A model-based active-adaptive controller for thermoacoustic instability

Active control of thermoacoustic instabilities in continuous combustion processes is desirable for operating at conditions of low NOx, high performance, and high efficiency. We have previously developed a model-based approach for active control design by taking into account underlying acoustics and heat release dynamics. While this model captures a number of the dominant dynamic features of a premixed laminar combustor, there are a number of uncertainties associated with it as well. In this paper, we study the sensitivity of this model with respect to parametric uncertainties, and the efficacy of a fixed control design for suppressing pressure oscillations. We show that under certain conditions, the fixed controller is inadequate and present a self-tuning controller which is capable of delivering the desired performance in the presence of these uncertainties. The controller proposed is based on a rigorous analytical foundation, and is shown through simulation results to lead to better performance than corresponding fixed controllers.