Modeling of Autonomous Microgrid Operated at Medium-Voltage Level and at Constant Frequency and Study of Its Voltage Profile

Abstract

To increase power level in an autonomous microgrid, higher voltage is necessary. In this paper, detailed Matlab/Simulink modeling of a microgrid operated at medium-voltage level and at constant frequency has been conducted. Modified boost converter and medium-frequency transformer isolated DC/DC converter are adopted for both solar energy and wind energy harnessing in order for them to be connected with the microgrid. This paper further adopted a differential evolution (DE)-based method to carry out load flow analysis to work out the voltage at each bus. Results obtained from the DE method are nearly the same at some nodes or buses as those from Matlab/Simulink platform-based time-domain fixed-step modeling, while at other nodes they are very close to each other. Then DE method can be used to carry out load flow analysis in more complex microgrids with more nodes to overcome the limited modelling capability of Matlab/Simulink and other tools. Moreover, this new research effort also paves the way for the stability analysis of large-scale microgrids.