Improved direct torque control for induction motor drives with rapid prototyping system

Direct torque control (DTC) is an AC drive control method especially designed to provide fast and robust responses. In standard DTC, torque and flux errors are used as hysteresis controller inputs to determine the space voltage vector necessary to reduce these errors. During steady state operation., however, there are torque, flux and current pulsations. A well-known characteristic of DTC algorithms is the switching frequency varying in dependant on parameters like flux and torque hysteresis bands and the motor operating conditions. In this paper a novel progressive algorithm for DTC is presented with respect to induction motors. High torque and flux oscillations are avoided. Experimental results of the new DTC method obtained by an experimental rapid prototype system for drives are presented.