Distributed Control Techniques for Effective Current Sharing and Voltage Regulation in DC Distributed Systems

DC microgrid is one of the feasible and effective solutions to supply reliable electricity as well as to integrate renewable energy resources. The control objectives of the DC microgrid are equal current sharing in per unit and the bus voltage regulation within permissible limits. The droop control is a reliable method adopted to implement the control of the distributed power system with multiple energy units. However, in the application of the distributed power system, the nominal voltage reference mismatch and unequal cable line parameters require a trade-off between bus voltage regulation and current sharing error. In this paper, a simplified compensation structure is proposed to minimize trade-off between proportional equal current sharing and the bus voltage regulation within permissible limits for unequal cable resistances. The proposed control scheme is improved transient performance of output current sharing and the bus voltage by using a voltage droop control and hysteretic current control. The global stability is also insured for the communication time delay. The performance of the proposed model is verified in the MATLAB/Simulink environment.