An improvement of sensorless control performance by a mathematical modelling method of spatial harmonics for a SynRM

This paper proposes a new method of modelling of inductance spatial harmonic components for a position sen-sorless control. The conventional methods for the sensorless control based on mathematical model consider only fundamental components of the inductances. This cause several problems including limited controller's bandwidth. The proposed method is based on the fact that the estimated back electromotive force (EMF) by the observer contains harmonic voltages induced by inductance spatial harmonics. By processing and analysing the estimated EMF at every operational region, only an interested order component among harmonic voltages is investigated in order to be modelled mathematically. Additionally, a simple feedforward compensation of the observer's input voltage by proposed mathematical model in sensorless control reduces the estimation errors of position and velocity and therefore the controller's high bandwidth is realized.