US 11,894,696 B2 · Method and apparatus for detecting electrically conductive foreign bodies during inductive energy transmission

Abstract

In a method and an apparatus for detecting electrically conductive foreign bodies during inductive energy transmission between a primary coil (1) and a secondary coil (2), at least one sensor coil (5) is arranged between the primary coil (1) and the secondary coil (2), and a current flowing in the sensor coil (5) due to the induced voltage during the energy transmission is detected and evaluated. In this case, the sensor coil (5) is connected to at least one capacitor to form a resonant circuit which is matched to the excitation frequency of the primary coil (1). The phase position of the current in the resonant circuit in relation to a reference signal is then used to determine whether there are electrically conductive foreign bodies (4) between the primary coil (1) and the secondary coil (2). A high degree of sensitivity, also in relation to small electrically conductive foreign bodies within the energy transmission path, is achieved by means of the method and the apparatus.

Claims12

Dependent claims

Method for detecting electrically conductive foreign bodies during inductive energy transmission between a primary coil (1) and a secondary coil (2), in particular during inductive charging processes, in which method at least one sensor coil (5) is arranged between the primary coil (1) and the secondary coil (2), and in which a current induced in the sensor coil (5) during the energy transmission is detected and evaluated,

characterized in that the sensor coil (5) is connected to at least one capacitor (C3s) to form a closed resonant circuit which is matched to an excitation frequency of the primary coil (1) and in that the phase position of the current in the closed resonant circuit in relation to a reference signal is used to determine whether one or multiple electrically conductive foreign bodies (4) are present between the primary coil (1) and the secondary coil (2);
wherein the reference signal is a voltage at the primary coil (1), or—in case of an excitation of the primary coil (1) based on a PWM signal—the reference signal is the PWM signal.

Apparatus for detecting electrically conductive foreign bodies during inductive energy transmission between a primary coil (1) and a secondary coil (2), in particular during inductive charging processes, which apparatus has at least one sensor coil (5) arranged above the primary coil (1),

characterized in that
the sensor coil (5) is connected to at least one capacitor (C3s) to form a close resonant circuit which is matched to an excitation frequency of the primary coil (1) and is connected to an evaluating device (6) which detects the current in the closed resonant circuit and which determines from a phase position of the current in the resonant circuit in relation to a reference signal whether one or multiple electrically conductive foreign bodies (4) are present between the primary coil (1) and the secondary coil (2);
wherein the evaluating device (6) is designed such that it uses a voltage at the primary coil (1) as the reference signal, or the primary coil (1) is connected to an excitation circuit which uses a PWM signal to excite the primary coil (1), and the evaluating device (6) is designed such that it uses the PWM signal as the reference signal.

Dependencies are inferred from the claim text.

Method and apparatus for detecting electrically conductive foreign bodies during inductive energy transmission

Life of this patent

Method and apparatus for detecting electrically conductive foreign bodies during inductive energy transmission

Life of this patent

Abstract

Claims12