Comparative evaluation of Fuzzy-PI and PI control methods for a three phase grid connected inverter

This research addresses the issue of power electronics control scheme for grid integration of a distribution generation unit. For the improvement of the current control and DC bus voltage control, the application of the PI and Fuzzy-PI controller is investigated. Theoretical and mathematical analysis of the internal structure of the PI and Fuzzy-PI controller is carried out. Using the software Matlab/Simulink, the behavior of the controllers for DC bus voltage and current control is investigated. A comparative evaluation of the controllers both in steady state and transient response is presented. Furthermore the PI and Fuzzy-PI controller are compared based on THD_i index of the inverter´s current. The ability of the inverter to provide ancillary services to the electric power system though the uninterrupted compensation of the reactive power of the load is studied, as well.