International Journal of Applied Electromagnetics and Mechanics - Volume 37, issue 4

Authors: Yang, Wan'an | Li, Yan | Hu, Chao | Song, Shuang

Article Type: Research Article

Abstract: magnetic flux intensity of the rectangular magnet is the function of its location and orientation. With the measured magnetic flux intensities at two points around the rectangular magnet by 3-axis magnetic sensors, a non-linear equation group is established, and the location and orientation of the rectangular magnet can be determined by seeking the solution of the equation group by using general Levenberg-Marquardt (L-M) algorithm. However, the time occupied by general L-M algorithm is too long to …realize real-time tracking for the rectangular magnet. We propose an improved method which computes Jacobin Matrix in L-M algorithm in parallel. Making use of the Open Multi-Processing (OpenMP) model, the parallel operation is implemented on the dual-core personal computer. As a result, the real-time tracking for the rectangular magnet is realized, and the tracking curve is smooth. Show more

Keywords: Rectangular magnet, parallelization, Levenberg-Marquardt algorithm, real-time tracking

DOI: 10.3233/JAE-2011-1397

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 37, no. 4, pp. 241-251, 2011

Authors: Xu, He-Xiu | Wang, Guang-Ming | Yang, Xiao-Lei | Chen, Xin

Article Type: Research Article

Abstract: In this paper, a novel ultra-wide band (UWB) bandpass filter (BPF) and its equivalent circuit model are presented by etching a Sierpinski carpet slot on a single negative metamaterial (MTM) transmission line (TL). The MTM TL, demonstrated with negative permeability within two bands, consists of a Koch slot etched in the ground plane and a series capacitive gap etched in the upper stepped-impedance conductor line. The BPF is investigated in depth using full-wave electromagnetic (EM) simulation, …electrical simulation and extracted constitutive EM parameters. Different geometrical elements on the overall performance of the filter are also systematically studied. A set of design guidelines and a simple method to extract lumped-element parameters are derived, which are of a practical value in future design. For verification, the developed BPF is fabricated and measured. Consistent results between simulation and measurement have confirmed the design, showing that the BPF with a relative bandwidth of 140.3% offers many advantages such as compact size, comparable low return loss and insertion loss, sharp and deep out-of-band rejection, and small variation in group delay. Show more

Keywords: Fractals, metamaterial, ultra-wide band (UWB), bandpass filter (BPF), suppression, and group delay

DOI: 10.3233/JAE-2011-1398

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 37, no. 4, pp. 253-262, 2011

Authors: Zhang, Chi | Tseng, King Jet | Zhao, Guangzhou

Article Type: Research Article

Abstract: A permanent magnet synchronous motor and an induction motor both having dual air-gap, axial flux configurations have been designed. Both of these two type motors have twin stators and double-side single rotor that is sandwiched between these two stators. On the double surfaces of both disk-type rotors, the permanent magnets are mounted and copper rotor-bars are filled in the slots respectively. The mathematical models of these two type motors have been derived, and the performances of …the motors are compared mathematically. Three-dimensional finite element method (FEM) is implemented to analyze the characteristics of these motors and make comparison between them. The analysis results support the feasibility of the motor structures and prove that the PM motor has higher torque density and efficiency when the same dimension is assigned to both motors. Show more

Keywords: Axial flux motor, axial flux PM motor, axial flux induction motor, 3D FEM analysis

DOI: 10.3233/JAE-2011-1399

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 37, no. 4, pp. 263-273, 2011

Authors: Izadi, M. | Kadir, M.Z.A. Ab | Gomes, C. | Ahmad, W.F. Wan

Article Type: Research Article

Abstract: In this paper, by considering the factors that influence the charge height variation along the lightning channel and using Maxwell's equations, general expressions in time domain for the evaluation of electromagnetic fields at an observation point are proposed. The lightning channel is assumed to be perpendicular to the ground surface and the ground conductivity is considered to be perfect. Our results showed that the proposed method has good agreement with the measured values, as we validated …the outcome using fields measured at close and intermediate distances from the lightning channel. A set of general equations, which has the ability of evaluating any given channel base current function and current model in time domain is also derived. Show more

Keywords: Return stroke current, lightning, electromagnetic fields, lightning channel

DOI: 10.3233/JAE-2011-1400

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 37, no. 4, pp. 275-289, 2011

Authors: Cheng, Jun | Ji, Hongli | Qiu, Jinhao | Takagi, Toshiyuki

Article Type: Research Article

Abstract: This paper presents a new synchronized switch circuit for piezoelectric semi-active vibration control. Recently, Synchronized Switching Damping (SSD) controllers have been used to switch piezoelectric materials in order to damp vibration. In contrary to standard active and passive piezoelectric damping, these switching shunt circuits allow a small implementation and require only little power and, moreover, they offer the advantage of self-adaptation with environmental variations and their broadband frequency efficiency. However, the control …performance of previous SSD approaches relies on the electrical quality factor of the switch circuit. This paper presents a novel form of the SSD with a negative capacitance, which is to maintain the environmental adaptation and bypass the influence of the quality factor to the damping system. The expression of the vibration attenuation at the resonance frequency is derived, and the effectiveness of this new circuit design is demonstrated by comparing with SSDI and negative capacitance shunt passive control of a resonant cantilever composite beam with embedded piezoelectric patch. Theoretical predictions and experimental results show a remarkable attenuation on the vibration of cantilever beam, which excels the other two techniques. Show more

Keywords: Piezoelectric materials, semi-active damping, synchronized switch damping (SSD), negative capacitance

DOI: 10.3233/JAE-2011-1402

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 37, no. 4, pp. 291-308, 2011

Article Type: Other

Abstract: Author Index to Volume 37 (2011

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 37, no. 4, pp. 309-312, 2011