International Journal of Applied Electromagnetics and Mechanics - Volume 59, issue 2

Authors: Chen, Dezhi | Feng, Zhiyu | Bai, Baodong | Kwon, Byung-il

Article Type: Research Article

Abstract: Power transformer iron core is mainly composed of electrical sheet steel, which is easily affected by temperature, harmonic, and DC bias. So it is necessary to measure the magnetic properties of electrical sheet steel under different temperature, and DC bias. This paper presents the experiment measurement system for the 27ZH100 electrical steel sheet under different temperature and DC bias, and the magnetic field, and current in the transformer core considering the different temperature and DC bias of electrical steel sheet. Experiment are supplied to obtain the B-H curves under different temperature and DC bias, which are required for the accurate …FEM (Finite element method) simulation setup. Finally, the simulation and experiment results of a transformer are verified by the experimental results under the different temperature and DC bias. Show more

Keywords: Power transformer, electrical sheet steel, DC bias, temperature, FEM, simulation and experiment

DOI: 10.3233/JAE-171137

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 669-677, 2019

Authors: Wang, Qingpeng | Bai, Baodong | Chen, Dezhi | Fu, Tiejun | Ma, Qiang

Article Type: Research Article

Abstract: The dielectric parameters of oil-immersed insulation paper, semi-conductive paper and mineral oil were measured at different temperature. The quantitative analysis about the influence of the equalizing cage density on the Inverted-type Oil-immersed Current Transformer (IOCT) electric field distribution was studied, and the temperature dependence of the insulation material dielectric parameters were taken into consideration. In high temperature conditions, the oil-paper damage of IOCT insulation system is generally not caused by electric breakdown but heat aging. The maximum electric field strength of oil-paper I is approximately reduced by 12.84%, and that of the oil-paper II is reduced by 0.35%, after the …equalizing cage density is increased. The increasing of the equalizing cage density will be beneficial to the electric field equidistribution of the IOCT insulation system. Show more

Keywords: IOCT, electric field equilibrium characteristics, equalizing cage, insulation parameter

DOI: 10.3233/JAE-171223

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 679-686, 2019

Authors: Lefevre, Yvan | El-Aabid, Sami | Llibre, Jean-François | Henaux, Carole | Touhami, Sarah

Article Type: Research Article

Abstract: In order to choose electric machines for transport applications, i.e. automotive, aerospace, railway and naval, a tool that can make quick tradeoffs of high specific torque electric motors has been developed. The level of the different technologies involved in an electrical machine can be quantified using the loadability concepts developed by experienced designers. After recalling these concepts, magnetic, electric and thermal balances are used to calculate the main sizes of an electric motor according to some targets. Specific power or specific torque can then be quickly assessed. The proposed approach is validated by applying the tool to some known high …torque industrial motors. Show more

Keywords: Loadability, specific power, specific torque

DOI: 10.3233/JAE-171059

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 687-694, 2019

Authors: Hu, Jiaming | Bai, Baodong | Chen, Dezhi | Guan, Rongyu | Dan, Fenglinzi

Article Type: Research Article

Abstract: In view of the bearing current of motor, a method of suppressing the bearing current using the field emission characteristics of carbon nanotubes is proposed. Firstly, the advantages of carbon nano-materials and their field emission properties are introduced. Secondly, the influence of the distance between the emitter tips and the anode metal plate on the electric field intensity is analyzed by software simulation. Finally, field emission experiments of TNF300 type carbon nanotube fibers under non vacuum conditions were carried out by means of probes, microscopes and other experimental equipment. After obtaining the voltage and current of carbon nano-materials at different …distances, the volt-ampere characteristic curves and the field emission characteristic curve were drawn, and the experimental results from different distances were compared and analyzed. Show more

Keywords: Field emission, carbon nanotubes, bearing current suppression, simulation and experiment

DOI: 10.3233/JAE-171199

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 695-702, 2019

Authors: Paplicki, Piotr | Palka, Ryszard | Wardach, Marcin | Prajzendanc, Pawel | Evelina Mognaschi, Maria

Article Type: Research Article

Abstract: In this paper, an improved configuration of the rotor for an Electric Controlled Permanent Magnet Synchronous machine (ECPMS-machine) is proposed by introducing axial bridges made by lamination or Soft Magnetic Composite (SMC) material in order to minimize mass and iron losses in the rotor. In addition, the influence of the small air-gap in the bridge lamination on a field-weakening range (FWR) of the machine is evaluated by three-dimensional finite-element analysis (3-D FEA). Moreover, the phase back-electromotive force (back-EMF) waveforms achieved by simulation for three novel rotor concepts at different DC coil currents are reported and compared with experimental results …obtained on a machine prototype. Show more

Keywords: Hybrid excited machine, magnetic bridges, FEA analysis

DOI: 10.3233/JAE-171200

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 703-711, 2019

Authors: Chen, Dezhi | Fang, Liwei | Feng, Zhiyu | Bai, Baodong | Kwon, Byung-il

Article Type: Research Article

Abstract: This paper proposes a novel analytical approach for losses and thermal of EPIM (explosion-proof integrative motor), aiming to improve the appropriate design variable frequency speed control system and induction motor. A loss and temperature rise of IGBTs, stator, rotor, and water- cooled heat sink of 1140 V/375 kW EPIM is investigated. Based upon the interaction variable frequency speed control system and induction motor, the loss and temperature curve are obtained. Accordingly, EPIM is designed. The experimental result of temperature is used to verify the accuracy of the proposed analytical approach calculating loss and temperature of EPIM.

Keywords: EPIM, loss and temperature, variable frequency speed control system, induction motor, simulation, experiment

DOI: 10.3233/JAE-171133

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 713-720, 2019

Authors: Park, Young-Un | Kim, Dae-kyong

Article Type: Research Article

Abstract: The proposed study analyzes the cogging torque of a single-phase BLDC motor with a tapered air-gap through use of a proposed analytical method with asymmetric slot function. Usefulness of the proposed analytical method was confirmed via comparison of cogging torque characteristics predicted through use of the proposed method against those predicted by 2-D finite element analysis as well as those observed experimentally.

Keywords: Asymmetric air-gap, asymmetric notch, analytical method, cogging torque, singlephase brushless DC motor, tapered air-gap, tapered teeth

DOI: 10.3233/JAE-171089

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 721-728, 2019

Authors: Kim, Sung-An | Park, Soo-Keun | Cho, Yun-Hyun

Article Type: Research Article

Abstract: This paper presents the cost reduction design of a brushless DC motor (BLDCM) considering twelve step control. The twelve step control can improve the output of the motor using the conventional six step control. Weight reduction can be effectively achieved by reducing rotor, stator and magnet through optimization of BLDCM using a response surface method (RSM). The BLDCM volume was decreased by about 45%, while satisfying basic performance requirements and improving efficiency. Original and optimized motors were built and tested. Experimental results are compared in terms of output power and efficiency.

Keywords: Brushless DC motor, sensorless control, twelve step, response surface method, finite element method analysis

DOI: 10.3233/JAE-171002

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 729-736, 2019

Authors: Darques, Kévin | Tounzi, Abdelmounaïm | Le Menach, Yvonnick | Beddek, Karim

Article Type: Research Article

Abstract: Shaft voltage is a well-known variable in the case of large turbo-generators for its potential destructive effect. However, as it is due to magnetic asymmetries, its use as a diagnosis indicator can be very interesting. Previous works were carried out to investigate the harmonic contents of this voltage in the case of some usual defects such as eccentricities or rotor short circuit. However, in our knowledge, no analysis has been conducted to determine the inherent effects of each of these defects solely while avoiding any interaction with the different other parameters of the machine. To this aim, the present paper …deals with the study of two simplified synchronous generators, of 2 and 4 poles, with a smooth slotless stator using a numerical model in order to quantify the inherent effect of static and dynamic eccentricities on the shaft voltage. The obtained results for both machines with each defect are presented and discussed. Show more

Keywords: Finite element analysis, fault diagnosis, shaft voltage

DOI: 10.3233/JAE-171205

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 737-744, 2019

Authors: Zhao, Wenliang | Shen, Haizhen | Fan, Xue | Wang, Xiuhe | Kwon, Byung-il

Article Type: Research Article

Abstract: This paper proposes a novel hybrid-excited wound-rotor synchronous machine (HE-WRSM) with asymmetrically positioned permanent magnets (PMs) to make full use of reaction torque and reluctance torque, thus to improve the machine performance, including torque, efficiency, and power factor. To highlight the advantage of the proposed HE-WRSM, the conventional WRSM and HE-WRSM are adopted for performance comparison under the same operating conditions. All machine characteristics are predicted by the finite element method (FEM) using the commercial software, JMAG-Designer. The analysis results finally demonstrate that the proposed HE-WRSM exhibits highly improved torque, power factor, and efficiency, when compared to the conventional machines. …Furthermore, the proposed HE-WRSM is verified to have superior endurance against the magnet irreversible demagnetization within two times of the rated current excitation. Show more

Keywords: Finite element method, hybrid-excited, wound-rotor synchronous machine, permanent magnets, torque

DOI: 10.3233/JAE-171179

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 745-753, 2019

Authors: Lin, Hao | Geng, Haipeng | Du, Tingchen | Xu, Xiangming | Zhang, Yanyan | Cheng, Wenjie | Yu, Lie

Article Type: Research Article

Abstract: The electromagnetism and rotor dynamics have been drawing great research interest due to their significance in the design of the high speed permanent magnet synchronous motor. However, it is challenging but essential to study the rotor supported by air foil bearings with cylindrical permanent magnet. Here the approach is reported to analyze a high speed PMSM rotor at the rating of 28.5 kW and 96,000 rpm. Through the analytic method and the finite element simulation, the expression for the magnetic flux density is obtained. Based on the rotor-bearing system discrete model, the critical speed is calculated by Campbell diagram. It comes to …the conclusion that the radius and length of cylindrical permanent magnet is reciprocally related to the magnetic flux density and critical speed values. Finally, results of the PMSM experimental device operating at 96,000 rpm are represented by rotor frequency spectrum and orbit diagram. Show more

Keywords: High speed motor, cylindrical permanent magnet, magnetic field, rotor critical speed, air foil bearing

DOI: 10.3233/JAE-171157

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 755-764, 2019

Authors: Sirewal, Ghulam Jawad | Lipo, Thomas Anthony | Kwon, Byung-il

Article Type: Research Article

Abstract: This paper presents a research on reducing the torque ripple in a brushless wound rotor synchronous machine (BL-WRSM). The basic brushless topology generates a third-harmonic current component in the stator to excite the rotor. The rotor has two types of windings, field winding and harmonic winding, which are connected with each other through a rotor mounted diode rectifier. Field winding has same number of poles as that of the stator armature winding to generate torque while the harmonic winding has three times the number of poles as that of the armature winding, to induce third harmonic current component and excite …the field winding. In this paper, the rotor harmonic winding is split in two branches and further a capacitor is connected in series with one branch to create a phase difference. Phase difference between the two harmonic winding branches reduces the peak-to-peak value of the DC current fed to the field winding and hence the torque ripple is reduced. Finite Element Analysis (FEA) is performed to verify the reduction in ripple percentage. Show more

Keywords: Wound rotor, synchronous machine, brushless excitation, torque ripple, ripple reduction, two-phase

DOI: 10.3233/JAE-171134

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 765-773, 2019

Authors: Sheng, Feng | Geng, Haipeng | Zhang, Bo | Yang, Baisong | Xia, Kai | Yu, Lie | Cheng, Wenjie

Article Type: Research Article

Abstract: This paper describes a program development in testing a 100 kW Permanent Magnet Synchronous Motor (PMSM) using multi-leaf foil bearings with bump foils. The testing program includes the motor speed up to 43000 rpm, and then slow down to zero speed. The orbit of the rotor and the electrical parameters of the motor are obtained. The success in the experiments shows that the design and fabrication of the compliant gas foil bearings and motor can provide a useful guide to the development of an advanced high speed rotating machinery.

Keywords: High-speed, permanent-magnet synchronous motor, multi-leaf foil bearings

DOI: 10.3233/JAE-171069

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 59, no. 2, pp. 775-783, 2019