Abstract:
This paper introduces an energy efficient induction motor drive suitable to operate at light load conditions.
The iron losses in the induction motor are significant when the machine is operated below the rated conditions. The
efficiency of the motor can be increased by keeping the flux level below the rated value. In this paper, the efficiency of
the induction motor has been improved by incorporating an efficiency optimization algorithm. Efficiency optimization
algorithm provides an optimum value of flux generating direct axis stator current, which controls the magnitude of the
rotor flux. At light loads, the optimization algorithm weakens the rotor flux from its rated value, thus reducing the core
losses. A 5.4-hp induction motor drive is simulated in SIMULINK to analyze the efficiency under different operating
conditions of the drive. The variation of efficiency under load change and speed change is observed. Simulation results
show that efficiency increases as the operation of induction motor drive shifts from unrated to rated conditions. The
implemented algorithm is tested under different operating conditions of IM Drive including sudden change in load and
reference speed. This paper also considers the transient performance of the drive with efficiency optimization
algorithm.
