Performance analysis of the DTC using a closed loop stator flux observer for induction motor in the low speed range

Abstract

Direct torque control (DTC) of an AC motor has the fast torque and flux dynamic responses even though it has very simple scheme to implement. However, DTC do not show good performance at low speed range with conventional open loop stator flux observer when stator resistance varied. Therefore, authors propose a new nonlinear stator flux observer in order to estimate the stator flux of induction motor at low speed and show its simulation results.