International Journal of Applied Electromagnetics and Mechanics - Volume 64, issue 1-4

Authors: Liu, Yan | Zhao, Wenliang | Fan, Xue | Wang, Xiuhe | Kwon, Byung-il

Article Type: Research Article

Abstract: This paper proposes an optimal design for a surface-mounted permanent magnet motor (SPMM) to reduce torque pulsations, including cogging torque and torque ripple, by using multi-grade ferrite magnets. Based on a conventional SPMM with single-grade ferrite magnets, the proposed SPMM is designed with four-grade ferrite magnets and then optimized to minimize torque pulsations by maintaining the required torque, utilizing the Kriging method and a genetic algorithm. The results obtained by the finite element analysis show that the optimized SPMM with multi-grade ferrite magnets exhibits improved airgap flux density distribution with highly reduced cogging torque and torque ripple by maintaining the …same average torque, as compared to the conventional SPMM. Furthermore, the analysis of the working points for the multi-grade ferrite magnets reveals that the optimized SPMM has good durability against the irreversible demagnetization. Show more

Keywords: Cogging torque, ferrite magnets, finite element analysis, genetic algorithm, optimal design, surface-mounted permanent magnet motor, torque ripple

DOI: 10.3233/JAE-209310

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 79-89, 2020

Authors: Yu, Mingjie | Zhao, Wenliang | Liu, Cong | Wang, Xiuhe | Kwon, Byung-il

Article Type: Research Article

Abstract: This paper deals with the design and analysis of a novel variable flux spoke-type motor (VFSM) for washing machines by focally considering the performance at the laundry and spin-drying operating modes. The key design goal is to obtain the high efficiency for the two operating modes. At the laundry mode, the ferrite and AlNiCo magnets are utilized together as the excitations to obtain a high magnetic loading, thus to obtain high torque and efficiency. At the spin-drying mode, the AlNiCo magnets are demagnetized by a pulse negative d-axis current to reduce magnetic flux density, thus to obtain low iron loss …and high efficiency. The outer rotor structure with the spoke-type magnet configuration is utilized to enhance the high output performances. The D2 L method is utilized to design the key parameters of the VFSM. To demonstrate the superiority of the designed VFSM, the electromagnetic characteristics are predicted by the finite element method (FEM). As a result, the volume size of the proposed VFSM is decreased by 19.4%, and the efficiency at the low-speed laundry mode is increased by 25.4%, when compared to the referenced commercial washing machine motor. Show more

Keywords: AlNiCo magnet, efficiency, ferrite magnet, finite element method, variable flux spoke type motor

DOI: 10.3233/JAE-209311

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 91-101, 2020

Authors: Hou, Shuo | Tan, Xing | He, Jincheng | Deng, Xi | Xi, Chen | Lu, Guangyao | He, Huan

Article Type: Research Article

Abstract: Most research about using piezoelectric stacks to suppress vibration of mechanical structures didn’t involve the similarity problem for the piezoelectric stacks. The goal of this paper is to investigate the dynamic similarity between a prototype piezo stack and a scaled up or down piezo stack, whilst discussing the feasibility of predicting the vibration of prototype structure which use the piezoelectric stacks for vibration control. To illustrate this problem concisely, a single-DOF system consists of a proof mass and a piezo stack shunted with a series RL circuit is considered. Firstly, the governing equation of such piezo-electromechanical system in frequency domain …is derived. Next the dynamic similarity of prototype and model stack is analyzed by similitude theory. After that the scaling laws are derived. Finally, a numerical simulation and relative error analysis are given to demonstrate the scaling laws. Show more

Keywords: Similarity theory, piezoelectric stack, scale factor

DOI: 10.3233/JAE-209312

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 103-110, 2020

Authors: Wei, Yutong | Wang, Yang | Wang, Meiling | Ye, Chaofeng

Article Type: Research Article

Abstract: This paper presents a new digital fluxgate current sensor based on second harmonic detection for DC and AC measurement. The sensor utilizes a feedback loop to obtain an almost zero-flux condition, i.e., a balance between the magnetic flux of the primary current and the feedback current, in which way the feedback current is proportional to the primary current. The AC magnetic flux is detected with an induction coil, and the DC zero-flux condition is realized by magnetic saturation effect method, where the magnetic core is periodically magnetized and then the second harmonic of the magnetization current is calculated as an …indication of the DC magnetic flux. After theoretical derivation, the operating principle of the sensor was investigated using a numerical simulation model built with Simulink of MATLAB. In addition, a prototype sensor was developed and tested. The experiment results demonstrate that the current sensor works properly for DC and AC measurement. The average error is about 0.06% for DC measurement. Show more

Keywords: Fluxgate current sensor, current measurement, digital sensor, magnetic saturation effect

DOI: 10.3233/JAE-209313

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 111-118, 2020

Authors: Wang, Junlei | Li, Guoping | Jin, Zunlong | Hu, Guobiao | Zhang, Kun | Zhang, Peng

Article Type: Research Article

Abstract: Harvesting energy from wind to supply low-power consumption devices has attracted numerous research interests in recent years. However, a traditional vortex-induced vibration energy harvester can only operate within a limited range of wind speed. Thus, how to broaden the effective wind speed range for energy harvesting is a challenging issue. In this paper, a slotted cylinder bluff body is proposed for being used in the design of a wind energy harvester. The physical prototype is manufactured and the wind tunnel test is performed for evaluating the actual performance of the prototyped energy harvester. The effect of the orientation of the …slot on the performance of the proposed energy harvester is experimentally investigated. As compared to the traditional counterpart without the slot at the lateral side of the bluff body, the proposed energy harvester demonstrates the superiority for realizing broadband energy harvesting. Due to the introduction of the slot, and by carefully tuning the orientation of the slot, both the vortex-induced vibration and the galloping phenomena can be stimulated within two neighboring wind speed ranges, leading to the formation of an extremely broad bandwidth for energy harvesting. Show more

Keywords: Wind energy harvesting, slotted bluff body, vortex-induced vibration, galloping

DOI: 10.3233/JAE-209314

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 119-127, 2020

Authors: Guan, Wei | Dong, Longlei | Zhou, Jinxiong

Article Type: Research Article

Abstract: With the engineering structures becoming more complicated, it is difficult to obtain complete measurement responses with limited sensors. Thus, carrying out the underdetermined modal identification will have practical engineering application values. In this paper, a new approach for underdetermined blind modal identification based on dictionary learning in the framework of compressed sensing (CS) is proposed. The principal idea is to estimate modal shapes using a clustering technique, and recover modal responses combing the estimated mode shapes matrix and the learned dictionary. The experiment results on a typical cantilever beam structure illustrate that the proposed method can perform accurate dynamic parameters …identification whether in underdetermined case or determined case. Show more

Keywords: Operational modal identification, dictionary learning, inverse problem

DOI: 10.3233/JAE-209315

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 129-136, 2020

Authors: Xia, Yubin | Liang, Dakai | Zheng, Guo | Wang, Jingling | Zeng, Jie

Article Type: Research Article

Abstract: Aiming at the irregularity of the fault characteristics of the helicopter main reducer planetary gear, a fault diagnosis method based on support vector data description (SVDD) is proposed. The working condition of the helicopter is complex and changeable, and the fault characteristics of the planetary gear also show irregularity with the change of working conditions. It is impossible to diagnose the fault by the regularity of a single fault feature; so a method of SVDD based on Gaussian kernel function is used. By connecting the energy characteristics and fault characteristics of the helicopter main reducer running state signal and performing …vector quantization, the planetary gear of the helicopter main reducer is characterized, and simultaneously couple the multi-channel information, which can accurately characterize the operational state of the planetary gear’s state. Show more

Keywords: Helicopter main reduction, kernel function, SVDD, fault diagnosis

DOI: 10.3233/JAE-209316

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 137-145, 2020

Authors: An, Junhao | Shi, Liwei | Han, Zhen | Tan, Di

Article Type: Research Article

Abstract: The switched reluctance starter generator (SRSG) without field winding and the doubly salient electromagnetic starter generator (DSESG) with field winding are compared in this paper. The influences of two arrangements of each variable winding and spacing variable winding for the performance of the starter generator were studied. Mathematical models of start mode and power generation mode were established respectively, and the influencing factors of starting torque and power generation phase voltage were derived. Next, the finite element simulation software was used to simulate the electromagnetic characteristics of machine. Finally, prototype experiment was made. The finite element simulation and prototype experiment …results proved that spacing excitation DSESG has a better prospect as automotive starter generator. Show more

Keywords: Switched reluctance starter generator (SRSG), doubly salient electromagnetic starter generator (DSESG), variable winding

DOI: 10.3233/JAE-209317

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 147-155, 2020

Authors: Ito, Koki | Kadomatsu, Takahisa | Obana, Kohei | Nakamura, Kenji

Article Type: Research Article

Abstract: This paper deals with development of in-wheel magnetic-geared motor for walking support machines. In a previous paper, a magnetic-geared motor for a walking support machine was prototyped. However, its efficiency was low, therefore improving the efficiency is necessary for practical use. This paper presents the improving efficiency of the magnetic-geared motor from the viewpoint of torque increasing and loss reducing by using a three-dimensional finite element method (3D-FEM). In addition, supporting method of pole-pieces and eddy current loss in housing were discussed. Furthermore, the proposed motor is prototyped. The experimental results show that its efficiency is 15% higher than the …previous motor. Finally, the walking support machine installed with two magnetic-geared motors is prototyped and demonstrated. Show more

Keywords: Magnetic-geared motor, walking support machines

DOI: 10.3233/JAE-209318

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 157-163, 2020

Authors: Deng, Dongge | Zhu, Mingzhi | Shu, Qiang | Wang, Baoxu | Yang, Fei

Article Type: Research Article

Abstract: It is necessary to develop a high homogeneous, low power consumption, high frequency and small-size shim coil for high precision and low-cost atomic spin gyroscope (ASG). To provide the shim coil, a multi-objective optimization design method is proposed. All structural parameters including the wire diameter are optimized. In addition to the homogeneity, the size of optimized coil, especially the axial position and winding number, is restricted to develop the small-size shim coil with low power consumption. The 0-1 linear programming is adopted in the optimal model to conveniently describe winding distributions. The branch and bound algorithm is used to solve …this model. Theoretical optimization results show that the homogeneity of the optimized shim coil is several orders of magnitudes better than the same-size solenoid. A simulation experiment is also conducted. Experimental results show that optimization results are verified, and power consumption of the optimized coil is about half of the solenoid when providing the same uniform magnetic field. This indicates that the proposed optimal method is feasible to develop shim coil for ASG. Show more

Keywords: Optimal design, 0-1 linear programming, shim coil

DOI: 10.3233/JAE-209319

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 64, no. 1-4, pp. 165-172, 2020