ABSTRACT
AC/AC conversion technology is an important subject area in research and industrial applications. In recent decades, the AC/AC conversion technique has been developed to a great extent. We can sort them into two parts. The converters developed in the last century can be called the traditional AC/AC converters that are introduced in this chapter. The new technologies of AC/AC conversion technology will be introduced in the next chapter [1-6].
A power electronic AC/AC converter accepts electric power from one system and converts it for delivering it to another AC system with a different amplitude, frequency, and phase. They may be of single-phase or three-phase type depending on their power ratings. The AC/AC converters employed to vary the rms voltage across the load at constant frequency are known as AC voltage controllers or AC regulators. The voltage control is accomplished either by (i) phase control under natural commutation using pairs of triacs, SCRs, or thyristors; or by (ii) on/off control under forced commutation using fully controlled self-commutated switches such as gate turn-off thyristors (GTOs), power bipolar transistors (BTs), insulated gate bipolar transistors (IGBTs), MOS-controlled thyristors (MCTs), and so on [7-8].
