Double ignition pulses correct allocation circuit for thyristors - has detectors for AC voltage rotating field direction followed by A=D converter

摘要

The allocation is made for different rotating field directions, depending on a polyphase AC voltage supplying a polyphase fully controlled thyristor bridge. A gate control unit delivering the ignition pulses, and a circuit detecting the direction of the polyphase AC voltage field rotation are provided. The gate control unit delivering the ignition pulses is followed by a diode matrix for double pulse formation for different field rotation directions. At least two selector components are connected to it in parallel. They are followed by a logic unit, an amplifier and a transformer, to whose outputs the thyristor gates are connected. The polyphase AC voltage detector of direction of field rotation delivers two different amplitude analogue signals and is followed by an analogue-digital convertor, controlling the selector component at different directions of rotation.