A simple dynamic overmodulation strategy for fast torque control in DTC of induction machine with constant switching frequency controller

Abstract

This paper presents a simple dynamic overmodulation method to obtain a quick dynamic torque response in Direct Torque Control with constant switching frequency (will be referred as DTC-CSF) induction machines. A fast dynamic torque control can be achieved by applying a voltage vector that produces the largest tangential flux component during the transient condition. To perform this, the flux error status produced from the flux hysteresis comparator is modified before it is being fed to the look-up table, during dynamic condition. The effects of different switching and operating condition on dynamic torque performance are presented. The main benefit of the proposed method is its simplicity since only minor modification is made to the basic DTC hysteresis-based structure.