Performance enhancing of grid-connected DC microgrids

Abstract

This chapter presented two proposed controllers for the inner-loop of the power converter of each DG in the DC microgrid. First, a finite-state-machine based controller is presented where the update in the duty cycle is based on the converter state. The state of the converter is determined according to the relative values of the output voltage for two consecutive samples with respect to the reference signal. The simulation results for the FSM in the two DGs microgrid with rating-based strategy showed that the controller succeeds to control the power converter of each DG. Although this method is simple in design and requires low processing time, the output suffers from large oscillations. Hence, an output voltage tracking performance recovery controller is proposed. The results presented ensure the robustness of the proposed method against wide load variations and uncertainties in system parameters. Further comparison with the classic methods proved the reliability of the proposed controller to account for model uncertainties and disturbances in heavy load conditions. Moreover, the resiliency of the proposed controller against parameters variations is