Robust Frequency Control in Interconnected Microgrids: An H$_2$/H$_{\infty }$ Control Approach

Abstract

The advancement of renewable energy resources and their implementation in the power sector poses a serious challenge of maintaining the frequency. In this article, a specified structure-based H <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_2$</tex-math></inline-formula> /H <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$_\infty$</tex-math></inline-formula> controller is proposed to stabilise the frequency of the interconnected microgrids system. The norms of the controller are optimized using the teaching-learning-based optimization. A dynamic frequency model of two area microgrids interconnected through a tie-line has been employed to inspect the frequency control of microgrids. Generation using numerous renewable resources and storage sources are considered in suitable combination. The dynamics of dc-link along with measurement unit are also considered in each of the microgrids. In addition, the microgrids are designed with demand response program to damp out the oscillations. A comparative analysis of controllers designed using various existing algorithms namely particle swarm optimization, genetic algorithm, and simulated annealing has been presented. The system response attained is compared to that of other forms of controllers in the literature. Varying input conditions are assumed for wind and solar generation units and their respective frequency responses are studied utilizing two of the best performing algorithms.