Nine level double flying capacitor multicell converter based on modulation technique

Multicell converter are a very interesting alternative for medium and high power drives. This paper presents a new configuration of double flying capacitor (DFCM) converter. The main advantages of the proposed converter in comparison with FCM and stacked multicell converter are doubling the rms and the number of output voltage levels, improving the output voltage frequency spectrum, and cancelling the midpoint of dc source. This can be obtained by adding two low frequency switches to the conventional configuration of FCM converter while the number of high-frequency switches and capacitors, voltage rating of capacitors and switches, and the number of high frequency switchings during a full cycle are kept constant. The control strategy is controlled by a modified phase-shifted pulse width modulation. The circuit is simulated using PSIM. The simulation results are presented to validate the effectiveness and advantages of the proposed configuration as well as its control strategy.