Multilevel Converter Interfaces for Sustainable Energy Systems
The advent of high power electronic modules has encouraged the use of more dc transmission and made the prospects of interfacing distributed dc power sources such as fuel cells, rectified wind turbines, and photovoltaics more easily attainable. A modular, scalable power electronics technology that is ideal for these types of interfaces is the transformerless multilevel converter. The use of a multilevel converter to control the frequency, voltage output, and real and reactive power flow at a dc/ac interface provides significant opportunities in the application and control of sustainable energy systems. The general function of the multilevel inverter is to synthesize a desired ac voltage from several levels of dc voltages. For this reason, multilevel inverters are ideal for connecting an ac grid with renewable energy sources or with energy storage devices such as capacitors or batteries. This presentation will give a brief overview of the different multilevel converter topologies and discuss how they may best interface with sustainable energy systems.