METHOD FOR STARTING OFF-LINE INVERTER WHOSE LOAD IS INSERTED BETWEEN TWO SERIES-CONNECTED BRIDGES USING DIODES CONNECTED IN PARALLEL OPPOSITION

摘要

FIELD: converter engineering; thyristor frequency converters for vacuum smelting of metals and special alloys.;SUBSTANCE: proposed method involves following procedures: stepped down supply voltage is applied to inverter input and control pulse train desired to meet conditions of inversion, to thyristors of arbitrarily chosen pairs of cophasal arms of bridges; oscillograms of voltages across switching capacitors are obtained, and if dc components of voltages are detected in these curves, inverter is turned off, control pulses of thyristors in each pair of cophasal sides of one of two inverter bridges are inverted in phase, and full supply voltage is applied to inverter input. Voltages across sides of inverter bridges are equalized under steady state conditions by eliminating dc components of voltages across switching capacitors.;EFFECT: enhanced operating reliability of inverter.;1 cl, 16 dwg