Efficiency Optimization with Improved Transient Performance of Indirect Vector Controlled Induction Motor Drive

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.