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1
Pan, Xue Hai. "Constant Voltage Analysis of Permanent Magnet Generator." Applied Mechanics and Materials 63-64 (June 2011): 970–73. http://dx.doi.org/10.4028/www.scientific.net/amm.63-64.970.
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This paper discusses and analysis the constant voltage of vehicle applied permanent magnet generator. The permanent magnet can produce magnetic field in an air gap with no excitation winding and no dissipation of electric power, when the rotor turns, the magnet field turns, the generator generates electricity, with the permanent magnet material of high remnant magnetic induction and the optimized design of the generator, the output voltage is improved when the engine at low speed. We develop a single-phase double half-wave electric regulator is to ensure the stability of the output voltage and can direct output direct current.
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Radovinsky, Alexey L., Leslie Bromberg, Joseph V. Minervini, et al. "Constant Field Toroidal SMES Magnet." IEEE Transactions on Applied Superconductivity 26, no. 3 (2016): 1–4. http://dx.doi.org/10.1109/tasc.2015.2509246.
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Xin, Yuanxu, and Xudong Wang. "Time constant analysis of micromotors for virtual reality helmets." Journal of Physics: Conference Series 2378, no. 1 (2022): 012072. http://dx.doi.org/10.1088/1742-6596/2378/1/012072.
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Abstract This paper focuses on the study of an ultra-micro permanent magnet stepper motor with automatic adjustment of interpupillary distance for VR helmets. To precisely adjust the rotation of the motor, the control requirements for the motor are very important, which also makes the time constant of the micro permanent magnet stepper motor of great significance. Starting from the voltage, torque balance equations and thermal balance equations, the paper analyzes and compares the electrical time constant, mechanical time constant, electromechanical time constant and thermal time constant of the micro permanent magnet claw-pole stepper motor in basic theory. Different specifications of micro permanent magnet claw-pole stepper motors were used to obtain some relationships between time constant and motor performance, which provided reference for the design and control research of micro permanent-magnet claw-pole stepper motors.
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Darmawan, Isra' Nuur, Asroful Abidin, Muhammad Afif Makruf Ramadhan, and Achmad Rizki. "Effect of Magnet Thickness and Width Variation on Back EMF of 18-Slot 16-Pole Permanent Magnet Synchronous Generator." Applied Engineering, Innovation, and Technology 1, no. 1 (2024): 39–46. http://dx.doi.org/10.62777/aeit.v1i1.11.
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Permanent magnet synchronous generators (PMSG) converts mechanical energy into electrical energy through electromagnetic induction, with the excitation field generated by permanent magnets instead of coils. This paper investigates the effects of varying magnet thickness and width on the back electromotive force (back EMF) of an 18-slot 16-pole PMSG using finite element method (FEM) simulations. The aim is to understand how these geometric parameters influence the back EMF values, which are crucial for generator design and performance evaluation. The FEM modelling results show that a 5 mm magnet thickness yields the highest back EMF value of 130.47 V, while a 15 mm magnet width produces a back EMF of 100.65 V. Additionally, the back EMF constant (KE) is maximized at 0.79 V·s/rad for a 5 mm magnet thickness and 0.55 V·s/rad for a 15 mm magnet width. These findings provide insights into optimising magnet dimensions for improving the efficiency and output characteristics of PMSGs in various applications.
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Son, Rak-Won, and Ju Lee. "Alternative Surface-Mounted Permanent Magnet Topology for Reducing Voltage and Torque Harmonics in Shaft Generators." Energies 16, no. 12 (2023): 4649. http://dx.doi.org/10.3390/en16124649.
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Traditional diesel generators on a merchant ship, composed of a wound rotor synchronous generator and a four-stroke diesel engine, supply electrical power for various loads. Recently, shaft generators for merchant ships have been increasingly replacing diesel generators to reduce CO2 emissions through fuel efficiency improvement. In particular, permanent magnet synchronous generators have replaced induction generators due to their high-efficiency characteristics at light loads. The surface-mounted permanent magnet rotor can be a suitable topology owing to the relatively short constant power range. This generator can also operate as a motor according to the propulsion mode, so minimizing the harmonics of the induced voltage with the torque pulsation being essential. This paper proposes an alternative surface permanent magnet topology. Three magnets comprise one pole, with one bread-loaf magnet and two rectangular magnets. It helps to simplify the magnetization and assembly of the rotor because of the flat bottom shape of the magnet. Due to the low remanence of two rectangular magnets at the pole edge, this rotor structure effectively makes the air-gap magnetic flux density sinusoidal with production costs reduced. The step-skew suppresses higher-order harmonics. The total harmonic distortion comparison of the two-dimensional finite element analysis and the no-load test result shows under 6% difference from the interior permanent magnet prototype machine. A comparison of harmonic characteristics with other rotors shows that the proposed modular pole has sufficient competitiveness compared to the tapered bread-loaf type. It can be applied as a substitute for the tapered bread-loaf magnet in direct-drive ship propulsion systems and is expected to shorten the manufacturing process and time.
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Akinloye, B. O., and G. O. Uzedhe. "Controllable single-phase smart synchronous generator towards solar-pneumatic power generation." Nigerian Journal of Technology 39, no. 2 (2020): 493–99. http://dx.doi.org/10.4314/njt.v39i2.19.
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This paper presents the development of a controllable single-phase surface-mounted permanent magnet synchronous generator (SPSMPMSG) for low speed applications. Presently, the world is faced with degrading climatic conditions that may be worsen if energy need is met by fossil fuel and other conventional means of generation. On the other hand, renewable alternatives are not always of constant speed, and are usually not high enough to turn conventional alternators. There is therefore a need for the development of alternators that can generate electricity from low speed sources. The development of permanent magnet from rare-earth materials has revolutionized the electrical generator development. Permanent magnet machines are characterized by high torque, low noise, high efficiency and high power factor. The use of these magnets also made it possible to add computer based controllability making the generator a smart machine. This paper presents a CAD design of smart generator at an input speed of 500rpm to a turbine to produce a constant output of 220V. Simulation and physical test results produce an output of 220V ± 1% and give a clear indication that low speed renewable energy sources can produce usable electrical power.
 Keywords: Smart generator, Permanent magnet generator, stator, rotor, Computer-aided design.
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Bolyukh, V. F., G. M. Suchkov, R. P. Mygushchenko, and M. E. Kalnytskyi. "Determination of parameters of an autonomous source of a constant magnetic field for a portable electromagnetic-acoustic transducer." Electrical Engineering & Electromechanics, no. 4 (July 2, 2025): 72–79. https://doi.org/10.20998/2074-272x.2025.4.09.
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Purpose. Determination of rational parameters of an autonomous source of constant magnetic field, ensuring the efficiency of using portable electromagnetic-acoustic transducers (EMAT) for diagnostics of remote ferromagnetic objects. Methodology. An analysis of the parameters of an autonomous magnetic field source consisting of a permanent magnet and a ferromagnetic screen magnetizing a ferromagnetic object with a flat surface, providing a central magnetic field along the magnet axis above 0.3 T, was carried out. Results. The results of experimental studies on a sample of an autonomous source, which contained 6 sections of a permanent magnet made of NeFeB ceramics with dimensions of 50´50´10 mm3, correspond to the results of calculating the magnetic field on the surface of a ferromagnetic sample with an error of up to 9 %. Experimental studies were carried out for EMAT with two magnetic field sources containing rectangular permanent magnets of the same height but different widths. Novelty. It has been established that in order to select rational parameters of an autonomous source of magnetic field, it is necessary to use an integral criterion that takes into account the magnetic field in the surface layer of a ferromagnetic object, the magnetic scattering field, the volume of a permanent magnet, which determines the mass and size indicators and cost of the source, and the force of attraction to the ferromagnetic object. Practical value. For portable EMAT, increasing the magnetic field in a remote ferromagnetic object either by increasing the volume of a permanent magnet or by decreasing the air gap between the magnetic field source and the ferromagnetic object provides increased EMAT efficiency by increasing the ratio of the amplitude of the received ultrasonic bottom pulses to the noise amplitude. References 27, figures 14.
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Heydari, M. B., M. Asgari, L. Gharib, A. Keshtkar, N. Jafari, and M. Zolfaghari. "A Novel Augmented Railgun Using Permanent Magnets." Advanced Electromagnetics 8, no. 1 (2019): 99–105. http://dx.doi.org/10.7716/aem.v8i1.961.
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A novel augmented railgun using a permanent magnet is proposed in this paper. The effects of the permanent magnet on the magnetic field and distribution of current density have been investigated. High current densities in the railguns can lead to high local temperature and erosion of the rails. Therefore, the current densities in the rails and armature should be decreased without the reduction of the Lorentz force which is required for acceleration. For this purpose, augmentation of the magnetic field can be used as an effective method. The Finite Element Method (FEM) simulations have been applied in this article to analyze the performance of the railgun in the presence of the magnets. Two augmented railgun structures have been introduced to produce a constant external magnetic field. For both structures, augmented railgun characteristics are studied in comparison to the railgun without the augmentation. The results show that augmentation with permanent magnet increases railgun efficiency, especially in low current railguns. For pulse current source I=30kA, Lorentz force of the augmented railgun with four magnets is 2.02 times greater than the conventional railgun.
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Armando, Eric, Sandro Rubino, Aldo Boglietti, Enrico Carpaneto, Salvatore Musumeci, and Daniele Martinello. "A Test Procedure to Evaluate Magnets Thermal Time Constant of Permanent Magnet Machines." IEEE Transactions on Industry Applications 57, no. 5 (2021): 4694–706. http://dx.doi.org/10.1109/tia.2021.3090745.
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SUMMERS, D. J. "MUON ACCELERATION USING FIXED FIELD, ALTERNATING GRADIENT (FFAG) RINGS." International Journal of Modern Physics A 20, no. 16 (2005): 3861–64. http://dx.doi.org/10.1142/s0217751x05027813.
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Given their 2.2 μs lifetime, muons must be accelerated fairly rapidly for a neutrino factory or muon collider. Muon bunches tend to be large. Progress in fixed field, alternating gradient (FFAG) lattices to meet these challenges are reviewed. FFAG magnets are naturally wide; low momentum muons move from the low field side of a gradient magnet to the high field side as they gain energy. This can be exploited to do double duty and allow a large beam admittance without unduly increasing the magnetic field volume. If the amount of RF must be reduced to optimize cost, an FFAG ring can accommodate extra orbits. I describe scaling FFAGs in which the bends in each magnet are energy independent and non-scaling FFAGs in which the bends in each magnet do vary with muon energy. In all FFAG designs the sum of the bends in groups of magnets are constant; otherwise orbits would not close. Ways of keeping the accelerating beam in phase with the RF are described. Finally, a 1 MeV proof of principle scaling FFAG has been built at KEK and began accelerating protons in June 2000 with a 1 kHz repetition rate.
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Mohammad, Ummu Atiqah Khairiyah B., A. K. M. Nurul Amin, Mohd Redzuan Bin Abdul Rappat, and Muammer D. Arif. "Effect of Application of a Combination of Magnets on Chatter Amplitude Reduction in Turning of Stainless Steel AISI 304." Applied Mechanics and Materials 393 (September 2013): 189–93. http://dx.doi.org/10.4028/www.scientific.net/amm.393.189.
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This paper presents the results of experimental investigations of vibration analysis conducted on Engine Lathe Harrison M390 using variable cutting speed, feed rate and depth of cut at constant tool overhang of 120mm as the machining parameters ascertain the effectiveness of TiN coated carbide insert in turning of hardened steel AISI 304. The experiments were designed based on the Response Surface Methodology (RSM) approach using DESIGN EXPERT (DOE) software to enhance statistical model using the capabilities of RSM to compare the effectiveness of application of a combination of a bottom and a side magnet with respect to the tool holder in terms of reduction of chatter amplitude. The experiments were performed under application of magnetic field from two permanent magnets with magnetic strength of 1200 Gauss each with one located at the bottom and the other at the side of the cutting tool with distance 1cm from the tool. The dimension of the bottom magnet was 25 x 25 x 50mm and that of the side magnet was 87 x 50 x 17mm. The vibration amplitude data for the two conditions were compared to identify the influence of magnet on chatter reduction. The results reveal that a maximum of 87% and an average of 50% reduction of chatter acceleration amplitude were achieved with the said arrangement of the magnets. Furthermore, empirical mathematical model of maximum chatter amplitude was developed for machining with magnet application to predict the cutting parameters with the lowest value of chatter amplitude and maximum material removal rate.
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Nor, Aishah Md Zuki, Nor Firdaus Kashfi Raja Othman Raja, Azhar Abdul Shukor Fairul, and Rizuan Che Ahmad Suhairi. "Analysis of linear motor with symmetrical EMF vector for household elevator application." International Journal of Power Electronics and Drive Systems 14, no. 01 (2023): 51~59. https://doi.org/10.5281/zenodo.7514480.
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Linear permanent magnet synchronous motor (LPMSM) has emerged as a viable alternative to other linear motors for higher thrust lifting action. With the advancement of permanent magnets, LPMSM could contribute to energy conversation while also being suitable for applications requiring higher thrust, such as elevator. However, because the existing LPMSM is larger in size, it requires more space to be equipped with a household elevator. To address this issue, a new LPMSM with increased thrust capability has been proposed. The new LPMSM is modelled and analyzed in terms of back EMF and force in this paper. For improved performance, a symmetrical EMF vector is applied to the new LPMSM. In terms of back EMF and force, 4 LPMSM models are studied. According to the results, 6 slot 4 pole has the highest back EMF when compared to the others. As a suitable combination of slot and pole, a symmetrical EMF vector is the suggested LPMSM at the end of this research.
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Karthick, K., S. Ravivarman, Ravi Samikannu, K. Vinoth, and Bashyam Sasikumar. "Analysis of the Impact of Magnetic Materials on Cogging Torque in Brushless DC Motor." Advances in Materials Science and Engineering 2021 (December 17, 2021): 1–10. http://dx.doi.org/10.1155/2021/5954967.
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The cogging torque is the most significant issue in permanent magnet applications, since it has a negative impact on machine performance. In this article, the impact of magnetic materials on cogging torque is analyzed on brushless DC motors (BLDC). The effect of neodymium magnets (NdFeB), compression molded magnet, and samarium cobalt (SmCo) magnet on the cogging torque is analyzed to the BLDC motor designed for hybrid electric vehicle traction that has the peak power rating of 50 kW motor with 48 stator slots and 8 rotor poles. With the presence of these three magnetic materials, the cogging torque is estimated independently using multiposition simulation. The multiposition is simulated using a transient application that runs at constant speed. The results of cogging torque, rotational speed, angular position of BLDC motor, and magnetic flux density distribution have been presented. Also, the maximal, mean, minimal, rectified mean, and rms values of cogging torque were provided.
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Xing, Feng, Jiajia Zhang, Mingming Zhang, and Caiyan Qin. "Design and Multi-Objective Optimization of an Asymmetric-Rotor Permanent-Magnet-Assisted Synchronous Reluctance Motor for Improved Torque Performance." Applied Sciences 14, no. 15 (2024): 6734. http://dx.doi.org/10.3390/app14156734.
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Permanent-magnet-assisted synchronous reluctance motors (PMA-SynRMs) are widely used in modern industry as a kind of electromagnetic energy conversion device with high output torque, high power density, high efficiency, and excellent speed regulation. In this paper, an asymmetric-rotor PMA-SynRM combined with a Halbach array is proposed based on the conventional PMA-SynRM without modifying the amount of permanent magnet. With the finite element no-load analysis, it is proven that the permanent magnet arrangement of this method can achieve better flux focusing effect and magnetic-axis-shift (MAS) effect. A significant increase and shift of the air-gap magnetic density has also been observed. Meanwhile, the load simulation demonstrated that the proposed model possesses higher utilization of permanent magnet torque and reluctance torque compared to the conventional model. In addition, a multi-objective optimization has been performed for the rotor structure of the proposed model, and the optimized model improved the average torque by 25.32% and reduced the torque ripple by 76.92% compared to the conventional model. Finally, the constant power speed range (CPSR) performance and anti-demagnetization performance have been analyzed for the three models. The results showed that the proposed and optimized models performed better on constant power speed range, and all three models of permanent magnets had good anti-demagnetization performance. The maximum demagnetization rate of the optimized model is reduced by 13.84% compared to the proposed model at an operating condition of 200 °C and nine times the rated current.
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Nagaya, K., and N. Arai. "Analysis of a Permanent Magnet Levitation Actuator With Electromagnetic Control." Journal of Dynamic Systems, Measurement, and Control 113, no. 3 (1991): 472–78. http://dx.doi.org/10.1115/1.2896434.
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This paper proposes an actuator in the magnetic levitation system using a permanent magnet and an electromagnet. In this system, the gravity force of the masses is supported by a strong permanent magnet in which two identical poles face each other. The vibration due to external disturbances is controlled by use of the electromagnet by changing magnetic fluxes of one of the permanent magnets. The analytical expressions for obtaining the levitation force, spring constant, and the control force versus the electric current in the electromagnet were derived using the equation of the electromagnetic theory. Numerical simulations under the control using the optimal regulator for the magnetically levitated body were carried out. To verify the present theoretical results, experimental results were also obtained.
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Martino, Michele. "Low-Frequency Analytical Model of Superconducting Magnet Impedance." Modelling and Simulation in Engineering 2022 (November 7, 2022): 1–13. http://dx.doi.org/10.1155/2022/2105847.
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A superconducting magnet for particle accelerators is often modeled as an ideal inductor, as it indeed exhibits a completely negligible resistance; this is fully satisfactory, as an example, for control purposes, as the time constant formed by the magnet inductance and the resistance of normal conducting cables connecting it to the power converter accurately describe the essentially dominant dynamics of the circuit. Such a model would however fail to correctly represent the noise attenuation mechanism at play in practical superconducting magnets, which also include a vacuum pipe or a beam screen in the inner part of the aperture, an iron yoke on the outer part, and, potentially, a stainless steel or aluminum collar in between. Even at relatively low frequencies, a more accurate model is therefore needed. A sufficiently general one is proposed and illustrated.
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Franse, J. J. M., and N. Miura. "Science and Techniques Using Pulsed Magnetic Fields." MRS Bulletin 18, no. 8 (1993): 44–49. http://dx.doi.org/10.1557/s0883769400037763.
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In this article, we examine materials behavior in the magnetic field region from about 40 T to 500 T using pulsed magnet technology. Examples of materials science using two different pulsed magnet technologies are described in this article.Semicontinuous MagnetsSince the late 1960s, the University of Amsterdam has operated a semicontinuous magnetic field installation that produces magnetic fields up to 40 T with typical time constants of about one second. The magnet coil is constructed from hard-drawn copper wire with a reinforcement cylinder of maraging steel positioned at roughly one third of the outer diameter. Before operation, the coil is cooled to 30 K by cold neon gas. The power for this installation is taken directly from a 10 kV connection to the public electricity grid. By means of a thyristor-based power control system, highly flexible field-time profiles can be realized: step-wise pulses can be generated with field levels constant within 10−4 during 100 ms; linearly increasing and decreasing fields as well as exponentially ripple-free decreasing fields are other examples of standard field-time profiles. Among the measuring techniques frequently used are magnetization, magneto-transport, quantum oscillations, relaxation phenomena, etc. Temperatures at which experiments can be performed range from 400 mK to room temperature. In the Netherlands, the Amsterdam High Field Facility has recently been combined with the High Magnetic Field Laboratory in Nijmegen, where static magnetic fields up to 30 T are produced in hybrid magnet systems, to form the Amsterdam-Nijmegen Magnet Laboratory (ANML). The high field research of ANML comprises semiconductors, magnetism in transition-metal compounds, heavy-fermion physics, superconductors, organic conductors, and magnetic separation. We present here a few selected topics.
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Frishman, Ye M., and M. I. Umanov. "Comparative analisys of vertical and horizontal static interaction forces between track and magnetic suspension vehicle." Science and Transport Progress, no. 41 (August 25, 2012): 136–41. http://dx.doi.org/10.15802/stp2012/7881.
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In the article an analysis of interrelation of vertical and lateral interaction forces acting in the magnetic suspension system having permanent magnets of rectangular cross section with the constant (throughout the magnet volume) value of magnetization vector is performed. It is found that the increase in the magnetic bend width (for track and vehicle) leads to improving the lateral stability index as well as reducing the elevating power and the magnetic suspension efficiency.
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Planche, Thomas. "Constant-tune cyclotrons." Journal of Instrumentation 18, no. 03 (2023): P03019. http://dx.doi.org/10.1088/1748-0221/18/03/p03019.
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Abstract In this paper we demonstrate that cyclotrons can be made to have precisely constant betatron tunes over wide energy ranges. In particular, we show that the horizontal tune can be made constant and does not have to follow the Lorentz factor γ, while still perfectly satisfying the isochronous condition. To make this demonstration we developed a technique based on the calculation of the betatron tunes entirely from the geometry of realistic non-hard-edge closed orbits. We present two particular cyclotron designs, one compact cyclotron and one ring cyclotron. The compact cyclotron design is backed up by a 3-dimensional finite element magnet calculation, that we also present here.
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Otsuka, A., and T. Kiyoshi. "High-Field Magnet Design Under Constant Hoop Stress." IEEE Transactions on Applied Superconductivity 18, no. 2 (2008): 1529–32. http://dx.doi.org/10.1109/tasc.2008.920531.
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Ma, Zhimin, and Xiaogang Qi. "Permanent magnet motor temperature compensated constant torque control." IFAC-PapersOnLine 51, no. 31 (2018): 68–70. http://dx.doi.org/10.1016/j.ifacol.2018.10.013.
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Wang, Chun Liu, Jin Jian Li, and Xiao Yun Feng. "Simulation of Permanent Magnet Synchronous Motor for Electric Vehicle Indirect-Torque Control System." Advanced Materials Research 383-390 (November 2011): 7438–43. http://dx.doi.org/10.4028/www.scientific.net/amr.383-390.7438.
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For the request of electric vehicle on drive motor, the permanent magnet synchronous motor (PMSM) get more and more attention by its small size and torque characteristics. By analyzing the traction motor characteristics with a constant torque starting and constant power operation, the space vector pulse width modulation (SVPWM) algorithm is used to replace the switching table for direct torque control (DTC) strategy. By analyzing the mathematical model of the PMSM, for the existence of permanent magnets, the rotor coordinate system is applied when calculating the stator flux. Meanwhile, the electric vehicle starting block and the brake block are simulated for the characteristics of that walk namely stop. The results show that the speed has a smooth transition and the torque has a quick response.
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Sarac, Vasilija Jovan, and Goce Stefanov. "Various Rotor Topologies of Line-Start Synchronous Motor for Efficiency Improvement." Power Electronics and Drives 5, no. 1 (2020): 83–95. http://dx.doi.org/10.2478/pead-2020-0006.
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Abstract Line-start synchronous permanent magnet motor (LSSPMM) is being considered as a replacement or alternative to asynchronous squirrel-cage motor (AM) in constant speed applications. This is due to the better efficiency and power factor than the asynchronous motor. There are various rotor topologies of LSSPMM concerning the magnets placement and their dimensions. The paper analyses six different rotor topologies in terms of achieving the best efficiency and power factor for the same output power of the motor with minimal consumption of permanent magnet material. All other motor design parameters remain unchanged, i.e. all motor topologies are analysed for the same stator laminations and the same motor windings. The numerical finite element method (FEM) models and dynamic models for obtaining transient characteristics of speed, torque and current verify the proposed design of various motor models. The results from all motor models are compared and adequate conclusions are derived regarding the optimal rotor topology in terms of obtaining the best efficiency and power factor with minimal consumption of permanent magnet material, for the same output power of the motor.
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Capogna, A., O. Doche, and L. Davoust. "Near-wall MHD turbulence: investigation of a spanwise magnet array configuration." Magnetohydrodynamics 58, no. 4 (2022): 455–64. http://dx.doi.org/10.22364/mhd.58.4.9.
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Direct numerical simulations of turbulent channel flows subjected to non-uniform magnetic fields are presented. The magnetic fields are delivered by spanwise distributions of permanent magnets located on the top and bottom walls of the channel. This configuration generates mainly magnetic field components perpendicular and transverse to the wall. Three different values of magnet thickness are considered. For each calculation, the average magnetic intensity imposed in a selective part (\it{i.e.} the turbulent inner layer) of the channel is kept constant so that the only parameter studied is the shape of the magnetic field. We show that larger magnets tend to create more homogeneous magnetic distributions in the near-wall region and lead to a better reduction in turbulent activity in this region. Figs 10, Refs 4.
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Ren, Ya Heng, Ye Qing Zhu, and Cun Ming Hao. "The Speed and Position Control Method for Constant Magnetism Synchronous Motors Running at Low Speed." Applied Mechanics and Materials 303-306 (February 2013): 1217–23. http://dx.doi.org/10.4028/www.scientific.net/amm.303-306.1217.
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In the rotor field oriented vector control system, the use of permanent magnet synchronous motor voltage equations and flux equations derived PMSM position and speed estimation method has its unique advantages, The advantage of this approach is to calculate a simple, fast dynamic response, and easy to implement. However, when permanent magnet synchronous motor running at low speed, back EMF would be very small, which can not guarantee the accuracy of estimates. In addition, the position and speed estimation parameters of permanent magnet synchronous motor is largely in dependence on the running status of permanent magnet synchronous motor ,and vulnerable to temperature and magnetic saturation phenomena.All of these elements will lead to error increase. In order to solve the problem of inaccuracy in parameters estimation of motors at low speed, PI controller is introduced to obtain the rotor speed information, and then make up for deficiencies in the estimation algorithm. At the same time, this method can be applied to achieve smooth switching of high speed switching of the motor.
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Kusumadewi, An-Nissa, Lisda Damayanti, Rukiah, and Risdiana. "Factors Affecting the Attractive Force of Dental Magnetic Attachment: A Literature Review for Guiding Dentists in Clinical Application." International Journal of Dentistry 2022 (June 14, 2022): 1–9. http://dx.doi.org/10.1155/2022/9711285.
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Aim. The aim of this review is to get a comprehensive description of the factors that may influence the attractive force of the dental magnetic attachment. Background. Dental magnetic attachment is a term for a magnet used as an overdenture retainer. Magnets that are widely used are permanent magnets such as neodymium iron boron (NdFeB) and samarium cobalt (SmCo). Theoretically, the magnetic attractive force in a permanent magnet has a constant retentive force, and the magnitude of the force will not decrease over time. However, several studies revealed that the magnetic attractive force can be decreased, resulting in the failure of overdenture retention. Some of the factors of reduced magnetic attraction that have been studied are corrosion and temperature. There are no articles that specifically review the factors that can influence magnetic attraction. Review Results. A total of 25,880 articles were obtained during a search on 3 journal databases: PubMed (2,647), ScienceDirect (23,184), and Scopus (229). From those publications, 15 articles reported relevant outcome data that were then extracted. Magnetic attractive force can be influenced by temperature, corrosion, keeper surface morphology, type of magnet, keeper-assembly size combination, inclination, insertion-removal cycle, gliding/loading cycle, number of magnets, crosshead speed, and force direction. Conclusion. Many factors can affect the magnetic attraction force of the dental magnetic attachment. Corrosion is the most likely factor to occur because the dental magnetic attachment is always in the oral environment which contains corrosive saliva and is susceptible to damage due to mastication forces.
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Meyer, Alexander, and Jörg Franke. "Towards an Energy Efficient Series Production of High Performance Permanent Magnet Synchronous Motors by Selective Magnet Assembly." Applied Mechanics and Materials 882 (July 2018): 111–18. http://dx.doi.org/10.4028/www.scientific.net/amm.882.111.
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When installing magnets on synchronous rotors, the target values of energy efficiency, vibration, noise emissions, power density and synchronism are decisively influenced by the quality of the rotor magnetic field. This depends on the real position of the magnets after mounting, on the polarization of the magnet and on the direction of magnetisation. However, large component tolerances in the magnet bodies also require tolerances in the rotor magnetic field. The quality assurance in the field of rotor production, which is largely lacking in the current state of the art, is compensated for by robust motor designs in order to keep the rejects low. Unconventional machine designs, such as the Halbach arrangement of the magnets, exploit optimization potential in terms of power density by eliminating the ferromagnetic component in the rotor and reduce harmonics due to the almost sinusoidal field shape, so that more efficient winding processes, such as linear winding in the stator with a constant low torque ripple compared to distributed winding, are used. At the same time, however, the requirement for homogeneity of the magnetic field increases due to the matching pairing of the magnets and the correct magnetic position when using sintered, isotropic rare earth magnets. By 100 % testing of magnets and rotors, it is possible on the one hand to exploit these design potentials and on the other hand to estimate the performance data of the motor before the final assembly test by means of data mining. In the framework of the E|MagTol project, the process feasibility of a logistics solution for storing magnetized goods has already been successfully investigated. In order to extend the potential uncovered in the previous project, it is necessary to record all process data of the rotor assembly process such as magnet geometry, magnet position, polarization and magnetization direction. The aim of E|S2MART is on the one hand to increase machine efficiency by compensating for component deviations by adapting or matching the magnetic position and magnetic parameters in a closed-loop control loop in the assembly process and on the other hand to significantly increase the energy efficiency of the assembly process. This is done by optimizing the magnetization process and coupling with inductive heating to replace the furnace process during the bonding process and to reduce the energy consumption during magnetization. On the basis of the existing process experience, the savings potential in the assembly process is estimated to be at least 70 % compared to conventional processes.
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Crescent, Onyebuchi Omeje, and Ugwuoke Eya Candidus. "A comparative braking scheme in auto-electric drive systems with permanent magnet synchronous machine." International Journal of Applied Power Engineering 11, no. 4 (2022): 251~263. https://doi.org/10.11591/ijape.v11.i4.pp251-263.
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Permanent magnet synchronous machines (PMSMs) are gaining popularity due to renewable energy and the electrification of transportation. Permanent magnet synchronous machines are receiving interest because of their great dependability, low maintenance costs, and high-power density. This research compares surface mounted permanent magnet (SMPM) with interior permanent magnet (IPM) synchronous machines using MATLAB. Mathematical models and simulation analyses of two permanent magnet synchronous machines under regenerative braking are presented. Maximum regeneration power point (MRPP) and torque (MRPP-torque) for two machine types were simulated at variable electrical speed and q-axis current. Simulation results showed IPMSM produced more output power due to saliency than SMPM at varying speed and current with higher MRPP and MRPP-Torque. Simulation was used to compare the dynamic impacts of constant and variable braking torques on an auto-electric drive's speed and produced torque on a plain surface and a sloppy driving plane. 81.68% and 74.95% braking efficiency were measured on level ground and a sloppy plane, respectively. Simulations indicated that lithium-ion battery state of charge varied linearly with constant braking torque and exponentially with varying braking torque, reflecting efficiency values. All simulations were in MATLAB/Simulink 2014.
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Cinti, Luca, and Nicola Bianchi. "Hybrid-Excited PM Motor for Electric Vehicle." Energies 14, no. 4 (2021): 916. http://dx.doi.org/10.3390/en14040916.
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This paper deals with the potentials of a Hybrid-Excitation Permanent-Magnet (HEPM) machine. The HEPM machine is characterized by a rotor including both permanent magnets (PMs) and excitation coils. The PMs produce a constant flux at the air gap of the machine, while an excitation current is supplied so as to regulate such a flux. A flux increase could be necessary during transient overload operations, while a flux decrease is useful during Flux-Weakening (FW) actions to operate at speeds higher than the nominal speed. Torque, power, efficiency, flux density and losses of an interior permanent magnet (IPM) motor and an HEPM motor are analyzed in detail. It is shown that this excitation winding produces a great advantage in terms of torque and power performance during the operations at speeds higher than the nominal speed. Despite the additional rotor losses, it is shown that there is a higher efficiency.
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Диев, Д. Н., И. А. Ковалев, М. Н. Макаренко та ін. "Высокотемпературная сверхпроводниковая магнитная система для изучения нейронной активности". Журнал технической физики 92, № 2 (2022): 250. http://dx.doi.org/10.21883/jtf.2022.02.52014.147-21.
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The paper describes a high-temperature superconducting magnetic system (HTS SMS) to equip an experimental stand intended for neuron activity researches under constant and low-frequency magnetic fields up to 1 T. The design of the magnetic system together with its electromagnetic and cryogenic parameters is briefly discussed. The test results of the preliminary experiments conducted in liquid nitrogen at 77 K for two interchangeable magnets are given. The first magnet was manufactured in the form of a double pancake coil wound with 4 mm high HTS tape. The second magnet was made of pure copper wire with no frame and was impregnated with a thermally conducting epoxy resin. The advantages of the HTS pancake coil were demonstrated in comparison with the cryo-resistive solenoid. Low energy consumption of the HTS magnetic system will allow conducting continuous non-invasive monitoring of biological objects in a magnetic field.
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Gil, Jeonghwan, Sesun You, Youngwoo Lee, and Wonhee Kim. "Back Electro Motive Force Estimation Method for Cascade Proportional Integral Control in Permanent Magnet Synchronous Motors." Actuators 10, no. 12 (2021): 319. http://dx.doi.org/10.3390/act10120319.
Full textAbstract:
A cascade proportional integral control method with back-electro motive force compensation has been widely used for permanent magnet synchronous motors. In the permanent magnet synchronous motor control, it is important to accurately know the back-electro motive force constant for torque generation as well as back-electro motive force compensation. In this study, a real-time back-electro motive force constant estimation algorithm is developed to improve the velocity tracking control performance. The proposed method consists of a proportional integral controller and a back-electro motive force constant estimator. The proportional integral controller is designed to reduce the velocity tracking error. The back-electro motive force constant estimator is designed to estimate the back-electro motive force constant. It was verified that the estimated back-electro motive force constant converges to the actual back-electro motive force constant. The estimated back-electro motive force constant is applied to the cascade proportional integral controller. To verify the effectiveness of the proposed method, the performance of the proposed method is validated experimentally.
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Zhumaev, M. R., M. Z. Sharipov, and M. N. Rizokulov. "Precession of magnetic moments with change of their orientations." Journal of Physics: Conference Series 2573, no. 1 (2023): 012032. http://dx.doi.org/10.1088/1742-6596/2573/1/012032.
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Abstract In the work the precession of the magnetization vector in nano-sized magnets is induced by a femtosecond laser pulse, the frequency of which lies in the transparency region of the magnet material. It is shown that an alternating magnetic field applied to the XOY plane generates the magnetic equilibrium position vectors and elliptical precession occurs if a constant magnetic field acts along the Z axis. In this case the precession angle changes periodically in time and the precession frequency is determined by the amplitude of the total magnetic field.
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Dziob, Daniel, Jakub Ramian, Jan Ramian, Bartosz Lisowski, and Jadwiga Laska. "Design and Construction of a Chamber Enabling the Observation of Living Cells in the Field of a Constant Magnetic Force." Cells 10, no. 12 (2021): 3339. http://dx.doi.org/10.3390/cells10123339.
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The aim of the work was to design and construct a microscopic stage that enables the observation of biological cells in a magnetic field with a constant magnetic force. Regarding the requirements for biological observations in the magnetic field, construction was based on the standard automatic stage of an optical microscope ZEISS Axio Observer, and the main challenge was to design a set of magnets which were the source of a field in which the magnetic force was constant in the observation zone. Another challenge was to design a magnet arrangement producing a weak magnetic field to manipulate the cells without harming them. The Halbach array of magnets was constructed using permanent cubic neodymium magnets mounted on a 3D printed polymer ring. Four sets of magnets were used, differing in their dimensions, namely, 20, 15, 12, and 10 mm. The polymer rings were designed to resist magnetic forces and to keep their shape undisturbed when working under biological conditions. To check the usability of the constructs, experiments with magnetic microparticles were executed. Magnetic microparticles were placed under the microscope and their movement was observed to find the acting magnetic force.
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Nishio, H. "Magnetic aftereffect constant of Nd-Fe-B sintered magnet." Journal of the Magnetics Society of Japan 13, no. 2 (1989): 209–12. http://dx.doi.org/10.3379/jmsjmag.13.209.
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Guo, Liang, and Hao Ding. "Design and Analysis of a Novel 2-D Permanent Magnet Array for Planar Actuator." Applied Mechanics and Materials 416-417 (September 2013): 253–57. http://dx.doi.org/10.4028/www.scientific.net/amm.416-417.253.
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A novel 2-D permanent magnet array for a planar actuator was proposed, in which the portion between adjacent magnetic poles was divided to four small rectangular solids. Magnetic fields of the permanent magnet array were analyzed systematically by 3D finite element method. The analysis results show that, compared with the well-known Halbach magnet array, the proposed array has higher permanent magnet utilization. Keeping the whole permanent magnet volume constant, the arrays with several improved structures were put forward. The magnetic field analyze results prove that the utilization is best, when the ratio between the height of the magnetic poles magnetized vertically and the height of the portion magnetized horizontally is about 2.
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Zhang, Huan Huan, Ke Bao Ye, and Guo Ping Yang. "Investigation of the Electric Vehicle Motor Constant Power Characteristics." Applied Mechanics and Materials 457-458 (October 2013): 688–91. http://dx.doi.org/10.4028/www.scientific.net/amm.457-458.688.
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The characteristics of traction motor for electric vehicle is introduced here. The qualitative analysis on the relation between the base speed ratio and power is showed. The emphasis is on the analysis and comparison for permanent magnet brushless DC motor, induction motor and switched reluctance motor.
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Ullah, Basharat, Faisal Khan, Muhammad Qasim, et al. "Lumped Parameter Model and Electromagnetic Performance Analysis of a Single-Sided Variable Flux Permanent Magnet Linear Machine." Energies 14, no. 17 (2021): 5494. http://dx.doi.org/10.3390/en14175494.
Full textAbstract:
A new Single-sided Variable Flux Permanent Magnet Linear Machine with flux bridge in mover core is proposed in this paper. The flux bridge prevents the leakage flux from the mover and converts it into flux linkage, which greatly influences the performance of the machine. First, a lumped parameter model is used to find the suitable coil combination and no-load flux linkage of the proposed machine, which greatly reduces the computational time and drive storage. Secondly, the proposed machine replaces the expensive rare earth permanent magnets with ferrite magnets and provides improved flux controlling capability under variable excitation currents. Multivariable geometric optimization is utilized to optimize the leading design parameters like split ratio, stator pole width, width and height of permanent magnet, flux bridge width, the width of mover’s tooth, and stator slot depth at constant electric and magnetic loading. The optimized design increases the flux linkage by 44.11%, average thrust force by 35%, thrust force density by 35.02%, minimizes ripples in thrust force by 23%, and detent force by 87.5%. Furthermore, the results obtained by 2D analysis are verified by 3D analysis. Thermal analysis is done to set the operating limit of the proposed machine.
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Ma, Der-Ming, and Jaw-Kuen Shiau. "THE DESIGN OF EDDY-CURRENT MAGNET BRAKES." Transactions of the Canadian Society for Mechanical Engineering 35, no. 1 (2011): 19–37. http://dx.doi.org/10.1139/tcsme-2011-0002.
Full textAbstract:
The eddy-current is created by the relative motion between a magnet and a metal (or alloy) conductor. The current induces the reverse magnetic field and results in the deceleration of motion. The proposed mechanism implements this phenomenon in developing a braking system. The potential applications of the braking system can be a decelerating system to increase the safety of an elevator or any guided rail transportation system. To provide scientific investigation for industrial application of magnetic braking, this study presents four systematic engineering design scenarios to design a braking system. The constant magnetic field is the simplest and easiest design to implement. The optimal magnetic field distribution is obtained by minimizing the deceleration effort. The piecewise-constant magnetic field distribution offers a compromise between performance and magnetic field requirements. The advantages of the section-wise guide rail are tolerable deceleration; and simple design requirement and manufacturing processes. In the study, an experimental braking system using constant magnetic field is build to demonstrate the design procedure.
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Ahma, Muneeb, Lakshmikant Bopche, Virendra Umale, and Saurabh K. Singh. "Examination of Permanent Magnet Synchronous Motor." International Journal of Engineering and Advanced Technology 8, no. 6s (2019): 1095–100. http://dx.doi.org/10.35940/ijeat.f1214.0886s19.
Full textAbstract:
This paper focus on various loading conditions onthe Permanent Magnet Synchronous Motor and its application using field oriented control technique. Constant torqueapplication irrespective of speed isalso presented. This technique helps in lift and belt conveyors handling constant weight of material per unit time, in pumping and compressing and electric locos. Results of simulation shows that proposed system has high acceleration and deceleration rate with vector control,overall quick and dynamic response as well as excellent controlling ability. The vector control is a excellent technology for analysis and design of PMSM drive system. It provides designing and debugging for practical drive system. Modeling and different kinds of Permanent Magnet Synchronous Machines are studied and Simulation is carried out in Matlab and performance is studied at different operating conditions.
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Goryca, Zbigniew, Kamil Paduszyński, and Artur Pakosz. "Model of the multipolar engine with decreased cogging torque by asymmetrical distribution of the magnets." Open Physics 16, no. 1 (2018): 42–45. http://dx.doi.org/10.1515/phys-2018-0008.
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Abstract This paper presents the results of field calculations of cogging torque for a 12-pole torque motor with an 18-slot stator. A constant angular velocity magnet and the same size gap between n-1 magnets were assumed. In these conditions, the effect of change of the n-th gap between magnets on the cogging torque was tested. Due to considerable length of the machine the calculations were performed using a 2D model. The n-th gap for which the cogging torque assumed the lowest value was evaluated. The cogging torque of the machine with symmetrical magnetic circuit (the same size of gap between magnets) was compared to the one of the asymmetrical machine. With proper choice of asymmetry, the cogging torque for the machine decreased by four times.
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A/L Krishna, Preshant, Aravind CV, Aminath Saadha, and F. Azhar. "Force Characteristics Analysis for Linear Machine with DC Field Excitations." MATEC Web of Conferences 152 (2018): 03005. http://dx.doi.org/10.1051/matecconf/201815203005.
Full textAbstract:
In urban regions and particularly in developing countries such as Malaysia with its ever-growing transport sector, there is the need for energy efficient systems. In urban railway systems there is a requirement of frequent braking and start/stop motion, and energy is lost during these processes. To improve the issues of the conventional braking systems, particularly in Japan, they have introduced linear induction motor techniques. The drawbacks of this method, however, is the use of permanent magnets, which not only increase the weight of the entire system but also increases magnetic cogging. Hence an alternative is required which uses the same principles as Magnetic-Levitation but using a magnet-less system. Therefore, the objective of this research is to propose an electromagnetic rail brake system and to analyze the effect of replacing permanent magnets with a magnet-less braking systems to produce a significant amount of brake thrust as compared with the permanent magnet system. The modeling and performance analysis of the model is done using Finite Element Analysis (FEA). The mechanical aspects of the model are designed on Solidworks and then imported to JMAG Software to proceed with the electro-magnetic analysis of the model. There are 3 models developed: Base Model (steel), Permanent Magnet (PM) Model and DC Coil Model. The performance of the proposed 2D models developed is evaluated in terms of average force produced and motor constant square density. By comparing the values for the 3 models for the same case of 9A current supplied for a 0.1mm/s moving velocity, the base model, permanent magnet model and DC coil model produced an average force of 7.78 N, 7.55 N, and 8.34 N respectively, however, with increase in DC current supplied to the DC coil model, the average force produced is increased to 13.32 N. Thus, the advantage of the DC coil (magnet-less) model, is, that the force produced can be controlled by varying the number of turns in the coil (N) or the current supply to the coil (I) given by the which is the simple principles of a solenoid: Force(mmf)=NI.
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Friedman, Benjamin M. C., Michael G. Abraham, Mark Paetkau, S. Richard Taylor, and Cynthia Ross Friedman. "Use of a varying turn-density coil (VTDC) to generate a constant-gradient magnetic field and to demonstrate the magnetic force on a permanent magnet." Canadian Journal of Physics 91, no. 3 (2013): 226–30. http://dx.doi.org/10.1139/cjp-2012-0405.
Full textAbstract:
In this study, we proposed that a constant gradient magnetic field could be generated by the construction of a current-carrying coil possessing a turn-density (number of turns per unit length) that varies linearly with axial position (i.e., a varying turn-density coil, VTDC). A VTDC is easily constructed and could be used to demonstrate how a ferromagnet placed in a magnetic field experiences a net force. Using the Biot–Savart law, we predicted that a ferromagnetic dipole suspended in a VTDC experiences a force proportional to the length of the dipole. We designed and executed an experiment to test our prediction. A coil with a turn-density varying at a rate of 0.11 cm−2 was constructed. Rare-earth magnets were suspended along the centre of the VTDC using a string that was attached to a mass resting on a scale. The scale reading measured the force experienced by the hanging magnet. The procedures were also carried out in a constant turn-density solenoid (control). A direct linear relationship between force and magnet length was observed in the VTDC, whereas no force was detected in the zero-gradient field solenoid (p < 0.000 001). Linear regressions suggested that the observed data matched the predicted values (95% certainty). The magnetic moment of 0.56 ± 0.21 J/T is in reasonable agreement with remnant magnetization for neodymium magnets of ∼1 T. We found that our easily-built VTDC produced a uniform gradient as no significant differences were observed when magnets were hung at different axial positions. Overall, the results were supportive of the theory. Our VTDC could be readily constructed and used in a physics classroom to demonstrate basic principles of electromagnetism.
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Omeje, Crescent Onyebuchi, and Candidus Ugwuoke Eya. "A comparative braking scheme in auto-electric drive systems with permanent magnet synchronous machine." International Journal of Applied Power Engineering (IJAPE) 11, no. 4 (2022): 251. http://dx.doi.org/10.11591/ijape.v11.i4.pp251-263.
Full textAbstract:
<span lang="EN-US">Permanent magnet synchronous machines (PMSMs) are gaining popularity due to renewable energy and the electrification of transportation. Permanent magnet synchronous machines are receiving interest because to their great dependability, low maintenance costs, and high-power density. This research compares surface mounted permanent magnet (SMPM) with interior permanent magnet (IPM) synchronous machines using MATLAB. Mathematical models and simulation analyses of two permanent magnet synchronous machines under regenerative braking are presented. Maximum regeneration power point (MRPP) and torque (MRPP-torque) for two machine types were simulated at variable electrical speed and q-axis current. Simulation results showed IPMSM produced more output power due to saliency than SMPM at varying speed and current with higher MRPP and MRPP-Torque. Simulation was used to compare the dynamic impacts of constant and variable braking torques on an auto-electric drive's speed and produced torque on a plain surface and a sloppy driving plane. 81.68% and 74.95% braking efficiency were measured on level ground and a sloppy plane, respectively. Simulations indicated that lithium-ion battery state of charge varied linearly with constant braking torque and exponentially with varying braking torque, reflecting efficiency values. All simulations were in MATLAB/Simulink 2014.</span>
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Diev D.N., Kovalev I.A., Makarenko M.N., et al. "High temperature superconducting magnetic system for neuron activity researches." Technical Physics 92, no. 2 (2022): 215. http://dx.doi.org/10.21883/tp.2022.02.52948.147-21.
Full textAbstract:
The paper describes a high-temperature superconducting magnetic system (HTS SMS) to equip an experimental stand intended for neuron activity researches under constant and low-frequency magnetic fields up to 1 T. The design of the magnetic system together with its electromagnetic and cryogenic parameters is briefly discussed. The test results of the preliminary experiments conducted in liquid nitrogen at 77 K for two interchangeable magnets are given. The first magnet was manufactured in the form of a double pancake coil wound with 4 mm high HTS tape. The second magnet was made of pure copper wire with no frame and was impregnated with a thermally conducting epoxy resin. The advantages of the HTS pancake coil were demonstrated in comparison with the cryo-resistive solenoid. Low energy consumption of the HTS magnetic system will allow conducting continuous non-invasive monitoring of biological objects in a magnetic field. Keywords: superconductivity, high-temperature superconductor, REBCO tape, cryogen magnetic system, magnetic field, neuron activity.
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Wang, Yi-Ren, and Po-Chuan Huang. "A Magneto-Electric Device for Fluid Pipelines with Vibration Damping and Vibration Energy Harvesting." Sensors 24, no. 16 (2024): 5334. http://dx.doi.org/10.3390/s24165334.
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This study introduces an innovative energy harvesting system designed for industrial applications such as fluid pipelines, air conditioning ducts, sewer systems, and subsea oil pipelines. The system integrates magneto-electric flow coupling and utilizes a dynamic vibration absorber (DVA) to mitigate the vibrations induced by fluid flow while simultaneously harvesting energy through magnetic dipole–dipole interactions in a vibration energy harvester (VEH). The theoretical models, based on Hamilton’s Principle and the Biot–Savart Law, were validated through comprehensive experiments. The results indicate the superior performance of the small-magnet system over the large-magnet system in both damping and power generation. The study analyzed the frequency response and energy conversion efficiency across different parameters, including the DVA mass, spring constant, and placement location. The experimental findings demonstrated significant vibration reduction and increased voltage output, validating the theoretical model. This research offers new avenues for energy harvesting systems in pipeline infrastructures, potentially enhancing energy efficiency and structural integrity.
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Darmawan, Isra' Nuur, Sahid Aktob Mudilulail, and Kholistianingsih Kholistianingsih. "Effect of Rotor Teeth Width Variations on Back EMF Constant of a 12-Slot 8-Pole Permanent Magnet Synchronous Generator: A Finite Element Analysis." Applied Engineering, Innovation, and Technology 1, no. 1 (2024): 23–30. http://dx.doi.org/10.62777/aeit.v1i1.10.
Full textAbstract:
Permanent Magnet Synchronous Generators (PMSGs) are widely used for converting mechanical energy into electrical energy through electromagnetic induction. Unlike conventional generators, PMSGs utilise permanent magnets to generate the excitation field, eliminating the need for external excitation coils. This study investigates the effects of rotor teeth width variations on the performance characteristics of a 12-slot, 8-pole PMSG using Finite Element Method (FEM) simulations. Specifically, the influence of rotor teeth width on flux density and back electromotive force (EMF) constant are explored. Three different rotor teeth widths, 5 mm, 7.5 mm, and 10 mm, are considered, and their impact on the generator's performance is evaluated. The FEM simulations reveal that increasing the rotor teeth width leads to a significant increase in the back-EMF constant values. The smallest back-EMF of 12.057 V and the lowest constant are observed for the 5 mm rotor teeth width, while the largest back-EMF of 20.774 V and the highest constant correspond to the 10 mm rotor teeth width. These findings highlight the importance of optimising rotor teeth geometry in PMSGs to achieve desired performance characteristics.
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Lee, Chih-Hao, Pai-Hsiang Cheng, Keh-Chyang Leou, Chih-Ming Hsieh, and Yu-Chuan Su. "Calculation of the Optimal Magnetic Duty Cycle for a Graded Coaxial Magnet of a Rotary Type Magnetic Refrigerator." Energies 18, no. 2 (2025): 289. https://doi.org/10.3390/en18020289.
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In the design of a rotary-type magnetic refrigerator, a high field of a coaxial magnet is desired. Typically, a high-field design can be achieved with a small duty cycle, which might not be optimized from the viewpoint of the thermal hydraulics of a magnetic refrigerator. In this work, a numerical simulation analysis of a graded coaxial magnet designed using a COMSOL program for a rotary-type active magnetic refrigeration (AMR) system was performed. The magnet structures are based on neodymium–iron–boron permanent magnets with thin gadolinium (Gd) and gadolinium-terbium alloy (Gd-Tb) plates as AMR materials. For a rotary-type magnetic cooling system, from the thermal–hydraulic point of view, the best duty cycle of a coaxial magnet should be 50% if the magnetic field can be kept constant during the period of duty cycles. However, the simulation calculation shows a serious reduction in the magnetic field strength at higher duty cycles, resulting in lower magnetic cooling efficiency. After considering the thermos-hydraulic part, the optimized duty cycle is around 30% in the case of a temperature span of 8 K between the hot and cold ends on a rotary-type magnetic cooling system. By applying graded Gd-Tb alloy along the flow direction, the performance of magnetic refrigeration improves significantly. Compared to a pure Gd AMR system, it is demonstrated that more than three times the increase in the cooling capacity can be achieved.
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Bykov, Evgeny M. ""I/Magnet" Association: How Do People with Magnet Implants Signify Their New Experience." Sociology of power 35, no. 2 (2023): 62–85. https://doi.org/10.22394/2074-0492-2023-2-62-85.
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Based on self-reports of people with magnet implants, I investigate a pair of correlational questions: "How do technologically modified humans signify their new experience?" and "How do we, non-modified readers, become able to conceive it?". In answering the first question I start with biosemiotics. It considers signs being embedded in the morphology of an organism. On the one side, a magnet becomes a part of a human morphology and bodily schema; on the other - unlike most living organisms, humans can vary signs arbitrarily. I switch the theoretical exposition of the relation between signs, the human body, and technology to Merleau-Ponty's phenomenology of perception, based on whose work Ihde conducted a phenomenological analysis of 4 regimes of technological mediations within the "I - World" correlation. His scheme was extended by Verbeek, who adds "cyborg relation" to the list. In the second part of the paper, I apply a vocabulary of material semiotics to the analysis of the "I/magnet" association. I separate quotes of MI-agents into several stages of existence of the association in question: emergence; interactions with constant magnets; interactions with electromagnetic devices; learning through others; actual non-expected associations; sense-formation; new risks of disruption of associations; normalization. I conclude with an attempt to answer 2nd initial question, about our (readers) conceivability by appealing to Barsalou's "perceptual symbol systems" approach, with the help of which I correlate synesthesia of MI-agents and semiosis - which transforms the field of meaning for a non-modified person.
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Komine, Takashi. "Combinatorial dependence of magnetic printing characteristics in double magnet master media for energy-assisted magnetic recording." AIP Advances 13, no. 2 (2023): 025310. http://dx.doi.org/10.1063/9.0000480.
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In this study, the combinatorial dependence in double magnet master for energy-assisted magnetic recording was investigated by the micromagnetic framework. Four kinds of master media, which are soft single magnet (SSM), hard single magnet (HSM), soft double magnet (SDM) and hard double magnet (HDM), were compared. Comparing single magnet and double magnet master media, more adequate combination of double magnet master media was discussed. The HSM, SDM, and HDM master media can write line/space (L/S) pattern with bit length of 20 nm, while the double magnet master media can clearly print L/S patterns comparing with single magnet in case of 10 nm. For higher coercivity EAMR media, the larger printing field causes larger recording field difference by utilizing SDM master media while in case of HDM the recording field difference is almost constant even if the printing field increases. As a result, since the recording field difference of SDM becomes larger than that of HDM as the printing field strengthens, thus, SDM master media can write the servo signals onto higher coercivity EAMR media. It was concluded that it is important for the low coercivity parts of double magnet master media to have a larger saturation magnetization due to enhancement of large recording field difference.
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Zhang, Longqi, Lei Zhao, and Shihao Li. "Analysis and Optimization Design of U-Shaped Ironless Permanent Magnet Linear Synchronous Motor." International Journal of Mechanical and Electrical Engineering 2, no. 2 (2024): 52–64. http://dx.doi.org/10.62051/ijmee.v2n2.08.
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The working speed of the U-shaped ironless permanent magnet linear synchronous motor is determined by the frequency and pole pitch. When the motor’s working speed is required to be constant, different combinations of frequency and pole pitch can be chosen. This article mainly discusses the influence of the pole pitch on the motor performance when other parameters are kept constant. First, the magnetic field of the motor permanent magnet is analyzed using the equivalent magnetizing current method to discuss the relationship between the pole pitch and the motor air gap magnetic field. Then, the finite element method is used to analyze the influence of the pole pitch on the motor air gap magnetic field, transverse edge effect, and electromagnetic thrust considering the saturation effect of the magnetic yoke. The research shows that under the conditions of constant motor basic structural parameters and speed, and the same amount of permanent magnet material, both the air gap magnetic density and the motor thrust line density have maximum values as the pole pitch changes. The research results have certain guiding significance for the design of this type of motor.