Application of Power Electronic Circuitry for Elimination of Flywheel in Process Machines

Abstract

It is felt highly probable to eliminate flywheel from the design of any process machine in general and for process machines with a certain demand torque characteristics in particular. It is felt that by proper interfacing of power electronic devices this may be possible. Elimination of flywheel from process machines helps reducing torsional vibrations in the power transmission system of any process machine. This should reduce fatigue in the components of power transmission system thereby prolonging equipment functional failure. Down time will be much less and profit earnings through uninterrupted production would be high. This paper proposes a convenient power electronic circuitry with reasonable control approach for the flywheel replacement of an induction motor for which it is necessary to generate supply torque at motor shaft exactly equal to demand torque. To meet this requirement, demand torque characteristic is sampled at 25 msec. In proposed solution to this problem, the torque requirement at every sample is met by adjusting the firing angle of thyristors which in turn adjusts the supply voltage at motor terminals. Depending on supply frequency the sampling period for demand torque characteristic may be varied. The present paper has a focus of evolving the details of functional feasibility of this concept only.