A Method for Mathematical Modeling Spatial Harmonics in a SynRM for Sensorless Control

Abstract

In this paper, we propose a new method for modeling the inductance spatial harmonic components in a SynRM for position-sensorless control. The conventional methods for sensorless control based on a mathematical model consider only the fundamental components of the inductances. As a result, several problems arise, including limited controller bandwidth. The proposed method is based on the fact that the back electromotive force (EMF) estimated by the observer includes harmonic voltages induced by the inductance spatial harmonics. We process and analyze the estimated EMF in every operational region so that only the component with the desired order from among the harmonic voltages is investigated for mathematical modeling. Sensorless control with the proposed model involves simple feedforward compensation to the observer's input voltage; as a result, the error in velocity and position estimation is reduced considerably, and high bandwidth can be achieved for the speed controller.