Modeling and Control of the Starter Motor and Start-Up Phase for Gas Turbines

Abstract

Improving the performance of industrial gas turbines has always been at the focus of attention of researchers and manufacturers. Nowadays, the operating environment of gas turbines has been transformed significantly respect to the very fast growth of renewable electricity generation where gas turbines should provide a safe, reliable, fast, and flexible transient operation to support their renewable partners. So, having a reliable tools to predict the transient behavior of the gas turbine is becoming more and more important. Regarding the response time and flexibility, improving the turbine performance during the start-up phase is an important issue that should be taken into account by the turbine manufacturers. To analyze the turbine performance during the start-up phase and to implement novel ideas so as to improve its performance, modeling, and simulation of an industrial gas turbine during cold start-up phase is investigated this article using an integrated modular approach. During this phase, a complex mechatronic system comprised of an asynchronous AC motor (electric starter), static frequency converter drive, and gas turbine exists. The start-up phase happens in this manner: first, the clutch transfers the torque generated by the electric starter to the gas turbine so that the turbine reaches a specific speed (cranking stage). Next, the turbine spends some time at this speed (purging stage), after which the turbine speed decreases, sparking stage begins, and the turbine enters the warm start-up phase. It is, however, possible that the start-up process fails at an intermediate stage. Such unsuccessful start-ups can be caused by turbine vibrations, the increase in the gradients of exhaust gases, or issues with fuel spray nozzles. If, for any reason, the turbine cannot reach the self-sustained speed and the speed falls below a certain threshold, the clutch engages once again with the turbine shaft and the start-up process is repeated. Consequently, when modeling the start-up phase, we face discontinuities in performance and a system with variable structure owing to the existence of clutch. Modeling the start-up phase, which happens to exist in many different fields including electric and mechanical application, brings about problems in numerical solutions (such as algebraic loop). Accordingly, this study attempts to benefit from the bond graph approach (as a powerful physical modeling approach) to model such a mechatronic system. The results confirm the effectiveness of the proposed approach in detailed performance prediction of the gas turbine in start-up phase.

Architecture of Distributed Control System for Gearbox-Free More Electric Turbofan Engine

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A scientometric analysis and critical review of gas turbine aero-engines control: From Whittle engine to more-electric propulsion

“…Performance models of gas turbines developed using the bond graph approach 89–93 are used in the design and optimization of control systems. For instance, Jafari et al 92,93 studied electric start systems of gas turbines and jetquads with the aid of the bond graph method.…”

“…37 Publications based on engine model or controller distribution: There are many investigations related to the distribution of aero-engine models and their controllers or any other electronic devices. Performance models of gas turbines developed using the bond graph approach [89][90][91][92][93] are used in the design and optimization of control systems. For instance, Jafari et al 92,93 studied electric start systems of gas turbines and jetquads with the aid of the bond graph method.…”

“…Performance models of gas turbines developed using the bond graph approach [89][90][91][92][93] are used in the design and optimization of control systems. For instance, Jafari et al 92,93 studied electric start systems of gas turbines and jetquads with the aid of the bond graph method. Also, regarding hybrid propulsion systems as a combination of electric systems and gas turbines, one can benefit from bond graph models of gas turbines.…”

Health monitoring system for the 10 MW Supercritical Carbon Dioxide S-CO2 Gas Turbine Power Plant

“…This failed start-up can be caused by the transmission vibrating. Siemens and General Electric believe that start-ups are receiving a lot of attention [153].…”