Design and Modeling of Two-Level Fuzzy-PID Controller with min-max Strategy for the Thermodynamic Model of Trainer Turbojet Engine

In this research, an accurate modeling of the thermodynamic behavior of a gas turbine for a trainer jet engine has been developed, considering volume dynamics, shaft dynamics, and the effects of altitude and Mach number changes. In order to maintain the engine within the acceptable operational range, a two-level fuzzy-PID controller has been designed to control the turbojet engine in a software environment aimed at examining the effectiveness of the designed method. This controller effectively controls all nonlinear thermodynamic behaviors and Mach/altitude variations. Additionally, a protective loop has been implemented to safeguard against engine shutdown, extreme temperature increase, and surge using a Min-Max strategy with a paired controller that communicates the controller response to the engine and prevents engine damage. This model has the capability to simulate engine performance in both transient and steady-state conditions. After validating the model using Gasturb 13 software, with a maximum error of 8.76%, simulation results indicate the capability of the hybrid two-level controller in different operation conditions, resulting in an average 26% shorter settling time, 21.5% shorter rise time, and no permanent error compared to PID control.