Li, Rui; Xu, Lie; Guo, Deyang: 'Accelerated switching function model of hybrid MMCs for HVDC system simulation', IET Power Electronics, 2017, 10, (15), p. 2199-2207, DOI: 10.1049/iet-pel.2016.0989
IET Digital Library, https://digital-library.theiet.org/;jsessionid=6f3q509gl3p2m.x-iet-live-01content/journals/10.1049/iet-pel.2016.0989