Optimum Input Volt-Ampere Control of Three-Phase Induction Motors Connected to Distributed Generating Systems

At light-load conditions, the power factor of a three-phase induction motor is very poor and it draws very large volt-ampere (VA) from the source. It is undesirable for a weak distributed generating system. Here voltage reduction method is employed and an optimum speed is found at which the input VA remains minimum irrespective of the load conditions. Moreover, a condition is also derived at which the input power is minimum at the optimum voltage, for every load and any induction motor. The control range is also found for which the voltage reduction method is effective for minimizing input power