The A CYCLO CONVERTER BASED INDUCTION MOTOR SPEED CONTROL

Abstract

The speed of the motor can be varied in two ways, one is by changing the number of poles and the second method is
by changing the frequency. The speed control through the first method is uneconomical and the number of poles
can’t be varied under running conditions and the size of the machine also becomes bulky. These problems can be
overcome by the second method. In this method, the frequency can be varied under running conditions also and
there is no change in the size of the motor. In this method, the frequency changing device is Cyclo-converter. A
Cyclo-converter is a power electronic device used to convert constant voltage constant Frequency AC power to
adjustable voltage adjustable frequency AC power without a DC link. In among all the methods this method is
simple, reliable and economical. The various speed of induction motor is obtained by varying the supply frequency
by using Cycloconverter. In the modern era, Power Electronic and motion control has emerged as a very important
technology in the industrial automation. In the industrial process, most of the drives are constant torque type and
need to drive such loads at different speeds, because of which generation of supply with variable frequency become
essential. Single phasecycloconverters are used for AC-AC power conversion particular for speed control of AC
drives. To avoid the voltage spikes that appear during the dead time, safe commutation strategy is employed. In this
project we convert the single phase uncontrolled to single phase controlled output using cycloconverter and this is
fed to a scott transformer to obtain three phase controlled output and these are going to be analyzed by MATLAB
Simulink.