Constrained model based control for minimum-time start of hydraulic turbines
Résumé
This paper introduces a simplified model of hydraulic turbines including the hydraulic nonlinear hill-chart and a first order model of the penstock. Based on the resulting reduced model, a graphical representation of the vector fields of the resulting controlled system is obtained under band unlimited actuator. This ideal 2D-graphical representation enables an exact evaluation of the lower bound on the minimum achievable start-time as well as the time structure of the control profile. The consequences of the use of a band-limited actuator is also analyzed enabling a close estimation of the lower bound on the start time in practical situations.