CONTROL DEVICE FOR TWO SETS OF BRIDGE THYRISTOR CONVERTER RECTIFIERS,CONNECTED IN PARALLEL OPPOSING

摘要

The control circuit has a window discriminator to detect the magnitude and direction of the stipulated current. The discriminator receives two reference voltages and a value describing the stipulated current. The discriminator's output is connected to a bistable flip-flop to select the converter group needed for controlling the speed of the motor, and to operate a pulse disabling circuit to prevent switch pulses being passed to thyristors in the converter groups, and to operate a polarity reverser to fix the sign of the control voltage and actual current.