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In the last years the use of the wireless power transfer systems has experienced a significant increase. In this context the study of the behavior of these systems has been the subject of debate for many researchers, in order to understand and improve their performances. This paper aims to bring a contribution in this regard. Based on previous studies, the paper makes a comparative analysis of three...
Recently the information from industry shows that inductive power transfer electric vehicle chargers that use tight coupling between the inductive coupler coils were achieved. This paper includes a theoretical and experimental study on the possibilities that tight coupling offers versus loose coupling - widely used so far - in what concerns the ratio between the output transmitted power and the efficiency...
This paper presents a study of the frequency splitting and bifurcation phenomena in the wireless power transfer systems. Using electric circuit model methods and mathematical calculus, the two phenomena are analyzed for all the possible configurations of the coupled circuits, i.e. seriesseries, series-parallel, parallel-series and parallel-parallel. For a specific case including two identical printed...
The paper proposes to analyze series-series magnetically coupled circuits that include circuits with different natural frequencies. An analytical-numerical calculation on this configuration of coupled circuits was realized. The work was centered on obtaining those frequencies that characterize the extreme points of the load active power — frequency characteristic. The mathematical calculus was correlated...
Recent approaches for time-domain analysis of lumped circuits deal with differential-algebraic-equation (DAE) systems instead of SPICE-type resistive models. Although simple and powerful, DAE models based on modified nodal approaches require some restrictions related to redundant variables or circuit topology. In this context, the paper proposes an improved version that allows treating nonlinear analog...
The paper focuses on the sensitivity analysis made on an inductively coupled contactless power transfer system. The study uses the symbolically form of the circuit functions. After that the circuit function was obtained, it was introduced in a Matlab program for processing and utilization in the sensitivities formulas. The sensitivity characteristics were obtained for each circuit parameter, the most...
In the context of the recent concerns related to the contactless energy transfer applications, the paper aims to present new aspects on the harmonics influence on the power transfer parameters. For this reason the inductively coupled circuits have not been studied independently, but closely related to the system elements they are connected, i.e. d.c. - a.c. converter. After an analysis of the harmonic...
This paper proposes to analyze the influence of the displacement of the capacitor plates on the performances of an electrical coupled contactless power transfer system. The armatures are of circular form and the values of their radii are different. Some formulae are obtained and based on them graphical representations are made in order to analyze the nonlinear behavior. Then these variable values...
This paper focuses on the differences between an ideal and a real electrical circuit diagram of a step-down dc-dc converter and their influences on the converter operation. For each diagram the circuit equations are obtained, processed accordingly and implemented in new created programs. The resulted waveforms are discussed and some conclusions are depicted.
This paper relies on the development of a model for an urban electric transportation system. This model is used to simulate the system operation both in normal and abnormal (short circuit) regimes. The simulation results are compared with the results of some theoretical studies presented in the technical literature and also with some experimental results. Unlike the theoretical idealized studies our...
The paper presents an improvement of sensitivity analysis methods of analog lumped circuits. A practical and reliable approach has been developed and implemented in a computation program intended for linear and/or piecewise-linear approximation of the nonlinear RLCM circuits containing any type of passive elements, independent and controlled sources. A powerful modified nodal approach to build the...
This paper presents a method to assess the losses in electromagnetic devices starting from accurately measured values of the voltages and of the currents, for many levels of supply voltages, including those that produce a strong saturation of the ferromagnetic core. The method was implemented in a MATLAB program that allows computing the total losses, but also their components (i.e. eddy current losses...
The problem of performances reconsideration of the electrostatic precipitators appeared as a consequence of new stipulations in Romanian legislation. The moral and physical wearing-out of the installations imposes certain technical measures to be taken for the purpose of reduction of the smokestock-emissions, so that they would be below the level of concentrations required by the environmental regulations...
This paper analyses the distribution of the electric field in an electrostatic precipitator through simulation techniques. For this reason the finite volume method is used. The computational program, created in MATLAB, considers the nonuniform distribution of the electrical charge density. The technique used to estimate the charge density in every point of the computational domain is similar to that...
The paper proposes effective solutions to include nonlinear inductors with soft ferromagnetic core in the time-domain circuit analyses. Three inductor models are developed, tested and compared. They are conceived for different degrees of accuracy related to the real devices. The models are robust and reliable due to the modeling concept that avoids numerical instabilities. An enhanced inductor model...
The paper proposes an effective time-domain modeling and simulation strategy of power transformers, using the SPICE circuit simulator. The nonlinear phenomena of the iron core are carefully considered, including saturation, static hysteresis and eddy currents. The principle of magnetic circuit modeling is based on analog lumped equivalent circuits and the SPICE implementation uses the principle of...
This paper proposes a novel model of dc series motors. The dependency between the field flux and current was replaced by the magnetic circuit of the motor. The magnetic circuit is modeled by electrical equivalent circuit which has nonlinear elements depending on the saturation and hysteresis phenomena. The nonlinear model of the dc motor considers also the nonlinear dependency of the load torque on...
This paper proposes to analyze some aspects of AC plunger-type magnet operation. For this purpose the simulation of its operation both in steady state and dynamic regime was made. Alternative models were used for the AC magnet, based on the electromagnetic field modeling in 2D and 3D respectively and a complex model based on equivalent electrical analog circuit. The models were implemented in commercial...
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