Digital Control System Development for an Intercooled Recuperated Gas Turbine

The on-going development of a full authority digital engine control (FADEC) system for the US Navy’s Intercooled Recuperated (ICR) gas turbine requires a high level of system coordination to achieve the primary benefits of reduced specific fuel consumption and improved specific output power relative to a simple cycle engine. This paper describes the system requirements analysis and the implementation of control algorithms leading to the preliminary ICR control system design. The ICR control system is required to coordinate the actions of over 30 actuators using data taken from over 150 sensors. Primary control of the engine output power is provided by regulation of the fuel metering valve. Thermal management of the intercooler, recuperator, and variable area power turbine nozzle results in maximum cycle efficiency within safe operating limits. The new electronic engine controller (EEC) is based on a new open architecture Futurebus + backplane and is fully redundant in all operationally critical control functions. The EEC also features an operating panel and video display for local operation and maintenance of the control system. The graphic display and function keys provide access to control functions as well as assisting maintenance activities with built-in test diagnostics to trouble shoot failed circuitry.