Self-controlled single-phase thyristor inverter - operates in parallel with several inverters and uses preset frequencies for inverter control

摘要

The thyristors are controlled by control elements determining the operating frequency and the current flow cut-off angle. When one invertor current (i) lag increases, or lead decreases with respect to the output voltage (u) of other invertors, this invertor frequency is increased, and when the current lead is increasing or lag decreasing, its frequency is reduced in accordance with a specified formula. Preset frequencies for the individual inverters so affect the respective control elements (42) as to provide the frequency dependent control. Preferably voltages (uo) are also preset for the individual inverters for changing the current flow cut-off angle of the thyristors.