ISSN 1805-3386

April 6, 2020


2012 No.2

Analysis of Squirrel Cage Motor with Broken Bars and Rings

Miksiewicz, R.

In the paper results of calculations and measurements of an induction motor with broken bars or rings are presented. The calculations were made using the circuit and circuit-field method. The stator current as diagnostic signal for estimation of a damaged squirrel cage motor has been taken. For separation of additional components in the stator current arising at a rotor asymmetry low-pass filters of Mathcad program were used.


Keywords: Electric machine, induction motor, broken bars, diagnostic.


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Asynchronous Generators with Dynamic Slip Control

Kalamen, L., Rafajdus, P., Sekerák, P., Hrabovcová, V.

This paper presents various systems for dynamic slip control of wound-rotor asynchronous generators. Particular systems are presented here and compared to each other. This paper thus yields a comprehensive overview of systems for converting wind energy to electrical energy using asynchronous generators with slip control.


Keywords: Asynchronous generator, dynamic slip control.


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Properties of Twelve-Pulse Rectifier with Short-Circuit Diodes

Mlynařík, L., Novák, J.

This paper deals with simulation and experimental efforts verifying influence of short-circuits of semiconductor diodes on subsequent action of twelve-pulse traction rectifier in traction power stations (3kV DC) of the Czech railway. A computer model of a traction power station, results and conclusion of research are described. To verify relevance of results obtained from simulations a measurement on a small laboratory model of twelve-pulse rectifier was performed. These results are part of this paper as well. Short-circuits are always examined using simple and multiple commutation of diodes.


Keywords: Primary current, current harmonic, rectifier, transformer, twelve-pulse connection, semiconductor diode.


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Higher Harmonics in Output Voltage of Inverters

Uhrík, M., Hüttner, Ľ., Duč-Anci, M.

The article presents the basic mathematical and programming tools for analyzing the higher harmonics of inverters. Harmonic spectrum of the output voltage in a simple and cascade connection of an inverter models are analyzed using Matlab/SimPower Systems. The influence of the cascade connection on the output voltage harmonic spectrum is observed. There is also analyzed the total harmonic distortion at different ways of switching.


Keywords: Converter circuits, simulations, harmonics.


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Structured System and Software Design of Distributed Control Computer of Mechatronic Facility for Space Research

Zdenek, J., Lettl, J., Bauer, J.

The structured system and software design method of the distributed control computer network of the mechatronic scientific facility for automatic high temperature material processing in the space in micro-gravitation environment is presented in the paper. The facility distributed computer controls special extra low speed vibrationless electric drives, multi-zone high temperature furnace heating system and several measurement devices. The computer is equipped with special technological language to be possible to specify experiment time flow. Computer network nodes have many user processes (threads) so efficient, reliable, self documented, and low overhead scheduler dispatcher is required. The table driven coroutines have been designed.


Keywords: Mechatronic, real time processing, software, cooperating FSM.


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Measurement on Five-Phase IM Fed from Ten-Pulse Frequency Converter

Chomát, M., Schreier, L., Bendl, J.

The mathematical model of a five-phase induction machine derived on base of the theory of space vectors and symmetrical components was verified by means of a comparison of simulation and experimental results. A multi-phase voltage source inverter was used to feed an experimental five-phase induction machine by ten-pulse supply voltage of constant frequency in different connection arrangements. Steady state operation was considered. The good agreement between the simulation and experimental results has proved the correct function of the mathematical and numerical model used.


Keywords: Five-phase induction machine, ten-pulse converter, symmetrical components.


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