Nonlinear Fuzzy Control Based on Fuzzy Anti-Windup of VSC-HVDC Embedded into AC Grid

In this work, new robust fuzzy control based on model recovery anti-windup strategy based on robust fuzzy anti-windup is proposed for disturbances of multivariable High Voltage Direct Current (HVDC) link embedded with AC grid subject to a wide range of parameter uncertainties. Saturations on both control and the states are also taken into account. This work concentrates on the fault ride-through capability of the AC embedded HVDC system which may be exploited to improve the stability of the AC embedded HVDC system. The developed robust control scheme is demonstrated to be effective for temporary short-circuit conditions. The algorithm utilizes fuzzy systems based on “Takagi-Sugeno” fuzzy models to represent a nonlinear AC embedded HVDC system. Sufficient conditions are derived for robust stabilization in the sense of Lyapunov stability and are formulated with linear matrix inequalities to obtain controller gains and anti-windup gains. First, a nonlinear robust fuzzy controller is designed subject to a disturbance with parameter uncertainties. Next, an additional anti-windup is designed to mitigate the adverse effects due to state and the control constraints. The proposed control system is compared with alternative frameworks existing in the literature based on robust control via simulations performed with MATLAB software, to illustrate the effectiveness of the proposed method.