Crest Factor Oriented Finite Set Model Predictive Control of the Mesh Microgrid

Single-phase voltage source inverters with an LC filter are widely used in islanded Microgrids (MGs) for Renewable Energy Sources (RES) or Distributed Energy Resources (DER). It is crucial for MGs that are highly penetrated by these energy sources to maximize the power quality in the presence of the higher order harmonics. This work presents the Finite Control Set Model Predictive Control (FCS-MPC) for a single-phase voltage source inverter with an LC filter, applicable in islanded MGs. It is a strategy that determines the optimal switching states within the inverters, operating over a finite set of possible voltage levels to regulate the power flow and voltage in the whole microgrid, while considering operational constraints. We propose to extend the cost function of this method to include not only the voltage and current factors, but also the Crest Factor (CF), which is calculated as the ratio of the peak value and the root mean square of the signal. This factor shows how extreme the peaks are and therefore indicates the power quality. The model performance was simulated using MATLAB/Simulink tools in a mesh microgrid with consideration of line impedance effects, where the power and load sharing were successfully validated with the use of Droop Control. Our approach improves the Total Harmonic Distortion (THD) of both voltage and current, comparing with the typically used cost functions.