SENSORLESS MEASUREMENT OF ELECTROMAGNETIC ACTUATOR DISPLACEMENT DEVICE

摘要

This invention pertains to sensorless measurement ofelectromagnetically induced displacement in actuators andsimilar units. Primarily, the device imposes a constantfrequency and amplitude excitation sine wave on a coilthrough a fixed impedance of a drive isolation network.The amplitude and phase of the voltage across the coilfluctuate depending upon the coil's inductance. Thisvariation in the value of the inductance is dependentupon the change in magnetic flux density generated bythe coil current and the displacement in air gap betweenthe coil pole and armature. Accordingly, a measurablemagnitude of displacement can be controllably imposedupon a system of solenoids. The displacement is thusmeasured and set without the use of extrinsic sensors.