Calculation of conduction power losses in double flying capacitor multicell converter

This paper proposes a detailed approach to analytically calculate the conduction power losses in double flying capacitor multicell (DFCM) converter. For this purpose, the rms and average current flowing through power switches and diodes in both high-frequency and low-frequency cells of DFCM converter are analytically calculated in detail in terms of the load peak current, load power factor and modulation index. Afterwards, an approach to obtain the parameters of the power switches and diodes from the datasheet and use them for calculation of conduction power losses is discussed. Finally, as an example, a 14MVA 3.3kV three-phase 9-level (line-to-line) DFCM converter is simulated and the obtained simulation results of the rms and average current flowing through the power switches and diodes matched with numerical results of the derived equations which validates the derived equations. Furthermore, its conduction power losses is analytically calculated using the presented equations by considering parameters of high-power switches (IGCT and IGBT modules) available in the market from ABB.