High-Power Modular Multilevel Converters With SiC JFETs

• Published in: IEEE transactions on power electronics 2012-01, Vol.27 (1), p.28-36
• Main Authors: Peftitsis, D., Tolstoy, G., Antonopoulos, A., Rabkowski, J., Jang-Kwon Lim, Bakowski, M., Ängquist, Lennart, Nee, H.
• Format: Article
• Language: English
• Subjects: Applied sciences; Capacitors; Circuit properties; Converters; Diodeless operation; Diodes; Direct current; Electric currents; Electric power; Electric, optical and optoelectronic circuits; Electrical engineering. Electrical power engineering; Electrical equipment; Electronic circuits; Electronics; Exact sciences and technology; high voltage direct-current transmission; high voltage directcurrent transmission; Insulated gate bipolar transistors; JFET; JFETs; Modular; modular multilevel converter; Multilevel; Power electronics, power supplies; Prototypes; Semiconductor electronics. Microelectronics. Optoelectronics. Solid state devices; SiC JFETs; Signal convertors; Silicon; Silicon carbide; Switching; Switching frequency; Switching, multiplexing, switched capacity circuits; Transistors
• ISSN: 0885-8993; 1941-0107; 1941-0107
• DOI: 10.1109/TPEL.2011.2155671

This paper studies the possibility of building a modular multilevel converter (M2C) using silicon carbide (SiC) switches. The main focus is on a theoretical investigation of the conduction losses of such a converter and a comparison to a corresponding converter with silicon-insulated gate bipolar transistors. Both SiC BJTs and JFETs are considered and compared in order to choose the most suitable technology. One of the submodules of a down-scaled 3 kVA prototype M2C is replaced with a submodule with SiC JFETs without antiparallel diodes. It is shown that the diodeless operation is possible with the JFETs conducting in the negative direction, leaving the possibility to use the body diode during the switching transients. Experimental waveforms for the SiC submodule verify the feasibility during normal steady-state operation. The loss estimation shows that a 300 MW M2C for high-voltage direct current transmission would potentially have an efficiency of approximately 99.8% if equipped with future 3.3 kV 1.2 kA SiC JFETs.