Switch=off circuit for static converter - has two semiconductor switches connected to smoothing capacitor and DC voltage source (NL 1.4.80)

摘要

A semiconductor switch (T1) is in series with the smoothing capacitor (Cp). A second semiconductor switch (T2) is connected in series with a d.c. voltage source (EO) to form a series circuit that is coupled in parallel with the first switch/smoothing capacitor circuit. The voltage source is of opposite polarity to the converter voltage. Three circuit configurations are described and all have the advantage of being simple and of providing effective overcurrent protection ensuring that neither fuses nor quick-action switches operate and the smoothing capacitor is not subjected to current surges.