International Journal of Applied Electromagnetics and Mechanics - Volume 63, issue 1

Authors: Zuki, Nor Aishah Md | Othman, Raja Nor Firdaus Kashfi Raja | Ahmad, Suhairi Rizuan Che | Shukor, Fairul Azhar Abdul

Article Type: Research Article

Abstract: This paper discusses the constants in various types Double Stator Permanent Magnet Brushless DC Motor (DSPM BLDC). Hybrid or electrical vehicles requires fast response motor that are capable of reacting as soon as possible. Thus, the motor should have a faster time response with lower electrical time constant, T e and mechanical time constant, T m . However, there are few literatures that reported the time response for a double stator topology. The time response relates to various constant parameters of the motor. It is known that double stator has high torque density which can be implemented …for other applications in the future. For this research, various DSPM BLDC motors had been redeveloped. Finite Element Method (FEM) was used to simulate the characteristics of DSPM BLDC motor that considered the presence of the analytically calculated T e and T m . The results show that the Double Stator Slotted Rotor Permanent Magnet Brushless DC Motor (DSPM-SR) had good performance such as highest back emf, torque and good time response. A prototype of DSPM-SR had been manufactured and measured. The percentage differences between Analytical-FEM and Analytical-Mea for T e and T m were 4.2% and 9.1%, respectively. As a conclusion, this paper reveals the constants that could affect the performance of double stator topology. Show more

Keywords: Double stator, electrical time constant, mechanical time constant

DOI: 10.3233/JAE-190126

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 1, pp. 1-17, 2020

Authors: Bai, Peigen | Shi, Pengpeng | Zhao, Yingsong | Chen, Hong-En | Xie, Shejuan | Chen, Zhenmao

Article Type: Research Article

Abstract: As one typical material of nuclear power plant structure, austenitic stainless steel (SS) is often accompanied by residual stress and plastic deformation during their manufacture and application, which may affect the structure service safety. In this paper, the effects of the composite state of residual stress and plastic deformation on the pulsed eddy current testing (PECT) signals of SS are studied theoretically and experimentally. By considering the electromagnetic properties in the composite state, the PECT theory is established for the 304 SS in the composite state. The numerical simulation is completed using the reduced vector potential method and the verification …experiment is also carried out. The comparison between simulation and experimental results shows that the peak value of the PECT signal increases with the increase of plastic deformation or residual stress. This means that if the residual stress is not considered in the composite state, the effectiveness of the PECT method for evaluating plastic deformation may be seriously affected. Show more

Keywords: 304 austenitic stainless steel, composite state, plastic deformation, residual stress, pulsed eddy current testing

DOI: 10.3233/JAE-190124

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 1, pp. 19-30, 2020

Authors: Yang, Xiaolong | Sun, Peng | Hao, Fuxiang

Article Type: Research Article

Abstract: In order to improve the pressure capability of the ferrofluid seal under the condition of large sealing gap, a diverging stepped ferrofluid seal with a large gap and two magnetic sources was designed. The magnetic field distributions in the gap of the ferrofluid seal were calculated by finite element method. The effects of the pole teeth number, the height of the pole teeth and the sealing gap on the pressure capabilities of the diverging stepped ferrofluid seal are studied and compared with ordinary ferrofluid seal. The results show that the change of the radial pole teeth number has little effect …on the pressure capability of the stepped ferrofluid seal. The pressure capability of stepped ferrofluid seal decreases with the increase of the axial pole teeth number. The pressure capability of the stepped ferrofluid seals reach maximum when the radial and axial pole teeth height is 0.6 mm. The pressure capability of stepped ferrofluid seal decreases as the radial sealing gap increases. The pressure capability of stepped ferrofluid seal decreases firstly and then increases with the increase of the axial sealing gap. Comparing with ordinary ferrofluid seal, the stepped ferrofluid seal has better pressure capability. Show more

Keywords: Large gap, diverging, ferrofluid, seal, numerical simulation

DOI: 10.3233/JAE-190127

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 1, pp. 31-44, 2020

Authors: Qiu, Li | Deng, Kui | Li, Yantao | Tian, Xi | Xiong, Qi | Chang, Peng | Su, Pan | Huang, Lantao

Article Type: Research Article

Abstract: The long-life driving coil is the prerequisite for electromagnetic forming industrial application. Up to date, the temperature rise is one of the major factors that restrain its working life. For the purpose of reducing the temperature rise of the driving coil, this paper proposes a new coupled cooling method, in which an extra cooling coil is placed on one side of the driving coil, then the Joule heating is coupledly transferred by delaying the breakover control of the driving coil. To achieve this purpose, a finite element simulation model of Electrical Circuit- Electromagnetic Field-Thermal Coupling in the plates setting of …the electromagnetic forming is established, after which the influence rules of coil turns, cross-sectional area and materials of cooling coil on temperature rise are analyzed. Then, this paper also establishes a coupled cooling circuit model, in which the influence of cooling coil structure parameters on the Joule heating of driving coil is analyzed. Furthermore, Simulation results show that effective Joule heating transfer can be reached by the best optimization scheme of the cooling driving coil. Specifically, the average temperature rise reduces by 13 degrees, namely 22.8% by using this new method. Show more

Keywords: Electromagnetic forming, driving coil, temperature rise, Joule heating

DOI: 10.3233/JAE-190062

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 1, pp. 45-58, 2020

Authors: Sun, Feng | Zhou, Jin | Wu, Huachun | Ueno, Satoshi

Article Type: Editorial

DOI: 10.3233/JAE-200024

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 1, pp. 61-61, 2020

Authors: Gao, Tian-yu | Zhou, Jin | Zheng, Ya-wei | Xu, Yuanping

Article Type: Research Article

Abstract: The high speed magnetic levitation turbine generator used in Organic Rankine cycle (ORC) system will produce wind friction loss due to the high density of work environment and high eddy current loss in the part of permanent magnet (PM) rotor, which obviously effect the performance and stability of PM. In order to minimize the loss of PM rotor, this paper presented a comprehensive optimization design for the stator and rotor structure of turbine-generator. Firstly, the physical performances coupled with design variables, such as loss, generator power, rotor dynamic, strength and axial force of AMB were analyzed, mainly analyzed the structural …variables coupled with design variables due to the effects of single constraint and the decoupling methods, which eliminated irrelevant variables in the final optimization. Neural network was used to establish agent models for each physical performance and brought into comprehensive optimization process of total PM rotor, which greatly improved the efficiency of optimization. The result of optimization is that the total rotor loss decreased 15.3% and all of other physical performance meet the requirements. Show more

Keywords: turbine generator, rotor loss, coupled structure variable, agent model, comprehensive optimization

DOI: 10.3233/JAE-209001

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 1, pp. 63-79, 2020

Authors: Yao, Yichen | Ma, Yanhui | Su, Yixin | Su, Jiageng | Yu, Suyuan

Article Type: Research Article

Abstract: Active magnetic bearings (AMBs) have been extensively used in the vibration reduction of rotating machinery because of active control technology. In fact, the mechanical characteristics of the magnetic bearing are also important for vibration isolation as the main vibration transmission path. In this paper, a finite element (FE) model of a 30 kW magnetic suspended prototype pump suspended by 5-DOF AMBs was established to simulate the vibration transmission of the system. Two external excitations, unbalanced force of the rotor and hydrodynamic force acted on the impeller were considered. Based on the model, several main factors that affect the vibration transmission of …magnetic suspended pump were investigated, such as mass distribution of the system, the equivalent stiffness of the AMBs and the rubber vibration isolators were investigated. Based on the above work, a new magnetic suspended pump was developed. The results of simulation and experiments show that the new design can effectively reduce the vibration transmission of the system. Show more

Keywords: Active magnetic bearings, magnetic suspended pump, equivalent stiffness, vibration isolation, model

DOI: 10.3233/JAE-209002

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 1, pp. 81-103, 2020

Authors: Gloess, Rainer | Goos, Alexander

Article Type: Research Article

Abstract: This article describes design rules for the magnetic constrains, the sensors and the controller for planar and linear stages for a scanning application with a resolution at nanometer level. The main advantage of magnetic levitated systems in relation to “standard” air bearing systems or mechanical guided systems is that they provide perfect cleanroom conditions. The other advantage is that there is no influence by inaccurate guiding. Because of closed-loop control in all 6 DOFs, there is also stationary accuracy and the highest repetition, which only depends on the resolution of the hysteresis-free sensor system. Most of industrial applications require free …access to the movable top plate, requiring that all types of sensors should be placed below the platform. The main challenge for pushing the technology into “industry nanometer level” is how to get it to work with low-price distance sensors at nanometer resolution and a motion range of millimeters. A key point is the design of the controller structure for fast access of the actuators and many sensors, in case of the new planar system there are 24 coil pairs and 23 sensors working in the servo loop at 20 kHz. Show more

Keywords: Magnetic levitation, incremental optical sensors, Halbach array, field mapping

DOI: 10.3233/JAE-209003

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 1, pp. 105-117, 2020

Authors: Rodriguez, Elkin | Costa, Felipe | Stephan, Richard

Article Type: Research Article

Abstract: Magnetic bearings offer the best solution to mitigate mechanical friction. A variety of geometries and new materials are being studied. The advantage of using a passive bearing system, like the Superconducting Magnetic Bearing (SMB), is that it offers low friction without the need of feedback control, increasing the reliability and decreasing the energy consumption. SMB devices work at very low temperatures that are often achieved with the use of Liquid Nitrogen inside of cryostats. This paper describes the design and experimental tests of a SMB passive magnetic bearing system. An innovative design of a cryostat that uses YBCO bulks …refrigerated by a cryocooler is presented. With this setup, it is possible to perform vibration tests in several temperatures from 45K up to 77 K to find the resonance speeds at each temperature. Pieces of equipment that use SMB can benefit from reducing the working temperature. The mechanical response of the pinning force may vary with the choice of refrigeration used. To perform those tests, units of accelerometers are installed on the rotor body and displacement sensors monitor the behavior as function of the rotor speed. This improved magnetic bearing will be used in energy storage systems to reduce the instability of the rotor used in flywheel applications by changing the refrigeration temperature of the superconductor. This investigation can lead to an improvement of the levitation force, the levitation gap and damping. Show more

Keywords: Superconducting magnetic bearing, cryocooler, YBCO bulks, natural frequency

DOI: 10.3233/JAE-209004

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 1, pp. 119-131, 2020

Authors: Ahmed, Firdausa | Kalita, Karuna

Article Type: Research Article

Abstract: Due to the salient features of stator and rotor in Switched Reluctance Motor the air-gap of the machine does not remain uniform during its motoring operation. This innate characteristic is responsible in producing considerable amount of radial force in the motor. However, on the other hand eccentricity or radial displacement of the rotor is another key cause to this production of radial force. In this paper a single winding structure called bridged configured winding in a 12/8 BSRM is delineated which can be used to deploy the radial displacement by injecting controlled current within the same winding. Initially a mathematical …model of the motor is developed and verified using finite element modeling. The developed model is analyzed by integrating a voltage source asymmetric converter for motoring operation and separate asymmetric converters for injecting currents into the winding to control the radial displacement of the motor. Investigations of radial forces at various rotational positions and controllability of radial displacement are carried out using a simple PID controller system. Show more

Keywords: Bearingless Switched Reluctance Motor (BSRM), Bridge Configured Winding (BCW), Finite element model, radial force, radial displacement, Switched Reluctance Motor (SRM)

DOI: 10.3233/JAE-209005

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 1, pp. 133-152, 2020

Authors: Pilat, Adam Krzysztof

Article Type: Research Article

Abstract: This elaboration presents an initial study of the elliptic rotor driven by the active magnetic bearing consisting of 6 poles. The analysis was realized using the virtual prototype - a numerical model of device. The model was realized with support of COMSOL Multiphysics software. The proposed geometry, selected materials and configuration were used to perform analysis if the electromagnetic forces and torque are available to drive the rotor of the elliptic shape. The control study is given to obtain a rotational motion for a fixed rotor placement at the bearing center. Numerical simulations were realized to demonstrate features and limitations …of the proposed solution. The solution in a form of Virtual Prototype allows to eliminate prototyping costs and extends the knowledge and dependencies of complex mechatronic systems like active magnetic levitation technology based ones. Show more

Keywords: Active magnetic bearing, elliptic rotor, control, virtual prototype

DOI: 10.3233/JAE-209006

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 1, pp. 153-170, 2020

Authors: Zhao, Xingqian | Shuai, Changgeng | Xu, Wei | Chen, Demin | Hu, Zechao

Article Type: Research Article

Abstract: To isolate the vibration transmitted from the propeller to the vessel’s hull, the main engine, the shaft together with the bearings are proposed to be installed on a large-scale isolation system. Permanent magnetic thrust bearing (PMTB) is applied to further reduce the vibration transmission. The Coulombian model is adopted to calculate the force and stiffness, which determine the application feasibility of the PMTB in vessels. Explicit computations are presented for stacked PMTB. The calculation result is compared with that obtained by finite element method (FEM) and experimentally tested. It is revealed that the Coulombian model is accurate enough and more …economic than the FEM, which make it advantageous to the structure design and parameter optimization of PMTB. In the influence study by Coulombian model, it is found that the airgap width can exponentially change the maximum axial magnetic force and stiffness; the radial width is not a sensitive factor for both force and stiffness; the axial length should be 4/5 of the radial thickness to obtain the largest force and decent stiffness. Show more

Keywords: Permanent magnetic thrust bearing, Coulombian model, finite element method, parameter optimization, magnetic force and stiffness

DOI: 10.3233/JAE-209007

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 1, pp. 171-186, 2020

Authors: Zhou, Ran | Yan, Mingyin | Guo, Yongquan | Jin, Junjie | Sun, Feng | Zhang, Xiaoyou | Oka, Koichi

Article Type: Research Article

Abstract: A proposed permanent magnetic suspension using flux path control mainly consists of a disk permanent magnet, two pairs of F-shape core and a servo motor, and controls the suspension force by changing flux path, and the load on the motor shaft is eliminated due to its symmetric offset optimal structure to make the motor reach zero power output. In order to verify the robustness of the system under external disturbances, this paper investigates and analyzes its suspension characteristics by using the simulation and the experiment. Firstly, the structure and the suspension principle of the system are introduced. Secondly, the dynamic …model is established, two kinds of controllers of the system are designed with the classic PD control method. Finally, the suspension characteristics of the system are studied through the simulation and the experiment. In the process of the experiment, the system is subjected to small step disturbance or small force disturbance, under the action of the real-time control system. The experimental results show that when the system is subjected to small step disturbance or small force disturbance in the process of the suspension, the suspended object will reach a new equilibrium position under the action of the real-time control system. Show more

Keywords: Permanent magnetic suspension, flux path control, zero power, PD control

DOI: 10.3233/JAE-209008

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. 63, no. 1, pp. 187-198, 2020