Active and Reactive Power Droop Controller Design for Reliable and Optimal Control of Renewable-Based Micro-Grid

Abstract

Technical concerns about micro-grid dynamics, particularly in autonomous (island) mode necessitate revision of current paradigms in control of energy systems. Advanced control techniques are imperative segments for micro-grid realization. In general, micro-grids and the integration of distributed energy resources (DER) units introduce a number of operational challenges that required to be addressed in the control design and protection systems such that the reliability and stability levels are not affected significantly and subsequently ensured that the distributed generations (DGs) potential benefits are wholly harnessed. In this paper, the micro-grid coordination strategy was investigated by simply analysing the present micro-grid situation and various control strategies. More so, active-reactive power (P/Q) and droop controller based on proportional-integral (PI) and model predictive control (MPC) were designed to control the inverter output of the micro-sources. A micro-grid model, which has two photovoltaic (PV) and one wind turbine (WT) blocks, were built in MATLAB/Simulink to simulate the following three cases in this study. The three cases are as follows, the switching of operation mode between the grid connected and islanded mode, increasing and decreasing of loads in islanded mode and the disconnection of one PV system at a certain time in islanded mode. Therefore, through the simulation analyses, the MPC controller utilized in this micro-grid as compared to the PI controller, achieved desirable efficiency of the inverter’s power control and shared the load power effectively.