Battery charging using induction motor's Slip power

Abstract

Mankind is facing major issues, power shortages is one among them. Instead of going for installations of new power houses substantial use of wastage power can reduce the intensity of the issue. Industries contribute major part of the load in any grid. There will be huge power losses in industrial applications. So, efficient installations of power recovery systems as a part of demand side management will reduce these power shortages to some extent. Almost all industries run on three phase Induction motor which is widely used. In Slip ring Induction motor, rotor terminals are available. Many speed control techniques have been developed because of this facility. One among them is Slip power recovery scheme in which the slip power is recovered and given back to supply. However, when the machine ratings are small to permit such an expensive and complex converters, it is more practicable to recover the slip energy and charge a small battery bank and use it for UPS to feed lighting other low power loads. This proposed work presents a model to use this slip power to charge a battery instead of giving it back to the supply. In this model the motor's rotor winding is connected to a rectifier via slip rings. Power from the rotor winding flows through the three phase rectifier to a switch-mode step up DC to DC converter to re-charge a bank of batteries. A dynamic model of the complete system is presented along with simulation results and hardware implementation.