A constant DC voltage control based method of the active power quality compensator for electrified railways

This paper proposes a novel control method for the active power quality compensator used in electrified railways. In the proposed method, only the constant dc voltage control is used to compensate the non-active and unbalanced active currents on the secondary side of the Scott transformer. Any schemes to detect the reactive and harmonic currents are not needed. Thus we can provide the simplest way to improve the power quality in electrified railways. The basic principle of the proposed control method is discussed. The validity and excellent practicability are confirmed by digital computer simulation using PSIM soft ware.