Robust H∞ control of a Hamiltonian system with uncertainty and its application to a multi-machine power system

The robust H_∞ problem for a class of generalised forced Hamiltonian systems with uncertainty is investigated. A design approach for the robust H_∞ controller is presented and the L₂-gain from the disturbance input to the regulation output signal is shown to be able to be reduced to any given level provided that a derived algebraic inequality has a solution. The proposed method is used to create a Hamiltonian-like model with uncertainty which is able to describe power system dynamics on a full scale. Consequently a decentralised nonlinear robust H_∞ control law can be produced for a multi-machine power system using the Hamiltonian function. Simulations performed on a six-machine system verify that the proposed excitation control can cope with large disturbances and can enhance the transient stability of the power system more effectively than other types of controllers.