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This article presents the numerical analysis of the magnetic field that occurs around the transformer after it has been switched off. The purpose of this analysis was to determine if it is possible to define the residual fluxes in the legs of transformer based on the measurements of this field. These studies have allowed us to determine the quantity and location of the sensors. The influence of the...
A hybrid genetic algorithm (HGA) is proposed to optimize the rotor shape of an Interior permanent magnet machine which is used in EV application. The novel method obtain lower iron loss and torque ripple as well as higher average torque and efficiency for the machine. The optimization results of the HGA design is compared with the initial and genetic algorithm designs. It is shown that the performance...
Because many electric devices using magnetic materials are developed in a modern society, it is important to evaluate its magnetization characteristics accurately. In this paper, we aim to calculate magnetic circuit method with summation of harmonics. One of the important ideas in hysteresis-based magnetic circuit calculation is based on the harmonic balance approach. A magnetization characteristic...
In this paper the optimization process of a wireless body area network is presented. The optimization goal is to improve the performance of the body area sensor network with respect to the on-body transmission channel and off-body link performance. The sensor network consists of one node with fixed position (1) towards the ear and two sensor nodes that are located on the chest (2) and the back (3),...
Rectennas operating as microwave electromagnetic energy harvesting systems has a low input power and, as a result, a very low output power is delivered to the load. In this paper, is purposed a method to increase the output power by the use of a parallel association of rectennas. The antennas simulations were carried out using Computer Simulation Technology software. Rectifier circuits were designed...
The finite difference time domain method (FDTD) is widely used in solutions of electromagnetic problems, but has as a condition of stability, the Courant-Friedrich-Levy (CFL), that limits the step time to be used. The method has a high computational processing time and memory usage in three-dimensional analysis for electromagnetic cavities due to the high number of resonance frequencies to be simulated,...
Electric traction systems are a potential source of stray currents. The important problem, technically is to evaluate the harmful effects (electrolytic corrosion) that an electrified railway has on nearby earth-return circuits (e.g. pipelines). This phenomenon is stochastic and may aggravate electrochemical corrosion in different pipeline regions depending on the position of the vehicle, the load...
This paper presents an overview of the different solutions of electrospinning systems. 3D parameterized numerical models for these systems were prepared too. The 3D models allows to analyze the distribution of the electric field. In addition, examples of calculations for the analyzed systems in the form of electric field quantities distributions are also shown. In this paper the authors used COMSOL...
A number of investigations were undertaken to enhance the behavior of high voltage outdoor insulators by adopting numerical methods of optimization, but no work is performed to account for the presence of pollution. In this paper, a shape optimization of a high voltage insulator is achieved with the objective of reducing the tangential electric field along its polluted surface by means of numerical...
The article presents an algorithm and computer software for the optimization of excitation system of permanent magnet synchronous motor. The software consists of two independent modules: a module containing mathematical model of the device and an optimization solver. The mathematical model of the motor has been elaborated in the Ansys Maxwell environment. The Bat Algorithm (BA) has been applied in...
Article presents method of storing and processing Big Data using object-oriented datatype in commercial relational database server. Methodology was presented based on genomic data. Additionally, some methods of pattern matching implemented in the object were described and commented. Due to set of numerical experiments based on real data the efficiency of the system was testified. Obtain results shows...
Visual saliency modeling is becoming important and challenging for many scientific disciplines (robotic systems, psychophysics, cognitive neuroscience and computer science). Proposed model indicates possible salient regions by taking into consideration face presence and motion which is essential in motion pictures. By combining face presence and motion we can obtain credible saliency map with low...
Two-stage SC + Finite Difference (FD) procedures have been proposed since a long time to solve electrostatic and magnetostatic field plane problems in case of inhomogeneous dielectric materials. This had allowed to overcome accuracy problems caused by convex corners in the domain boundary and relevant field singularities, and to apply FD solvers in rectangular domains. In this paper, compound procedures...
Induction machines are commonly used in traction applications due to their robustness and lower production costs when compared to the Permanent Magnet Synchronous Motor (PMSM). In such traction applications, the induction machines are mainly operated by field oriented control. This control technique requires an accurate knowledge of the machine's parameters. The accuracy of the parameters influence...
In this paper the problem of design optimization of a microwave wearable antenna is investigated. Reference is made to a specific antenna design that is wideband vee antenna which is characterized by 6 geometrical parameters. Those parameters were automatically adjusted with an evolution strategy based algorithm to obtain the impedance matching of antenna located in the proximity of the human body...
A novel stochastic finite-difference time-domain (S-FDTD) technique is presented in this paper for the precise and rapid assessment of electromagnetic field statistical properties. The featured algorithm is systematically verified through detailed comparisons with the results obtained via existing, yet rather resource (CPU and memory) consuming, Monte Carlo-FDTD and other stochastic implementations.
Topology optimization is one of the mathematical methods for finding the optimal structure of electrical machinery. Because topology optimization can make a design with much higher degree of freedom in terms of structure than other optimization methods, there is a possibility for achieving a completely new shape that is not limited to the conventional model. The optimized structure is strongly dependent...
Technical condition of large power transformers has large impact on reliability of a power system since they are the connection points for generators and distribution system. Power transformers can experience various faults that can disrupt their reliable operation such as mechanical defects caused by magnetostriction or electrodynamic forces. Magnetostriction is a phenomenon occurring in transformer...
This paper presents a summary of a vibrational behavior investigation of a 27 slots / 24 poles combination surface mounted synchronous electric motor. To achieve this investigation, first, an electromagnetic analysis is done using a quasi 3D finite element model allowing to consider the rotor skewing and to compute the machine magnetic quantities. Second, a modal analysis is done using a 3D FE structural...
Carbon nanotubes (CNTs) are long cylindrical structures of carbon atoms hexagonal connections and having the aspect ratio higher than 1000. For immense electrical and mechanical properties, great specific surface and high thermal and chemical stability, since Ijima discovery in 1991 [1], carbon nanotubes attracts great attention among many research groups because due to possible applications. CNTs...
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