| 摘要 |
1,179,977. Thyristor firing circuits. BROWN, BOVERI & CO. Ltd. 6 Sept., 1968 [8 Sept., 1967], No. 42514/68. Heading H3T. In a pulse generator having two parallel connected branches, one branch includes a resistor R1 in series with a thyristor T1 and diode D1 inversely connect across the thyristor T1, the other branch includes a resistor R2, diode D2, thyristor T2 and primary winding AB of a pulse transformer for firing a thyristor, and capacitors C1, C2 and a resistor R3 are connected as shown with a resistor R4 connected to a terminal for connection to a voltage U2 higher than that U1 connected to the parallel branches. When thyristor T1 is ON capacitors C1 and C2 charge via T1, R2, inductor La and T1, R3, R4 respectively. Then if T2 is fired ON these capacitors C1 and C2 discharge via T2 and the pulse transformer AB and thyristor T1 turns OFF. The extinction of T1 does not affect the discharging of C2 since capacitor Q discharges via diode D1 and the combined effect of these capacitors Cl, C2 discharging produces a sharply rising firing pulse (Fig. 1, not shown), in the secondary of the pulse transformer AB. Diode D2 isolates the higher voltage U2 from the capacitor C1 and so prevents current flow through the low-resistance path R4, R2, R1 when T1 is ON. The pulse transformers AB have an auxiliary primary winding connected in series with thyristor T1 so that when it is conductive the magnetization of the cores, produced when T2 was conductive, is reversed. The circuit may be used for the simultaneous firing of a plurality of thyristors. |
