Novel exciter circuit for ignition of gas turbine engines in aerospace applications

Ignition Exciter System (IES) convert electrical energy at low voltage levels into high intensity sparks capable of firing an air fuel mixture in gas turbines. Generally, electronic switches are in series with the energy discharge path of the spark current. It requires bulky storage capacitor to account for the excessive loss in the series switches. These configurations reduce energy transfer efficiency, and lead to bulkier ignition exciter system. Proposed ignition exciter topology is designed to improve efficiency, reduce real estate and weight; which are major requirements of a high energy discharge system in space constrained environments such as in aerospace applications. Proposed topology makes an effective utilization of key characteristics of passive circuit elements in the formation and sustaining high energy spark. The spark formation circuit consists of an inductive element, utilized to generate high voltage pulse; sufficient enough to initiate an arc. The spark sustaining circuit consists of capacitive element, supplying only the spark energy once the igniter plug becomes conductive. The proposed circuit topology promises to meet the requirements of spark energy delivery into the spark plug at drastically reduced peak current levels. The proposed topology promises higher system efficiency, reduced part count and thus shall reduce the product cost, while making the overall ignition exciter system more reliable. This paper provides the proposed IES circuit design, parameter selection and circuit simulations results for 28VDC to 20kVDC, 18kW peak power IES system.