An adaptive virtual inertia control design for energy storage devices using interval type-2 fuzzy logic and fractional order PI controller

Abstract

This research paper introduces a novel methodology, referred to as the Optimal Self- Tuning Interval Type-2 Fuzzy-Fractional Order Proportional Integral (OSTIT2F-FOPI) controller for inverter-based energy storage system (ESS) to regulate the input and output power of ESSs, aimed at enhancing the frequency control of microgrids (MGs) with varying levels of renewable energy sources (RESs) integration. The proposed method entails the integration of a self-tuner interval type-2 fuzzy logic controller (IT2FLC) and FOPI controller within a virtual inertia (VI) control loop. Within the OSTIT2F-FOPI control framework, the IT2FLC block tunes the parameters of the FOPI controller in an online method to deal with problems associated with fixed gains of the FOPI controller. Consequently, the VI control unit can emulate varying degrees of inertia and damping based on the integrated levels of RESs or load variations. The self-tuning capability of the proposed method enables real-time performance improvement of the system, resulting in enhanced frequency stabilization and improved control efficiency, particularly in low-inertia MGs. Moreover, a different control methodology, referred to as EO-FOPI-based VI, is developed to compare and assess the results achieved by the suggested OSTIT2F-FOPI control framework. This alternative method incorporates Equilibrium Optimization (EO) to adjust VI and FOPI parameters and provide a comparative analysis of the obtained outcomes.