Application of a Position Sensorless Control to a Reluctance Synchronous Drive Including Flux Weakening

Abstract:
This paper discusses a position sensorless or encoder- less control applied to an industrial Synchronous Reluctance Machine (SynRM) drive. Since several years SynRMs gained popularity and represent an alternative to other machine types in certain applications. In this industrial spooling application the induction machine (IM) rotor is replaced by a SyRM rotor with same stator and the drive operates in the constant torque as well as in flux weakening operation. In addition with the sensorless methods the overall drive system is simplified significantly. First by the utilization of a SynRM and further by the sensorless control. Hence, a real low cost approach with simple and robust structure is reached. The performance of the SynRM in field oriented control based on sensor and finally without encoder is shown in this work. At low speed and standstill the well known current slope based methodology without any harmonic or pulse excitation provides the rotor angle information. For higher speeds a Back-EMF model is implemented. The drive is successfully operated in flux weakening operation by Maximum Torque Per Ampere (MTPA) strategy. Experimental results of both methods are presented and show sufficient operation and given limitations.