Journal Volume 12 Issue 1

Currents Physical Components in Circuits with Nonsinusoidal Voltages and Currents - Part 2: Three-Phase Linear Circuits

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Leszek S. Czarnecki

This paper summarizes the present state of discussions on power phenomena, power definitions and compensation in three-phase three-wire linear circuits with nonsinusoidal voltages and currents. In particular, definitions of the arithmetic and geometric apparent powers are discussed. It is shown that these two powers result in an erroneous value of power factor of unbalanced loads even if voltages and currents are sinusoidal.

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Sampled Method of Active Power Filter Control (Part II)

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Andrzej Szromba

The aim of the paper is to demonstrate how to use sampled method of control of a shunt active power filter to maintain invariable power of a supplying voltage source, even though the supplied load varies randomly. The definition by S. Fryze of load current components is used as a basis for the construction of a family of shunt active power filters. The distinctive property of these filters is maintaining non-deformed source current in every one individually considered period T.

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Experimental Investigations of the Upqc Arrangement

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Grzegorz Benysek

This paper presents the fundamental properties and dependences describing the UPQC (Unified Power Quality Conditioner) arrangements. The UPQC devices simultaneously permit to fulfill the following functions: voltage and current harmonics compensation, network voltage and load current symmetrization as well as network voltage stabilization and power flow control. The selected results of the experimental investigations conducted on the small power laboratory model have been described.

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Grid Voltages Sensorless Control of the PWM Rectifier with Active Filtering

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Daniel Wojciechowski

The paper presents structure and experimental results of the control system of the PWM rectifier with active filtering function. Proposed control system was designed for maximum filtering performance in steady state. This task is realized by predictive algorithms applied for both control as well as calculation of grid currents. Accuracy of these algorithms strongly depends on precise information about future samples of equivalent electromotive force of the grid, which is in general distorted and unbalanced.

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Power Electronics Harmonic Analysis Based on the Linear Time Periodic Modeling

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Vanya Ignatova, Pierre Granjon, Seddik Bacha

This paper presents an analytical frequency-domain method for harmonics modeling and evaluation in power electronic systems. The considered system is described by a set of differential equations, which are converted in the frequency domain and presented in a matrix form. Indeed, currents and voltages are described in terms of Fourier series and arranged in a vector form. The passive elements and the switching functions are then represented by harmonic transfer matrices.

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Decomposition of EMI Noise into Common and Differential Modes in PWM Inverter Drive System

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Adam Kempski, Robert Smolenski

In this paper an analytical approach to decomposition of total phase EMI noises through algebraic calculations and the Fourier transform has been presented. Separating conducted EMI noise into different, common and differential mode (CM and DM) HF current components is important for a proper spectral analysis and application of EMI mitigation techniques. The results of calculations have been compared to EMI currents measured on the motor side of the PWM drive system.

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Capacitive Coupling And Parasitic Capacitances of Converter’s – EMC

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Irena Kováčová, Dobroslav Kováč

The paper is dealing with some electromagnetic compatibility (EMC) problems of converters and inverters, which are utilized for feeding of electric machines and its analyzing by PSPICE program. The main attention is focused on implications of parasitic capacitance and capacitive coupling existence.

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Energy Consumption of Water Pumping for Selected Control Systems

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Leszek Szychta

The article defines the coefficient of the unit energy consumption of water pumping in pump group. Correct pump operation in pump group are described during cascade control, at variable rotational speeds and in the highest range of efficiency. A method of determining the unit energy consumption of water pumping for these control systems are defined at any daily demand and known pump H(Q) and efficiency curves are plotted at nominal rotational speed.

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Sensorless Control of Surface Mounted Permanent Magnet Synchronous Motors Using Matrix Converters

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David Saltiveri, Antoni Arias, Greg Asher, Mark Sumner, Pat Wheeler, Lee Empringham, Cesar Silva

This paper investigates the influence of the power converter on the performance of Surface Mounted Permanent Magnet Synchronous Motor drives, which employ High Frequency voltage injection to achieve low and zero speed control.  Experimental results demonstrate the remarkable performance of the sensor less speed and position control employing the Matrix Converter and the contributions of the Space Modulation Profiling technique.

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The Solution of Solid Charge Direct Resistance Heating with Similarity Theory

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Pavel Novák, Jozef Janoščik, Dušan Medveď

The place of generation of technologic heat is important applied criteria for classification of electric heating. According to that, the direct heating is if the heat is generated directly in the heated material, or the indirect heating if material is heated indirectly by the heat generated in conversion element.  Possibilities of practical application of both methods are typical for resistant heating. Considering indirect heating, the charge is out of influence of electromagnetic field, this directly does not influence its temperature field.

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