Dynamic Performance Improvement of Induction Motor Under Energy Optimal Control

Model Based Control (MBC) is one of the energy optimal controllers used in vector-controlled Induction Motor (IM) to control the excitation of the motor in accordance with the torque and speed. MBC improves the performance of the motor, but it produces ripples in the torque and speed. This paper investigates the opportunity for improving dynamic performance in a three-phase IM operating with MBC and proposes two control schemes: (i) a low pass filter in the output of MBC and (ii) torque producing current (iqs) injection in the output of speed controller. During load transition pre and post operation of MBC is also analyzed. Dynamic performance of a 1-hp, three-phase squirrel-cage induction motor with mine –hoist load diagram is investigated in MATLAB/SIMULINK environment. Motor dynamics are improved with the two proposed scheme in terms of overshoot, undershoot and settling time of the torque profile. Key-Words: induction motors dynamics, loss minimization, mine hoist load, model based control, speed controller.