International Journal of Applied Electromagnetics and Mechanics - Volume Pre-press, issue Pre-press

Authors: Li, Ming | An, Yuejun | Zhang, Zhiheng | Deng, Wenyu | Wang, Guangyu | Qi, Lijun | Kong, Xiangling | Bi, Delong | Shi, Yong | Zhu, Sheng

Article Type: Research Article

Abstract: Canned induction motors fed by inverters are widely used in pharmaceutical, chemical, and nuclear fields. It is necessary to analyse the effect of time harmonic injected by the inverter on the performance of the canned induction motor. However, the existing researches are to consider the inverter and the motor separately, without analyzing the reverse effect of the induction motor as a nonlinear active load on the time harmonics of the inverter. Therefore, this paper establishes a field-circuit coupling analysis model of the canned induction motor considering the influence of load, and studies the effect of time harmonic current under different …load conditions on the electromagnetic field, eddy current loss, and temperature field of the canned induction motor. The paper first uses the analysis method to determine the relationship between the time harmonic voltage of the inverter and the time harmonic current of the motor. Then, the electromagnetic field distribution, eddy current loss, and temperature field distribution of the canned induction motor under different load conditions are calculated. Besides, the laws of time harmonic current on the electromagnetic field, can loss and motor temperature distribution are found. These research results can not only provide a meaningful reference for analysis of the canned induction motor but also provide methods for design optimization and multi-physical field modeling analysis of the canned induction motor. Show more

Keywords: Canned induction motor, time harmonic, can eddy current loss, field-circuit coupling analysis, temperature field

DOI: 10.3233/JAE-201552

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-17, 2021

Authors: Heya, Akira | Hirata, Katsuhiro

Article Type: Research Article

Abstract: Space recognition is a crucial issue for autonomous systems such as unmanned aerial vehicles, walking robots, and autonomous cars. These systems are necessary to obtain information using a camera while moving. However, reduction in recognition accuracy and system size increase has created problems. To solve these problems, we proposed the three-degree-of-freedom (DOF) actuator for image stabilization. This paper proposes a novel initial position estimation method and sensorless attitude estimation method for the three-DOF actuator to further downsize and reduce weight. The effectiveness of the proposed methods is verified by a magnetic field analysis, using a three-dimensional finite element method and …numerical simulations. Show more

Keywords: Multiple-degree-of-freedom actuator, three-degree-of-freedom actuator, electromagnetic actuator, sensorless position estimation, image stabilization

DOI: 10.3233/JAE-201537

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-15, 2021

Authors: Li, Xiaoning | Wang, Xiaoyuan | Gao, Peng | Gu, Yuxi

Article Type: Research Article

Abstract: The disc coreless permanent magnet synchronous machine (PMSM) has a special coreless structure. This kind of PMSM has very low inductance, which is referred to as the low-inductance PMSM(LIPMSM) in this paper. The LIPMSM offers many advantages to drive systems. However, the current fluctuates strongly when driven by general converters, which makes the LIPMSM difficult to be popularized into modern drive systems. To tackle the above problems, a converter with output inductance is used. The influences of the inductance on the performance of the LIPMSM system are analysed, including current fluctuations, the maximum speed without flux weakening and the current …response time. Based on above analyses, a method of obtaining the optimal inductance is proposed to obtain the optimal inductance simply and efficiently. The method has been verified through simulations and experiments. The system cannot work due to the huge current fluctuations when driven by the general converter. By using the converter with the optimal inductance, the current fluctuations have been reduced to 2 A. The experimental LIPMSM can reach 11000 rpm with very short response time of the current. Therefore, the LIPMSM system performance can been improved significantly and meet the requirements by using the converter with the optimal inductance. Show more

Keywords: Disc coreless permanent magnet synchronous machine (DCPMSM), low inductance, current fluctuations, maximum speed, optimal inductance

DOI: 10.3233/JAE-201605

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-18, 2021

Authors: Halim, M.F.M.A. | Sulaiman, E. | Othman, R.N.F.K.R.

Article Type: Research Article

Abstract: The inclusion of high energy density permanent magnet (PM) in MG contributes to the high eddy current loss in magnetic gear and reduces its efficiency. There was limited research done that focused on gear efficiency behavior over a broader range of speed and in different gear ratios. In this paper, the function of gear efficiency concerning gear ratio and rotational speed is proposed. Torque and eddy current loss data were obtained through transient magnetic analysis using finite element software at several rotational ranges and gear ratios. The analytical approach through mathematical substitution was discussed to confirm the finding in the …simulation. The result showed that the gear efficiency decreases as the speed increases. Nonetheless, the gear efficiency revealed improvement in efficiency as the gear ratio increases. Finally, gear efficiency behavior was modeled using the curve fitting method. Subsequently, based on the correlation study, an equation was proposed, yielding a 1% error compared to the new simulated data. With this proposed method and equation, the analysis and estimation of gear efficiency behavior over wider speed and gear ratios are simplified, thus reducing the need to perform simulation over different speeds and gear ratios. Show more

Keywords: Magnetic gear, machine design, gear efficiency, eddy current loss, curve fitting modeling

DOI: 10.3233/JAE-201576

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-19, 2021

Authors: Fang, Hong Wei | Wang, Yu

Article Type: Research Article

Abstract: The magnetic gear integrated permanent magnet synchronous generator (MG-PMSG) can reduce the acoustic noise and mechanical loss, which are caused by the mechanical gear box. It also has the merits of increasing efficiency and reducing system volume when it is used for wave energy conversion system. In this paper, an improved bat algorithm (BA) based on velocity weighting factor is proposed. The improved BA is applied for the optimization design of permanent magnet (PM) to reduce the cogging torque of MG-PMSG. The numerical model is constructed by response surface methodology (RSM). The influences of key pole shape parameters on cogging …torque were investigated, including the eccentric distance, the pole-arc coefficient and the permanent magnet thickness. A global optimization design is then carried out by using the improved BA, so that the magnet dimensions corresponding to the optimal cogging torque are obtained. Finally, the performances of the MG-PMSG with the optimized permanent magnet are analyzed by finite element method. Results show that cogging torque, steady torque ripple and back electromotive force (EMF) waveform distortion of the optimized MG-PMSG are reduced. Show more

Keywords: Magnetic gear, wave energy conversion, cogging torque, bat algorithm, response surface methodology

DOI: 10.3233/JAE-201615

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-18, 2021

Authors: Lin, James | Harada, Akinori | Oka, Koichi

Article Type: Research Article

Abstract: This papers discusses a method of magnetic levitation which allows a levitated platform to remain both level and zero-power under arbitrary eccentric loading conditions. A hardware system is proposed and developed which laterally displaces hybrid electromagnets (HEMs) to counteract the moments caused by eccentric loads. In this system, the displaced HEMs are the same HEMs which are used for the levitation of the platform. A mathematical formulation is provided to explain the control methodology, and data from successful experimental trials of the developed hardware is discussed.

Keywords: Zero-power levitation, magnetic levitation, tip-tilt control

DOI: 10.3233/JAE-200011

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-12, 2021

Authors: Liu, Qing | Zhang, Shiping | Li, Yuanyuan | Lei, Gang | Wang, Li

Article Type: Review Article

Abstract: This paper presents a state-of-the-art survey on the development of the hybrid gas-magnetic bearing (HGMB) technology. HGMBs are proposed to complement the advantages of gas bearings and magnetic bearings for enhanced bearing performance. Nevertheless, there are a number of inherent challenges in their designs, analyses, and performance characteristics that must be taken into account for proper functionality and reliable operation. For this purpose, substantial results in theory, numerical simulations, and experiments concerning rotor dynamics, mechanical structures, control systems, and operation modes are discussed to help further investigation and implementation of HGMBs. In addition, future developments of HGMBs in industries and …remaining challenges are discussed. Show more

Keywords: Hybrid gas-magnetic bearings (HGMBs), rotor dynamics, bearing configuration, hybrid mode

DOI: 10.3233/JAE-201579

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-26, 2021

Authors: Yang, Guohui | Zhang, Chengning | Zhang, Shuo

Article Type: Research Article

Abstract: Permanent magnet synchronous machines (PMSMs) are widely used owing to high power density, high efficiency, etc. Core losses account for a significant component of the total loss in PMSMs beside winding losses. Therefore, it is necessary to consider core losses when designing PMSMs according to actual research applications. In this paper, taking four typical rotor structures (surface-mounted, embedded, “—” shape, “V” shape) as examples, an analysis method is proposed to predict the influence of different rotor structures on core loss of PMSMs. In the case of the same stator and winding structures, due to the influence of the rotor structure …on the magnetic circuit, the corresponding variation law of the magnetic field in the stator core is studied. This method analyzes the radial and tangential components of magnetic flux density vector of the 4 representative points (stator tooth tip, middle tooth and yoke part), and then evaluates the entire core loss through finite element analysis results. In order to verify the method, a prototype was manufactured. The experimental results show good performance of the proposed method of this paper. It provides reference for selecting the appropriate rotor structure and designing the corresponding PMSM according to different specification. Show more

Keywords: Permanent magnet synchronous machines, rotor structure, core loss, magnetic field distribution, magnetic flux density

DOI: 10.3233/JAE-201569

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-14, 2021

Authors: Cheng, Yuhua | Liu, Chunwu | Wang, Minghao | Wang, Gaofeng | Ghovanloo, Maysam | Li, Wenjun

Article Type: Research Article

Abstract: Recent progress on human brain science requires developing advanced neural recording system to capture the activity of large neural populations accurately, across a large area of the brain, and over extended periods. Recently proposed distributed neural recording systems with numerous implanted devices require reliably energizing them wirelessly. Random distribution of these mm-sized implants and brain motion place them at different positions and orientations with respect to the power transmitter. Therefore, traditional wireless power transfer techniques fall short of reaching sufficient power for all implants simultaneously, rendering some implants nonfunctional. In this paper, a three-layer power transmitting array with three-phase coil …excitation current is introduced, which is capable of producing omnidirectional and homogeneous magnetic field across the volume where the Rx coils are located. The individual coil dimensions in the array is optimized to improve the worst-case scenario in terms of homogeneity, which is further verified by the measurements using a scaled-up prototype system. The measurement results show that the minimum received voltages is improved from 0.34 V for 10-mm side-length hexagonal transmitting coil array to 0.83 V for the optimal case, i.e., 35 mm side-length hexagonal transmitting coil array. Show more

Keywords: Omnidirectional, distributed, wireless power transfer, three-phase three-layer coil array, coil radius, optimization

DOI: 10.3233/JAE-201582

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

Authors: Wu, Tong | Yu, Guoliang | Pang, Jiarui | Wang, Can | Yang, Han | Qiu, Yang | Zhang, Yi | Zhu, Mingmin | Zhou, Hao-Miao

Article Type: Research Article

Abstract: This work presents an easy way to improve the low-frequency properties in a small-size LTE/WWAN smartphone antenna by just loading a soft magnetic ferrite film on the strong radiation area. The base non-magnetic antenna, which only takes up an 11 mm × 30 mm no-ground space, can achieve hexa-band operation covering 822–914/1710–3244 MHz bands by co-designing a meandering strip and a T-shaped feeding strip. With loading a small-size ferrite film (2 mm × 15 mm) at the strong radiation strip, the frequencies can be shifted to cover the range of 692–1191/1698–3020 MHz, which shows a fully covering of octa-band operation, especially including the best long-term-evolution band, …LTE700, without enlarging the size of base antenna. In addition, the radiation characteristics of the magnetic antenna with ferrite film loading show a limited change at upper bands (1710–2690 MHz) but an acceptable level at lower bands (698–960 MHz). Both experimental and simulated results have been taken out and shown the consistent tendency. This optimization method of low-frequency properties by introducing a commercial ferrite film on the antenna has provided a simple and convenient way to solve the frequency deviation in the practical smartphone applications. Show more

Keywords: Multiband antenna, ferrite loading, frequency modulation, LTE700 band

DOI: 10.3233/JAE-201599

Citation: International Journal of Applied Electromagnetics and Mechanics, vol. Pre-press, no. Pre-press, pp. 1-10, 2020