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Baoding, China

Zhang Y.,Shenyang University of Technology | Li Y.,Northwest University for Nationalities | Liu Y.,Baoding Tianwei Group Co. | Xie D.,Shenyang University of Technology | Bai B.,Shenyang University of Technology
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2013

The iron core loss in induction motors is closely related to both magnetization forms of the iron core and magnetic property of the electric steel sheets under different magnetization conditions. In this paper, three kinds of magnetic property models considering alternating magnetization, mixed alternating and rotating magnetization of electric steel sheets, i.e improved E&S model, complex E&S model and traditional B-H curve, have been presented, the corresponding loss calculation formula were given. Furthermore, taking a three-phase induction motor as an example, the effectiveness of 3 kinds of magnetic property models and loss computations mentioned above was verified in terms of finite element numerical calculations and experimental tests for a prototype. The results show that in order to compute the core losses of three-phase induction motors accurately, the vector magnetic property model taking both alternating magnetization and rotating magnetization of electric steel sheets into account simultaneously should be coupled with the finite element analysis. © 2013 Chinese Society for Electrical Engineering.

Zheng W.,CAS Academy of Mathematics and Systems Science | Cheng Z.,Baoding Tianwei Group Co.
IEEE Transactions on Magnetics | Year: 2012

Grain-oriented (GO) silicon steel laminations are widely used in iron cores and shielding structures of power equipments. When the leakage magnetic flux is very strong and enters the lamination plane perpendicularly, the eddy current loss induced there must be taken into account in electromagnetic design. It is preferable to accurately compute three-dimensional (3-D) eddy currents at least in a few outer sheets of the lamination stack. Since the coating film applied to each sheet is only 2-5 μm thick, finite element modeling of 3-D eddy currents is very difficult in GO silicon steel laminations of large electromagnetic devices. This paper proposes an inner-constrained separation technique (ICST) to compute the 3-D eddy currents. Instead of the coating film, the ICST introduces an inner constraint into the A-formulation to separate the laminations from each other. By the ICST, the 3-D eddy currents can be computed accurately without meshing the coating film. Numerical experiments are carried out on the TEAM (Testing Electromagnetic Analysis Methods) benchmark model P21 cM1 and the numerical results show good agreement with the measured data. © 2012 IEEE.

Huang L.,Nanjing Southeast University | Yu H.,Nanjing Southeast University | Hu M.,Nanjing Southeast University | Zhao J.,Nanjing Southeast University | Cheng Z.,Baoding Tianwei Group Co.
IEEE Transactions on Magnetics | Year: 2011

In this paper, a novel flux-switching permanent-magnet linear generator (FSPMLG) is proposed for wave-energy extraction. The 2-D finite-element method (FEM), combined with the equivalent circuit, is implemented to investigate the electromagnetic characteristics of the FSPMLG. The optimal structure of the linear generator has advantages of better voltage waveform and minimal cogging effect. The numerical analysis is validated by experiments. The results indicate that these kinds of linear generators are suitable for the application of wave energy conversion. © 2011 IEEE.

Li H.,North China Electrical Power University | Li Q.,North China Electrical Power University | Xu X.-B.,Clemson University | Lu T.,North China Electrical Power University | And 2 more authors.
IEEE Transactions on Magnetics | Year: 2011

A modified method, which combines chaos optimization method and simulated annealing algorithm, is proposed to calculate the Jiles-Atherton (J-A) model parameters. The new method is validated by comparing its computation results with measurement data. Then, the validated J-A model is used in numerical modeling of Epstein frame, and the numerical results are found to be in good agreement with measurement data. © 2011 IEEE.

Zhao X.-J.,North China Electrical Power University | Li L.,North China Electrical Power University | Cheng Z.-G.,Baoding Tianwei Group Co. | Lu J.-W.,Griffith University | Jiao C.-P.,Baoding Tianwei Group Co.
Zhongguo Dianji Gongcheng Xuebao/Proceedings of the Chinese Society of Electrical Engineering | Year: 2010

In this paper the harmonic-balanced finite element method (HBFEM) was applied to study the DC bias phenomenon in power transformers. Variables in electric circuits and magnetic field were represented in harmonic forms duo to the periodic characteristic of electromagnetic field under steady-state excitation. The harmonic-balanced finite element equation was set up by means of the harmonic decomposition of magnetic reluctivity, considering the coupling of electric circuit and magnetic field. The harmonic solutions of exciting current and magnetic vector potentials were calculated directly to analyze the relationship between DC bias and DC flux. The local vortex characteristic of flux distribution in each harmonic was also presented. An Epstein frame-like core model was applied to carry out the DC bias experiment. A good agreement between calculated results and experimental data proves the effectiveness of HBFEM in the investigation of DC bias phenomenon. © 2010 Chin. Soc. for Elec. Eng.

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