DEVICE FOR CONTROL OVER TWO THYRISTORS CONNECTED IN PARALLEL OPPOSITION Russian patent published in 1994 - IPC

FIELD: electrical engineering. SUBSTANCE: resistor-capacitor networks 7, 8 and 9, 10 are connected in series, resistors 11 and 12 are connected in parallel to them. During different half-cycles networks are shunted either with diodes 14 or 15 in series with current-limiting element 13, either diodes 16 or 17 in series with controlling junctions of thyristors 1 or 2 and controlling key element 6. During idle run voltages across networks change from amplitude of mains voltage to zero and their sum is equal to mains voltage. With unblanking of controlling element one of thyristors is driven to conduction supplying voltage to load 3. Then after recharge through open thyristor voltages across capacitors level and till thyristor is open capacitors discharge to resistors 11 and 12. With cut-off of open thyristor mains voltage charges one capacitor and discharges other capacitor. When voltage across the latter equals zero during next half-cycle other thyristor unblanks and process of recharge of capacitors repeats till total mains voltage is supplied to load. EFFECT: improved efficiency of control. 2 dwg