Apparatus for providing ignition to a gas turbine engine and method of short circuit detection

摘要

A solid state, bipolar, ignition exciter for gas turbine engines is described for delivering high energy pulses to one or more igniter plugs. A storage capacitor is charged with typically 12 to 20 Joules of stored energy and discharged through a solid state switch and a series-connected ignitor plug. The solid state switch consists of a plurality of silicon controlled rectifiers (SCRs) connected in series, in combination with other components connected in parallel with each SCR. Protection is provided against transients in voltage by means of resistance-capacitance snubber circuits connected in parallel with each SCR. Protection is provided against transients in current by means of inductance connected externally, and in series with, the solid state switch. Protection is provided against damage from reverse voltages by means of a reverse current path through the solid state switch, typically by means of a diode or series-connected diode chain connected in parallel with the SCRs. Thus, the solid state switch of the present invention conducts current alternately in forward and reverse directions once the SCRs are switched to their conducting state, providing bipolar current flow to the igniter plug. Controlling means and short circuit protection circuits are also described.