SINGLE-PHASE REVERSAL PROTECTIVE DEVICE FOR OFF- LINE INVERTERS BUILT AROUND TURN-OFF THYRISTORS Russian patent published in 1998 - IPC

FIELD: units and devices incorporating off-line inverters built around turn-off thyristors, such as no-break power supplies, induction-motor drives, frequency changers of induction-heating devices, and the like. SUBSTANCE: device incorporating turn-off pulse shapers for both thyristors of one phase, turn-on pulse shapers for both thyristors of same phase, status sensors connected in parallel with control inputs of these thyristors, and primary control pulse unit whose outputs are connected to inputs of turn-off and turn-on pulse shapers for both thyristors is provided, in addition, with normally open switching device introduced in each thyristor controlled by status sensor of other thyristor so that switching device is closed only when status sensor responds to negative potential across gate electrode of cut- off thyristor. EFFECT: improved reliability in preventing accident developing due to single- phase reversal in any type of inverters built around turn-off power thyristors. 1 dwg