Open AccessMulti‐object control of an isolated DC–DC modular multilevel converter
Author(s) -
Chen Yu,
Zhao Shanshan,
Li Zuoyu,
Kang Yong
Publication year - 2018
Publication title -
iet power electronics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.637
H-Index - 77
eISSN - 1755-4543
pISSN - 1755-4535
DOI - 10.1049/iet-pel.2017.0151
Subject(s) - modular design , direct current , ac power , grid , controller (irrigation) , computer science , power control , voltage , power (physics) , engineering , control theory (sociology) , electronic engineering , electrical engineering , control (management) , physics , agronomy , geometry , mathematics , quantum mechanics , artificial intelligence , biology , operating system
Two medium voltage direct current (MVDC) grids can be connected via an isolated DC–DC modular multilevel converter (DC–DC MMC) to enhance the power transmission and supporting abilities. DC power, DC terminal currents, arm energy balancing and active/reactive power through inner AC link need to be controlled in such a DC–DC MMC, and the submodule and grid fault situations should also be addressed. Therefore, a multi‐object controller is inherently required. This study thus proposes a multi‐object control frame that can realise not only DC power regulation but also inner dynamic control, reactive power optimisation and fault riding through. To facilitate the controller design, a detailed dynamic model of DC–DC MMC is also derived, and such a model is turned into different forms according to different control objects. The proposed control method and the main design considerations are given in a detailed mathematical way. A full‐scale simulation system containing a 6 MW DC–DC MMC, a 20 kV MVDC grid, a 10 kV MVDC grid, and several sources and loads is built to verify the control compatibility, and a down‐scale low‐power prototype is also built to test the control performance.