An intelligent indirect dynamic torque sensor for permanent magnet brushless DC drives

In this paper, the authors present a technique for indirect sensing of the dynamic torque feedback signal which is applicable to permanent magnet brushless DC drives. This technique is based on a judicious use of the motor equations and on parameter estimation methods. It is intelligent in the sense that the technique provides self-calibration at start-up, and in the paper, the authors also present a design to extend the technique to overcome effects of parameter drifts by incorporating real-time online parameter estimation. The effectiveness of the proposed intelligent indirect dynamic torque sensor is demonstrated in a typical speed and position control experimental setup, where the performance obtained is shown to be superior to that obtained with conventional sinusoidal current controllers.