Switch=on system for inverter with transformer - limits first trigger pulse to quarter of operating frequency period to reduce starting current and voltage distortion

摘要

The switch-on system is used with static inverters having an output transformer as a magnetic voltage regulator. In order to avoid a very high starting current which can be caused by magnetic saturation the first triggering pulse for the converter is limited to one quarter period of the operating frequency. Subsequent impulses are set at a half period. The pulse variation can be set by electronic logic elements. The result is a starting current which does not exceed twice the full load current and a steady output voltage after about three periods. There is no voltage overshoot.