SYSTEMS, METHODS, AND APPARATUS FOR DETECTING FERROMAGNETIC FOREIGN OBJECTS IN A PREDETERMINED SPACE

摘要

An apparatus for detecting a presence of an object (1150) is provided. The apparatus includes an inductive sensing coil (1102) that is configurable to generate a first magnetic field. The inductive sensing coil (1102) is configured to have an electrical characteristic that is detectable when generating the first magnetic field. The electrical characteristic varies as a function of a second time-varying magnetic field simultaneously applied to the object. The apparatus comprises a controller (1140) configured to detect a change in the electrical characteristic and determine a presence of the object based on the detected change in the electrical characteristic. The electrical characteristic comprises one or more of an equivalent resistance, an equivalent inductance, an equivalent impedance, and an impulse response of the inductive sensing coil. The object comprises one or more of a ferromagnetic object, a metallic film and a metallic foil.