Evaluation of converter topologies for improved power quality in DC traction substations

Abstract

A high power converter is developed for improved power quality in DC traction substation applications. The proposed converter can be used as both an inverter and an active power filter (APF). As an inverter, it can recycle regenerative energy caused by decelerating trains and as an APF, it can compensate for harmonic distortion produced by the rectifier substations. This paper evaluates the different topologies which can be used to implement this converter. A multilevel topology for the converter is considered because of the high power and high dynamic bandwidth requirements. A comparison is made between using a multilevel inverter and using a combination of a multilevel chopper and a lower voltage inverter.