Journal Volume 11 Issue 2

Design of DC Permanent Magnet Disc Motor and improving its EMC

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Irena Kováčová, Ján Kaňuch, Dobroslav Kováč

This paper deals with construction design of DC permanent magnet disc motor by classical calculation method and its verifying by computer finite element simulation method. The paper deals also with the computer analysis of the electromagnetic compatibility (EMC) problems focused to the area of electrical machines, which can also disclose the startling facts concerning. A problem of interference between electric motor and surroundings space caused by electromagnetic field radiation is discussed too.

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Currents' physical components (CPC) in circuits with nonsinusoidal voltages and currents - part 1: single-phase linear circuits

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Leszek S. Czarnecki

The paper summarizes the present state of discussions on power phenomena, power definitions and compensation in single-phase linear circuits. The main concepts developed over several decades on how various non-active powers in circuits with nonsinusoidal voltages and currents should be defined and compensated are presented along with a detailed discussion of these concepts. The paper presents also the concept of the single-phase load current decomposition into Currents’ Physical Components (CPC) and its application for power definitions and compensation in such circuits.

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Optimum EMC design of flyback and load resonant converters using toroids with air gaps

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Alexander Stadler, Manfred Albach, Thomas Dürbaum

In this paper the external magnetic stray field is investigated in transformers realized on gapped toroids with a rectangular cross section. An analytical method is used in which the field distribution is calculated by means of orthogonal expansion. As a conclusion it is shown that optimum EMC design for the case of a flyback converter is given by the results for a simple inductor. In case of a load resonant converter minimum parasitic induction is obtained, if the winding conducting maximum current is located exactly above the air gap.

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Environmental EMC aspects of resistance welding equipment

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Reinhard Doebbelin, Thoralf Winkler, Andreas Lindemann

Resulting from the connection between the change rate of a magnetic field and the induced currents in an exposed hu­man body, pulsating magnetic fields have to be evalu­ated analysing the waveforms of the field or the field-generating current. A corresponding assessment guideline is given in the German safety regu­lation on “Electromagnetic Fields” BGV B11. Considering the specific output current waveforms of resistance welding installa­tions, in the paper appropriate procedures to determine the waveform-dependent exposure limits are explained by the examples of an a.c. resistance welding machine and a resistance welding inverter.

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Conducted EMI Mitigation in Switched Mode DC-DC Converters by Spread Spectrum Techniques

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Artur Knitter, Jarosław Łuszcz, Piotr J. Chrzan

In this paper effectiveness of spread spectrum modulation techniques to the electromagnetic interference (EMI) suppression is investigated. Comparative evaluation of spread spectrum methods is reviewed and demonstrated with the aid of function generator and EMI receiver. Obtained results indicate advantageous features of random carrier frequency modulation (CFM), which results in more steady spectral distribution.

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Multiresonant ZVS boost convertor

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Elżbieta Szychta

The article presents properties of multiresonant voltage-increasing converter to be applied in DC voltage supply systems. The configuration of the system elements enables application of the technique of zero voltage switching (ZVS) of semi-conductor elements, which yields high operating frequencies of the system while maintaining high energy efficiency and reliability of operation. Results of simulation tests of the converter, based on Simplorer, are discussed. Regulation characteristics are presented and the converter’s efficiency is determined.

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Classical control of the neutral point in 4-wire 3-phase DC-AC converters

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Qing-Chang Zhong, Leslie Hobson, Marcel G. Jayne

In this paper, the classical control techniques are applied to the neutral point in a 3-phase 4-wire DC-AC power converter. The converter is intended to be connected to 3-phase 4-wire loads and/or the power grid. The neutral point can be steadily regulated by a simple controller, involving in voltage and current feedback, even when the three-phase converter system (mostly, the load) is extremely unbalanced. The achievable performance is analyzed quantitatively and the parameters of the neutral leg are determined. Simulations show that the proposed theory is very effective.

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Utilization of a neutral wire filter inductor in a three-leg four-wire active power filter

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Sami Pettersson, Mika Salo, Heikki Tuusa

Three-leg active power filter topology is the cost effective solution implementing a four-wire active power filter but it has some disadvantages compared to four-leg topology. The lack of a neutral wire filter inductor results in larger filter losses and therefore the efficiency of the topology is impaired. The neutral wire filter inductor is typically used with the four-leg four-wire active power filter topology and significantly reduces switching frequency current ripple. In this paper the suitability of a neutral wire filter inductor for the three-leg topology is studied.

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Sampled method of active power filter control - part I

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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 under discussion family of filters is designed to work synchronically with a time period T. The period T may be regulated in some range. The distinctive property of these filters is maintaining non-deformed source current in every one individually considered period T.  

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Energetic parameters of induction motors as the basis of energy saving in a variable speed drive

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Oleg Muravlev, Olga Muravleva, Eugenia Vekhter

Energy saving is an important factor of economic growth and effectiveness growth of national economy. Solving the problem of energy saving is possible when improving a variable speed electric drive based on induction motors which should be designed and manufactured for special energy saving technologies. New approach to induction motor design taken into account service condition is required. Energetic characteristic increase is a determining factor. In this factor energy saving effectiveness evaluation mathematical model has been presented.

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