INDUCTIVE SENSING BASED ON B-H CURVE NONLINIARITY

摘要

An inductive sensing system is based on nonlinearity of the B-H curve for an inductive sensor with an inductor coil wound onto a magnetic core. A DC magnetic field source magnetically couples into the magnetic core a pre-defined DC magnetic-core field, such that the inductive sensor is configured for a magnetic-core operating point on the B-H curve where the value of the second derivative d²B/dH² is substantially maximum, such that sensing operation is in the nonlinear region around the magnetic-core operating point. An inductance-to-digital conversion (IDC) unit is configured to acquire sensor measurements from the inductor coil corresponding to coil inductance as representing a sensed magnetic-core field. The IDC unit converts the sensor measurements into sensor data corresponding to changes in the sensed magnetic-core field relative to the magnetic-core operating point in response to a sensed condition that affects the DC magnetic field in the magnetic core.