Analysis of PM Eddy Current Loss in Rotor-PM and Stator-PM Flux-switching Machines by Air-gap Field Modulation Theory

2020 ◽  
Vol 67 (3) ◽  
pp. 1824-1835
Author(s):  
Peng Su ◽  
Wei Hua ◽  
Mingjin Hu ◽  
Zhe Chen ◽  
Ming Cheng ◽  
...  
Keyword(s):  
Eddy Current ◽  
Eddy Current Loss ◽  
Air Gap ◽  
Current Loss ◽  
Modulation Theory ◽  
Field Modulation

scholarly journals An Alternative Method for Calculating the Eddy Current Loss in the Sleeve of a Sealless Pump

Actuators ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 78
Author(s):  
Tomislav Strinić ◽  
Bianca Wex ◽  
Gerald Jungmayr ◽  
Thomas Stallinger ◽  
Jörg Frevert ◽  
...  
Keyword(s):  
Eddy Current ◽  
Three Dimensional ◽  
Eddy Current Loss ◽  
Theoretical Background ◽  
Air Gap ◽  
Magnetic Flux Density ◽  
Pump Impeller ◽  
Current Loss ◽  
Faraday’S Law ◽  
Transient Simulations

A sealless pump, also known as a wet rotor pump or a canned pump, requires a stationary sleeve in the air gap to protect the stator from a medium that flows around the rotor and the pump impeller. Since the sleeve is typically made from a non-magnetic electrically conductive material, the time-varying magnetic flux density in the air gap creates an eddy current loss in the sleeve. Precise assessment of this loss is crucial for the design of the pump. This paper presents a method for calculating the eddy current loss in such sleeves by using only a two-dimensional (2D) finite element method (FEM) solver. The basic idea is to use the similar structure of Ampère’s circuital law and Faraday’s law of induction to solve eddy current problems with a magnetostatic solver. The theoretical background behind the proposed method is explained and applied to the sleeve of a sealless pump. Finally, the results obtained by a 2D FEM approach are verified by three-dimensional FEM transient simulations.

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.

Influence of Power Factor on the Performance of Bulb Tubular Turbine Generator

2020 ◽  
Vol 14 (1) ◽  
pp. 95-102
Author(s):  
Hongbo Qiu ◽  
Hangyu Shen ◽  
Cunxiang Yang ◽  
Ran Yi
Keyword(s):  
Low Power ◽  
Flux Density ◽  
Power Factor ◽  
Eddy Current ◽  
Torque Ripple ◽  
Eddy Current Loss ◽  
Air Gap ◽  
Turbine Generator ◽  
Current Loss ◽  
Transient Electromagnetic

Background: In recent years, many patents have been dedicated to increasing the rated power factor of generators. However, hydro-generators often encounter uncontrollable factors, such as dry season, power network adjustment, and so on, resulting in low power factor operation. In other words, the generator is often in a low power factor operating state. In order to provide data reference for power plant in regulating power factor, it is necessary to analyze the performance of generator in low power factor operation. Objective: The performance of the generator is analyzed when the power factor decreases, and the influence of low power factor operation on the generator is obtained. Methods: Taking a 24MW bulb tubular turbine generator as an example, a 2D transient electromagnetic field model is established. The correctness of the model is verified by comparing the test data and the simulation data. The torque, eddy current loss and air gap flux density of the generator under different power factor are calculated. Results: When the power factor deceases from 0.99 to 0.85, the air gap flux density increases from 0.713 T to 0.749 T, the torque ripple increases from 150.5 kN⋅m to 179.9 kN⋅m, and the rotor eddy current loss increases from 17.48 kW to 18.15 kW. Conclusion: The results show that the torque ripple and eddy current loss will increase with the decrease of power factor when the generator lagging phase operation. The torque ripple and eddy current loss increase by 3.8 % and 1 % respectively with the power factor decrease by 0.02 % with power factor between 0.99 and 0.85.

Performance analysis of magnetic gear with Halbach array for high power and high speed

2020 ◽  
Vol 64 (1-4) ◽  
pp. 959-967
Author(s):  
Se-Yeong Kim ◽  
Tae-Woo Lee ◽  
Yon-Do Chun ◽  
Do-Kwan Hong
Keyword(s):  
Permanent Magnet ◽  
Eddy Current ◽  
High Power ◽  
High Speed ◽  
Torque Ripple ◽  
Eddy Current Loss ◽  
Element Analysis ◽  
Current Loss ◽  
Halbach Array ◽  
Magnetic Gear

In this study, we propose a non-contact 80 kW, 60,000 rpm coaxial magnetic gear (CMG) model for high speed and high power applications. Two models with the same power but different radial and axial sizes were optimized using response surface methodology. Both models employed a Halbach array to increase torque. Also, an edge fillet was applied to the radial magnetized permanent magnet to reduce torque ripple, and an axial gap was applied to the permanent magnet with a radial gap to reduce eddy current loss. The models were analyzed using 2-D and 3-D finite element analysis. The torque, torque ripple and eddy current loss were compared in both models according to the materials used, including Sm2Co17, NdFeBs (N42SH, N48SH). Also, the structural stability of the pole piece structure was investigated by forced vibration analysis. Critical speed results from rotordynamics analysis are also presented.

Development of Interior Permanent Magnet Motors with Concentrated Windings for Reducing Magnet Eddy Current Loss

2009 ◽  
Vol 129 (11) ◽  
pp. 1022-1029 ◽  
Author(s):  
Katsumi Yamazaki ◽  
Yuji Kanou ◽  
Yu Fukushima ◽  
Shunji Ohki ◽  
Akira Nezu ◽  
...  
Keyword(s):  
Permanent Magnet ◽  
Eddy Current ◽  
Eddy Current Loss ◽  
Permanent Magnet Motors ◽  
Current Loss ◽  
Interior Permanent Magnet
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