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Možnosti zvyšování účinnosti indukčních motorů použitím kombinovaného statorového vinutí
Schreier, Luděk ; Bendl, Jiří ; Chomát, Miroslav
Jsou analyzovány dvě základní varianty zapojení kombinovaného statorového vinutí asynchronního stroje. Účelem použití kombinovaného vinutí je potlačení vybraných skupin vyšších prostorových harmonických proudové vrstvy a indukce ve vzduchové mezeře a toku ve jhu za účelem snížení ztrát a zlepšení účinnosti. Jsou uvedeny diferenciální rovnice pro obě uvažované varianty. Na základě numerického řešení těchto rovnic byla ukázána schopnost jednotlivých variant potlačovat vyšší harmonické. Platnost rovnic byla ověřena experimentálním měřením na fyzikálním modelu asynchronního stroje se statorovým kombinovaným vinutím.
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Mathematical Description of Combined Stator Winding of Induction Machines
Schreier, Luděk ; Bendl, Jiří ; Chomát, Miroslav
The contribution is focused on estimation of properties of induction machines with the combined stator winding. The paper analyses the influence of the shift between the windings and the influence of the number of conductors of these windings on the currents and the torque of the machine with regard to the fundamental spatial wave. The result of the analysis is the set of differential equations describing operation of the machine with the combined windings.
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Transient Behavior of Active Front-End Rectifier under Unbalanced Voltage Supply
Chomát, Miroslav ; Schreier, Luděk ; Bendl, Jiří
Operation of voltage-source inverter supplied with unbalanced system of voltages is investigated in the paper. This situation can lead to problems in operation of an electric drive as voltage pulsations can arise in the DC-bus. Suitable kontrol methods may be applied to eliminate this effect in the aktive front-end rectifier. The paper particularly focuses on transient processes that accompany operation of the drive. They can be caused by changes in control of the drive, changes in load, or changes in the supply voltages.
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Influence of Third Space Harmonic on Properties of Five-Phase Induction Machine
Schreier, Luděk ; Chomát, Miroslav ; Bendl, Jiří
The paper deals with the necessity to consider higher space harmonic waves of a current layer, magnetic flux density and yoke flux in a five-phase induction motor fed from a tenpulse frequency converter. It is shown that especially the third space harmonic influences currents and torque of the machina considerably. The influence depends on connection arrangements of the converter and stator of the five-phase induction machine. Theoretical results are verified by experimental measurements.
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Measurement on Five-Phase IM Fed from Ten-Pulse Frequency Converter
Chomát, Miroslav ; Schreier, Luděk ; Bendl, Jiří
The mathematical model of a five-phase induction machine derived based on the theory of space vectors and symmetrical components was verified by means of 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 voltage supply 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.
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Induction Machine Operation Mode Type Effect Onto The Losses
Skalka, Miroslav ; Schreier, Luděk ; Janda, M. ; Ondrůšek, Č.
This paper deals with analysis of losses behavior of Induction Machine for both operation mode types (motor/generator). The purpose of this work is the definition of eqiuvalent circuit parameters and theirs non-linear behavior depending on various factors - slip, mechanical torque, temperature. In this paper would be presented behavior of iron losses and joule losses of rotor and stator with specific parameters behavior. The whole analysis is done in ANSYS (by FEM) and MATLAB program.
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