Sensorless rotor position and speed estimation for a synchronous reluctance motor

A method of sensorless position and speed estimation for the synchronous reluctance motor using only the measurement of current available at the stator terminals is introduced. The ability to make this estimation is due to the variation of inductance with the rotor position. The technique does not require accurate measurement of machine parameters, only that the inductance be significantly different in both the d- and q-axes. Using the estimated rotor position, rotor speed can be calculated using a modified zero-crossing technique. The result,, of several simulations are presented, demonstrating the algorithm´s suitability for a variety of load torques, speeds and saliency ratios. The results of the practical implementation of this work using a 22 kW synchronous reluctance machine are also presented.