Bifurcation Analysis and Active Control of Surge and Rotating Stall in Axial Flow Compressors via Passivity

摘要

Gas turbines are widely used nowadays in industries and aeronautics. They have always suffered however from important aerodynamic instabilities, namely, rotating stall and surge which occur in the compressor stage. These nonlinear instabilities can cause component stress, lifespan reduction, noise, and vibration. Despite considerable efforts to stabilize axial compressors at efficient operating points, preventing and suppressing rotating stall and surge are still challenging problems. In this work, we address issues concerning the modelling, bifurcation analysis, stability and active control of these performance limiting phenomena. The nonlinear surge and stall oscillations are simulated using the Moore and Greitzer nonlinear model (the so-called MG3) for constant speed axial compressors (CSACs) and are further analyzed via Bifurcation Analysis For control purposes, the MG3 model is then appended with a closed-couple valve actuator. Due to certain passivity properties of this model, a robust multi-input multi-output passivity-based control approach is applied to tackle the stabilization problem. The main advantage of this approach is that robust stabilization and high performance control can be achieved by simple control laws and limited control efforts. Analytical developments and time-domain simulations demonstrate that the developed control laws can effectively damp out rotating stall and surge limit cycles by throttle and close-coupled valve actuations. The robust performance of the controller is validated in the presence of bounded mass flow and pressure disturbances, as well as model uncertainties.