Regeneration inverter system for DC traction with harmonic reduction capability

This paper proposes a DC power system, which can generate the excessive DC power form DC bus line to AC source in substations for traction system. The proposed regeneration inverter system for DC traction can be used as both an inverter and an active power filter (APF). As a regeneration inverter mode, it can recycle regenerative energy caused by decelerating tractions and as an active power filter mode, it can compensate for harmonic distortion produced by the rectifier substation. From the viewpoint of both power capacity and switching losses, the system is designed on the basis of three phase PWM inverters and composed of parallel inverter system, output transformers and an LCL filter.