Showing 27 results for Finite Element
M. Ghaseminezhad, A. Doroudi, S. H. Hosseinian, A. Jalilian,
Volume 17, Issue 1 (3-2021)
Abstract
Nowadays study of input voltage quality on induction motors behavior has become a controversial subject due to the wide application of these motors in the industry. The impact of grid voltage fluctuations on the performance of induction motors can be included in this area. The majority of papers devoted to the influence of voltage fluctuations on the induction motors are focusing only on the solving of d-q state equations or steady-state equivalent circuit analysis. In this paper, a new approach to this issue is investigated by field analysis which studies the effects of voltage fluctuations on the magnetic fluxes of induction motors. New analytical expressions to approximate the airgap flux density and the torque under-voltage fluctuation conditions are presented. These characteristics are also calculated directly by the finite-element method considering the magnetic saturation and the harmonic fields. Finally, experimental results on a typical induction motor are employed to validate the accuracy of analytical and simulation results.
J. Sepaseh, N. Rostami, M. R. Feyzi,
Volume 17, Issue 4 (12-2021)
Abstract
A new axial magnetic gear (AMG) with enhanced torque density and reduced cogging torque is proposed in this paper. In the new structure, the direction and width of permanent magnets in high-speed rotor are changed and permanent magnets are removed from the modulator while the low-speed rotor remains unchanged. The torque density of the proposed magnetic gear is enhanced by using an appropriate direction and pole pitch for permanent magnets of high-speed rotor. The proposed AMG is compared with recent structures in the literature with the highest torque density. Three-dimensional (3D) finite element analyses are employed to obtain the cogging torque and torque density. The results of the analysis indicate that not only torque density increases but also cogging torque decreases dramatically.
S. Hasanzadeh, M. Yazdanian, S. M. Salehi,
Volume 18, Issue 3 (9-2022)
Abstract
Over the past four decades of developing superconducting machines, many topologies have been suggested. The most successful topology of high-power superconducting (HPS) machines is an air-cored radial flux synchronous machine. There are two possible topologies for this type of machine, rotational field, and stationary field. In this paper, the relative advantages and disadvantages of these topologies are compared in detail. Analytical study of these topologies shows that the inversed machine topology leads to more efficient high-temperature superconductor (HTS) wire utilization and hence more economical production. In order to confirm the result obtained by analytical calculations, 2-D finite element model (FEM) of the machine is utilized.
F. Tootoonchian, M. Amiri,
Volume 19, Issue 1 (3-2023)
Abstract
Multi-Speed resolvers are desirable position sensors for high performance closed-loop control of inverter driven machines due to their high accuracy. However, developing a winding with high number of poles with limited number of slots is a main challenge in achieving multi-speed function. Therefore, in this paper different winding configuration are proposed to achieve 5-X performance of a disk type wound-rotor resolver. Then, the best winding is chosen for experimental verification. In addition to the accuracy of the sensor, the optimal winding selection index is defined considering copper usage, number of winding layers (overlapping or non-overlapping configurations), the number of turns for each coil of the winding (variable or constant turn configurations), and the amplitude of the fundamental harmonic. An objective function is defined involving all the mentioned indices with different weights determined based on the importance of each index. Finally, a prototype of the sensor with the best winding is built and tested. The experimental measurements verify the results of the simulations that are obtained using 3-D time setting finite element analysis.
M. K. Rashid, A. M. Mohammed,
Volume 19, Issue 2 (6-2023)
Abstract
Nowadays, magnetic gears (MGs) have become an alternative choice for mechanical gears because of their low maintenance, improved durability, indirect contact between inner and outer rotors, no lubrication, and high efficiency. Generally, although these advantages, MGs suffer from inherent issues, mainly the cogging torque. Therefore, cogging torque mitigation has become an active research area. This paper proposed a new cogging torque mitigation approach based on the radial slit of the ferromagnetic pole pieces of MGs. In this method, different numbers and positions of slits are applied. The best results are gained through an even number of slits which shows promising results of cogging torque mitigation on the inner rotor with a small mitigation in the mean torque on both rotors. This work is done by using Simcenter and MATLAB software packages. The inner rotor’s cogging torque has mitigated to 81.9 %, while the outer rotor’s cogging torque is increased only by 2.75 %.
Ali Jabbari, Hassan Moradzadeh, Rasul Lotfi,
Volume 19, Issue 4 (12-2023)
Abstract
Along with the development of hybrid electric vehicles, researchers are trying to reduce existing limitations such as noise and environmental concerns and improve the efficiency and reliability of these systems. The use of magnetic gear technology is one of the solutions that have been recently proposed to remove these limitations and achieve higher benefits. In this paper, a mechanically coupled magnetic geared (MCMG) machine has been introduced. An accurate analytical model based on the subdomain method is presented to calculate the magnetic machine performance. To do this, first, a pseudo-Cartesian coordinate system is specified, and then the constitutive equations, i.e. Laplace’s and Poisson’s equations are rewritten for different regions of the machine. The separation of variables method was used to determine the general solution of the equations. Then by applying appropriate interface and boundary conditions, the Fourier coefficients of the equations were determined. To verify the analytical results, the performance of the proposed magnetic machine is numerically simulated using the finite element method in commercial software, and then a prototype is built and tested in three distinct modes. By comparing the analysis results with numerical simulation results and experimental tests, the high accuracy of the proposed analytical model can be confirmed.
Ali Zarghani, Pedram Dehgoshaei, Hossein Torkaman, Aghil Ghaheri,
Volume 20, Issue 1 (3-2024)
Abstract
Losses in electric machines produce heat and cause an efficiency drop. As a consequence of heat production, temperature rise will occur which imposes severe problems. Due to the dependence of electrical and mechanical performance on temperature, conducting thermal analysis for a special electric machine that has a compact configuration with poor heat dissipation capability is crucial. This paper aims to carry out the thermal analysis of an axial-field flux-switching permanent magnet (AFFSPM) machine for electric vehicle application. To fulfill this purpose, three-dimensional (3D) finite element analysis is performed to accurately derive electromagnetic losses in active components. Meanwhile, copper losses are calculated by analytic correlation in maximum allowable temperature. To improve thermal performance, cooling blades are inserted on the frame of AFFSPM, and 3D computational fluid dynamics (CFD) is developed to investigate thermal analysis. The effect of different housing materials, the external heat transfer coefficient, and various operating points on the components' temperature has been reported. Finally, 3-D FEA is used to conduct heat flow path and heat generation density.
