Lahdo, T. Strohla, S. Kovalev
File Type: Journal Paper
Issue:Volume: 34      Number: 4      Year: 2019
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Title: Identification of the Structural Deviations Impacting the Dynamics of a Flexible Multispan Rotor on Full Electromagnetic Suspension
Abstract: An algorithm for accounting for identification of the structural deviations impacting the dynamics of a flexible multispan rotor on full electromagnetic suspension 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 against the scale model of a rotor on active magnetic bearings.
Author(s): V. F. Ovchinnikov, M. Y. Nikolaev, V. N. Litvinov, D. V. Kapitanov
File Type: Journal Paper
Issue:Volume: 34      Number: 4      Year: 2019
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Title: Dynamics of an Electromechanical Touchdown Bearing Mechanism
Abstract: Safety bearings are used as a back-up system for the rotor-systems that use active magnet bearings for supporting the rotor. When the control fails due to unexpected events, the rotor drops on the safety bearings that prevent further damages of the system. This paper presents dynamic studies of a novel electromechanical safety bearing solution. The parts of the studied system are modeled as rigid bodies and the purpose is the study the dynamics of a real system in means of simulation. The safety bearing mechanism is manufactured and measured in the laboratory environment. The study shows that the dynamic behavior of the system can be repeated using the simulation tools that combines mechanical description of the system, electromagnetics and control system. Also, the electromechanical safety bearing solution seems to be feasible from the dynamic perspective.
Author(s): J. E. Heikkinen, H. Kauppila, A. Smirnov, T. Sillanpaa, E. Sikanen, J. Sopanen
File Type: Journal Paper
Issue:Volume: 34      Number: 4      Year: 2019
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Title: Torque and Bearing Reaction Forces Simulation of Micro-Magnetic Gears
Abstract: Specific torque and bearing reaction forces are simulated for two models of axial flux magnetic gears. The models cover simulation in two scale ranges: hundreds of microns and tenths of microns. The simulations presented are performed considering currently available magnetic properties in the microscale and potentially achievable ones. Specific torque of the models is between 2.76 up to 8.24 Nm/kg. This range is large enough to overpass conventional toothed microgear specific torque. This means that micro magnetic gears can not only provide conversion of speed and torque without friction but also to be more compact.
Author(s): M. Muñoz-Martínez, E. Diez-Jimenez, M. J. Gómez-García, R. Rizzo, A. Musolino
File Type: Journal Paper
Issue:Volume: 34      Number: 4      Year: 2019
Download Link:Click here to download PDF     File Size: 2882 KB

Title: Stability Experiment of the High-Speed Active Magnetic Bearing-Flywheel System in the Rotating Frame
Abstract: The active magnetic bearings (AMBs) can greatly improve the stability of the flywheel system and increase the maximum flywheel speed. However, if the active magnetic bearing-flywheel system (AMB-FS) is placed in a rotating frame, the strong gyroscopic effect of high-speed flywheel will greatly affect the system stability. In this study, to realize the high stability of the AMB-FS at ultra-high flywheel speed with low power consumption, the cross feedback PID control was applied in the AMB-FS. The system stability and the performance of AMBs were studied. In the experiment, the gyroscopic effect of the flywheel was effectively suppressed. In the vacuum environment, the flywheel could runs stably at any speed within the range of 0 to 30000 rpm, and the power consumption of AMBs was only 17.82 W and the system had no need of cooling measures. The flywheel speed could exceed 31200 rpm and still possessed the speeding potential. The rotating frame test showed that the maximum frame rotational speed could reach 3.5 deg/s at the rated flywheel speed of 30000 rpm, and the AMBFS run stably.
Author(s): J. Yu, Y. Zhou, H. Zuo, K. Zhang, P. Liu, Y. Li, P. Pu, L. Zhao, Z. Sun
File Type: Journal Paper
Issue:Volume: 34      Number: 4      Year: 2019
Download Link:Click here to download PDF     File Size: 2353 KB

Title: Nonlinear Analysis of Rotor-AMB System with Current Saturation Effect
Abstract: The analysis on nonlinear dynamics of a rotor-AMB system is conducted in this paper. The nonlinearity of electromagnetic force and current saturation effect are taken into account. The nonlinear model of the rotor-AMB system is built and the nonlinear dynamic behaviors of the system in both resonance region and non-resonance region are investigated through numerical integration method. This paper shows that the rotor-AMB system can exhibit some complicated nonlinear dynamic behaviors, such as soft spring characteristic of the amplitude-frequency response curve, the jump phenomenon, and pitchfork bifurcation. And the effects of exciting force and current saturation on these nonlinear dynamic behaviors of the system are discussed.
Author(s): X. Zhang, T. Fan, Z. Sun, L. Zhao, X. Yan, J. Zhao, Z. Shi
File Type: Journal Paper
Issue:Volume: 34      Number: 4      Year: 2019
Download Link:Click here to download PDF     File Size: 1515 KB

Title: Applied Adaptive Controller Design for Vibration Suppression in Electromagnetic Systems
Abstract: In engineering tests, the vehicle-track coupled vibration is very easy to occur on the elastic support beams for a magnetic levitation (maglev) system. The fundamental waves, higher order harmonics, and other components related to the mode of track vibrations are often observed in the gap, acceleration and current sensors. This paper aims to design an adaptive filter to suppress these vibration components and improve the ride comfort for the passengers. Firstly, an adaptive selfturning filter is designed to filter out wideband signals and noise from the original signals, and enhance the strength of the fundamental wave and the harmonic components related to the mode of track vibration. Secondly, a narrow-band bandpass filter is presented to extract these enhanced periodical signals related to the track mode, and then the enhanced signals are configured as the reference inputs of the subsequent adaptive noise canceller. Thirdly, the adaptive noise canceller filters out periodical vibration components related to the track mode. Finally, the designed digital adaptive filter is applied to a real maglev system and suppresses coupled vibration on the elastic support beams effectively.
Author(s): Z. Zhang
File Type: Journal Paper
Issue:Volume: 34      Number: 4      Year: 2019
Download Link:Click here to download PDF     File Size: 1394 KB

Title: Experimental Verification of Nonlinear Position-Flux Zero-Bias Control for Heteropolar Active Magnetic Bearing
Abstract: This study presents experimental verification of a nonlinear position-flux control for active magnetic bearing (AMB) system operated with zero-bias flux. Recently developed controllers for nonlinear fluxcontrolled AMB applications are complicated and inherently difficult to implement. Therefore, three designs of low-order controllers are proposed using nonlinear feedback tools including Lyapunov-based techniques and control Lyapunov functions (CLFs). The control objective is to globally stabilize the rotor mass position in the AMB system. Responses of the AMB system states to initial condition and to external load disturbance are presented and the simulation and experimental results for transient responses are compared. The overshoots are compensated for the zero neighbourhood, and the rotor position amplitude does not exceed 2.5% of the air gap.
Author(s): A. Mystkowski, A. Kierdelewicz
File Type: Journal Paper
Issue:Volume: 34      Number: 4      Year: 2019
Download Link:Click here to download PDF     File Size: 2011 KB

Title: Calculation and Experiment of Electromagnetic Force of the Axial AMB used in HTR-PM Main Helium Blower Prototype and its Dual Material Selection Method
Abstract: The Active Magnetic Bearing (AMB) is used in the main helium blower in the High Temperature Reactor-Pebble-bed Modules (HTR-PM) which is being constructed in Shandong province, China. The axial AMB is very large and works under extreme conditions. The calculation deviation of the electromagnetic force of the axial AMB was studied experimentally. Through measuring B-H curve of the material in large range of magnetic field intensity, considering flux leakage in calculation, and considering residual magnetism and the change of the gas gap in measurement, the calculation deviation reduces to 10%, with most values less than 5%. The material selection method of the axial AMB working under extreme conditions was studied experimentally. Through measuring the electromagnetic force when the stator and the thrust disc are made of different materials, it’s found that the force mostly depends on the stator. Combined with the analysis of the stress distribution of the stator and the thrust disc under working condition, the dual material selection method is proposed. That is, the stator material should have good magnetic properties and its mechanical properties are not very important, however, the thrust disc material should have good mechanical properties, and its magnetic properties are not very important.
Author(s): X. Liu, Z. Shi, N. Mo, J. Zhao, G. Yang
File Type: Journal Paper
Issue:Volume: 34      Number: 4      Year: 2019
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Title: Loss Calculation and Thermal Analysis of Axial AMB in HTR-PM Helium Circulator
Abstract: The helium circulator is one of the important components of the High Temperature Gas-cooled Reactor Pebble Bed Module (HTR-PM). It uses the electromagnetic suspension technology to support the rotor, the so-called magnetic bearing technology. Considering the performance and safety issues on the axial active magnetic bearing(AMB) caused by potential high temperature, this paper calculates copper loss, iron loss and wind loss in axial AMB and simulates temperature field under a normal operating condition, and compares the results with the experimental data.
Author(s): H. Zuo, Z. Shi, Y. Zheng, J. Yu, T. Fan, N. Mo
File Type: Journal Paper
Issue:Volume: 34      Number: 4      Year: 2019
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Title: Theory and Simulation of Linearized Force Coefficients for Active Magnetic Bearings with Multiple Magnetic Poles
Abstract: Active magnetic bearing (AMB) is a kind of typical mechatronic product which is widely used due to its high performance. Since the electromagnetic force is strongly nonlinear, the force-displacement coefficient and the force-current coefficient need to be linearized in the process of controlling the AMB. This paper analyzes the three most common magnetic bearings and gives their linearized force formulas. Simulations show that the formulas have high precision. In addition, the source of errors is also analyzed in this paper.
Author(s): T. Fan, J. Yu, Z. Sun, X. Liu, X. Zhang, J. Zhao, X. Yan, H. Zuo, Z. Shi
File Type: Journal Paper
Issue:Volume: 34      Number: 4      Year: 2019
Download Link:Click here to download PDF     File Size: 1670 KB

Title: Disturbance Rejection for a Zero-bias Controlled Active Magnetic Bearing Based on Disturbance Observer and Notch Filter
Abstract: This paper introduces a nonlinear disturbance observer plus general notch filter based zerobias control strategy to handle disturbance and reduce power consumption for the radial magnetic bearing in the magnetically suspended spindle. The zero-bias control is used to decrease the power consumption of magnetic bearings, as large power consumption causes temperature rise of system and temperature drift of sensor. The suspension of the rotor is affected by complicated disturbance including non-periodic and periodic disturbance. In order to reduce the deviation of rotor brought by external disturbance, the nonlinear disturbance observer is used. However, since the response lag to the disturbance, the nonlinear disturbance observer cannot suppress the periodic imbalance force well. Therefore, the general notch filter is introduced to reduce the periodic vibration. The effectiveness on the disturbance suppression and power reduction of the proposed method is verified by experiment results.
Author(s): H. Rong, K. Zhou
File Type: Journal Paper
Issue:Volume: 34      Number: 4      Year: 2019
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Title: The Interaction Forces in Magnetic Support Systems of Vertical Type
Abstract: In this article, the vertical and horizontal forces of the interaction of permanent magnets in a Magnetic Suspension (support) System of Vertical Type (MSVT) are considered. The magnetic support system contains multi-row magnetic bands (strips), which have alternating polarity. The magnetization vector, M, is directed horizontally, as opposed to classical support systems where M is directed vertically. The results of the comparison of the vertical and lateral forces for the classic Magnetic System of Horizontal Type (MSHT) and the MSVT are presented too. An effectiveness factor, mu eff = fz/mg, is adopted (where fz is the vertical force per unit length of magnetic band and mg is its weight) and is used as the principle criterion for comparison. In this paper it is shown that when the vertical displacement of the moving part of the support system of MSVT causes the vertical force, fz, to reach its maximum, the lateral force fy is at its minimum.
Author(s): E. Frishman
File Type: Journal Paper
Issue:Volume: 34      Number: 4      Year: 2019
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Title: Analysis and Experimental Study on Uncertain Fault of Active Magnetic Bearing Displacement Sensor
Abstract: Active magnetic bearing (AMB) has been gradually applied to high speed rotating equipment to suspend rotor as it has many advantages, but some uncertain faults always appeal in the process of application. Meanwhile, displacement sensor is a key equipment of AMB control system, but when it is used in high speed atomizer, some uncertain problems are happened, such as expected range cannot be adjusted, and data characteristics cannot match well in the X-Y direction. In view of these problems, we gather electrical parameters in different frequencies, and establish the corresponding equivalent circuit models, to analyze the reasons of uncertain faults. Then we propose the high frequency electrical parameters characteristic analysis method to realize reliable judgment and reveal the essence of uncertain faults. Finally, comparative experiments are carried to verify the analysis methods, the results show that the electrical parameters of fault characteristic analysis method established for uncertain faults of displacement sensor has good theoretical and practical value.
Author(s): Y. Zheng, X. Liu, G. Yang, H. Zuo, Z. Sun, Z. Shi
File Type: Journal Paper
Issue:Volume: 34      Number: 4      Year: 2019
Download Link:Click here to download PDF     File Size: 1728 KB