coordinated control of multiple hvdc links using input–output exact linearization

this paper is concerned with the investigation of a new control technique for the conventional high voltage direct current (hvdc) link. the proposed technique relies upon nonlinear state feedback linearization of the ac/dc power system. the idea in input–output exact feedback linearization is to algebraically transform nonlinear systems dynamics into a linear control problem using a nonlinear pre-feedback loop, and then for the linearized power system one can design another feedback loop using a well established technique such as a linearquadratic regulator. the primary goal of the controller presented in this paper is to contribute to the enhancement of both the transient and the small-signal stability of the power system. since the proposed state feedback linearization does not rely on the assumption that there is only small deviation of the states from an equilibrium, the enhancement of both is feasible. the simulation results obtained in the framework of the study show that the proposed controller is capable of stabilizing the system in various system operating conditions.