PD distributed control and stability analysis for DC microgrids with multiple time delays

• Published in: Electric power systems research Vol. 236; p. 110909
• Main Authors: Chen, Yongpan, Wan, Keting, Zhao, Jinghan, Yu, Miao
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.11.2024
• Subjects: DC microgrid; Proportional-differential distributed control; Stability analysis; Time delay; Proportional-differential distributed control; Stability analysis; Time delay; DC microgrid
• ISSN: 0378-7796
• DOI: 10.1016/j.epsr.2024.110909

•A proportional-differential distributed control method for DC MGs is proposed.•Accurate current sharing and bus voltage regulation are achieved.•The time delay margin (TDM) of DC MGs with multiple delays is determined.•The proposed control can improve the stability of DC MGs with multiple delays.•An indicator is defined to quantify the TDM enhancement effect of each differential gain. Distributed control is widely used for coordination of multiple distributed generations (DGs) in a microgrid (MG), but the information transmission in practice is inevitably suffered from time delays, which will deteriorate system performance and even cause system instability. To solve this problem, a proportional-differential (PD) distributed control method for DC MGs is proposed in this paper. Firstly, a small-signal system model considering multiple time delays including measurement delay and communication delay is established. The introduction of time-delayed differential terms results in the system being transformed into a neutral time-delayed system (NTDS). Then, the time delay margin (TDM) under different delayed scenarios is accurately determined by the frequency-domain stability analysis, and the relationship between the TDM and the differential gain is quantified. Compared with the conventional proportional (P-type) distributed control method, the TDM is enhanced effectively. In addition, an indicator is proposed to quantify the enhancement effect of introducing differential terms on TDM. Finally, the effectiveness of the proposed method and the accuracy of the stability analysis are verified by simulation and hardware-in-loop (HIL) tests.