National Repository of Grey Literature 4 records found  Search took 0.01 seconds. 
Some Aspects of Matrix Converter System Realization
Lettl, Jiří ; Flígl, S.
Matrix converters, initially called direct frequency changers in general only, have attracted an amount of interest over the past twenty-five years already, but with the rapid progress in the semiconductor devices and control circuits they find once again new utilisation. The presented paper deals with the recent concept of hybrid and power splitting traction drive systems.
Noise, Vibration and Electromagnetic eFFects Generated by Semiconductor Converters in Traction Vehicles
Budek, P. ; Chmelíček, M. ; Jehlička, Vladimír
New problems emerge in the vehicles of city mass transportation due to application of new power switching devices and their control circuitry. Measurements were performed in a low-floor trolleybus ŠKODA 21Tr equipped with power converters based on GTOs and IGBTs. They were aimed at finding the sources of noise and vibrations in the passenger space, at verifying their influence and finding methods for their limitation. Similarly, The same attention was paid to the problems of electromagnetic interference.
Control Strategy of Parallel Hybrid Filter for Harmonic Mitigation
Škramlík, Jiří ; Valouch, Viktor
The strategy features a small sensitivity against a disturbed supply voltage system and enables us to set grid phase currents in the phase with respective voltages. The expected properties of the PHF control system have been confirmed by experimental tests in the laboratory. The data show that the modified control strategy yields better results than those obtained by using control systems reported previously, especially in case of an unsymmetrical and non-sinusoidal voltage system and the demand of zero reactive power withdrawn from the grid.
Short-Circuit Protection of IGCT Voltage Source Inverters through the Use of Semiconductor Fuses
Bartoš, Stanislav ; Semerád, Radko ; Škramlík, Jiří
The power switching devices IGCT exhibit high values of the parameter I2t. This property enables their short-circuit protection by the so called semiconductor fuses. For both the thyristors and the rapid semiconductor fuses, the parameter I2t is usually defined for a half-sine current wave with the duration of 10 ms. However, in the dc feeding line of an inverter, the short-circuit waveforms are strongly different, and the best way to find the proper fuse for protection is to employ appropriate computer software.

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