N Turbine 1 f(u) 1 Tl.s Power Output Rotor Inertia -+ Torque P.U. Rotor Load Torque1 0.3 Per Unit Gain 1 KF K_droop Td.s+1 2 12 S_base/T_rate Figure 4. The gas turbine model in MATlAB/Simulink. Per Unit Rotor Speed 1-0.23 1-WMIN Mim Fuel Flow W *X.s+W Per Unit min X Y.s+Z Per Unit Low ValueSaturation Product Speed Governor Select Speed Control w_ref Speed Ref 1 + - - Valve Control Turbine Rated Exhaust Temp WMIN Add 950 TR 2.5s+1 Thermo Couple TT.s Fuel Temp Control 2 0.3s+1 +- 1 + + + + - 1 TCD.s+1 1 5 Combustor 1 TFU.s+1 Gas Fuel System a b.s+c Valve Positioner Air Control Turbine 2 Tx 0.8 W_F Time Delay W_F N f (u) Radiation Shield 0.2 15s+1 Temperature Control First, we discuss the modeling of gas turbine engine and its control system. The analytical modeling work aims to develop a control algorithm that enables an electric motor drive system to simulate the speed-torque behavior of a gas turbine engine as it drives an electric generator supplying power to electrical loads. Figure 3 shows the concept of the proposed engine emulation system. In principle, the performance of the engine is emulated by setting the speed reference of the motor drive according to the performance predicted by a realtime model of the gas turbine engine. When the generator is driven by the engine, its speed can be affected by variations in the speed reference of the free turbine governor and the generator torque when changes of electrical load occur. Therefore, the motor drive system includes closed-loop speed control to minimize the error between the reference signal for the motor controller from the engine observer and the actual motor speed. For the first step, a gas turbine engine model must be developed and replaced with the turbine engine observer. A literature review reveals that in recent years considerable research activities have been carried out in the field of modeling and simulating gas turbines. Many researchers employed a simple methodology to estimate the parameters of a Rowen's model for heavy-duty single-shaft gas turbines. They applied simple physical laws and thermodynamic assumptions to derive the gas turbine parameters using the performance and operational data. A variety of simulated tests were performed in a MATLAB/ Simulink environment, and the results were compared with the manufacturers' test data and verified against the results of scientific articles. Furthermore, it is notable that the applied methodology can be applied to any size of gas turbines. Figure 4 shows the transfer function block diagram based on Rowen's model for a heavy-duty gas turbine for dynamic simulation, including fuel and control systems. The IEEE Electrific ation Magazine / d ec em be r 2 0 1 4 27