Control circuit for rotary field converter - uses phase shifted voltages to control firing pulses for thyristors on machine side

摘要

The control system for a rotary field motor converter uses an auxiliary rotary voltage system for the frequency and voltage variable rotary armature voltage system for initiating the firing pulses for the thyristors of the converter on the machine side. This operates at the same frequency as the armature rotary voltage system and its phase position can be shifted relative to it by a control voltage. The zero points for the auxiliary system directly releases the firing pulses for the thyristors without a delay device. The release of further firing pulses following the zero points is blocked until the commutation has been safely connected. The instantaneous voltage of the armature system is formed so that a first signal section for all three phases is cyclically and symmetrically added or subtracted to a further section multiplied by a signal voltage. At least one of the multiplied voltages is now in phase or in phase opposition to the first signal section.