H-inf control for windmill power systems

The method for H-inf control design using the frequency criteria of H-inf control theory is applied to the windmill power system. H-inf control theory expresses the behavior of the target system by a transfer function as in the classical control theory, and it tries to satisfy several design specifications by limiting the norm of the closed-loop transfer function. The important concept of the H-inf control theory is that the H-inf norm represents the magnitude of the transfer function, and absolute maximum value of its frequency response is used for its evaluation. The robust performance of H-inf control is confirmed by the simulation result for the designed controller. The simulation results show that the H-inf control provides effective damping of the power system oscillations and satisfactory control performance with good robustness