Dynamic Behavior Analysis of Touchdown Process in Active Magnetic Bearing System Based on a Machine Learning Method

Magnetic bearings are widely applied in High Temperature Gas-cooled Reactor (HTGR) and auxiliary bearings are important backup and safety components in AMB systems. The performance of auxiliary bearings significantly affects the reliability, safety, and serviceability of the AMB system, the rotating equipment, and the whole reactor. Research on the dynamic behavior during the touchdown process is crucial for analyzing the severity of the touchdown. In this paper, a data-based dynamic analysis method of the touchdown process is proposed. The dynamic model of the touchdown process is firstly established. In this model, some specific mechanical parameters are regarded as functions of deformation of auxiliary bearing and velocity of rotor firstly; furthermore, a machine learning method is utilized to model these function relationships. Based on the dynamic model and the Kalman filtering technique, the proposed method can offer estimation of the rotor motion state from noisy observations. In addition, the estimation precision is significantly improved compared with the method without learning. The proposed method is validated by the experimental data from touchdown experiments.

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Dynamic Behavior of the AMB’s Vertical Arranged Rotor During Its Drop Process

Volume 1: Plant Operations, Maintenance, Engineering, Modifications, Life Cycle and Balance of Plant; Nuclear Fuel and Materials; Plant Systems, Structures and Components; Codes, Standards, Licensing and Regulatory Issues ◽

10.1115/icone22-30062 ◽

2014 ◽

Cited By ~ 2

Author(s):

Xiao Kang ◽

Guojun Yang ◽

Suyuan Yu

Keyword(s):

High Temperature ◽

Dynamic Behavior ◽

Rotational Frequency ◽

Magnetic Bearing ◽

Active Magnetic Bearing ◽

Axial Stiffness ◽

Experimental Conditions ◽

Auxiliary Bearing ◽

Amb System ◽

Stiffness And Damping

The active magnetic bearing (AMB) system is a crucial part in the helium circulator system of the 10MW high temperature gas-cooled reactor (HTR-10). Though the AMB has been widely used in industrial fields, it is still limited in the research of the dynamic behavior of AMB’s vertical arranged rotor with axial magnetic load during its drop process. This paper establishes the dynamic model of such drop process by Matlab. Meanwhile using the Hertz contact theory establishes the contact model of different configurations. Analyze the axial friction between the rotor and thrust interface of the inner ring of Auxiliary Bearing System (ABS). Besides, the numerical model is verified by the drop experiment with the axial magnetic force. Moreover, this paper analyzes the influence of the rotor’s drop rotational frequency and the axial bracing features including stiffness and damping on the dynamic behavior during vertical arranged rotor’s drop process. Moreover, the paper provides the optimal axial stiffness and damping for the ABS satisfying the experimental conditions so as to reduce the contact force. Such results provide important references to the design of the ABS with a vertical arranged rotor and its application in HTR-10 and High Temperature Reactor-Pebblebed Modules (HTR-PM).

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Modelling, Analysis and Identification of the Parallel and Angular Misalignments in a Coupled Rotor-Bearing-AMB System

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.4048352 ◽

2020 ◽

Author(s):

Siva Srinivas R ◽

Rajiv Tiwari ◽

Ch. Kanna Babu

Keyword(s):

Mathematical Model ◽

Vibration Suppression ◽

Magnetic Bearing ◽

Active Magnetic Bearing ◽

Identification Algorithm ◽

Rotor Systems ◽

Force Moment ◽

Coupling Force ◽

Auxiliary Bearing ◽

Amb System

Abstract The standard techniques used to detect the misalignment in rotor systems are loopy orbits, multiple harmonics with predominant 2X component, and high axial vibration. This paper develops a new approach for the identification of misalignment in coupled rotor systems modelled using 2-node Timoshenko beam finite elements. The coupling connecting the turbine and generator rotor systems is modelled by a stiffness matrix, which has both static and additive components. While the magnitude of static stiffness component is fixed during operation, the time varying additive stiffness component displays a multi-harmonic behaviour and exists only in the presence of misalignment. To numerically simulate the multi-harmonic nature coupling force/moment as observed in experiments, a pulse wave is used as the steering function in the mathematical model of the additive coupling stiffness (ACS). The representative TG system has two-rotor systems, each having two discs and supported on two flexible bearings - connected by coupling. An active magnetic bearing (AMB) is used as an auxiliary bearing on each rotor for the purposes of vibration suppression and fault identification. The formulation of mathematical model is followed by the development of an identification algorithm based on the model developed, which is an inverse problem. Least-squares linear regression technique is used to identify the unbalances, bearing dynamic parameters, AMB constants and importantly the coupling static and additive stiffness coefficients. The sensitivity of the identification algorithm to signal noise and bias errors in modelling parameters have been tested. The novelty of paper is the representation and identification of misalignment using the ACS matrix coefficients, which are direct indicators of both type and severity of the misalignment.

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Dynamic Behavior Analysis of Touchdown Process in Active Magnetic Bearing System Based on Kalman Filtering

10.1115/icone22-30058 ◽

2014 ◽

Cited By ~ 1

Author(s):

Zhe Sun ◽

Xiao Kang ◽

Jingjing Zhao ◽

Guojun Yang ◽

Zhengang Shi

Keyword(s):

Dynamic Analysis ◽

Dynamic Model ◽

Kalman Filtering ◽

Experimental System ◽

Magnetic Bearing ◽

Active Magnetic Bearing ◽

Extended Kalman Filtering ◽

Experiment Data ◽

Filtering Technique ◽

Bearing System

Magnetic bearings are widely applied in High Temperature Gas-cooled Reactor (HTGR) and auxiliary bearings are important backup and safety components in AMB systems. The dynamic analysis of the AMB rotors touchdown process is an important foundation for designing auxiliary bearings. In this paper, a data-based dynamic analysis of the touchdown process is proposed. The dynamic model of the touchdown process is firstly established and then the nonlinear extended Kalman filtering technique is applied. Based on the dynamic model and Kalman filtering technique, the proposed method can offer estimations of rotor’s displacements, velocities and accelerations from noisy observations. The proposed method is validated by the experiment data from touchdown experiments. The touchdown experiments are performed on an experimental system with a 440kg heavy rotor, the rotational speed in the experiments is 5000RPM and no brake is applied.

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BIFURCATION ANALYSIS IN FLEXIBLE ROTOR SUPPORTED BY ACTIVE MAGNETIC BEARING

International Journal of Bifurcation and Chaos ◽

10.1142/s0218127401003437 ◽

2001 ◽

Vol 11 (08) ◽

pp. 2163-2178 ◽

Cited By ~ 27

Author(s):

MING-JYI JANG ◽

CHA'O-KUANG CHEN

Keyword(s):

Dynamic Behavior ◽

Bifurcation Analysis ◽

Coupling Effect ◽

Power Spectra ◽

Magnetic Bearing ◽

Active Magnetic Bearing ◽

Flexible Rotor ◽

Factors Affecting ◽

Operational Conditions ◽

Amb System

In this paper, bifurcation analysis of the dynamic response of active magnetic bearing (AMB) with flexible rotor is presented, which includes the coupling effect between X-Y directions caused by rotational motion. The AMB systems include many nonlinear factors, such as mass imbalance, mass ratio with disk and journal, material property of shaft, and magnetic forces, etc., and its dynamic behavior are inherently nonlinear. Bifurcation diagrams of shaft journal's center, trajectories, power spectra, and Poincaré maps are used to analyze the dynamic behavior of the AMB system under different operational conditions. The key factors affecting the dynamic characteristics of the AMB system are identified. It will be beneficial to the design of AMB system.

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Thermal Analysis and Simulation of Auxiliary Bearings and Its Application in the High Temperature Reactor-10

Journal of Tribology ◽

10.1115/1.4031003 ◽

2015 ◽

Vol 138 (1) ◽

Cited By ~ 14

Author(s):

Yulan Zhao ◽

Guojun Yang ◽

Zhengang Shi ◽

Lei Zhao

Keyword(s):

High Temperature ◽

Magnetic Bearing ◽

Active Magnetic Bearing ◽

Hertzian Contact ◽

Thermal Growth ◽

Study Results ◽

New Energy ◽

Huge Impact ◽

Auxiliary Bearing ◽

Amb System

The auxiliary bearing is applied to provide mechanical uphold for the rotational dropping rotor when contact event happens due to the active magnetic bearing (AMB) failure emergencies. During the rotor drop process, the auxiliary bearing will endure huge impact force and friction heat generation. The thermal behavior will affect the mechanical interaction and dynamic behavior of the auxiliary bearing and even induce rapid failure especially when excessive temperature growth occurs. The Institute of Nuclear and New Energy Technology (INET) of Tsinghua University in China has proposed the 10 MW high-temperature gas-cooled reactor (HTR-10). It is designed to guarantee the inherent safety and economic competitiveness. The dry-lubricated ceramic auxiliary bearing is utilized to protect the AMB and aims to ensure the safety of the AMB system in the HTR-10 in the case of the special operational requirements in the reactor. This paper simulates the process of the rotor drop on the auxiliary bearings in the AMB system of the helium blower of the HTR-10, including the analysis of thermal growth based on the Hertzian contact model and a one-dimensional (1D) thermal heat transfer network model. The study results demonstrate the validation of the bearing models and elucidate different responses between mechanical and ceramic auxiliary bearings during contact events. The research in this paper offers important theoretical bases for the auxiliary bearing design to guarantee the safety of the whole system.

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Preliminary Research of Auxiliary Bearing in HTR-10GT Project

Volume 2: Fuel Cycle and High Level Waste Management; Computational Fluid Dynamics, Neutronics Methods and Coupled Codes; Student Paper Competition ◽

10.1115/icone16-48163 ◽

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.

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Stabilization of Active Magnetic Bearing System Subject to Base Motion

Volume 5: 19th Biennial Conference on Mechanical Vibration and Noise, Parts A, B, and C ◽

10.1115/detc2003/vib-48546 ◽

2003 ◽

Cited By ~ 1

Author(s):

Hyun-Sik Kim ◽

Ha-Yong Kim ◽

Chong-Won Lee ◽

Tae-Ha Kang

Keyword(s):

Dynamic Model ◽

Magnetic Bearing ◽

Active Magnetic Bearing ◽

Effective Control ◽

Motion Platform ◽

Inverse Dynamic ◽

Inverse Dynamic Model ◽

Feed Forward ◽

Amb System ◽

Feed Forward Controller

The active magnetic bearing (AMB) systems mounted in moving vehicles are exposed to the disturbances due to the base motion, often leading to malfunction or damage as well as inaccurate positioning of the systems. Thus, in the controller design of such AMB systems, robustness to base disturbances becomes an essential requirement. In this study, effective control schemes are proposed for the homo-polar AMB system, which uses permanent magnets for generation of bias magnetic flux, when it is subject to base motion, and its control performance is experimentally evaluated. The base motion of AMB system is modeled as the dynamic disturbances in the gravity and base excitation forces. To effectively compensate for the disturbances, the angle feed-forward controller based on the inverse dynamic model and the acceleration feed-forward controller based on the normalized filtered-X LMS algorithm and the inverse dynamic model are proposed. The performance test of the prototype AMB system is carried out, when the system is mounted on a six degrees-of-freedom motion platform. The experimental results show that the performance of the proposed controllers for the AMB system is satisfactory in compensating for the disturbances due to the base motion.

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