A Unified Control of Super-capacitor System Based on Bi-directional DC-DC Converter for Power Smoothing in DC Microgrid

Li Xialin; Li Pengfei; Ge Leijiao; Wang Xunyang; Li Zhiwang; Zhu Lin; Guo Li; Wang Chengshan

DOI:10.35833/MPCE.2021.000549


A Unified Control of Super-capacitor System Based on Bi-directional DC-DC Converter for Power Smoothing in DC Microgrid



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Author: Xialin Li¹,Pengfei Li²,Leijiao Ge¹,Xunyang Wang¹,Zhiwang Li³,Lin Zhu¹,Li Guo¹,Chengshan Wang¹
Author Affiliation: 1.the Key Laboratory of Smart Grid of Ministry of Education, Tianjin University, Tianjin 300072, China;2.the School of Information and Electronic Engineering, Hebei University of Engineering, Handan 056038, China;3.the Binhai Power Supply Bureau of State Grid Tianjin Electric Power Company, Tianjin 300480, China
Foundation:	This work was supported in part by the National Nature Science Foundation (No. 51977142), National Key R&D Program of China (No. 2020YFB1506803), and Tianjin Natural Science Foundation (No. 20JCQNJC00350).

Abstract:	To improve the equivalent inertia of DC microgrids (DCMGs), a unified control is proposed for the first time for a bi-directional DC-DC converter based super-capacitor (SC) system, whereby power smoothing and SC terminal voltage regulation can be achieved in a DCMG simultaneously. The proposed control displays good plug-and-play features using only local measurements. For quantitative analysis and effective design of the critical parameter of unified control, two indices, equivalent power supporting time and inertia contributed by the unified controlled SC system, are introduced firstly. Then, with a simple but effective reduced-order model of a DCMG, analytical solutions are obtained for the two indices. In addition, a systematic design method is presented for the proposed unified control. Finally, to verify the proposed unified control, a switching model is developed for a typical DCMG in PSCAD/EMTDC, and theoretical analyses are conducted for different operating conditions.
Keywords:	DC microgrid ; DC-DC converter ; super-capacitor ; unified control ; equivalent power supporting time and inertia ; power smoothing

Received:August 09, 2021 Online Time:2023/05/23



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