A position error compensation way for sensorless linear motor drive using high frequency injection

This paper presents a method of improving sensorless control based on the high frequency injection (HFI) for linear motor. The d- and q-axis incremental self- and mutual-inductance are determined by finite element analysis. The estimated mover position error caused by the cross-coupling magnetic saturation between the d- and q-axis is quantitatively analyzed. The error caused by filters in a HFI system is analyzed based upon filter group delay theory. A simple-to-design on-line compensation method is proposed based upon filters and cross-coupling magnetic saturation in a HFI system, which minimizes the position error. Finally, the simulation and experiment show a significant improvement in the accuracy of the mover position estimation.