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The paper presents a simulation of braking of an automotive vehicle while downhill running with electric power recovery. The automotive vehicle is driven with a three-phase induction motor supplied from an accumulator battery through a voltage inverter. Mathematical model of the vehicle is described by voltage-current equations of an induction motor, the equation of motion of the vehicle, resistance...
This article presents measurement results of static properties of selected soft magnetic materials at the boiling temperature of liquid nitrogen. Obtained values have been compared to parameters of materials at the room temperature. An influence of the low temperature on the shape of initial magnetization curve and magnetic hysteresis loop form hes been examined. Also the change of permeability, remanence...
The paper deals with the analysis of the sensorless vector controlled induction motor drive with the MRAS-type speed estimator. Two types of MRAS speed estimators, with classical PI controller and fuzzy logic controller in the speed adaptation loop were described and their dynamical performance in the sensorless drive were compared. The sensitivity to parameters changes of the induction motor equivalent...
In this paper density problems are restricted to the current and the heat conduction. Analysis of the current density leads to system integral equations of the Fredholm type [4-5]. That problem in timeprovides to the mathematical model determined by the system of integro-differenti al equations [2-3] and it is extended for few conductors. The functions density for heat conduction problems are determined...
Basic equations of radiative heat transfer have been presented, along with typical Dirichlet and Neumann boundary conditions for established stales. Possible methods of solving integral equations describing radiative heat transfer have been identified, and these have been limited to iterative and projection methods. We restrict to method of successive approximations, discretization method, Galerkin...
The paper deals with the effects of electromagnetic fields on human organism. The hazards due to these fields and the effects of their interaction with biological objects are discussed, and the problems related to dosimetry and the normalization and legal conditions related to protection of human habitable and work environment are dealt with. Moreover, the results of analyses of electromagnetic interaction...
In the article the new development tool of analog and digital systems, utilizing Analog Devices ADSP-BF5XX Blackfm processors - LabVIEW Embeded Module for Bfackfin Processors, is presented. The chosen proprieties and mechanisms of working are described, as well as example of end-user application created with aid of this tool - onephase analyzer of current in electrical grid.
The ODS (Operating Deflection Shapes) method used for the estimation of the influence of weak external extortions on the functioning of chosen structural elements of the chimney is presented in this paper. The chosen method permits to build a virtual model of the investigated object and then to „reproduce'' the behavior of a real structure, using the results of executed measurements. The analysis...
New circadian pholoreceptors are be able to regulate natural body clock. Using spectral circadian efficiency function it is possible to define circadian quantities. Calculation of circadian illuminance distribution using interreflections can be done using spectral values of reflectance and spectral distribution of radiation.
The paper deals with the possibilities for initiating electrical breakdown in vacuum by microparticles. Duration of the travel of charged spherical microparticles of various diameters accelerated by the electric field, and their velocities in the moment of impact against the electrode of opposite polarity are calculated. It was shown that the velocities are sufficiently high to induce plastic deformations...
Boundary Element Method for simulation of spatially homogeneous objects of electroencephalography and tomography is presented in this paper. The four layer spherical model (representing skin, skull, CSF layer and brain) of the real head approximated with isoparametric six nodes triangles was considered. For different kinds of boundary conditions formulation of the algebraic system of equations was...
The paper presents the results of frequency and time-frequency analyses of the acoustic emission signals arising during degradation of methyl polymetacrylate in a strong electric field. The frequency analysis was carried out with the use of Fourier Fast Transform method (FFT), while the time-frequency analysis - with the use of Short-Term Fourier Transform (STFT). The MatLafa software package was...
This paper presents a new construction of SR motor for oscillatory and vibratory drives. As a result of a change to magnetic circuit shape magnetic pull is much reduced, and the mass ratio of rotor to stator and the electromagnetic torque meaningfully increases. These changes do not, however, deteriorate any of the other parameters of the motor. For the computation of an optimal shape of the magnetic...
This paper serves the idea of applying joint time-frequency representations for analysis of non-stationary signals in electrical engineering. Main directions of researches are concentrated around Cohen's class of transformation that gives some possibilities of adaptation to analysed signal by choosing appropriate kernel function. Performed theoretical discussion allowed to suggest affine subclass...
This paper presents a proposal of evolution strategy associated with the controlled random search algorithm for more accurate optimization of the three-phase induction motors. Application of the elaborated, so called hybrid optimization procedure, make possible accurate localization of the optimal independent variables vector and decrease of the results standard deviation obtained by repeatedly applied...
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