Constant slip control of induction motor at light load

The most widely used AC motor drives adopt the rated flux control (RFC) method. However, at light load condition, RFC causes excessive iron loss, thus the conversion efficiency of the drive system is impaired. This paper introduces a new control approach-constant slip control (CSC), which minimizes the stator current at light load, so that the iron loss and reactive power consumption of the motor are decreased. Simulation results compare the power consumption of CSC with that of RFC in order to validate the theoretical development. In the last part, realization of CSC is discussed.