Predictive Voltage and Frequency Restoration for Decentralized FCS-MPC based Droop Controlled DGs in AC Microgrids

Abstract

Droop control provides a decentralized method of control between distributed generators (DGs) in the primary control (PC) level of islanded AC microgrids (MGs). However, this results in deviations of the system’s voltage and frequency (V/f). Secondary control (SC) is therefore required to restore such deviations. This paper presents a simple V/f restoration technique that utilizes finite control set MPC (FCS-MPC) to achieve primary and secondary control for a MG system. It makes use of the predicted voltages and currents from the FCSMPC to estimate V/f deviation parameters to enable restoration. The simulation carried out in MATLAB/Simulink shows that the controller maintains V/f values within the standard limits and achieves accurate power sharing. Unlike existing secondary controllers, this technique does not require any linear PI controllers in the secondary control layer. Additionally it does not directly require frequency or voltage information in the secondary control layer, making the design process uncomplicated and faster.