Open AccessA Novel Start-up Strategy for MMC-based Medium-voltage DC Distribution System with Low Inrush Current
Author(s) -
Limin Yang,
Yiying Zhu,
Ming Lei
Publication year - 2021
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1914/1/012038
Subject(s) - inrush current , controllability , voltage , capacitor , modular design , reliability (semiconductor) , computer science , current (fluid) , scalability , power (physics) , electrical engineering , process (computing) , electronic engineering , engineering , automotive engineering , physics , transformer , mathematics , quantum mechanics , database , operating system
To realize medium-voltage dc distribution system, the modular multilevel converter (MMC) is commonly adopted due to its high-level scalability and reliability for medium-voltage high-power energy conversion. Since the capacitors’ voltages of the MMC are insufficient when the uncontrolled pre-charging stage is finished, large inrush current exists when the MMC is unlocked for active charging, which can cause malfunction of protection and threat the successful start-up of the whole system. This paper presents a detailed analysis on the causes of inrush current during the MMC’s active charging process. Based on the analysis, a novel start-up strategy of the MMC is proposed to achieve improved controllability of the MMC’s ac-side currents for inrush current suppression. The simulation results from a full-scale simulation model demonstrate that the inrush current can be effectively suppressed during the MMC’s active charging process.