Open AccessA Centralized Shifted Voltage Control Method for Accurate Power Sharing in DC Islanded Microgrids
Author(s) -
MinhDuc Pham,
HongHee Lee
Publication year - 2021
Publication title -
renewable energy and power quality journal
Language(s) - English
Resource type - Journals
ISSN - 2172-038X
DOI - 10.24084/repqj19.242
Subject(s) - voltage droop , microgrid , voltage drop , voltage , control theory (sociology) , controller (irrigation) , computer science , voltage regulation , voltage reference , voltage controller , renewable energy , voltage source , electronic engineering , engineering , control (management) , electrical engineering , agronomy , artificial intelligence , biology
Due to line impedance mismatch among renewable energy sources (RESs), it is hard to realize accurate power sharing in the DC microgrid system. To solve this issue, a distributed power sharing strategy for adjusting the RES output voltage is developed by adding shifted output voltage into each local controller. Thanks to the shifted voltage, the influence of voltage drop caused by the droop controller is effectively mitigated, so that the DC bus voltage is constantly balanced regardless of the load changes. The proposed method is realized with a centralized approach, and all the required control variable to determine the reference voltage is transmitted through low-bandwidth communication. The controller design and system stability are analyzed in detail with a simplified microgrid model. Small-scale DC microgrid is simulated to verify the effectiveness of the centralized shifted voltage control method.