Design and Simulation of Isolated AC-DC Fly Back Conversion System for High Energy Ignition Unit of Gas Turbine Engines

A high energy ignition system is used in the gas turbine engine to provide desired heat energy which ignites the fuel and compressed air passing through the combustion chamber. The high energy output of the ignition system depends on the suitable selection of converter mechanism. Therefore, an AC-DC fly back converter mechanism is used in the exciter unit which supplies high input voltage (3000V) to the gas discharge tube. This converter design provides input and output side electrical isolation and assures the safety of the system. Also, by incorporating this circuit with the ignition coil, the desired output of 3-6 joules and spark rate of 200 to 350 micro seconds can be achieved. This paper discusses the procedures involved in estimating the parameters for design of fly back conversion mechanism for HEI unit and simulating the designed circuit using MATLAB/SIMULINK for performance analysis and further optimization.