Using modern methods for load frequency control in smart grids and the design of robust controllers

The integration of Electric Vehicles (EVs) into smart grids is getting attention as EVs become increasingly widespread, and this trend is expected to continue in the near future. Thus, this thesis examines the integration of EV aggregators as a source into one- and multi-area traditional Load Frequency Control (LFC) systems to contribute to the frequency regulation and flexibility of smart grids. To investigate the effect of time delays caused by various communication needs, particularly digitalization in smart grids, two frequency domain methods have been used to calculate the time delay margins at which the system can maintain its stability. These methods are the direct method, which can be used in cases of commensurate time delays, and the Advanced Clustering with Frequency Sweeping (ACFS) method, which can be used in both commensurate and incommensurate time delay cases. In the thesis, the stability boundary locus approach is also utilised to obtain the stability regions on the controller parameter space of classical PI and fractional order PI controllers. In addition, the generalised Kharitonov theorem is employed to guarantee the robustness of the controllers against various parametric uncertainties and perturbations.