Delay Margin Computation in Micro Grid Systems with Time Delay by using Fractional Order Controller

Abstract

The purpose of this article is to obtain maximum time delay in remote controlled micro grid power systems, so that stability can be guaranteed for large values of time delays. With long delay margin, micro grid power system robustness can be provided. For this purpose, fractional order proportional integral derivative controller is used. Micro grid power system includes photovoltaic panels (PV), fuel cells (FC), wind turbines (WT), ultra-capacitors (UC) and a diesel generator (DG). There are two control loops in the proposed micro grid power system. One is local controller for DG control and the other is remote controller. Fractional order proportional integral derivative (FOPID) controller is used in remote controller. FOPID controller provides five degree of freedom, whereas proportional integral derivative controller provides three degree of freedom. Instead of three variable adjustments in PID, in FOPID controller five variables are adjusted so that wide time delay margin can be obtained. By using FOPID controller better delay margins are obtained with respect to literature findings and also robustness of micro grid power system is secured. The proposed design methodology has shown that by using FOPID controller more robustness with respect to time delay can be obtained in micro grid power systems.