MRAS-based sensorless field oriented controlled axial flux permanent magnet synchronous machine with additional parameter adaptation

Abstract

The characteristics of a sensorless control method for synchronous machines with a parallel model are investigated, in consideration of additional online parameter adaptation. Using error compensated reference voltage inputs the parallel model’s parameters are adapted to the synchronous machine by comparing the model current output with the measured current values. Thus the adaptation to the reference transfer behavior of the system is accomplished using an implicit method. After describing the difference between the reference and the adaptive model mathematically, the system stability is analysed using Popov's hyperstability condition. An additional stability criterion could be derived from the full machine model. The extension of the sensorless control was achieved through a simultaneous adaptation algorithm accounting for coupling effects caused by the influence of misalignment of the field-coordinates.