A novel zero dynamics design method and its application to hydraulic turbine governor

Based on differential geometric control theory, this work proposes a novel zero dynamics design method for a class of nonlinear non-minimum phase systems, which using dynamic feedback to the controlled system to obtain stable zero dynamics through dimension extension. Nonlinear control law is then derived by means of the linear control design method. Furthermore, both the optimality of the control law and the closed-loop system´s stability are mathematically and strictly proved using HJB equation and centre manifold theory respectively. A nonlinear optimal governor controller is also proposed on the foundation of ideal hydraulic turbine model. The simulation results show that the novel governor control strategy for hydraulic turbines could enhance transient stability of power systems more effectively than the conventional control law.