A nine-switch nine-level converter new topology with optimal modulation control

Multilevel power converters are becoming increasingly used in several
sectors: energy, grid-tie renewable energy systems, High voltage direct
current (HVDC) power transmission, and a multitude of industrial
applications. However, the multilevel converters consist of several drives and
a high number of power switches, which leads to a considerable cost and an
increased size of the device. Thus, a novel topology of a multilevel
bidirectional inverter using a reduced number of semiconductor power
components is proposed in this paper. Without any diode clamped or flying
capacitor, only nine switches are used to generate nine voltage levels in this
new topology. The proposed multilevel converter is compared with the
conventional structures in terms of cost, the number of active power
switches, clamped diodes, flying capacitors, DC floating capacitors, and the
number of DC voltage sources. This comparative analysis shows that the
proposed topology is suitable for many applications. For optimum control of
this multilevel voltage inverter and to reduce switching losses in power
semiconductors, a hybrid modulation technique based on fundamental
frequency modulation and multi-carrier-based sinusoidal pulse-width
modulation schemes is performed. The effectiveness of the proposed
multilevel power converter is verified by simulation results.