Combined frequency and voltage control of two-area multi-source interconnected microgrids via the 2DOF-TIDμ controller

Abstract

The focus of this study is the utilization of a new two degree of freedom fractional controller, namely the two degree of freedom tilt-integral-derivative controller with fractional derivative (2DOF-TIDμ) and filter, optimized by the coot algorithm, for voltage and frequency regulation in two interconnected microgrids comprising of various sustainable and renewable sources. Both microgrids comprise of a biomass combined heat and power, biodiesel generator, micro-hydro turbine generator and biogas turbine generator along with a battery and superconducting energy storage system. In addition, the first microgrid includes a geothermal power plant, whereas the second microgrid a wind power plant. Furthermore, a power system stabilizer and a unified power flow controller are included in the system. The study aims to present an appropriate controller for the frequency and voltage control of interconnected microgrids which could be isolated communities and/or farms. The controller is compared with the 2DOF-PID and 2DOF-TID controllers, in various scenarios. The scenarios include various simultaneous step load perturbations in both microgrids, penetration of renewable energy sources in one or both areas and injection of noise in the control channels. The results indicate that the 2DOF-TIDμ controller has better transient response and is more effective at suppressing deviations than the other controllers.