International Journal of Applied Electromagnetics and Mechanics - Volume 46, issue 1

Authors: Ye, Peng | Shu, Liang | Wu, Guichu | Zhou, Liang

Article Type: Research Article

Abstract: The closing process of intelligent AC contactor can be affected by selection phase angle and the dynamic control strategy. A control strategy is proposed to compensate the influence of closing process at different phase angles. The mathematical model of the closing process is established by analyzing the dynamic characteristics of the contactor. Simulation and experimental comparisons show that the proposed model can predict the dynamic response of the closing process effectively. The relationship between the …closing phase angle and the end speed is analyzed by using the experimental measurements. The selection phase angle and dynamic control is implemented by combining voltage zero crossing and PWM section control technology. The input voltage and the zero-crossing signal are taken as the control input while the PWM duty cycles and the strong excitation time are taken as the control output. The control strategy is implemented by using the lookup table. Experimental results show that by using the proposed strategy, the contactors can be closed with the same phase angle. Therefore the consistency of the dynamic closing process of the intelligent contactors can be guaranteed. Also, the movable armature end speed of the closing is reduced 31.5% and the closing time is decreased 15.6%. The mechanical life of the contactor has been increased about 4 times in the durability test. Show more

Keywords: PWM, selection phase angle control, intelligent contactor, voltage zero crossing

DOI: 10.3233/JAE-141741

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 1, pp. 1-10, 2014

Authors: Gulistan, Samina | Abbas, M. | Syed, A.A.

Article Type: Research Article

Abstract: Fractional dual solutions to the Maxwell equations for a dielectric slab placed in an unbounded dielectric magnetic medium are determined using the fractional curl operator. For extreme values of the intrinsic impedance of the host dielectric magnetic medium, the geometry becomes equivalent to that of a PEC or a PMC waveguide. In this way, the fractional dual fields for the PEC and PMC waveguide are also easily obtained.

Keywords: PEC, PMC, fractional curl operator, fractionalization, waveguides

DOI: 10.3233/JAE-141742

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 1, pp. 11-21, 2014

Authors: Gajdoš, L'ubomír | Šperl, Martin | Kaiser, Jaroslav | Mentl, Václav

Article Type: Research Article

Abstract: It is generally accepted that not all cyclic stresses below the fatigue limit are non-damaging. Particularly in spectrum loading, the inclusion of some cyclic stresses below the fatigue limit can reduce the fatigue life of a component. It is believed that the boundary between damaging and non-damaging stresses is the so-called micro-plastic limit (MPL) defined as a macro-stress at which dislocation pile-up stresses begin to obstruct the magnetic domains in rotation to the direction of the …tensile stress. This paper shows that MPL can be determined from changes in magnetic permeability during tensile loading. In our work, changes in magnetic permeability were measured indirectly – by measuring changes in electrical impedance (a.c. resistance and inductance). Measurements were performed on normalized low-C steel CSN 411375, and the microplastic limit was determined by evaluating the ΔR – σ and ΔL – σ records. Show more

Keywords: Damage, fatigue, microplastic limit, electrical impedance

DOI: 10.3233/JAE-141743

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 1, pp. 23-33, 2014

Authors: Qiu, Li | Wen, Xibo | Li, Hongsheng | Li, Tiegang

Article Type: Research Article

Abstract: The relative permeability and electrical conductivity of the pan material, both of which vary with temperature, play an important role in thermal power of induction cooker system. A series of finite element models, including a variable relative permeability electromagnetic model, a variable electrical conductivity electromagnetic model, and an electromagnetic and thermal coupling model, have been built by ANSYS software to analyze the variation of the thermal power with relative permeability and electrical …conductivity in this paper. It is indicated that thermal power increases with the relative permeability increasing, but its growth rate decreases. When the electrical conductivity increases, thermal power increases, reaches a peak value, and then decreases. Considering the variation of the relative permeability and electrical conductivity with pan temperature, the simulation results show that thermal power decreases a lot when the temperature of the material exceeds a definite value due to the low relative permeability in this case. Finally, the induction heating mechanism is clearly understood and the simulation results provide useful guidance for induction cooker design. Show more

Keywords: Material property, thermal power, induction cooker system, finite element method

DOI: 10.3233/JAE-141744

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 1, pp. 35-42, 2014

Authors: Le, Yun | Fang, Jiancheng | Han, Bangcheng | Zhang, Yin

Article Type: Research Article

Abstract: A hybrid radial magnetic bearing (HRMB) with permanent magnet creating bias flux is used to reduce the power consumption. Laminated cores are widely used in HRMB to reduce eddy currents. Nevertheless, when the frequencies of rotation and control currents are extremely high, eddy-current effects in laminated iron cores still have a significant influence on the behavior and performance of magnetic bearings. In order to predict performance and guide design of the HRMB system in high frequency, …an analytical method based on equivalent circuit model whose parameters are frequency-dependent is used in this paper. The analytical results show that, the eddy currents induced due to rotor movement and dynamically changing control currents will result in considerable magnitude decrease and phase lag of bearing stiffness. Furthermore, the eddy current effect on HRMB can be reduced by increasing the air gap, decreasing the laminations thickness and decreasing the laminations conductivity. Finally, a prototype is designed and fabricated; the experimental results demonstrate the validity of the analysis. Show more

Keywords: Hybrid magnetic bearing, dynamic stiffness, laminations, equivalent conductivity

DOI: 10.3233/JAE-141746

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 1, pp. 43-60, 2014

Authors: Peng, Chia-Mei | Chen, I.-Fong | Chou, I.-Tung

Article Type: Research Article

Abstract: In this paper, a compact dual-band power divider embedded with defect microstrip with periodic loading (DMSWPL) slow-wave structure is presented. The occupied space is effectively reduced by about 66.89% compared to the conventional dual-band Wilkinson power divider. The structure of this power divider and the formulas used to determine the design parameters have been given. Experimental results show that all the features of a conventional Wilkinson power divider, such as an equal power split, impedance matching …at all ports, and a good isolation between the two output ports can be fulfilled at GSM-band (880 MHz ∼ 960 MHz) and DCS-band (1710 MHz ∼ 1880 MHz) simultaneously. Show more

Keywords: Dual-band, defect microstrip, Wilkinson power divider, slow-wave structure, periodic loading

DOI: 10.3233/JAE-141747

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 1, pp. 61-68, 2014

Authors: Cheng, Yu-Ting | Chiu, Chien-Ching | Chang, Shuo-Peng | Hsu, Jung-Chin

Article Type: Research Article

Abstract: The application of two techniques to reconstruct the shape of a two-dimensional periodic perfect conductor from mimic the measurement data is presented. A periodic conducting cylinder of unknown periodic length and shape scatters the incident wave in half-space and the scattered field is recorded outside. After an integral formulation, the microwave imaging is recast as a nonlinear optimization problem; a cost functional is defined by the norm of a difference between the measured scattered electric fields …and the calculated scattered fields for an estimated shape of a conductor. Thus, the shape of conductor can be obtained by minimizing the cost function. In order to solve this inverse scattering problem, transverse magnetic (TM) waves are incident upon the objects and two techniques are employed to solve these problems. The first is based on an particle swarm optimization (PSO) and the second is a self-adaptive dynamic differential evolution (SADDE). Both techniques have been tested in the case of simulated mimic the measurement data contaminated by additive white Gaussian noise. Numerical results indicate that the SADDE algorithm is better than the PSO in reconstructed accuracy and convergence speed. Show more

Keywords: Inverse scattering, frequency-domain, self-adaptive dynamic differential evolution, particle swarm optimization

DOI: 10.3233/JAE-141748

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 1, pp. 69-79, 2014

Authors: Zare, Mohammad Reza | Misron, Norhisam | Aris, Ishak | Wakiwaka, Hiroyuki

Article Type: Research Article

Abstract: Detailed analytical and experimental approaches were performed to calculating the ratio of the pull-in thrust to the input power of High Density Transverse Flux linear Stepper Motor (HDTFLSM) with considerations of the electrical time constant, the mechanical time constant and the friction. The analytical approach involves the use of Fourier series analysis to derive the equation for the pull-in thrust to input power ratio. The experimentation was performed under different load conditions until the motor come …to the standstill value. A chopped voltage was applied to motor at different speeds and the obtained results were compared with those for normal voltage. Comparison between analytical and experimental results shows good agreement, for instance at 0.22 m/s the difference percentage on normal voltage and chopped voltage are 6.1% and 6.7%, respectively. The chopped voltage has higher ratio of the pull-in thrust to the input power compare to normal voltage so that the machine performance can be improvised to a greater extent. The maximum improvement percentage of 18.8% on pull-in thrust to input power ratio for motor with chopped voltage was obtained at 0.22 m/s. Show more

Keywords: High density, linear motor, pull-in thrust, transverse flux, stepper motor

DOI: 10.3233/JAE-141749

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 1, pp. 81-93, 2014

Authors: Fernando, W.U. Nuwantha | Gerada, Christopher

Article Type: Research Article

Abstract: Certain aircraft and military applications require high speed machines with low stack-length and the lowest possible weight. Hence, the accommodation of the highest bore diameter may seem the natural option. However, a rotor design with high diameter results in significant increase in mechanical stresses in the employed magnet retention. In a sleeved magnet retention mechanism, the sleeve thickness can be increased in order to accommodate the stresses. However, this will result in significant drop in …air-gap flux-density and will not yield the high power density expected by the machine. This paper presents an analytical technique that combines the sleeve stress model and the air-gap flux density model to calculate the optimal rotor diameter to achieve the maximum power of the machine design for a minimum stack-length. The technique is applied to both a Carbon Fibre sleeve version and a metallic sleeve version. The analytical calculation of the stresses is validated with mechanical finite-element simulations. The machine design with the analytical calculations is validated with electromagnetic finite element simulations. The results confirm the rotor design strategy and the design technique. Show more

Keywords: Magnet retention, carbon-fiber sleeve, power density, high-speed machine, permanent magnet machine, stress analysis

DOI: 10.3233/JAE-141750

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 1, pp. 95-109, 2014

Authors: Liu, L.L. | Feng, W.J. | Ma, P.

Article Type: Research Article

Abstract: The fracture behavior of a penny-shaped crack in a constrained magnetoelectroelastic cylinder of finite radius under magnetoelectromechanical loads is investigated. The crack surfaces are assumed to be magnetoelectrically permeable. Eight kinds of possible boundary conditions at infinity are considered. The potential function theory and Hankel transform method are used to obtain a system of dual integral equations, the solution of which is further given by solving a Fredholm integral equation of the second kind. The field …intensity factors are obtained and analyzed. The effects of both the ratio of crack radius to cylinder radius and the applied magnetoelectrical loads at infinity on the stress intensity factor are evaluated. The obtained results and/or conclusions could be of particular interest to the analysis and design of smart sensors/actuators constructed from magnetoelectroelastic composite laminates. Show more

Keywords: Penny-shaped crack, cylinder, field intensity factors, magnetoelectroelastic material

DOI: 10.3233/JAE-141765

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 46, no. 1, pp. 111-124, 2014