Open AccessImproved hybrid modular multilevel converters with dc short‐circuit fault ride‐through capacity
Author(s) -
Lei Yuhang,
Si Gangquan,
Zhu Jianwei,
Zhang Yanbing
Publication year - 2019
Publication title -
the journal of engineering
Language(s) - English
Resource type - Journals
ISSN - 2051-3305
DOI - 10.1049/joe.2018.8495
Subject(s) - converters , topology (electrical circuits) , modular design , insulated gate bipolar transistor , fault (geology) , voltage , fault tolerance , diode , electrical engineering , electronic engineering , power (physics) , computer science , engineering , physics , quantum mechanics , seismology , geology , operating system , distributed computing
Modular multilevel converter (MMC) has become a promising converter alternative for transmission voltage‐source converter high‐voltage direct current applications. The main issue and challenge of MMC is how to handle the dc short‐circuit fault. Based on the half‐bridge MMC, this study proposed an improved hybrid MMC topology which has the dc faults ride‐through capability and requires less switching devices contrast with the present hybrid topology. The improved hybrid topology consists of m half‐bridge submodules and n modified half‐bridge sub‐modules (e‐RBSM) which consists of an insulated gate bipolar transistor (IGBT), two reverse blocking IGBTs (RB‐IGBTs), two diodes and a resistance. The required number of e‐RBSM n is deduced according to the dc short‐circuit fault ride‐through requirement. Moreover, the analysis of the fault current blocking mechanism and electrical stress of the power switches is made in detail. Furthermore, the improved topology allows all RB‐IGBTs not to conduct simultaneously by employing the parallel circuit including a diode and a resistance, therefore, it reduces the requirement of trigger pules operation. Simulation results on PSCAD/EMTDC verify the efficiency of the proposed topology and strategy.