International Journal of Applied Electromagnetics and Mechanics - Volume 55, issue 3

Authors: Wang, Huijun | Pang, Mingqi | Qu, Zheng | Tang, Shaofei

Article Type: Research Article

Abstract: In this paper, one modular switched reluctance motor (SRM) with four degrees of freedom (DOF) for self-bearing application is investigated and designed. Different from the conventional SRM, proposed modular SRM consists of two motors, in which each motor has one torque control and two radial control DOFs. Biased flux is supplied by the axial permanent magnet, which can reduce the copper loss. Firstly, basic structure and operating principle are briefly introduced. Basic design is presented and analysis model for the suspending force is developed. Furthermore, parametric analysis is implemented for showing the effect of sizes on the performances. Finally, finite …element analysis and experimental results verifies the validity of proposed method. Show more

Keywords: SRM, design, radial force, self-bearing

DOI: 10.3233/JAE-160120

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 3, pp. 343-358, 2017

Authors: Wang, Dazhi | Shi, Tongyu | Wang, Xingyu | Wang, Xinghua

Article Type: Research Article

Abstract: The purpose of this paper is to obtain a 3D analytical model of permanent magnetic eddy-current couplings and optimize several parameters by using the multiple population genetic algorithm (MPGA). Firstly, on the basis of the analytical model, the formulas of key parameters are deduced. By using permanent magnet thickness, pole-arc coefficient and copper plate thickness as variables and taking output torque in steady state, rotational inertia and the volume of the couplings as optimization goals, this paper proposes a multi-objective optimization function with entropy coefficients and uses the MPGA to optimize structure parameters. The validity and feasibility of the proposed …method is proved through 3D finite element analysis (3D-FEA) and experimental results. The results confirm that compared with another two optimization algorithms from the papers which had already published, optimization by the multiple population genetic algorithm based on the 3D analytical model has good effect on optimization of structural parameters. Show more

Keywords: Permanent magnet eddy-current couplings, analytical method, entropy-based weight, multi-objective optimization, multiple population genetic algorithm

DOI: 10.3233/JAE-160131

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 3, pp. 359-372, 2017

Authors: Wang, Xiaoguang | Fu, Jing | Zhao, Xuan | Hou, Leilei

Article Type: Research Article

Abstract: With the continuous development of magnetic bearings in aerospace and military, reactor turbine power generation, flywheel energy storage and other fields, the request for the reliability of magnetic bearing system becomes higher. In order to improve the reliability of the magnetic bearing, a novel axial magnetic bearing with multi rings in peripheral direction (AMB-MRC) is proposed. By studying the influence of rings number and current direction through coils on bearing capacity, as well as the method of redundant reconstruction and the property after reconstruction, the corresponding design criteria are proposed. The redundancy, bearing capacity and eddy current loss of the …AMB-MRC compared with the existing AMB-MRR with 2 rings. The results show that the bearing capacity of proposed novel bearing is nearly equal to AMB-MRR with 2 rings when their volume is the same, but the redundancy of proposed novel bearing is better in improving the reliability of the magnetic bearing system. Show more

Keywords: AMB-MRC, bearing capacity, redundancy, temperature field, eddy current loss

DOI: 10.3233/JAE-170024

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 3, pp. 373-390, 2017

Authors: Cheng, Xin | Wang, Bo | Chen, Qiang | Zhang, Lin | Liu, Han | Song, Shao

Article Type: Research Article

Abstract: Power amplifier is a crucial part of the active magnetic bearing system, and its precision characteristic is decisive to the overall systematic performance. The bi-state and tri-state modulations are both widely used in the design of DSPA, and generally there are many approaches to realize the design. DSPA will have different output performance under different modulations. In this paper, we propose a unified design of digital switching power amplifier (DSPA), which can be compatible with different modulations by configuration of hardware only. As many factors will influence the current ripple characteristic of DSPA, an approach based on Fourier series has …been proposed to establish the equivalent mathematical model of DSPA under both bi-state and the tri-state modulations. We analyze the approximated theoretical ripple characteristic of DSPA with the unified architecture design discussed, and provide the simulation based on the equivalent mathematical model, then establish the experimental platform to verify the analysis of current ripple characteristic under different conditions. Experimental results show that the ripple characteristic has been influenced mainly by bus voltage, modulation frequency and time constant of load, and the approach proposed in this paper can effectively describe the ripple characteristic of DSPA under different modulations. Show more

Keywords: Current ripple characteristic, unified design, digital switching power amplifier, active magnetic-levitated bearings

DOI: 10.3233/JAE-170033

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 3, pp. 391-407, 2017

Authors: Su, Sanqing | Yi, Shuchun | Wang, Wei | Sun, Haojiang | Ren, Guangchao

Article Type: Research Article

Abstract: Previous research of metal magnetic memory (MMM) primarily focused on uniaxial stress-magnetic field behaviors and the judgment criterion of stress concentration zone mainly depended on the tangential and normal component of MMM signals. Magnetic field gradient was only mentioned as an auxiliary condition. In this paper, the variation characteristic of magnetic field gradient under bending load was investigated. Four-point bending tests of Q235B I-steel beams were carried out. The results show that all magnetic field gradient curves are centrosymmetric about midpoint of measurement line. The position of concentrated load can be preliminarily predicted by the mutational point of magnetic field …gradient slope on the flange and accurately judged by the zero-crossing position of magnetic field gradient on the web. Whether a specimen is under eccentric compression or not, can be determined by comparing average characteristic parameter values on both sides of specimen. The variation law of magnetic field gradient on both the flange and web can be well explained by the modified Jiles-Atherton model, which is constructed by replacing stress σ with equivalent stress σ eq . The calculated results are in good agreement with measured data. Show more

Keywords: Metal magnetic memory, magnetic field gradient, Jiles-Atherton model, bending test, characteristic parameter

DOI: 10.3233/JAE-160119

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 3, pp. 409-421, 2017

Authors: Liu, Chunming | Li, Xiaohan | Li, Xinjie

Article Type: Research Article

Abstract: Transformers in the power systems are sometimes influenced by the DC bias and produce abnormal vibration or noise. This paper presents a method to simulate the transformer vibration increase due to the DC bias. A three-dimensional finite element model coupling the circuit – magnetic field – mechanical field is established for the simulating. Firstly, the 3D magnetic field in the iron core is calculated through combing the circuit equation and magnetic field equation. Secondly, the magnetostrictive force derived from the magnetic field is used to establish the transient structural force field model, so that the vibration displacement can be calculated. …Based on the method, the vibration at different positions of the transformer iron core with different DC bias is investigated. The simulation shows that the vibration of the iron core is quite sensitive to the DC bias. The vibration amplitude significantly increases and the vibration waveform becomes asymmetrical and sharp with the increase of DC current. The odd frequency component, represented by 50 Hz and 150 Hz, appears and grows faster than the 100 Hz and 200 Hz component. The model and the simulation results can be used to guide the structural designing of transformers and promote the fault diagnosis method of transformers based on the vibration signal monitoring. Show more

Keywords: DC bias, transformer iron core vibration, magnetostrictive, finite element method

DOI: 10.3233/JAE-160132

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 3, pp. 423-433, 2017

Authors: Xing, Jichun | Zhao, Longwei

Article Type: Research Article

Abstract: For a non-contact piezoelectric motor modulated by electromagnetic field, the equation of the free vibration for the driving system of the motor is given. Using the boundary conditions and continuity conditions, the natural frequencies and mode functions of the driving system are obtained. The variation law of the natural frequency is investigated, when the system parameters of the driving system are changed in a certain range. The results show that the change of the system parameters of piezoelectric stacks and driving beams has obvious effects on odd order natural frequencies of the driving system; the change of the system parameters …of the center shaft have obvious effects on even order natural frequencies; In the odd order modes, the maximum vibration amplitude of the driving system occurs at the junction of the driving beam and the center shaft. It is conducive to output of the motor rotation angle. All the results are useful for design and control of operating performance of the motor. Show more

Keywords: Free vibration, non-contact, modulated by electromagnetic field, natural frequency, mode function

DOI: 10.3233/JAE-170002

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 3, pp. 435-451, 2017

Authors: Liu, Yapi

Article Type: Research Article

Abstract: The standard method for measuring magnetic properties of permanent magnets is the closed circuit method using an iron-cored electromagnet. With the advances of modern high quality permanent magnetic materials, it has become more and more important to measure their magnetic properties accurately both at room and elevated temperatures. Many problems have arisen when using this traditional DC hysteresigraph to test these new materials, such as those based on rare earth intermetallic compounds, bonded magnetic materials and nanocrystalline exchange-coupled magnets. The physical knowledge on these principal problems including magnetic properties of material, magnetic properties of product, specimen, uniform magnetization, saturation magnetization, …the influence of the saturation of the poles, and the influence of Hall probe, etc., is important in the research and development of new materials and also nondestructive evaluation (NDE). These problems are discussed in this paper qualitatively and the current statuses to solve these problems are also presented. Show more

Keywords: Magnetic measurement, material property, uniform magnetization, saturation magnetization

DOI: 10.3233/JAE-170007

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 3, pp. 453-479, 2017

Authors: Safdarzadeh, Omid | Hekmati, Arsalan

Article Type: Research Article

Abstract: In this paper, a comprehensive design procedure for the Brushless DC (BLDC) motors is proposed and the governing equations are derived from the motor flux linkage and are utilized in the flowchart presented for the BLDC motor design. The proposed algorithm is based on the weighted target functions optimization. This algorithm is developed for a surface-mounted permanent-magnet inner-rotor 2pole-3slot pattern BLCD motor. A 120 watt 8pole-12slot 4000 rpm BLDC motor is designed by means of the flowchart as a case study. The resulted parameters from the flowchart are used to make the 3-D model analysed by finite element analysis (FEA). …Then, FEA results are compared with the flowchart results to verify the proposed design algorithm. Output parameters of a fabricated BLDC motor having the same physical properties are measured and presented to show the applicability of the algorithm. Show more

Keywords: BLDC motor, design optimization, finite element analysis, weighted functions

DOI: 10.3233/JAE-170008

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 3, pp. 481-497, 2017

Authors: Bai, Yaxiang | Huo, Yuan | Fan, Xuejie

Article Type: Research Article

Abstract: In order to improve the thawing qualities of aquatic products, shrimps (Penaeus vannamei) as a representative of aquatic products, were thawed with high voltage electric field (HVEF) at different voltages. It was compared with an air-thawed control on the basis of thawing time and the post-thawing quality of the shrimps. The results showed that HVEF can reduce the thawing time of shrimps significantly. Compared with air-thawed control, the thawed shrimps under HVEF had better post-thawing qualities such as lower thawing loss, lower total bacteria count and lower total volatile basic nitrogen (TVB-N). HVEF thawing has advantages. This suggests an application …potential for HVEF treatment in the thawing and storage of frozen aquatic products. Show more

Keywords: High voltage electric field (HVEF), thawing, shrimps, post-thawing quality, total volatile basic nitrogen (TVB-N)

DOI: 10.3233/JAE-170020

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 55, no. 3, pp. 499-506, 2017