SINGLE PHASE AC to AC CONVERSION WITHOUT FREQUENCY RESTRICTIONS

Single Phase AC to AC conversion finds various applications in domestic drive systems, street- light dimmers and fan regulators. Conventionally, this conversion is done by using thyristor based power electronic circuits such as AC Voltage Controllers and Cyclo-Converters. However, these devices provide either no frequency control as in AC Voltage Controllers or limited frequency control as in cyclo-converters. For unrestricted frequency control AC-DC-AC conversion is usually undertaken. It is proposed to use fully controlled devices such as IGBT’s (insulated gate bipolar transistor) in direct single phase AC to AC power conversion. Matrix Converters are power electronic converters that facilitate direct AC-AC conversion without any intermediate DC stage. Matrix converters make use of self-commutating devices like IGBTs thus eliminating the frequency constraints of cyclo-converters. The additional attractive features include sinusoidal input and output current, improved power factor and regeneration capabilities.