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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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Příspěvek k analýze asynchronního stroje se dvěma třífázovými statorovými vinutími
Schreier, Luděk ; Bendl, Jiří ; Chomát, Miroslav ; Skalka, Miroslav
This paper analyses situation in induction machines with two three-phase windings on the stator fed by two totally independent voltage sources. To analyze the situation in these machines, the method of space vectors has been used. The paper shows a mathematic description of such a machine based on a system of differential equations. The waveforms of currents and torque of the machine for various time shifts of voltages of both the feeding sources are shown. The results of the simulation show the necessity to exactly maintain the optimal time shift of both the voltages.
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Influence of Induction Machine Operation Mode Type Onto The Equivalent Circuit
Skalka, Miroslav ; Schreier, Luděk ; Janda, M. ; Ondrůšek, Č.
This paper deals with analysis of Induction Machine equivalent circuit parameters for both operation mode types (motor/generator). The purpose of this work is the definition of equivalent circuit parameters and theirs non-linear behavior depending on various factors - slip, mechanical torque, temperature. The temperature influence for longitudinal resistances is done - which means, the stator and rotor resistance value depends on passing current. At the end an electromagnetic field comparison for the same operation point in both operation mode types will be presented. The whole analysis is done in ANSYS (by FEM) and MATLAB program.
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Charging Capacitors of Multilevel Inverter from dc Intermediate Circuit
Bejvl, Martin
The paper deals with computer simulations of flying capacitors charging in a capacitor-clamped multilevel inverter from DC link side using an auxilinary voltage source. This charging is a transient process, which is necessary before the inverter can be put into operation. Purpose of these simulations is to estimate voltage waveforms on different nodes and devices of the inverter during this transient process in advance. There are also compared 4 charging methods, which differ in way of switching power semiconductor devices.
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Software Phase Lock Loops of PWM Rectifiers
Šimek, Petr ; Škramlík, Jiří ; Valouch, Viktor
In the paper the properties of three PLL techniques (known under names DSC-, DDSRF- a FVAVG-PLL) for different states of the feeding three-phase voltage system are assessed. As a crucial quality criterion of synchronization to the positive component of the fundamental harmonic voltage the errorbetween an estimated and real angle of the positive component of the fundamental harmonic voltage vector was selected. Two sampling periods Ts=0.05 ms and 0.5 ms as well as two gain values of a PL-type compensator were treated.
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Prostorové rozložení oscilací v modulovaném proudu plazmatu
Gruber, Jan ; Šonský, Jiří
Electric current in a vertically oriented DC plasma torch was modulated with frequencies varying in the range 15 Hz ? 7.5 kHz. Resulting plasma jet optical radiation was recorded by the high-speed CCD camera. The length of the record and the time resolution were sufficient for the application of the FFT yielding a detailed view of the oscillation phenomena in the plasma flow. Significant oscillations were identified and their distributions in the jet plane examined. In this work we show influence of current modulation on the dominant frequencies of oscillations and their spatial distributions.
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Vliv nestabilit na určení střední teploty ve volném proudu termického plazmatu
Hlína, Jan ; Šonský, Jiří ; Šlechta, Jiří
We have used results acquired by a multi-directional optical system for temperature measurements with a high temporal resolution to compare mean temperatures in the jet obtained by averaging the instantaneous temperature fields with the temperature values acquired in the usual way from averaged radiation intensities. The comparison shows differences in results yielded by both methods which are caused by the nonlinear dependence of radiation intensity on temperature.
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Electromagnetic Field Calculation of IM for Different Equivalent Circuit Parameters
Skalka, Miroslav ; Schreier, Luděk ; Ondrůšek, Č.
This paper contains a calculation of electromagnetic field distribution of Induction machine for different equivalent circuit parameters due to the loads - each step is calculated for different rotor and stator currents. The definition of parameters and the real values of rotor and stator currents were presented on the XVI. Inter. Symposium on Electric Machinery in Prague. These data were used for a calculation of electromagnetic field distribution of Induction Machine (IM) by finite element method in ANSYS.
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