The general configuration of a turboshaft gas turbine control systems model is
presented. The control systems included the relationships between the engine and its
limitations such as a compressor surge line limit, exhaust gases temperature, the speed
of the engines spools. The control system is of Multi Input Single Output (MISO) type,
where the inputs to the controller are the limitation signals and the demand whither the
only single output is the fuel valve new setting. The main parameter that the system
controls by is that the fuel mass flow rate and the device which is doing this job is the
fuel controller. The control system changes the fuel flow according to the engine
demands by changing the fuel valve angle (θ) .
The time responses of each effective parameter was predicted for a different fuel
valve angle and introduce the most effective specifications of the time response of the
system (delay time, rise time, settling time and maximum overshoot). The behavior of
the maximum overshoot value (if founded) is increasing with the fuel valve increasing.
The value of delay, rising, and settling times decreases with the fuel valve angle
increases. The present results show a good agreement with the previous works.