A review of multilevel inverter topologies, control techniques, and applications

Multilevel inverters have become indispensable for most power electronic applications in medium and high voltage ranges. Besides the advantages of obtaining lower total harmonic distortion and reducing the total dv/dt across the semiconductor switches, it can produce any number of levels to suit the high voltage and power application demands. The emergence of new topologies overpowered on the traditional ones which, multiples its ability to produce a higher number of levels with less number of components. Moreover, the recently developed topologies of MLI uses asymmetrical dc sources to obtain the same levels with less number of semiconductor switches resulting in a reduction of capital costs and boosting the system reliability. Practically, the asymmetrical dc sources can be obtained from various types of renewable energy sources including photovoltaic, wind turbine system, fuel cell, etc. Finally, the various recently developed techniques for modulation plays a crucial role to enhance the overall performance of MLI. This paper presents a survey for traditional and recent topologies of MLI along with the advantages offered by the new topologies. A survey for the control techniques of MLI according to switching frequency are also presented.