Optimization of a synchronous reluctance machine for an industrial drive application regarding to sensorless control

Abstract

In this paper synchronous reluctance machine topologies for an industrial drive application are investigated regarding to sensorless control and regarding to the flux weakening operation. An induction machine drive shall be replaced by a synchronous reluctance machine because of lower machine costs and the possibility of sensorless control. The induction machine stator is intended to be equipped with the SynRM rotor to provide a modular machine concept. Two different rotor types, a flux barrier and a salient pole machine topology are discussed. By finite element simulation methods both machine types are designed for a possible operation in flux weakening range with low harmonics. The flux barrier rotor was already built up as machine prototype and was operated by a position sensorless control. Based on this implementation key requirements for the optimization of a salient pole machine are identified. To overcome drawbacks of the salient machine topology several design measures like rotor skewing, stator coil pitching, rotor pole shaping and unequal pole angles are considered. Finally, a salient pole machine design with low harmonics is reached which is expected to be well operated in deep flux weakening range. However, the final design shows a lower torque compared to the flux barrier machine.