AUTHOR=Lu Wenbiao , Xiao Qian , Jia Hongjie , Mu Yunfei , Cui Mingjian , Jin Yu , Li Tianxiang , Zhang Yuwei , Yu Xiaodan 

TITLE=An improved energy management for MVDC distribution system based on exponential droop control

JOURNAL=Frontiers in Energy Research

VOLUME=Volume 10 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/energy-research/articles/10.3389/fenrg.2022.995968

DOI=10.3389/fenrg.2022.995968

ISSN=2296-598X

ABSTRACT=The energy management optimization and DC voltage stability are the main challenges when loads surging and renewable energy sources (RESs) fluctuations occur in the medium-voltage DC distribution system (MVDC-DS). To solve these issues, this paper proposes a dual-time scale energy management method based on improved droop control for the MVDC-DS. Firstly, a ±10kV three-terminal hybrid modular multilevel converter (MMC)-based ring MVDC-DS with DC fault ride-through capability is constructed, which including electric vehicle charging stations, energy storage stations, multiple loads and RESs. Secondly, the droop control adopted by the hybrid MMC is improved by exp-function to achieve higher power quality. On this basis, a dual-time scale energy management method is proposed to minimize the electricity purchasing cost. The reference powers of each controllable unit are optimized in the long time-scale, and the parameters of improved droop control are optimized in the short time-scale. Finally, a case study is conducted on the ±10kV three-terminal hybrid MMC-based ring MVDC-DS, and the results indicate that the proposed method can improve the economy and power quality of system, and the exp-droop control can maintain the normal system operation under different conditions.