Circuit arrangement for mains-voltage synchronisation of two-pulse rectifier circuits

摘要

The invention relates to a circuit arrangement for the floating synchronisation of the phase-gating control of power-electronic converter circuits to the mains AC voltage. The object of the invention is to create a simple, operationally reliable circuit, to prevent incorrect synchronisation in the event of voltage dips, to ensure rapid readiness for use and to enable the control transformer to be supplied from voltage sources which are separate from the power section. The object is achieved in that a parallel circuit comprising a two-pulse bridge-rectifier circuit, a resistor and a capacitor is connected to a further parallel circuit, comprising a zener diode, a further capacitor and a series circuit comprising a transistor, resistor and light-emitting diode of an opto-coupler on the one hand, directly, and on the other side via a diode, in that this diode is connected in reverse-parallel with respect to the base-emitter diode of the transistor, and in that the bridge-rectifier circuit is connected via a bias resistor to the synchronising AC voltage. <IMAGE>