Displacement sensor with a magnetic target and transducer connector to an analyzer circuit for automotive applications where the displacement of a rotating object is to be determined

摘要

Sensor comprises a magnetic transducer (3) connected to a processor that determines the displacement of a magnetic target (2) attached to a moving component. The transducer comprises a magnetic circuit with a coil connected to a power supply (4) with a compensation current (Ic) to produce a magnetic field opposing the target magnetic field so that there is a resulting null field. The power supply includes means (6a) for superimposing a radio-frequency current (Irf) on the compensation current with the amplitude such that a saturating magnetic field is generated in the material of the magnetic circuit each time the current alternates. A harmonic analyzer (6b) is used to analyze the resulting voltage (V1) at the coil terminals to control the amplitude and reduce it to zero by variation of the compensation current. Analysis of the resulting compensation current yields the displacement of the target.