Showing 33 results for Finite Element
V. Abbasi, L. Hassanvand, A. Gholami,
Volume 13, Issue 3 (9-2017)
Abstract
Specific and sensitive operation of circuit breakers makes an individual position for them in power networks. Circuit breakers are at the central gravity of variations and execution operations. Therefore, an optimum operation is the main reason to investigate about new gases to be used in MV and HV circuit breakers instead of SF6. The arc process has enormous complexity because of hydrodynamic and electromagnetic combination equations, and that is the exact reason why most of the previous simulations were processed in two-dimension analysis. But, in this paper a three-dimension simulation with sufficient results has been fully discussed. Different evaluations on the other gases have taken under study in order to find a suitable substitute instead of SF6 gas, which can also bring an optimum operation for the breakers and can be even friendly with the environment. The simulations have been carried out based on the finite element method (FEM) and magneto-hydrodynamic equations. A three-dimension model under the transient state has been chosen in the simulations to find a feasible substitute for SF6 gas. The main factors of the analysis are threefold as follows: arc temperature on the different regions, the cooling ability and arc resistance. CO2, CF3I and N2 are nominated to substitute the SF6 gas and their effects on cooling ability, nozzle evaporation, contacts erosion and arc resistance will be discussed.
F. Mahmouditabar, A. Vahedi, P. Ojaghlu,
Volume 14, Issue 1 (3-2018)
Abstract
Permanent magnet motors have been considered for a variety of applications due to their features such as high power density and high efficiency. One of the issues that should be investigated in the design of these motors is the demagnetization problem. Usually, the demagnetization analysis is carried out in a steady state, while demagnetization effect in dynamic condition is more considerable due to pulse shaped of armature field. Based on this fact, in this paper, dynamic demagnetization is investigated for an IPM V‑shaped magnet. This study has been done for two types of magnet, each one in static & dynamic conditions and the results are compared. Moreover, the effect of flux weakening regime on demagnetization is investigated.
F. Tootoonchian, F. Zare,
Volume 14, Issue 3 (9-2018)
Abstract
Disk Type Variable Reluctance (DTVR) resolvers have distinguished performance under run out fault comparing to conventional sinusoidal rotor resolvers. However, their accuracy under inclined rotor fault along with different types of eccentricities includes static and dynamic eccentricities are questioned. Furthermore, due to thin copper wires that are used for signal and excitation coils of resolver there is high risk of short circuit fault in the coils. So, in this study the performance of the sinusoidal rotor DTVR resolver under the mentioned faults are studied. The quality of output voltages along with position error of the sensor is discussed. 3-D time stepping finite element method is used to show the effect of different faults. Finally, the prototype of the studied resolver is constructed and tested. The employed test bed is built in such a way that is able to apply controllable level of different mechanical faults. Good agreement is obtained between the finite element and the experimental results, validating the success of the presented analysis.
M. Tahmasebipour, M. Modarres,
Volume 14, Issue 4 (12-2018)
Abstract
In this paper, a highly sensitive piezoresistive differential pressure microsensor is proposed. This microsensor is consisted of a silicon microcantilever (Length=145 µm; Width=100 µm; Thickness=0.29 µm) and two piezoresistors were mounted (via proper connections) on the microsensor for measuring the created pressure difference. Applying pressure to the microcantilever induces longitudinal and transverse stresses in the piezoresistors, changing their electric resistance and, consequently, the output voltage in the reading circuit of the microsensor. Longitudinal and transverse stresses, different relative sensor resistances resulting from different pressures, voltage variations along the piezoresistors, and microcantilever deflection resulting from different pressures were investigated. To improve the sensor sensitivity, effect of doping concentration, piezoresistors width, and the width of the structure placed under the piezoresistors were studied. In addition, we studied how increasing the width and length of the beam influenced the sensitivity of the sensor. Based on analysis results, the sensor sensitivity was increased from 0.26 W/Pa to 15.78 W/Pa (~60 times). To evaluate the behavior and performance of the proposed microsensor, the following characteristics were analyzed: maximum microcantilever displacement, von Mises stress distribution along the beam and microsensor resistance variations.
S. Hajiaghasi, Z. Rafiee, A. Salemnia, T. Soleymani Aghdam,
Volume 15, Issue 3 (9-2019)
Abstract
Since the insulators of transmission lines are exposed to different environmental conditions, it is important task to study insulators performance under different conditions. In this paper, silicone rubber insulators performance under different environmental conditions including rainy, icy, salt and cement are proposed and exactly is studied. Electric fields (E-fields) and voltage distributions along the insulator under various conditions have been evaluated. Moreover, the corona rings effects on insulator performance under these conditions have been presented. A 230 kV silicone rubber insulator is selected, modeled and simulated with finite element method (FEM) using the COMSOL software. The simulation is repeated for different environmental conditions and efficiency of corona ring for each scenario is evaluated. The results indicate that environmental conditions have a significant effect on the insulator performance and the corona ring somewhat alleviate the adverse effect of environmental conditions on the insulator performance.
H. Sheykhvazayefi, S. R. Mousavi-Aghdam, M. R. Feyzi,
Volume 15, Issue 4 (12-2019)
Abstract
In this paper, a new design of permanent magnet linear synchronous motor (PMLSM) for electromagnetic launcher system (EMLs) has been investigated in terms of the requisite amount of average launching thrust force and thrust force ripple minimization through finite element method. EMLs are a kind of technology used to develop thrust force and launch heavy loads with different applications including military, aerospace, and civil applications. A linear motor as a major part of the system plays a substantial role in this application providing sufficient load launch force. Cogging force and its mitigation techniques are principle challenges in linear motor operation leading to thrust ripples and detrimental effects on positioning precision and dynamic performance of the moving part. In the proposed design, some modifications have been made in the conventional PMLSM structure. Semi-closed slot construction is used for the primary and the pole shoes width has been changed to access minimum thrust ripple value. In order to attain further optimization in PMLSM’s thrust ripple profile, some other modifications have been considered in PM’s shape as arc-shaped magnetic poles. The latter assists to enforce air gap flux density distribution as sinusoidal as possible, and makes further ripple reduction. The results exhibit that the proposed structure has low weight and it is more economical compared to conventional PMLSM with rectangular shape magnet. In addition, the Average thrust force and ripple are improved providing suitable thrust force for throwing the load.
A. N. Patel, B. N. Suthar,
Volume 16, Issue 1 (3-2020)
Abstract
Cogging torque is the major limitation of axial flux permanent magnet motors. The reduction of cogging torque during the design process is highly desirable to enhance the overall performance of axial flux permanent magnet motors. This paper presents a double-layer magnet design technique for cogging torque reduction of axial flux permanent magnet motor. Initially, 250 W, 150 rpm axial flux brushless dc (BLDC) motor is designed for electric vehicle application. Initially designed reference axial flux BLDC motor is designed considering 48 stator slots and 16 rotor poles of NdFeb type single layer permanent magnet. Three-dimensional finite element modeling and analysis have been performed to obtain cogging torque profile of reference motor. Additional layer of the permanent magnet is created keeping usage of permanent magnet same with an objective of cogging torque reduction. Three-dimensional finite element modeling and analysis have been performed to obtain cogging torque profile of improved axial flux BLDC motor with double layer permanent magnet design. It is analyzed that double-layer magnet design is an effective technique to reduce the cogging torque of axial flux BLDC motor.
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.
Mohammad Abouhosseini Darzi, Mohammad Mirzaie, Amir Abbas Shayegani Akmal, Ebrahim Rahimpour,
Volume 21, Issue 3 (8-2025)
Abstract
Bushings are one of the most important components of electrical equipment such as power transformers, reactors, capacitors. Most of the installed bushings have Oil-Immersed Paper (OIP) insulation structure. Bushing failure is caused by various reasons such as poor manufacturing process, overloading and also poor installation process, but moisture ingress is one of the main reasons of OIP bushing defect during its operation. In this paper, the electric field distribution of OIP bushings in multiple situations are simulated and effects of moisture distribution are analyzed. The simulations are stablished in polluted and clean surfaces of the studied bushing and done by COMSOL Multiphysics Software. The results show that non-uniform moisture distribution has a significant effect on electric fields of OIP insulation. This effect strongly increases with increasing the pollution on the external insulator of the bushing.
Mohammad Reza Eesazadeh, Zahra Nasiri-Gheidari,
Volume 21, Issue 4 (11-2025)
Abstract
This research focuses on electromagnetic position sensors, particularly synchros, which play a crucial role in the closed-loop control systems of permanent magnet synchronous machines (PMSMs). Compared to two-phase resolvers, three-phase synchros provide enhanced reliability by ensuring continued operation even in the event of an open-circuit fault. One of the key challenges in designing such sensors lies in selecting optimal windings and configurations while also developing efficient modeling techniques to minimize computational complexity. To address this issue, the study introduces a matrix-based method for designing wound rotor (WR) synchros. This approach allows for flexible configurations depending on the number of pole pairs and stator tooth counts. The proposed design methodology ensures adaptability and precision, making it a valuable tool for engineers working on electromagnetic sensor development. To validate the effectiveness of the proposed method, the Field Reconstruction Method (FRM) is employed, providing a fast and accurate modeling technique that can be implemented using MATLAB. Additionally, a comparative analysis is conducted with finite element analysis (FEA) to confirm the accuracy and reliability of the approach. Results demonstrate that the matrix-based method is an efficient and effective solution for optimizing WR synchro designs, significantly improving performance and computational efficiency.
Akinola Oladeji, Samuel Nahum,
Volume 22, Issue 1 (3-2026)
Abstract
Grounding systems are critical for ensuring electrical safety, minimizing fault currents, and enhancing infrastructure reliability, particularly in regions with high-resistivity soil. This study presents the design, simulation, and field implementation of a low-resistance earthing system integrating bentonite, charcoal, and sodium chloride to reduce soil resistivity. Using ETAP software, the performance of the Finite Element Method (FEM) and IEEE Std. 80-2013 grounding models are compared under a 30kA fault current scenario. FEM simulations predict a ground resistance of 0.028 Ω and a Ground Potential Rise (GPR) of 627.4 V, while the IEEE method yields 0.269 Ω and 5996.5 V, respectively. Field measurements using a UNI-T Ground Tester validate the FEM results, recording an actual ground resistance of 0.023 Ω, well below the IEEE-recommended 1 Ω threshold, surpassing this conventional benchmark by 98%. A comparative analysis of recent studies highlights the superiority of the composite material approach. The FEM model’s accuracy in capturing soil stratification and material effects is validated, while safety metrics (step/touch voltages) adhere to the IEEE standard. This work bridges theoretical innovation and practical implementation, offering a replicable framework for resilient grounding systems in challenging environments.
Ilhem Boutana, Mohamed Rachid Mekideche,
Volume 22, Issue 1 (3-2026)
Abstract
Electromagnetic Tube Expansion (EMTE) is a high-velocity forming process that utilizes transient magnetic fields to plastically deform tubular workpieces without physical contact. The process requires the generation of large currents via a capacitor bank, producing intense magnetic pressures to achieve deformation. While EMTE offers significant advantages in precision and efficiency, a comprehensive understanding of the interplay between key working conditions and deformation mechanisms remains crucial for optimizing its performance. This paper presents a numerical investigation into the effects of critical working conditions on the electromagnetic tube expansion process. Using a coupled finite element model, the transient magnetic field and resultant tube deformation are analyzed under varying conditions. The results provide insights into the relationship between process parameters and deformation outcomes, highlighting the potential for optimizing EMTE systems for enhanced efficiency and uniformity. This study contributes to advancing the theoretical and practical understanding of EMTE, by offering guidance for the design of more effective forming strategies and equipment.
Mohammad Ali Razavi, Farid Tootoonchian, Zahra Nasiri Gheidari,
Volume 22, Issue 1 (3-2026)
Abstract
Synchros are electromagnetic sensors utilized to determine the angular position of a rotating shaft. This paper examines the impact of leakage flux from the Rotary Transformer (RT) on the induced voltages and the position detection accuracy of the Wound-Rotor (WR) synchro. Various methods are proposed to mitigate the negative effects of leakage flux from the RT. The leakage flux paths, which couple with the signal winding, are identified. Based on this analysis, the optimal distance between the sensor and the RT is calculated to minimize the adverse effects of leakage flux on the synchro's accuracy. Additionally, the RT structure is modified to reduce the leakage flux. Another effective approach involves the use of Electromagnetic Interference (EMI) shielding. In this context, a shield frame is designed for the RT, and the impact of different shield materials on reducing leakage flux is investigated. The results show that a copper-based shield significantly reduces the adverse effects of leakage flux and improves the sensor’s accuracy. To evaluate the effectiveness of the proposed methods, they are assessed through 3-D Time-Stepping Finite Element Analysis (3-D TSFEA) and experimental measurements on a prototype sensor. The experimental results show close agreement with the 3-D TSFEA, confirming the accuracy of the findings.
Mohammad Negintaji, Aghil Ghaheri, Ebrahim Afjei,
Volume 22, Issue 1 (3-2026)
Abstract
In the rapidly advancing domain of wireless power transfer systems, particularly for electric vehicle charging, the design of the magnetic coupler plays a crucial role in determining both system efficiency and practical implementation. Variations in coupler system designs lead to differences in self-inductance, mutual inductance, and AC resistance, directly impacting the energy transfer efficiency and power delivery capability of the system. This paper proposes a novel coil design for wireless power transfer systems, incorporating Double-DZ (DDZ) and Quadrature (Q) coils to improve lateral and yaw misalignment tolerance. The proposed design integrates the advantageous features of three structures—SDDP, DDQP and TTP—to introduce a novel configuration, DDZ-DDQZ, which enhances system stability and performance. By increasing misalignment tolerance, this method substantially enhances the robustness and real-world feasibility of wireless power transfer for electric vehicle charging.
