A new reliable supplied gate drive circuit for SCRs with breakover diodes for protection

A gate drive circuit for silicon controlled rectifiers (SCR) is presented which provides the combined functions of reliable firing performance, overvoltage protection to the device with a breakover diode (BOD), and status report of both the firing circuit and the SCR to the controller for judgement. In order to save cost and space, the gate drive circuit is self supplied eliminating auxiliary power supply. The gate drive circuit is isolated from the controller and the gate pulse generator with optic fibers for safety. The design has already been successfully applied in a thyristor-controlled reactor (TCR), and some experimental results are presented.