Direct torque control for brushless doubly-fed machines

A closed-loop torque and magnetic flux control strategy for a brushless doubly fed motor drive is presented. The controller utilizes a predictive method which estimates the required change of flux and torque for a given set of input values. Simulation results for a prototype torque controller illustrate improved system performance over V/Hz converter control. Torque and flux responses in the controlled case are decoupled and fast response and settling characteristics are achieved. The predictive controller is much more robust to load disturbances than the V/Hz and allows for faster speed response