International Journal of Applied Electromagnetics and Mechanics - Volume 61, issue 2

Authors: Ye, Lezhi | Liu, Yupeng | Li, Desheng

Article Type: Research Article

Abstract: We propose a novel dual air-gaps and liquid-cooled eddy current retarder (ECR) based upon observing the (1) heat fade of the continuous braking and (2) large rotor weight of the traditional ECR for heavy vehicles. The new ECR maintains a low working temperature because of the liquid cooling stator structure. The eddy current distribution and braking torque characteristic curves are obtained by finite element method (FEM). Combining with 3-D FEM, Kriging approximation model is employed to optimize the structural parameters of rotor tooth. Based on the optimization method, the number of rotor teeth is determined to be 12. The braking …torque increases by 14.8% after optimization and the rotor tooth weight decreases by 9.5%, which reduces the adverse influence on the vehicle transmission system. The bench test was carried out to verify the optimized calculation results and the braking torque can be stepless controlled by adjusting the excitation current. Compared with traditional ECR, the dual air-gaps and liquid-cooled ECR has better continuous braking performance and is more suitable for heavy vehicle auxiliary braking. Show more

Keywords: Dual air-gaps, eddy current retarder, liquid cooling, Kriging model, structural optimization

DOI: 10.3233/JAE-180109

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 2, pp. 157-170, 2019

Authors: Li, Xiangchao | Ma, Xiaoqi | Liu, Yinping | Wan, Zhicheng | Cai, Lujin | Xu, Xiaopei

Article Type: Research Article

Abstract: Based on the invalidation and damage of the field effect transistors under lightning radiation, we establish the breakdown experiment with open-circuit voltage wave and the protection experiment with TVS as the protection device. The junction field effect transistor and the metal oxide semiconductor field effect transistor are used as material. We draw some conclusions. In the breakdown experiment, the breakdown voltage of the MOSFETs is higher than that of the JFETs as a whole. The MOSFET can be adopted in the amplifier circuit which is expected to get higher input resistance and breakdown voltage. The drain-source resistance can recover to …the original resistance value after being placed a period of time, but the gate-source resistance is irreversible. The invalidation of the device under test is due to the breakdown of gate-source. The TVS can protect the FTEs well. The change of pin resistance of the MOSFET is inconspicuous. MOSFETs are more stable for debugging and development of the amplifier circuit. The results provide some significance for the development and improvement of the lightning electric fields change measuring instruments in the future. Show more

Keywords: Field effect transistor, JFET, MOSFET, invalidation

DOI: 10.3233/JAE-180100

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 2, pp. 171-183, 2019

Authors: Yao, Xing-Yan | Pecht, Michael

Article Type: Research Article

Abstract: Magnetorheological (MR) dampers are important devices for reducing and controlling vibration. Dynamic response time is one of the key factors that determines the control ability and application of the MR damper. Metal foam MR dampers are potentially superior to conventional dampers due to their low cost and fast response. The dynamic response time of metal foam MR dampers is distinct from conventional dampers. In this paper, the effects of different metal foam materials on the dynamic response time of metal foam dampers are studied. Three response time parameters were defined, and an experimental system including a DC motor, force sensor, …damper, and time relay was designed to collect dynamic response time parameter values using metal foam Cu and Ni, respectively. The experimental results show that the response time of MR dampers is faster using Ni rather than Cu metal foam due to the different permeability of the materials. The magnetic resistance model and Ansys simulation further prove that magnetic flux density is the main contributor to the differences in response time. Show more

Keywords: Magnetorheological (MR) fluid, MR damper, metal foam, dynamic response time

DOI: 10.3233/JAE-190022

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 2, pp. 185-199, 2019

Authors: Coufal, Oldřich | Bátora, Branislav | Radil, Lukáš | Toman, Petr

Article Type: Research Article

Abstract: A method is proposed for the calculation of current density in a long solid metallic conductor placed in an external variable magnetic field. The external magnetic field is perpendicular to the conductor and constant on straight lines parallel to the conductor. The conductor is passive, connected to neither a voltage source nor a current source. It is assumed that the external magnetic field is quasi-stationary and is not affected by the magnetic field of the currents induced in the conductor under examination. The frequency of external field does not exceed 1 MHz and the displacement current is neglected. The proposed method …enables the calculation of current density not only in the steady state but also in the case that the external field has an arbitrary time-dependent course. Results are given of the calculation of current density in conductors with symmetrical and unsymmetrical cross section, with constant and non-constant resistivity in the conductor cross section, for both homogeneous and non-homogeneous external steady-state sinusoidal field, and for switching the external sinusoidal field on and off. Show more

Keywords: Applied classical electromagnetism, magnetic induction, eddy currents, numerical simulation

DOI: 10.3233/JAE-180118

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 2, pp. 201-224, 2019

Authors: He, Yichao | Liang, Guanqun | Xue, Bing | Peng, Zhizhao | Wei, Yintao

Article Type: Research Article

Abstract: Magnetorheological (MR) damper is one of the key technologies in the field of semi-active suspensions. However, the dynamic model and control strategy are not yet well established. A unified MR damper model and its inverse characterization are proposed to investigate MR damper dynamics. First, a novel unified model is proposed to describe the shear term of the MR damper force. This forward unified MR damper model uses one set of parameters to describe all MR force behavior under all currents and velocities, which agrees well with experimental data. Then, an inverse MR model based on the adaptive neuro-fuzzy inference system …(ANFIS) technique has been established, where the precise training data are obtained from the proposed unified hysteretic model. A clear step-wise modeling process is proposed to decrease coupling degree of system which can be beneficial to improve inverse modeling efficiency. The inverse MR model is used for a semi-active suspension control, which can obtain the excitation current, exactly tracking the desired damping force computed by suspension control algorithm. Finally, validation of the proposed ANFIS inverse model has been conducted by comparison with three traditional empirical inverse approaches. The results reveal that the ANFIS inverse model could achieve much more tracking capability for the desired damping force and thus contributes to the development of semi-active suspension controllers. Show more

Keywords: Magnetorheological damper, unified model, inverse characteristics, adaptive neuro-fuzzy inference system, suspension controller

DOI: 10.3233/JAE-180114

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 2, pp. 225-245, 2019

Authors: Xu, Yongming | Ai, Mengmeng | Wang, Wenyi | Wang, Yaodong

Article Type: Research Article

Abstract: Due to the high rotational speed, the permanent magnet of surface-mounted high-speed permanent magnet generator is easily damaged by the centrifugal force. So a high strength alloy sheath is installed to protect the permanent magnet. The material, thickness and eddy current loss of the composite sheath of the high-speed permanent magnet generator with rotor strength constraint is studied thoroughly in this paper. Generator rotor strength under different limit conditions is calculated by numerical analysis method based on the thick-cylinder theory of elastic mechanics. Various methods have been used to reduce the eddy current. The composite sheath of high-speed permanent magnet …generator on the basis of rotor strength constraint is presented. Change of the material, thickness of each layer of the sheath is determined by calculation of stress and eddy current loss and optimized design of composite sheath with reasonable stress distribution and lower eddy current loss. Strength test of prototype rotor is carried out. Show more

Keywords: Electromagnetic high-speed permanent magnet generator, strength constraint, composite sheath, eddy current loss

DOI: 10.3233/JAE-180117

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 2, pp. 247-262, 2019

Authors: Zhang, Xiao | Li, Changxing | Wang, Xiaoguang | Zhao, Yun | Li, Liang

Article Type: Research Article

Abstract: The controllability of the distribution of Lorentz force on tube is poor in electromagnetic forming when using a conventional single coil forming system. To solve this issue, a triple-coil forming system was developed in this work, which includes three coils and two independent power supplies. To validate the effectiveness of the system, experimental studies for the forming of aluminium tube AL6061 under different conditions were carried out. Results showed that when using this novel forming system, the deformation behavior of tube can be obviously improved, including larger deformation depth, better performance of sizing, and lower occurrence of cracking.

Keywords: Electromagnetic forming, lorentz force distribution, deformation depth, sizing, cracking

DOI: 10.3233/JAE-180122

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 2, pp. 263-272, 2019

Authors: Diaz Florez, Guillermo A. | Mombello, Enrique E. | Voss, Stephan

Article Type: Research Article

Abstract: There are currently two main trends in solving magnetic field problems, numerical methods, of which the Finite Element Method (FEM) is undoubtedly the most popular, and analytical methods, of which there is a great diversity of approaches. The main advantage of numerical methods is their flexibility in modeling complicated geometries; however, its calculation times are generally considerable. Analytical methods attain very short calculation times by sacrificing flexibility. This paper presents the mathematical formulation of a new linear surface element for the semi-analytical solution of axisymmetric magnetic field problems. The importance of this formulation is that it is capable of dealing …with arbitrary geometries while retaining the flexibility of numerical methods with considerably shorter calculation times. The results of the application of the proposed formulation to a case study are presented in the validation section. The results obtained are compared with those calculated with FEM showing an excellent agreement between them. Show more

Keywords: Magnetic field, numerical methods, analytical methods, surface current

DOI: 10.3233/JAE-180107

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 2, pp. 273-292, 2019

Authors: Wang, Siqi | Liu, Yongkai | Li, Decai | Zhang, Zhili

Article Type: Research Article

Abstract: With the emergence of shared bicycles, people travel is more and more convenient. However, the smart bicycle lock with wireless transceiver system must have sufficient electric energy for normal work. In this paper, a ferrofluid-based planar vibration energy harvester is proposed to convert low-frequency vibration energy into electrical energy. The electromagnetic generator is designed and studied experimentally. The energy harvesting system is installed in the backseat and the front basket turning with the front fork, respectively. Experimental results indicate the collected energy is 0.010 J in the backseat and 0.020 J in the front basket for the maximal experiment distance of 1.16 km, …respectively, which can meet the demand of the smart bicycle lock. Show more

Keywords: Ferrofluid, Energy harvester, Shared bicycle, Vibration

DOI: 10.3233/JAE-180123

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 2, pp. 293-300, 2019

Authors: Klach, Moufida | Aloui, Helmi | Neji, Rafik

Article Type: Research Article

Abstract: This paper presents the modeling by Magnetic Equivalent Circuit model (MEC) of a Simple Excited Automotive Alternator (SE2A) where DC-excitation winding is transferred from rotor side to stator one rather than in conventional automotive claw pole alternators, to overcome the disadvantages of the ring-brush system. Following the resolution of the MEC using Newthon-Raphson numerical method, the alternator performances at both no-load and under resistive load regimes are achieved considering the saturation effect. It has been found that alternator’s performances carried out using the proposed MEC are with closed proximity to experimental records on a built prototype of the considered alternator. …Then, a modified SE2A is proposed by the integrating Barium ferrites permanent magnets between adjacent rotor claws in order to combine the high-energy density of permanent magnets with the commonly controllability. This configuration is named the Hybrid Excited Automotive Alternator (HE2A). The improvement of its topology performance is provided through the optimization of the device topology based on a Sequential Quadratic Programming (SQP) coupled to a magnetic equivalent circuit considering iron losses minimization case. It has been found that the efficiency of the alternator could be improved especially at high speed rate. Show more

Keywords: Claw pole alternator, simple excitation, experimental tests, hybridization, optimization, iron losses

DOI: 10.3233/JAE-170021

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 61, no. 2, pp. 301-313, 2019