DC microgrid dynamic performance assessment and enhancement based on virtual impedance method

Abstract

A dynamic performance assessment method is proposed for DC microgrids. With the control scheme modeled as virtual impedance, an actively controlled slack converter terminal of a DC network can be modeled as a circuit branch in S-domain. Using Thevenin's equivalent, transfer functions of a DC microgrid are then deduced. A control scheme is proposed to enhance the dynamics of a DC system with multiple slack terminals. A case study of a multi-terminal DC microgrid is performed to analyze and enhance its dynamics. Time domain simulation and experiments are carried out to validate the proposed analytical and enhancement method.