International Journal of Applied Electromagnetics and Mechanics - Volume 68, issue 1

Authors: Lin, Qian | Wu, Hai-Feng | Liu, Lin-Sheng | Cao, Chun

Article Type: Research Article

Abstract: This paper discusses the impact of the adjacent channels on the 1-dB compression point, the IP3 and the IP5 of Radio Frequency (RF) amplifier by n -tone test. By combining the theoretical derivation and software simulation, the model analysis for the third/five order polynomial nonlinear amplifier has been achieved. Moreover, the control variable method is adopted to draw the curves for the input/output signals. The research shows that the 1-dB compression point, the IP3 and the IP5 drop as n increases, and they all have symmetry for a given n . The fifth-order polynomial nonlinear amplifier model is proposed, …the research shows that the adjacent channels have a great impact on the 1-dB compression point, the IP3 and the IP5 of the desired channel. This effect must be taken into account in actual RF amplifier designs and wireless communication architectures. Show more

Keywords: RF amplifier, the nonlinear effect, adjacent channels, intermodulation, n-tone test

DOI: 10.3233/JAE-210015

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 68, no. 1, pp. 1-12, 2022

Authors: Karaçuha, Kamil | Tabatadze, Vasil | Veliyev, Eldar Ismailovich

Article Type: Research Article

Abstract: An accurate hybrid method (numerical-analytical method) for the diffraction of H-polarized electromagnetic plane wave by perfectly electric conducting cylindrical bodies containing edges and a longitudinal slit aperture is proposed. This method is the combination of the Method of Moment and semi-inversion method. The current density function is expressed as the Chebyshev polynomials forming a complete orthogonal set of basis functions. Then, the initial problem is reduced to a system of linear algebraic equations. After inversion, the unknown coefficients are obtained. Then, near and far-field distributions, radar cross-sections are obtained. The resonances are observed for different values of the aperture size, …radius of the arc, and the results are compared with previous outcomes. Show more

Keywords: Circular cylinder arc, diffraction, H-polarization, resonance, scattering

DOI: 10.3233/JAE-210018

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 68, no. 1, pp. 13-27, 2022

Authors: Ye, Kuan | Zhou, Kai | Ren, Zhigang | Zhang, Ruizhe | Li, Chunsheng | Sun, Hongyu | Huang, Songling

Article Type: Research Article

Abstract: The power transmission tower’s ground electrode defect will affect its normal current dispersion function and threaten the power system’s safe and stable operation and even personal safety. Aiming at the problem that the buried grounding grid is difficult to be detected, this paper proposes a method for identifying the ground electrode defects of transmission towers based on single-side multi-point excited ultrasonic guided waves. The geometric model, ultrasonic excitation model, and physical model are established, and the feasibility of ultrasonic guided wave detection is verified through the simulation and experiment. In actual inspection, it is equally important to determine the specific …location of the defect. Therefore, a multi-point excitation method is proposed to determine the defect’s actual position by combining the ultrasonic guided wave signals at different excitation positions. Besides, the precise quantification of flat steel grounding electrode defects is achieved through the feature extraction-neural network method. Field test results show that, compared with the commercial double-sided excitation transducer, the single-sided excitation transducer proposed in this paper has a lower defect quantization error in defect quantification. The average quantization error is reduced by approximately 76%. Show more

Keywords: Transmission tower, ground electrode, Lamb wave, defect detection, feature extraction-neural network

DOI: 10.3233/JAE-210039

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 68, no. 1, pp. 29-43, 2022

Authors: Chen, Zhuo | Ma, Ye | Zhang, Kaihe | Zhou, Chenxi | Huang, Xiaoyan | Zhang, Jian

Article Type: Research Article

Abstract: High temperature superconducting (HTS) tapes could be introduced into large scale electrical machines in order to improve the power density. However, the alternating current (AC) loss of HTS tapes will cause the reduction of efficiency. On the basis of analytical and numerical model calculations, this paper presents an optimal design of the HTS armature winding aiming at lower AC loss. The main contribution of this work is that the relationship between the installation parameters and the AC loss of such HTS armature windings has been figured out based on the analysis of the shape feature of the HTS tape and …the external magnetic field. When the tape is placed along a particular direction where the perpendicular component of external magnetic field has the lowest amplitude, the AC loss is the smallest. The modified installation location and angle are found based on the proposed generator. These results are verified using finite element method (FEM). Show more

Keywords: AC loss, armature winding, high temperature superconducting (HTS), wind power generator, electrical machine

DOI: 10.3233/JAE-210045

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 68, no. 1, pp. 45-57, 2022

Authors: El-Dabe, Nabil T.M. | Abou-Zeid, Mohamed Y. | Oauf, Mahmoud E. | Mostapha, Doaa R. | Mohamed, Yasmeen M.

Article Type: Research Article

Abstract: The present investigation analyzes the influence of Cattaneo–Christov heat and mass fluxes on peristaltic transport of an incompressible flow. The fluid is obeying Bingham alumina nanofluid. The fluid flows between two co-axial vertical tubes. The system is expressed by a varying radially magnetic field with respect to the space. Soret effect and non-Darcy porous medium are taken into account. The governing system of equations is tackled by utilizing the approximations of long wave length with low Reynolds number and with the help of homotopy perturbation method (HPM). It is noticed that the axial velocity magnifies with an increase in the …value of Bingham parameter. Meanwhile, the value of the axial velocity reduces with the elevation in the value of the magnetic field parameter. On the other hand, the elevation in the value of thermal relaxation time leads to a reduction in the value of fluid temperature. Furthermore, increasing in the value of mass relaxation time parameter makes an enhancement in the value of nanoparticles concentration. It is noticed also that the size of the trapped bolus enhances with the increment in the value of Bingham parameter. The current study has many accomplishments in several scientific areas like medical industry, medicine, and others. Therefore, it represents the depiction of the gastric juice motion in the small intestine when an endoscope is inserted through it. Show more

Keywords: MHD, peristaltic flow, Bingham model, alumina nanofluid, Cattaneo–Christov heat flux, non-Darcy porous medium

DOI: 10.3233/JAE-210057

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 68, no. 1, pp. 59-84, 2022

Authors: Wu, Qingle | Yang, Guolai | Tang, Enling | Wang, Liqun | Wang, Xiuye

Article Type: Research Article

Abstract: Various technologies have ever been developed to minimize the detent force of linear motors. Although the traditional modular structure can effectively reduce the detent force, the width of the flux barrier and the number of units severely limit its application. To solve these, this paper proposes a new modular type of tubular permanent magnet synchronous linear motor (TPMSLM), which consists of two identical unit motors. For simplification, a subdomain analytical method of the unit motor is firstly established, and its accuracy is verified by a comparison with that of the finite element method. Using the two approaches, the important parameters …of the motor are analyzed. A modified two-unit modular TPMSLM is also proposed through the star vectograms of the electromotive force, which achieves thrust performance similar to the traditional three-unit modular TPMSLM with a smaller axial size. Moreover, to make full use of the volume of the flux barrier, end teeth are added at both ends of the unit motors. The simulation results indicate that a reasonable end tooth structure can not only reduce the magnetic leakage phenomenon of the end but also effectively improve the thrust of the motor. Show more

Keywords: Modular TPMSLM, subdomain analytical model, thrust characteristic, detent force

DOI: 10.3233/JAE-210091

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 68, no. 1, pp. 85-104, 2022

Authors: Xia, Wentao | Long, Zhiqiang | Dou, Fengshan

Article Type: Research Article

Abstract: A magnetic suspension and balance system (MSBS) is a kind of aerodynamic test equipment for aircraft. It uses levitation control technology to replace the mechanical support and strain measurement technology in traditional wind tunnel balance. It has the advantage of no model support to interfere with the wind tunnel flow field and make the test environment more realistic, but the MSBS has technical difficulties to be solved. It is difficult to control and stabilize because it has a large suspension gap, nonlinear magnetic field, a long-acting distance of magnetic force, and uses a visual sensor to feedback the position of …the controlled object that it has signal noise. At present, there are few studies on the suspension control method and suspension performance of MSBS. In this paper, in order to solve the above technical difficulties, the vertical control of the MSBS is taken as the research object, the electromagnetic field of the vertical coil is modeled and analyzed. A new control algorithm based on a fast-tracking differentiator (FTD) is proposed to solve the signal noise problem in MSBS. The influence of various factors in the control link on the suspension system is analyzed, and its optimization is carried out to improve the performance of the suspension system. Show more

Keywords: MSBS, electromagnetic field modeling, levitation control, performance optimization

DOI: 10.3233/JAE-210121

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 68, no. 1, pp. 105-122, 2022

Authors: Ye, Lezhi | Zhang, Yulong | Cao, Mingguang

Article Type: Research Article

Abstract: To solve the problem of complex operating device and permanent magnets (PMs) demagnetization at high temperature, a new type of permanent magnet fluxed-switching coupler (PMC) with synchronous rotating adjuster is proposed. Its torque can be adjusted by rotating a switched flux angle between the adjuster and PMs along the circumferential direction. The structural feature and working principle of the PMC are introduced. The analytical model of the novel PMC was established. The torque curves are calculated in transient field by using the three-dimensional finite element method (3-D FEM). The temperature distribution of the novel PMC under rated condition is calculated …by 3-D FEM, and the temperature distribution of the PM is compared with that of the conventional PMC. The simulation and test results show that the maximum temperature of copper disc and PM of the novel PMC are 100 °C and 48 °C respectively. The novel PMC can work stably for a long time under the maximum load condition. Show more

Keywords: Permanent magnet coupler, switched flux, torque prediction, thermal analysis, transmission efficiency

DOI: 10.3233/JAE-210127

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 68, no. 1, pp. 123-140, 2022