Speed Sensorless Control of Synchronous Reluctance Motor At Full Speed Range

Synchronous reluctance motor (SynRM) is a special synchronous motor that completely utilizes reluctance torque to operate. Because of its low cost, solid structure and no risk of demagnetization at high temperatures, it has gradually attracted attention in recent years. In order to increase the reliability of the control system and take advantage of the low cost of synchronous reluctance motor, a sensorless control strategy in wide speed range is introduced in this paper. In low speed range, a high frequency voltage injection method is used to get the rotor position information. In middle or higher speed range, an active flux observer is introduced to realize the vector control. For the purpose of maintaining the stability, we adopted a weighted function method during the switching between these two observation methods. Finally, the proposed method is verified by experiments on a 5.5-kw SynRM which can work well down to 0 rpm and up to 1500rpm.