Identification of PM Synchronous Machines Parameters for Design and Control Purposes

The knowledge of the machine magnetic parameters is of paramount importance for the design and control on synchronous machine drives. Among those machines, Synchronous Reluctance (Rel) and PM-assisted Synchronous Reluctance (PM/Rel) machines have highly nonlinear current to flux linkage relationships, due to magnetic saturation, including cross interference between the d and q rotor axes. This chapter reviews the modelling of nonlinear PM Synchronous machines of all types, and the techniques for identification of their current to flux linkage relationship. The cases of PM/Rel and Rel machines are covered by this general analysis. The identification and manipulation of the flux maps is useful in all phases of the machine’s life, from machine design to the implementation of control algorithms. Non-accurate magnetic parameters lead to torque and power capability miscalculations, non-optimal efficiency strategies over the drive duty cycle, deteriorated and chattering control response, instability of position self-sensing control. Accuracy of flux maps is a cornerstone of high-performance control around zero speed in servomotor drives. Classical and more recent identification techniques existing in the literature are explored, including self-commissioning methods. The flux maps approach is compared to the more popular inductance-based modeling approach, and commented. Results are presented for motor prototypes of different kinds, including PM/Reluctance machines.