Active compensation for a driving system with chopper and DC motor

The paper deals with the behavior of a load consisting of an uncontrolled rectifier+chopper+DC motor at the supplying from the AC line. Experimental data are presented for the analyzed cases with current absorbed by motor from the AC line of approximately 100 A rms in two cases: with or without an power active filter. The necessity to protect the DC motor, not only the supplying line, is underlined. The tests were performed on a stand using a schematic for energy recovering that can also be found in the case of real driving from a tram. The difference between the active compensation from a tram and its counterpart from the transforming substation AC/AC 20kV/0.4 kV is presented.