International Journal of Applied Electromagnetics and Mechanics - Volume 53, issue 2

Authors: Bao, Xiaohua | Wang, Hanfeng | Di, Chong

Article Type: Research Article

Abstract: Eccentricity is a common fault during the operation of electrical machines due to manufacturing error and effect of rotor deflection. Therefore, eccentricity fault has been a research hotspot in recent decades for the reliable running of machines. The monitoring signals for detecting eccentricity have been proposed in many published papers. However, the effects of rotor slot number on the magnitudes of characteristic signals are seldom investigated. Thus, this paper presents the relationship between the number of rotor slots and the monitoring signals under static, dynamic and mixed eccentricity on the basis of the previous papers. The theoretical analysis shows that …not all electrical machines generate the principal slot harmonics in the stator current. But these harmonics in the air-gap magnetic field are easily detected for all machines when the machines are under static or dynamic eccentricity. Moreover, the effect of rotor slot number on the low-frequency components under mixed eccentricity is also predicted. Detailed simulations are presented for a high voltage submersible motor with 40, 41, 42, 43 and 44 rotor slots under various conditions. And these results well verify the theoretical predictions. Show more

Keywords: Eccentricity, monitoring signals, rotor slot number, submersible motor

DOI: 10.3233/JAE-150056

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 2, pp. 181-192, 2017

Authors: Yang, Beibei | Hu, Yefa | Vicario, Francesco | Zhang, Jinguang | Song, Chunsheng

Article Type: Research Article

Abstract: A floating raft system is a special double-layer isolation system aiming to reduce the level of noise and vibration and has been widely applied to many kinds of ships and submarines. It can isolate vibration of hosts and auxiliary machines and reduce the structural noise of ships and submarines effectively. It can also protect the equipments and instruments in ships and submarines from being damaged, and makes them to be operated properly when ships and submarines are subjected to external loads and sudden shocks. However, the floating raft system is generally a flexible structure and it is subject to multiple …frequency disturbances. The design of control systems to enhance its isolation performance is an active area of research. This paper presents improvements achieved by using a dynamic step FXLMS controller whose main benefit is to balance convergence speed and steady-state error by making the convergence coefficient vary with time. The mathematical model of the dynamic system to be used in the controller is obtained by the observer/Kalman filter identification (OKID) method. The performance of the new solution (dynamic step size FXLMS with OKID model) is compared with previous work based on a fuzzy controller and a dynamic model identified via the prediction error method. Both simulated and experimental results confirm the validity and the benefits of the approach. Show more

Keywords: Floating raft system, magnetic suspension isolator, observer/Kalman filter identification, dynamic step size FXLMS algorithm

DOI: 10.3233/JAE-150167

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 2, pp. 193-209, 2017

Authors: Yadghar, Amir Ata | Mokhtari Kondori, Mania | Navardi, Mohammad Javad

Article Type: Research Article

Abstract: This paper presents switched reluctance motor features improvement by presenting new geometries dimension optimization. The design goals are ripple of torque and weight reduction and average torque increase. To achieve these goals not only design of previous research of a normal SRM is improved, but also new geometries with optimised dimension are suggested. The performance analysis of SRM is carried out by a finite element method software. A multi objective genetic algorithm coded by MATLAB, has been employed to perform the numerical analysis to obtain solutions. COMSOL 4.3 has been selected for FEM analysis in order to establish a better …online link to MATLAB. To reach a reliable solution, the being optimized parameters of each suggested geometry, has been widely changeable by MOGA as long as there is no conflicts between others. The method of optimization and the new suggested geometries has been applied to a 6/4 SRM and simulation results have been declared and discussed. Show more

Keywords: Switched reluctance motor (SRM), finite element method (FEM), dynamic geometry, multi objective genetic algorithm (MOGA), torque ripple optimization, torque optimization, weight optimization

DOI: 10.3233/JAE-160012

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 2, pp. 211-226, 2017

Authors: Muthukumaran, S. | Senthil Kumar, A. | Vendan, S. Arungalai | Kudiyarasan, S.

Article Type: Research Article

Abstract: In this paper the joining of dissimilar metal couple SS-Cu employing the magnetic pulse welding (MPW) technique that deploys magnetic pressure to force the primary metal against the target metal cleansing away contaminants from surface while driving intimate metal-to-metal contact, producing a weld. MPW process is very fast, produces no heat affected zone (HAZ) and may be performed without filler metals and protective gases. Nevertheless, a thin film (10 to 40 μ m) of two welded metals in the form of intermetallic phases were observed, in which melting and solidification processes took place. This paper focuses on the interface for …studying the typical wavy pattern and mutual diffusion of elements happening in the zone. The transition zone is composed of elements intermetallics, micro cracks and micro pores. The weld interface composition, structure and morphology were studied by optical and scanning electron microscopy (SEM). Energy-dispersive spectrometry (EDS) was used in order to evaluate the local distribution of alloying elements at the joint interface and its vicinity and also Nano-hardness tests were performed across the bonding zone at regular increments. The results of joints characterization allowed determining the optimal MPW process parameters. Show more

Keywords: MPW, Al, SS, Magnetic flux, welding

DOI: 10.3233/JAE-160029

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 2, pp. 237-249, 2017

Authors: Xiong, Chunbao | Guo, Ying

Article Type: Research Article

Abstract: Present paper aims to investigate a generalized electromagneto-thermoelastic diffusion problem for a half-space with variable properties in the context of the fractional order theory of thermoelastic diffusion. The variable properties are taken as linear functions of the temperature. The half-space is initially placed in an external magnetic field with constant intensity, and subjected to a time-dependent thermal load and a chemical load, respectively. The governing equations of the problem in the fractional order generalized electromagneto-thermoelastic diffusion are formulated. The bounding surface in contact with a permeating substance is prescribed to be traction-free. To solve the problem, normal mode analysis is …adopted and the distributions of the non-dimensional temperature, displacement, stress, induced magnetic field, induced electric field, chemical potential and concentration are obtained and represented graphically. The effects of fractional order parameters are evaluated by comparing the results obtained in the presence and absence of fractional order parameters. Show more

Keywords: Generalized electromagneto-thermoelastic diffusion, fractional order theory of thermoelastic diffusion, normal mode analysis, diffusion relaxation time, thermal relaxation time

DOI: 10.3233/JAE-160038

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 2, pp. 251-269, 2017

Authors: Jiang, Zhaoneng | Wan, Ting

Article Type: Research Article

Abstract: In this paper, an efficient hybrid algorithm is proposed to analyze the large-scale electromagnetic scattering and radiation problems. It utilizes the adaptive cross approximation (ACA) algorithm to form the impedance matrix for interactions inside a subdomain, while the impedance matrix for interactions belongs to different subdomains is calculated by multilevel fast multipole method (MLFMM). The direct solver based on multilevel compressed block decomposition (MLCBD) is utilized to solve the matrix equation for each subdomain which is called as the inner iteration. Due to its negligible extra cost for the new excitation, the proposed hybrid algorithm is especially efficient for analyzing …electromagnetic scattering problems with multiple incident fields (monostatic scattering computations). Numerical examples are presented to demonstrate its validity and efficiency. Show more

Keywords: Multilevel compressed block decomposition (MLCBD), method of moment (MoM), overlapped domain decomposition method (ODDM), electromagnetic scattering

DOI: 10.3233/JAE-160039

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 2, pp. 271-281, 2017

Authors: Zhang, Yi | Zeng, Zhong | Yao, Liping | Qiao, Long | Yin, Linmao | Lu, Yiyu

Article Type: Research Article

Abstract: The skin effect appears when a rotating magnetic field (RMF) penetrates the melt with electrical conductivity, and the skin effect becomes more obvious with the increased dimensionless shielding parameter K. In this paper, an analytic solution, based on the Bessel functions for the distribution of the rotating magnetic field with the skin effect in melt was derived. In order to model the interaction of the rotating magnetic field and melt convection, the polynomial of the analytic solution was truncated in different terms. In addition, the applicative range of K for different truncation was estimated. Then the rotating magnetic field with …truncation was introduced to the rotating magnetic field Φ1 -Φ2 model. Through the simulation results of the finite volume method, the estimated range of K for the approximate magnetic field with different truncation was verified. Show more

Keywords: Rotating magnetic fields, the skin effect, computer simulation, fluid flows

DOI: 10.3233/JAE-160041

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 2, pp. 283-302, 2017

Authors: Tang, Yujuan | Yang, Zhong | Wang, Xinjie | Wang, Jiong

Article Type: Research Article

Abstract: A novel linear-type piezoelectric ultrasonic actuator for application in a Smart Fuze Safety System (SFSS) is investigated in this paper. Considering the requirements of SFSS, the structural parameters of the piezoelectric ultrasonic actuator are initially determined. Furthermore, sensitivity analysis of the structural parameters to the frequency consistency is conducted using finite element (FEM) software. To validate the results of FEM, the frequency sweep tests of the piezoelectric ultrasonic actuator are performed to determine the stator's actual working mode frequencies with PSV-300-B Doppler laser vibrometer system. Additionally, the results of frequency sweep test are compared with that of the FEM analysis, …and further verified by impedance analyzer. To investigate the overall performance of the piezoelectric ultrasonic actuator, vibration modes of actuator's stator, output speed and force of the piezoelectric ultrasonic actuator are tested. The experimental results show that the output speed and force of the actuator can reach 88.2 mm/s and 2.3 N respectively, which can meet the demands of the SFSS. Show more

Keywords: Linear piezoelectric ultrasonic actuator, smart fuze safety system, mode analysis, sensitivity analysis

DOI: 10.3233/JAE-160044

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 2, pp. 303-313, 2017

Authors: Kawaguchi, Hideki | Satoh, Kohki | Timoshkin, Igor V. | Given, Martin J. | MacGregor, Scott J.

Article Type: Research Article

Abstract: Beyond on remarkable progresses in a technology of high-voltage pulse, it is considered to apply the high-voltage pulsed electric field to an inactivation of a microorganism. In particular, the method of the high-voltage pulse has advantage in the inactivation of bacteria in foods, since conventional methods such as heat disinfectant, X-ray or gamma-ray are expected to induce negative secondary effects, changes of flavor, taste, texture of the foods, and so on. In the treatment of the microorganism by the high-voltage pulse, the microorganism is destroyed by pure mechanical stress force created by externally applied electric field, and therefore there are …no negative secondary effects. However, it should be carefully evaluated how much strong stress force can be produced by reasonable voltage and pulse duration of the high-voltage pulse for the inactivation of the microorganism. Then, evaluation of the stress force for cases of complete sphere and axis-symmetric shapes of the microorganism were presented by using an analytical formula or 2-D FEM. In this paper, an electrostatic field analysis by using 3-D BEM with a thin layer approximation for a membrane of the microorganism is presented to aim to evaluate the stress force for arbitrary shape microorganism. Show more

Keywords: High-voltage pulsed electric field, electrostatic field analysis, finite difference method, boundary element method, Maxwell's stress

DOI: 10.3233/JAE-160047

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 2, pp. 315-325, 2017

Authors: Chen, Zhenfei | Li, Zhixin | Ma, Hongzhong

Article Type: Research Article

Abstract: Electromagnetic torque model is built in this paper for permanent-magnet synchronous machine (PMSM) with non-sinusoidal back electromotive force (back-EMF) and current. Electromagnetic torque is divided into four parts depending on the different combinations of fundamental and harmonic component. Effects of current harmonic order, amplitude and initial angle on average torque and torque ripple are investigated based on the mathematic model. Desired harmonic parameters are obtained from the analysis, in order to suppress the torque ripple as much as possible. Further, a method for reducing the 5th and 7th harmonic components of torque ripple is proposed, according to the …characteristics of back-EMF harmonic distribution. The proposed method is greatly simplified and more feasible by only injecting 5th and 7th harmonic currents. The theoretical analysis validity has been proved by finite element (FE) simulation, and the FE results show that torque ripple would be more effectively reduced by injecting proper harmonic current than weakening it merely. Show more

Keywords: Back-EMF harmonics, harmonic current injection, electromagnetic torque ripple, permanent-magnet synchronous machine (PMSM)

DOI: 10.3233/JAE-160056

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 53, no. 2, pp. 327-336, 2017