Enhancing Voltage Stability in Bipolar Microgrids

Abstract

This work proposes a solution for effectively integrating renewable energy systems into EV charging stations, focusing specifically on a bipolar DC microgrid framework to address increased loads. One of the main challenges tackled is asymmetrical loading within the bipolar DC network, which can lead to voltage drops at the neutral point. To address this, the paper examines a DC-to-DC converter with an integrated output voltage balancing method, eliminating the need for additional converters or control mechanisms. It also examines the design of a compensator for the closed-loop control of the DC-to-DC converter by developing a state-space model of the examined topology, obtaining a small-signal transfer function, and employing a k-factor method to design a compensator for voltage control. The proposed techniques and designs are validated through mathematical modeling and simulations using MATLAB/Simulink, supported by Typhoon HIL experimentation. The findings show significant potential for improving power transfer efficiency in practical EV charging station applications. © 2024 IEEE.