Possibilities to increase input impedance or power factor of line side converters supplied by DC or AC railway network

In order to investigate the possibilities to increase the input impedance or the input power factor of railway line side power converters, several different structures of converter control were investigated on mathematical models and a laboratory model of 2.5 kW boost converter connected to a DC or AC supply network. The final choice was the solution with a boost converter on the input of the line side converter with cascade control of input current and output voltage of the boost converter. This solution assures high performances of input impedance or input power factor as well as allowable level of current disturbances in both DC and AC supply networks.