synchronous Generator excitation control device automatically (AER) is an important part of the automatic device in power system, the phase shift trigger unit's mission is to produce can change the phase of the pulse, is used to trigger the thyristor rectifier bridge, make its control Angle and subject to change with the change of the voltage of the generator, so as to achieve the goal of automatic regulating excitation.Phase-shift trigger unit is formed by synchronization, phase shift, pulse, pulse amplification, if processes is not good, the synchronous voltage will affect the accuracy of the phase shifting trigger pulse, thus affecting the generator excitation.In semiconductor excitation system of synchronous voltage produced is very trouble, with the use of microcomputer for synchronous voltage processing provides a great convenience.

The role of synchronous voltage

According to the Silicon controlled rectifier circuit Conduction control requirements for the thyristor, thyristor is added on the favorite on voltage and control on phase must cooperate with reasonable or thyristor trigger pulse will not be able to work properly, it is called synchronization.In thyristor excitation system, therefore, must draw synchronous voltage to ensure thyristor trigger pulse and the main circuit of synchronization.

The generation of synchronous voltage

Determining the synchronous voltage and controllable rectifier circuit wiring pattern.

Three phase half controlled silicon rectifier circuit, the anode group of rectifier element is holding in the natural flow point change flow, common cathode group of SCR should inherit the anode voltage of timing A range of trigger conduction, three phase trigger pulse should press + A, B +, + C crosstalk in 120°Send out.

Three-phase controlled silicon rectifier circuit, common cathode group thyristor is only in the anode potential of the highest period of interval can be conduction start group for the cathode pulse should be issued in this period, three phase trigger pulse should press + A, B +, + C phase sequence in 120°Send out.Anode sets of SCR is only in its lowest cathode potential is it possible to guide a range bin, a total of anode sets trigger pulse should be issued in this period of interval.Three phase trigger pulse should press -, - A, B, C phase sequence in turn 120 ° apart.The six phase trigger pulse should press + A - > - C - > + - > - A - > B + C - > B phase sequence in turn 60 apart°Send out.

So the phase-shifting trigger unit with must accept a main circuit voltage phase relationship of voltage signal, to ensure that the trigger pulse issued as required.Synchronous voltage can be obtained with synchronous transformer, synchronous voltage using the appropriate connection, main circuit voltage transform into a trigger circuit required number of amplitude, phase and phase synchronization of voltage, as phase-shift trigger unit synchronization signal.