Position sensorless control of a linear interior permanent magnet oscillatory machine, with experiments

The investigated linear machine works as a mechanical oscillator using springs to reduce the overall power consumption and two electromagnets having their twin circular coils (which surround a ring-shape permanent magnet) connected in series. The actuator can be controlled with a single phase inverter. In this paper sensorless closed loop position control based on a FEM assisted estimator that uses two extra coils placed near the main coils is presented. Experiments were performed, using a cascaded architecture control approach having two combined sliding mode (SM) plus PI controllers, to validate the position sensorless control.