Method for controlling the converter valves of two or more parallel resonant circuit inverters fed from a common direct current source, each with an induction furnace, and system for carrying out the method

摘要

A method is proposed for driving the converter valves of two or more load-commutated parallel-tuned-circuit invertors which are supplied from a common DC source and are connected in series on the DC side, using in each case one induction furnace, which method enables continuously variable adjustment or regulation of the power emitted to the induction furnaces, a current flow from the DC source via the parallel-tuned circuit which is connected to this invertor being set by triggering in each case two diagonally opposite converter valves of an invertor. In each case two diagonally opposite converter valves (A11,A12 or B11,B12 or A21,A22 or B21,B22) of an invertor are triggered in a time-delayed manner, so that a "short-circuit current" is temporarily produced via two converter valves (A11,B12 or B11,A12 or A21,A22 or B21,B22), which are connected directly in series, of this invertor. IMAGE