METHOD FOR DETECTING AN ELECTRICALLY CONDUCTIVE FOREIGN BODY AND DEVICE FOR INDUCTIVELY TRANSMITTING ELECTRICAL ENERGY
First Claim
1. Method for the detection of an electrically conductive foreign body on a device for the inductive transmission of electrical energy from a stationary unit with a power supply unit and a primary coil to a mobile unit with a secondary coil and an electric consumer, in which, initially, electric power is fed from the power supply unit to the primary coil, this feed-in is interrupted, and the curve over time of the decay of an electric operating variable of the primary coil caused by this is measured, wherein at least one parameter of the measured curve is compared with a corresponding parameter of a reference curve, which was determined with an interruption of the power feed-in to the primary coil without the presence of an electrically conductive foreign body in the region of the magnetic field produced by the primary coil, in that with the aid of this comparison, a determination is made as to whether an electrically conductive foreign body is present in the region of the magnetic field produced by the primary coil, wherein with the determined presence of a foreign body from the curve over time of the decay of the measured electric operating variable, a measure is determined for the power that is consumed by the foreign body with the normal operation of the device, and in that with the aid of this determined measure, the power fed into the primary coil is reduced to such an extent that the power consumed by the foreign body remains below a predefined threshold.
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Accused Products
Abstract
In a method for detecting an electrically conductive foreign body at a device for inductively transmitting electrical energy from a stationary unit having an electrical power supply unit and a primary inductor to a mobile unit having a secondary inductor and an electric load, electrical power is initially fed from the electrical power supply unit into the primary inductor and the feed-in is interrupted. The curve over time of the resulting decay of an electrical operating variable of the primary inductor is measured and at least one parameter of the measured curve is compared with a corresponding parameter of a reference curve in the event of an interruption of the power feed-in into the primary inductor without the presence of an electrically conductive foreign body. The comparison is used to determine whether an electrically conductive foreign body is present in the region of the magnetic field produced by the primary inductor.
76 Citations
15 Claims
- 1. Method for the detection of an electrically conductive foreign body on a device for the inductive transmission of electrical energy from a stationary unit with a power supply unit and a primary coil to a mobile unit with a secondary coil and an electric consumer, in which, initially, electric power is fed from the power supply unit to the primary coil, this feed-in is interrupted, and the curve over time of the decay of an electric operating variable of the primary coil caused by this is measured, wherein at least one parameter of the measured curve is compared with a corresponding parameter of a reference curve, which was determined with an interruption of the power feed-in to the primary coil without the presence of an electrically conductive foreign body in the region of the magnetic field produced by the primary coil, in that with the aid of this comparison, a determination is made as to whether an electrically conductive foreign body is present in the region of the magnetic field produced by the primary coil, wherein with the determined presence of a foreign body from the curve over time of the decay of the measured electric operating variable, a measure is determined for the power that is consumed by the foreign body with the normal operation of the device, and in that with the aid of this determined measure, the power fed into the primary coil is reduced to such an extent that the power consumed by the foreign body remains below a predefined threshold.
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14. Device for the inductive transmission of electric energy from a stationary unit with a power supply unit and a primary coil to a mobile unit with a secondary coil and an electric consumer, wherein the device has a means for the feed-in of electric power from the power supply unit into the primary coil and for the subsequent interruption of this feed-in and has a means for the measurement of the curve over time of the decay of an electric operating variable of the primary coil caused in this way, comprising means for the comparison of at least one parameter of the measured curve with a corresponding parameter of a reference curve, which was determined with an interruption of the power feed-in into the primary coil, without the presence of an electrically conductive foreign body, in the region of the magnetic field produced by the primary coil, means for the determination, with the aid of this comparison, as to whether an electrically conductive foreign body is present in the region of the magnetic field produced by the primary coil, means for the determination of a measure for the power consumed by the foreign body, with the normal operation of the device, from the curve over time of the decay of the measured electric operating variable, with the detected presence of a foreign body, and a means for the reduction of the power fed into the primary coil, with the aid of the determined measure, to the lowering of the power consumed by the foreign body below a predefined threshold.
Specification