Structure and Suspension Force Analysis on Six-Pole Five Degrees of Freedom AC Hybrid Magnetic Bearing

2021 ◽  
pp. 1-1
Author(s):  
Tao Zhang ◽  
Qianyun Le ◽  
Weiguo Zhu
Keyword(s):  
Degrees Of Freedom ◽  
Magnetic Bearing ◽  
Force Analysis

Suspension force analysis of six-pole radial-axial magnetic bearing for energy storage flywheel

2019 ◽  
Vol 34 (01n03) ◽  
pp. 2040066
Author(s):  
Jintao Ju ◽  
Jiaan Wang ◽  
Yanfei Wang ◽  
Zhikang Wu ◽  
Ying Qin
Keyword(s):  
Degrees Of Freedom ◽  
Magnetic Bearing ◽  
Low Power Consumption ◽  
Force Analysis ◽  
Element Analysis ◽  
Compact Structure ◽  
Three Phase ◽  
Phase Converter ◽  
Current Characteristics ◽  
The Mathematical Model

This paper proposes a six-pole radial-axial hybrid magnetic bearing (RAHMB) used in a flywheel system. The radial and axial bias fluxes are generated by one permanent magnet and the radial control coils are driven by a three-phase converter. So, it has the advantages of compact structure, low power consumption and simple driver. First, the work principle is introduced. Then, the mathematical model is built. The force-current characteristics with different eccentricities, the coupling between radial two degrees of freedom (DOF) and the coupling between radial and axial DOF are analyzed based on the analytical model. Finally, the analyses are validated by 3D finite element analysis in the Maxwell software. The results have shown that the coupling between radial and axial DOF is very small. However, the force-current curves of radial two DOFs turn out to be nonlinear and coupled with the increase of rotor eccentricity.

scholarly journals Nonlinear Behavior of a Magnetic Bearing System

1995 ◽  
Vol 117 (3) ◽  
pp. 582-588 ◽  
Author(s):  
L. N. Virgin ◽  
T. F. Walsh ◽  
J. D. Knight
Keyword(s):  
Degrees Of Freedom ◽  
Initial Conditions ◽  
Nonlinear Behavior ◽  
Analytical Techniques ◽  
Magnetic Bearing ◽  
Forced Response ◽  
The Mathematical Model ◽  
Two Degree Of Freedom ◽  
Sensitivity To Initial Conditions ◽  
Bearing System

This paper describes the results of a study into the dynamic behavior of a magnetic bearing system. The research focuses attention on the influence of nonlinearities on the forced response of a two-degree-of-freedom rotating mass suspended by magnetic bearings and subject to rotating unbalance and feedback control. Geometric coupling between the degrees of freedom leads to a pair of nonlinear ordinary differential equations, which are then solved using both numerical simulation and approximate analytical techniques. The system exhibits a variety of interesting and somewhat unexpected phenomena including various amplitude driven bifurcational events, sensitivity to initial conditions, and the complete loss of stability associated with the escape from the potential well in which the system can be thought to be oscillating. An approximate criterion to avoid this last possibility is developed based on concepts of limiting the response of the system. The present paper may be considered as an extension to an earlier study by the same authors, which described the practical context of the work, free vibration, control aspects, and derivation of the mathematical model.

Force Analysis of a Slotless Lorentz-Type Active Magnetic Bearing Actuator

2018 ◽  
Author(s):  
Guzman Borque Gallego ◽  
Leopoldo Rossini ◽  
Timon Achtnich ◽  
Christof Zwyssig ◽  
Douglas Martins Araujo ◽  
...  
Keyword(s):  
Magnetic Bearing ◽  
Active Magnetic Bearing ◽  
Force Analysis

Rotor Dynamics of Flywheel Energy Storage Systems

1991 ◽  
Vol 113 (1) ◽  
pp. 11-18 ◽  
Author(s):  
C. P. Jayaraman ◽  
J. A. Kirk ◽  
D. K. Anand ◽  
M. Anjanappa
Keyword(s):  
Control Systems ◽  
Degrees Of Freedom ◽  
Magnetic Bearing ◽  
System Stability ◽  
Dynamic Equations ◽  
Dynamic Coupling ◽  
First Order ◽  
Torque Response ◽  
Resonance Frequencies ◽  
Computer Simulation Program

This paper deals with the dynamic analysis of the magnetic bearing stack system. The stack consists of a single flywheel supported by two magnetic bearings. To model the system, the dynamic equations of a magnetically suspended flywheel are derived. Next, the four control systems controlling the four degrees-of-freedom of the stack are incorporated into the model. The resulting dynamic equations are represented as first-order differential equations in a matrix form. A computer simulation program was then used to simulate the working of the magnetic bearing stack. Real time plots from the simulation are used to show the effect of dynamic coupling on torque response. Frequency response is used to determine the resonance frequencies of the stack system. It is found that system stability depends on flywheel speed. On the basis of the above results suggestions are made to improve stability and allow the stack to be spun beyond 60,000 rpm.

scholarly journals Modeling and Analysis of Coupling Performance of Dynamic Stiffness Models for a Novel Combined Radial-Axial Hybrid Magnetic Bearing

2014 ◽  
Vol 2014 ◽  
pp. 1-17 ◽  
Author(s):  
Bangcheng Han ◽  
Shiqiang Zheng
Keyword(s):  
Degrees Of Freedom ◽  
Eddy Currents ◽  
Dynamic Stiffness ◽  
Dynamic Performance ◽  
Magnetic Bearing ◽  
Coupling Coefficients ◽  
Dynamic Displacement ◽  
Modeling And Analysis ◽  
Magnetic Circuits ◽  
Save Energy

The combined radial-axial magnetic bearing (CRAMB) with permanent magnet creating bias flux can reduce the size, cost, and mass and save energy of the magnetic bearing. The CRAMB have three-degree-of-freedom control ability, so its structure and magnetic circuits are more complicated compared to those of the axial magnetic bearing (AMB) or radial magnetic bearing (RMB). And the eddy currents have a fundamental impact on the dynamic performance of the CRAMB. The dynamic stiffness model and its cross coupling problems between different degrees of freedom affected for the CRAMB are proposed in this paper. The dynamic current stiffness and the dynamic displacement stiffness models of the CRAMB are deduced by using the method of equivalent magnetic circuit including eddy current effect, but the dynamic current stiffness of the RMB unit is approximately equal to its static current stiffness. The analytical results of an example show that the bandwidth of the dynamic current stiffness of the AMB unit and the dynamic displacement stiffness of the CRAMB is affected by the time-varying control currents or air gap, respectively. And the dynamic current stiffness and the dynamic displacement stiffness between the AMB unit and the RMB unit are decoupled due to few coupling coefficients.

Multi-Input–Multi-Output Control of a Utility-Scale, Shaftless Energy Storage Flywheel With a Five-Degrees-of-Freedom Combination Magnetic Bearing

2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Xiaojun Li ◽  
Alan Palazzolo
Keyword(s):  
Energy Storage ◽  
Degrees Of Freedom ◽  
Magnetic Levitation ◽  
High Strength ◽  
Magnetic Bearing ◽  
Detailed Model ◽  
Loop Control ◽  
Modeling And Control ◽  
Power Capability ◽  
Utility Scale

The modeling and control of a recently developed utility-scale, shaftless, hubless, high strength steel energy storage flywheel system (SHFES) are presented. The novel flywheel is designed with an energy/power capability of 100 kWh/100 kW and has the potential of a doubled energy density when compared to conventional technologies. In addition, it includes a unique combination magnetic bearing (CAMB) capable of providing five-degrees-of-freedom (5DOF) magnetic levitation. Initial test results show that the CAMB, which weighs 544 kg, can provide a stable lift-up and levitation control for the 5543 kg flywheel. The object of this paper is to formulate and synthesize a detailed model as well as to design and simulate a closed-loop control system for the proposed flywheel system. To this end, the CAMB supporting structures are considered flexible and modeled by finite element modeling. The magnetic bearing is characterized experimentally by static and frequency-dependent coefficients, the latter of which are caused by eddy current effects and presents a challenge to the levitation control. Sensor-runout disturbances are also measured and included. System nonlinearities in power amplifiers and the controller are considered as well. Even though the flywheel has a large ratio of the primary-to-transversal moment of inertias, multi-input–multi-output (MIMO) feedback control demonstrates its effectiveness in canceling gyroscopic toques at the designed operational spinning speed. Various stages of proportional and derivative (PD) controllers, lead/lag compensators, and notch filters are implemented to suppress the high-frequency sensor disturbances, structural vibrations, and rotor imbalance effects.

Optimal Control of a Nonlinear Magnetic Bearing System Using the Trigonometric Collocation Method

2008 ◽  
Author(s):  
C. Nataraj ◽  
Steven Marx
Keyword(s):  
Optimal Control ◽  
Collocation Method ◽  
Degrees Of Freedom ◽  
Magnetic Bearing ◽  
Degree Of Freedom ◽  
Lookup Table ◽  
Base Excitation ◽  
Strongly Nonlinear ◽  
Trigonometric Collocation ◽  
Bearing System

Magnetic bearings are non-contacting, with the rotor being suspended between electromagnets, and therefore they can eliminate the need for lube oil and reduce machinery wear. The magnetic bearing is naturally unstable, and very nonlinear. This paper proposes a method designed to suppress the motion of a nonlinear magnetic bearing system rotor due to base excitation. The method combines PD feedback with feedforward optimal control, where a measured base motion is used to select a control signal designed to suppress the rotor response. The signal is generated from a combination of subharmonic frequencies and optimized coefficients stored in a lookup table. The trigonometric collocation method (TCM) is used to generate solutions for the four degree-of-freedom system made up of a shaft suspended at each end by a magnetic bearing. The TCM method uses a trigonometric series to simulate the multiharmonic behavior of each degree-of-freedom of strongly nonlinear systems. The method is easy to use and its advantage over numerical methods is that it demands less computation, particularly with higher numbers of degrees-of-freedom.

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