Input characteristics of naturally commutated single-phase asymmetrical convertors

Thyristor control is increasingly being used for voltage control on a.c.-supplied traction vehicles. Although such equipment improves the traction performance, it also introduces disturbances into lineside signaffing and telephone circuits. This paper defines the input characteristics of single-bridge and multibridge asymmetrical convertor circuits. Using the equations developed in this paper, the harmonic spectrum of the traction current can be predicted and subsequently used for noise and disturbance calculations.