ABSTRACT
This chapter introduces three circuits: AC/DC/AC boost-type converter, three-level AC/DC/AC converter and three-level AC/DC/AC Impedance-source inverters. AC/DC/AC and DC/AC/DC conversion technologies are a special subject area in research and industrial applications. AC/DC/AC converters are usually used in synchronous and asynchronous AC motor adjustable speed drives. DC/AC/DC converters are usually used in high-voltage equipment to isolate the source side and load side. Some renewable energy sources are AC voltage sources, for example, wind turbines. The output AC voltage of a wind turbine depends on wind speed and other factors. For induction generators, there are two possibilities; it can have an AC-to-DC converter followed by a DC-to-AC inverter in both stator and rotor or only AC to DC followed by a DC-to-AC inverter connected in the rotor of induction generators. Distributed generation sources usually have no standard and stable output voltage and frequency. Wind turbine is a typical example, although it is an AC voltage source.
