An Industrial Survey on Electric Drives and Scope of Multilevel Inverter Based Induction Motor Drives in Sugar Industry

A typical sugar industry has electric motors ranging from a few kW to a few MW. For controlled speed–torque characteristics, at most of the places, variable frequency drives (VFDs) are used. DC drives are also used in place of VFDs at milling and batch type centrifugal machines. Slip ring induction motor (SRIM) drives are invariably used at sugarcane preparation station and also at some large pump and fan loads of the industry. At many places, the type and configuration of electric drives need to be reviewed keeping in view the recent developments in the area and improvements in similar applications in other industries. There is also a need to review the aspect of efficiency and harmonics associated with these conventional electric drives in the industry. Further, the VFDs, wherever installed in the sugar industry, are, invariably, 2-level inverter-based induction motor drives. The potential of the multilevel inverter (MLI)-based induction motor drives, being improved one, also needs to be explored in the industry. This paper presents a survey on types of electric drives presently being used for various applications in the sugar industry, their merits and demerits, further possible improvements in them for power saving and reduction in harmonics along with the potential of application of MLI-based induction motor drives, wherever feasible, in the industry.