Analysis of balancing algorithms for Quasi- Two/Three-Level Single Phase Operation of a Flying Capacitor Converter

Today's standard medium voltage converters are operated with low switching frequencies and contain bulky passive components. One concept to change this is the Quasi-Two-Level operation (Q2O) of multilevel converters with fast switching semiconductors to minimize passive components. The Flying Capacitor Converter (FCC) with SiC semiconductors and operated with Q2O is thus a converter with minimized passive components. In this paper, a comparison of balancing algorithms for Quasi-Two-Level operation of a FCC is presented. The differences between the various methods are demonstrated by simulation and measurement results. Furthermore, a modulation principle with balancing for Quasi-Three-Level operation of a FCC is introduced. With the FCC, it is easy to upgrade from the Q2O to Quasi-Three-Level operation (Q30) to take full advantage of a three-level output voltage.