Practical evaluation of two stator flux estimation techniques for high performance direct torque control

The performance of the direct torque control method for AC servo drives is heavily dependent on the accuracy of the stator flux estimate. In this paper two estimation techniques are compared experimentally. The first uses a lagging integrator to solve the stator flux equation and the second is based upon the Luenberger observer. Practical results are obtained showing that the Luenberger observer offers greatly improved robustness to parameter variation.