ولی اله غفاری

Nonlinearities are integrated into human life. Each system with which people interact has nonlinearities. Therefore, the nonlinear control of such systems is of greate importance. Thus, this study proposes a tuning method to composite nonlinear feedback (CNF) control for a class of nonlinear systems subjected to actuator saturation. The CNF control law constitutes linear and nonlinear feedback terms. The linear control law is designed to provide a closed-loop system with a small damping ratio, quick response, and large overshoot while simultaneously not transcending actuator limits, and the output tracks a set-point. The nonlinear part increases the damping ratio of the overall closed-loop system to eliminate the overshoot stemmed from the linear part. To improve the transient response, the controller gains are optimally obtained via the linear matrix inequality (LMI) approach. The parameters of the damping term are tuned through an innovative algorithm. To evaluate the suggested tuning technique and compare it with the existing methods, some nonlinear systems such as a chemical reactor, the Lorenz equations, and a typical system are simulated in MATLAB. The most vital aspect of boost converters in DC microgrids is the load uncertainty and use of solar energy (photovoltaic panel) which can be a challenging task owing to the perturbation of irradiance and uncertainty. In this work, a novel nonlinear technique, i.e., the so-called composite nonlinear feedback (CNF) control is comprehensively investigated to enhance transient response and address output voltage regulation for DC-DC boost converter connected to an uncertain DC input. Strikingly, the nonlinear part is automatically tuned whereby the transient performance of the DC-DC boost converter improves significantly. To assess such a technique, a boost converter is implemented in MATLAB Simulink considered different scenarios such as changing load, DC input, and voltage reference. Both the quantitative outcomes and