| 摘要 |
PURPOSE:To cotinue the gate drive of a thyristor by an alive pulse generator by providing a failure discriminator for monitoring the output signals of a plurality of pulse generators, thereby isolating the defected pulse generator from the system. CONSTITUTION:Control signals a(a-A-a-C) for deciding firing phase and conducting period and forward voltage detecting voltage signals b(b-A-b-C) are inputted to pulse generators PG(PG-A-PG-C), and output signals c(c-A-c-C) are applied as photogate signals to thyristors T(T1-Tn) via majority decision logic circuits MC(MC-A-MC-C) and light emitting elements L(L1A-LnC). On the other hand, defect discriminator FD(FD-A-FD-C) compares by AND the output signals d(d-A-d-C) with the signals c-A, c-B, c-C. When it is discriminated that the gate signal c-A is, for example, malfunctioned, it can detect that the gate signal c-A is malfunctioned, thereby detecting that the pulse generator PG-A is malfunctionecd. Accordingly, the failure discriminator FD can identify which pulse generator is malfunctioned from the failure signals e-A, e-B, e-C. |
