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

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

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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Design of DC Permanent Magnet Disc Motor and improving its EMC

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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Environmental EMC aspects of resistance welding equipment

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.

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

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. For a switch mode dc-dc converter, random and periodical sinusoidal CFM is systematically tested.

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EMC shielding in power electronics multilayers

The integration of passive components in printed circuit boards by using structured layers of different material leads to completely new technical challenges, both in technological realisations and in simulations or modelling of the embedded components. The integration of inductive components is very interesting due to the substantial place reduction on the surface of the printed circuit board. In this context the shielding of the stray field of these inductive components leads to some new approaches in magnetic field calculation and simulation by planar structures.

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Multiresonant ZVS boost convertor

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

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

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

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.

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

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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Developments of Power Quality studies in Electric Transportation System

The paper deals with the update studies on Power Quality for electric traction systems. Probabilistic methods of analysis are presented both for the supply lines and the rolling stocks. Simulation software tools are created for disturbance propagation studies and examples of application are reported with reference to the Italian railway case.

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Estimation of Voltage Unbalance in Power Systems Supplying High Speed Railway

The electric high speed railway loads supplied by the three phase power system represent one of the main sources of voltage unbalance perturbation in the grid. The power system configuration and the load conditions influence the degree of this power quality perturbation. The present paper deals with the problems raised by the practical determination of the voltage unbalance factor in conformity with the European and IEEE standards.

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