Modeling of Eddy Current Loss for Magnetic Thrust Bearings

2011 ◽  
Author(s):  
Yongsheng Tian ◽  
Yanhua Sun ◽  
Lie Yu
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
Magnetic Field Intensity ◽  
Fem Simulation ◽  
Eddy Current Loss ◽  
The Finite Element Method ◽  
Current Loss ◽  
Surface Magnetic Field ◽  
Thrust Bearings ◽  
The Magnetic Field

In this paper, an analytical model for calculating eddy current loss in magnetic thrust bearings (MTBs) is presented. The surface magnetic field intensity, considering the skin effect of eddy current, is varying with the frequency and can be calculated by effective reluctance method. The magnetic field distribution and eddy current loss can be obtained from it. Finally, the validity of the model is verified by the finite element method (FEM) simulation and experimental results.

scholarly journals Combining the Magnetic Equivalent Circuit and Maxwell–Fourier Method for Eddy-Current Loss Calculation

2019 ◽  
Vol 24 (2) ◽  
pp. 60
Author(s):  
Youcef Benmessaoud ◽  
Frédéric Dubas ◽  
Mickael Hilairet
Keyword(s):  
Magnetic Field ◽  
Equivalent Circuit ◽  
Eddy Current ◽  
Separation Of Variables ◽  
Fourier Method ◽  
Eddy Current Loss ◽  
Current Loss ◽  
Magnetic Equivalent Circuit ◽  
Loss Calculation ◽  
The Magnetic Field

In this paper, a hybrid model in Cartesian coordinates combining a two-dimensional (2-D) generic magnetic equivalent circuit (MEC) with a 2-D analytical model based on the Maxwell–Fourier method (i.e., the formal resolution of Maxwell’s equations by using the separation of variables method and the Fourier’s series) is developed. This model coupling has been applied to a U-cored static electromagnetic device. The main objective is to compute the magnetic field behavior in massive conductive parts (e.g., aluminum, magnets, copper, iron) considering the skin effect (i.e., with the eddy-current reaction field) and to predict the eddy-current losses. The magnetic field distribution for various models is validated with 2-D and three-dimensional (3-D) finite-element analysis (FEA). The study is also focused on the discretization influence of 2-D generic MEC on the eddy-current loss calculation in conductive regions. Experimental tests and 3-D FEA have been compared with the proposed approach on massive conductive parts in aluminum. For an operating point, the computation time is divided by ~4.6 with respect to 3-D FEA.

scholarly journals Analysis and Experiment of Eddy Current Loss in Radial Magnetic Bearings with Solid Rotor

2018 ◽  
Vol 198 ◽  
pp. 04002 ◽  
Author(s):  
Zengyuan Yin ◽  
Yuanwen Cai ◽  
Weijie Wang ◽  
Yuan Ren
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
Eddy Current Loss ◽  
Magnetic Bearing ◽  
Magnetic Bearings ◽  
Fourier Series Expansion ◽  
Eddy Current Losses ◽  
Current Loss ◽  
Radial Magnetic Bearing ◽  
The Magnetic Field

In order to reduce power losses for the aerospace applications, this paper analyzes the eddy current losses produced by high-speed rotating solid rotor core magnetic bearings of magnetically suspended control & sensitive gyroscope (MSCSG). An analytical model of the eddy current loss of a solid rotor radial magnetic bearing (RMB) is presented. Considering the difference between NNNN and NSNS magnetic circuits of RMB, the magnetic field expressions of stator magnetic poles are listed. The magnetic field of stator poles is replaced by Fourier series expansion. According to the magnetic field distribution around the magnetic pole surface and the boundary conditions of the rotor surface, the mathematical expression of eddy current loss is obtained. The measurement method of rotational power loss in radial magnetic bearing is proposed, and the results of the theoretical analysis are verified by experiments in the prototype MSCSG. The experimental results show the correctness of calculation results. Eddy current loss models and test methods provide theoretical support for analyzing eddy current losses in solid rotors and reducing power consumption.

Effect of Axial Grooves on Eddy Current Loss within Giant Magnetostrictive Material (GMM) Rod

2014 ◽  
Vol 574 ◽  
pp. 615-620
Author(s):  
Chao Run Si ◽  
Xian Jie Zhang ◽  
Jun Biao Wang
Keyword(s):  
Eddy Current ◽  
Magnetic Field Intensity ◽  
Thermal Power ◽  
Groove Depth ◽  
Eddy Current Loss ◽  
Current Loss ◽  
Giant Magnetostrictive Material ◽  
Magnetostrictive Strain ◽  
Magnetostrictive Actuator ◽  
The Magnetic Field

The non-linear relationship between the magnetic field intensity and magnetostrictive strain which is caused by the thermal expansion produced by the eddy current loss in the GMM rod, will affect the precision and stability of GMM actuator. This paper tries to reduce the eddy current loss in the GMM rod to improve the performance of magnetostrictive actuator by machining radial grooves in the surface of the rod. The numerical results show that the axial grooves can be effective in reducing thermal power loss. The groove size and number are both optimized by numerical method. The results show that the groove depth and number has great impact on the unit volume eddy current loss while the groove width has little or no impact. The test of the magnetostrictive strain shows that the linearity of the GMM rod with grooves is significantly improved. The radial grooves in the GMM surface can reduce the eddy current loss and improve the performance of GMM actuator.

Eddy Current Loss and Shielding Research of the Tank in Power Transformer

2012 ◽  
Vol 468-471 ◽  
pp. 1086-1089 ◽  
Author(s):  
Yong Ming Xu ◽  
Chao Du ◽  
Da Wei Meng
Keyword(s):  
Magnetic Field ◽  
Eddy Current ◽  
Power Transformer ◽  
Element Model ◽  
Eddy Current Loss ◽  
Calculation Model ◽  
Ultrahigh Pressure ◽  
Tank Wall ◽  
Current Loss ◽  
Leakage Magnetic Field

The problem about the eddy current loss which is caused by leakage magnetic field in ultrahigh pressure large capacity power transformer is becoming more extrusive. It is very significant to research the power transformer leakage magnetic field and eddy current loss on the tank wall thoroughly and accurately. 3D finite element model of power transformer leakage magnetic field and eddy current loss is established in this paper, the eddy current loss on the tank wall is calculated and the distribution is analyzed. For the eddy current loss could be reduced by magnetic shielding, new calculation model are established respectively, then eddy current loss on tank wall could be got with shielding. The best size and location of the shielding could be analyzed after changing the height of the shielding, which provided the important evidence to reduce tank wall eddy current loss effectively. The calculating methods have been proved to be accuracy after experiment.

scholarly journals Research on the influence of driving harmonic on electromagnetic field and temperature field of permanent magnet synchronous motor

2017 ◽  
Vol 66 (2) ◽  
pp. 295-312 ◽  
Author(s):  
Hongbo Qiu ◽  
Wenfei Yu ◽  
Yonghui Li ◽  
Cunxiang Yang
Keyword(s):  
Magnetic Field ◽  
Permanent Magnet ◽  
Eddy Current ◽  
Torque Ripple ◽  
Eddy Current Loss ◽  
Air Gap ◽  
Current Harmonics ◽  
Motor Torque ◽  
Current Loss ◽  
Harmonic Currents

AbstractAt present, the drivers with different control methods are used in most of permanent magnet synchronous motors (PMSM). A current outputted by a driver contains a large number of harmonics that will cause the PMSM torque ripple, winding heating and rotor temperature rise too large and so on. In this paper, in order to determine the influence of the current harmonics on the motor performance, different harmonic currents were injected into the motor armature. Firstly, in order to study the influence of the current harmonic on the motor magnetic field, a novel decoupling method of the motor magnetic field was proposed. On this basis, the difference of harmonic content in an air gap magnetic field was studied, and the influence of a harmonic current on the air gap flux density was obtained. Secondly, by comparing the fluctuation of the motor torque in the fundamental and different harmonic currents, the influence of harmonic on a motor torque ripple was determined. Then, the influence of different current harmonics on the eddy current loss of the motor was compared and analyzed, and the influence of the drive harmonic on the eddy current loss was obtained. Finally, by using a finite element method (FEM), the motor temperature distribution with different harmonics was obtained.

Finite Element Analysis of AMB Eddy-Current Loss in HTR-PM Primary Helium Circulator

2018 ◽  
Author(s):  
Jinpeng Yu ◽  
Yan Zhou ◽  
Mo Ni ◽  
Guojun Yang ◽  
Lei Zhao
Keyword(s):  
Magnetic Field ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Eddy Current ◽  
Electromagnetic Force ◽  
Eddy Current Loss ◽  
Element Analysis ◽  
Current Loss ◽  
Resistance Torque ◽  
Current Magnetic Field

In the active magnetic bearing (AMB) system, the eddy current is generated during the rotation of the rotor, which brings about the AMB loss and eddy-current magnetic field. The eddy-current magnetic field will reduce the electromagnetic force and generate the resistance torque of the AMB. Basing on the AMB of the Primary Helium Circulator (PHC) in HTR-PM, two-dimensional (2D) and three-dimensional (3D) AMB models are built and analyzed with finite element analysis (FEA) in maxwell. The 2D FEA shows that the eddy-current loss and the resistance torque increase as the rotor speed increases, and the eddy-current magnetic field will affect the air-gap magnetic field and reduce the electromagnetic force. The 3D FEA shows that dividing the rotor in insulate sheets can reduce the eddy-current loss. The loss and the sheets thickness have a linear relationship, which is different from the theoretical analysis.

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