Abstract
In the literature, many studies on stability analysis of dc microgrids have been conducted. However, most of them mainly focus on small-signal stability. On the other hand, few works analyze large-signal stability, but the major part of these works is based on a single unit or a simple cascaded system as a case study. Different from those, this article aims to address the large-signal stability analysis of a dc microgrid from a system-level perspective. First, the equivalent model of a droop-controlled dc microgrid is developed. Subsequently, the Lyapunov-based large-signal stability analysis and the stability criterion are derived, and mixed potential theory is used to make comparisons to verify the effectiveness of the derived criterion. The equilibrium point stability for different operation stages was obtained by means of theoretical calculation. Furthermore, the instabilities principle as well as their physical interpretation is revealed. In this article, the bus voltage is used as the only index to assess the microgrid power balance. Hence, the power load limit can be obtained by taking into consideration the stability and voltage deviation constraints. Finally, simulation and experimental results from a four-converter dc microgrid system verify the feasibility of the proposed theoretical analysis.
| Original language | English |
|---|---|
| Article number | 9177328 |
| Journal | IEEE Transactions on Power Electronics |
| Volume | 36 |
| Issue number | 4 |
| Pages (from-to) | 4224-4236 |
| Number of pages | 13 |
| ISSN | 0885-8993 |
| DOIs | |
| Publication status | Published - Apr 2021 |
Bibliographical note
Funding Information:This work was supported in part by the National Key R&D Program of China under Grant 2018YFB0904700, in part by the Fundamental Research Funds for the Central Universities under Grant 2019QN119, and in part by VILLUM FONDEN under the VILLUM Investigator Grant 25920: Center for Research on Microgrids. Recommended for publication by Associate Editor F.W. Fuchs.
Funding Information:
Manuscript received June 18, 2020; accepted August 10, 2020. Date of publication August 25, 2020; date of current version November 20, 2020. This work was supported in part by the National Key R&D Program of China under Grant 2018YFB0904700, in part by the Fundamental Research Funds for the Central Universities under Grant 2019QN119, and in part by VILLUM FONDEN under the VILLUM Investigator Grant 25920: Center for Research on Microgrids. Recommended for publication by Associate Editor F. W. Fuchs. (Corresponding author: Wenqiang Xie.) Wenqiang Xie is with the School of Electrical and Electronic Engineering, North China Electric Power University, Beijing 102206, China, and also with the Department of Energy Technology, Aalborg University, 9220 Aalborg, Denmark (e-mail: bjxiewenqiang@163.com).
Publisher Copyright:
© 2020 IEEE.
Keywords
- DC microgrids
- droop control
- large-signal stability
- Lyapunov function