engleski

Research into Possibilities to Increase Input Impedance of Voltage and Frequency Converters Fed from DC Network

High level requirements have been applied to static voltage and frequency converters by which a tolerable disturbance level, generated into the network by means of converters is determined. European railway supply network is specific due to two types (AC & DC) and four voltage levels. One of the very important requirements when converter is considered operating on DC network is the input impedance higher than permitted by UIC regulation in the frequency range from 50 Hz to 100 Hz. Based on research by means of mathematical models and physical model 2.5 kW power, according to the regulations, the solution has been chosen and described in this paper. It is the active filter in voltage and frequency converter DC link, carried out as a controlled switching DC-DC converter, which enables meeting the requirements regarding input impedance By controlling the switching DC-DC converter, maintaining link voltage in steady and transient states during load or input voltage changes has been solved at the same time. The shown results of measurement on the physical model give an insight into the dependence of input impedance on impressed signal frequency according to UIC 550.

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