| 摘要 |
PURPOSE:To eliminate the unbalance for the voltage and the switching loss when the serial connection is given to the self-arc-extinguishing semiconductor elements by adding the reactor. CONSTITUTION:With addition of reactor 22, the exhaustion speed of the storage charge can be delayed for gate turn-off thyristor GTO14 of GTO14 and 15 connected in series, that is, the storage time of GTO14 can be increased. And with turn-off command (a) given to input terminal 11, gate circuits 12 and 13 conduct each, and the DC voltage is applied directly to GTO15 and to GTO14 via reactor 22 respectively. Then storage charge exhaustion speed dIg1/dt of GTO13 is delayed to reactor 22 as shown by turn-off gate current Ig1 and Ig2 (d) of GTO14 and 15. Thus the same storage time can be obtained between GTO14 and 15, and accordingly the cut-off properties is made identical between GTO14 and 15 as shown by the anode voltage plus current VA1, VA2, IA1 and IA2 (e). Thus the balance is kept for the switching loss as well as the voltage sharing at the turn-off time. |
