A Communication-Free Economic Dispatch Control Scheme of Cascaded-Type Microgrids for Operating Cost Minimization

This article addresses the economic dispatch problem in cascaded-type microgrids (CMGs), aiming to minimize operating costs while accounting for capacity constraints, frequency restoration, and load voltage quality. To solve the problem, we propose a communication-free economic dispatch control scheme. In the proposed method, the frequency term is based on the local transmission line current to ensure the power factor angle consistency and achieve frequency restoration. The output voltages of distributed generators (DGs) are regulated using an optimal economic optimization function to minimize the total active operating costs (TAOCs) and ensure the load voltage quality of CMGs. The proposed control scheme offers several key advantages: 1) the construction of the proposed scheme only requires local voltage and current measurements, eliminating the need for communication and making it a fully communication-free approach; 2) the optimal economic dispatch, considering capacity constraints, is realized, leading in reduced operating costs for CMGs; 3) frequency could be controlled at a specific value, ensuring frequency restoration; and 4) the scheme effectively regulates load voltage, maintaining a constant and high-quality voltage output. Furthermore, the stability analysis of the proposed control strategy has been proven. Finally, the feasibility of the suggested approach has been validated through simulation and experimental investigations.