For grid integration of renewable generation units, a power frequency
transformer operated at 50 or 60 Hz is generally used to step-up the low output
voltage (usually B690 V) to the medium voltage level (typically 6–36 kV).
Because of the heavy weight and large size of the power frequency step-up
transformer, the grid integration system can be expensive and complex for
installation and maintenance. To achieve a compact and lightweight direct grid
connection, a medium voltage multilevel converter may be an alternative
approach. Different multilevel converter topologies with switching and control
issues are analyzed for their medium voltage applications. The practical implementation
issues are also reported in this chapter. It is expected that the medium
voltage multilevel converter would have great potential for future renewable
generation and smart microgrid applications.