International Journal of Applied Electromagnetics and Mechanics - Volume 31, issue 4

Authors: Arehpanahi, Mehdi | Milimonfared, Jafar

Article Type: Research Article

Abstract: In this paper dynamic analysis of switched reluctance motor (SRM) at startup, loading and remove loads based on surface current method (SCM) is proposed. Using combination of time stepping method and SCM in case of saturation, surface currents on the boundaries for dynamic analysis will be depending on time and rotor position. Simulation results and computation time are compared with Finite Element Method (FEM).

Keywords: Dynamic analysis, surface current method, FEM, SRM and saturation

DOI: 10.3233/JAE-2009-1057

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 31, no. 4, pp. 193-206, 2009

Authors: Zhang, C.L. | Chen, W.Q. | Yang, J.S.

Article Type: Research Article

Abstract: We perform a theoretical analysis on electrically forced, coupled thickness-shear and flexural vibrations of rectangular piezoelectric plates of monoclinic crystals. Mindlin's first-order theory for piezoelectric plates is used, simplified by the flexure-twist approximation by Mindlin and Spencer. Two types of boundary conditions are considered. Trigonometric series solutions are obtained. The motional capacitance of the plates and its frequency dependence under a time-harmonic driving voltage, an important property when the plates are …used as piezoelectric resonators, are calculated and examined from the series solutions for quartz and langasite plates. Show more

Keywords: Piezoelectricity, plate, vibration

DOI: 10.3233/JAE-2009-1058

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 31, no. 4, pp. 207-218, 2009

Authors: Shen, Hui | Ji, Hongli | Qiu, Jinhao | Zhu, Kongjun

Article Type: Research Article

Abstract: This paper designs and investigates a vibration damping system powered by harvested energy with the implement of the so-called SSD (Synchronized Switch Damping) technique, which is a semi-passive approach. In the semi-passive approach, the piezoelectric element is switched from open circuit to closed circuit synchronously with the structure motion. Due to this switching procedure, a phase shift induced between the strain of vibration and the resulting voltage, thus creating energy dissipation. A low-power version of …the switching circuit for nonlinear processing of voltage has been designed, and by combining the switching circuit with an energy harvesting subsystem, a semi-passive vibration damping system without external power supply has been successfully developed. Its effectiveness in the single-mode resonant damping of a composite beam is validated by the experimental results. Show more

Keywords: Piezoelectric devices, structural damping, semi-passive damping, energy harvesting

DOI: 10.3233/JAE-2009-1059

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 31, no. 4, pp. 219-233, 2009

Authors: Chi, Chieh-Tsung

Article Type: Research Article

Abstract: This paper focuses on a novel control algorithm and its implementation method for providing voltage compensation to the coil of an AC electromagnetic contactor during voltage sags. Firstly, a new diagnosis algorithm is designed for correctly and timely detecting the voltage-sag event. When this new algorithm is embedded in the voltage compensation circuit and in series with the AC core of the contactor, the abnormal disengagement of the contactor contacts during voltage sag event could …be eliminated through several experimental results. Another one designing point is that the dynamic position of armature can only be determined by a simple estimation method. In addition, the estimated position of armature and the applied voltage and coil current are taken as inputs by a single-chip based controller and provide the compensation voltage as output if voltage-sag event occurs. The above-mentioned new algorithm has been implemented in the laboratory. Show more

DOI: 10.3233/JAE-2009-1060

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 31, no. 4, pp. 235-255, 2009

Authors: Tongsomporn, Damrongsak | Afzulpurkar, Nitin | Sitthisak, Onjira

Article Type: Research Article

Abstract: We did an experimental study to examine head instabilities and noise of tunneling magnetoresistance (TMR) sensors using in high-density perpendicular recording systems. It found that the instability signatures on the transfer curves could be categorized into two groups; permanent magnet/free layer (PM/FL) failure and synthetic antiferromagnetic layers/antiferromagnetic layer (SAF/AFM) failure. The thermal-mechanical stress from the adaptive flying height (AFH) heater as well as head-disk interaction potentially degrades PM resulting in the reduction …of the FL stabilizing field, therefore TMR ratio and signal increases. The non-uniformity of PM remnant magnetization and the switching of PM grains especially near the edge potentially degrade the biasing field. Scanning electron microscope images of these weak heads show rough surface and scratches close to the active area of read sensor. The deep scratches by particles in the head-disk interaction and shallow scratches by the slider lapping process is a potential cause to degrade PM. In another group, the thermal-mechanical stress from AFH heater potentially reduces the exchange-bias field and thermal stability of SAF/AFM layers allowing partial flipping of SAF edge magnetization, consequently it induces voltage fluctuations and hysteresis loops in the transfer curves. Show more

Keywords: Adaptive flying height, head-disk interaction, thermal-mechanical stress, head instabilities

DOI: 10.3233/JAE-2009-1061

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 31, no. 4, pp. 257-265, 2009