Receiver for a pulsed eddy current system
AssigneeABB Schweiz AG
InventorsMartin Zlatanski, Parham Davami, Jarl Sobel, Thomas Wiik, Jan Nilsson
Life of this patent
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Abstract
A receiver for a Pulsed Eddy Current (PEC) system configured to detect a changing electromagnetic field generated by eddy currents induced in an object of an electrically conductive material. The receiver includes an electrically conductive receiver coil, a high-voltage receiver channel, a low-voltage receiver channel, and an over-voltage protection connected between the receiver coil and the LVRC. The OVP includes a bias circuit B, a diode D connected between the receiver coil and the bias circuit, and a capacitor C connected between the bias circuit and the LVRC.
Claims15
A receiver for a Pulsed Eddy Current, PEC, system configured to detect a changing electromagnetic field generated by eddy currents induced in an object of an electrically conductive material, the receiver comprising:
- an electrically conductive receiver coil;
- a high-voltage receiver channel, HVRC;
- a low-voltage receiver channel, LVRC;
- and
- an over-voltage protection circuit, OVP, connected between the receiver coil and the LVRC, the OVP including:
- a bias circuit;
- a diode connected between the receiver coil and the bias circuit;
- and
- a capacitor connected between the bias circuit and the LVRC;
- wherein the bias circuit is configured for providing a bias threshold for forward biasing or reverse biasing the diode depending on a voltage induced in the receiver coil;
- and
- wherein the capacitor is configured for preventing the LVRC from seeing a bias voltage or current of the bias circuit.
A PEC system comprising:
- a transmitter configured to generate a changing electromagnetic field which induces eddy currents in an object of an electrically conductive material arranged within the electromagnetic field;
- and
- a receiver for a Pulsed Eddy Current, PEC, system configured to detect a changing electromagnetic field generated by eddy currents induced in an object of an electrically conductive material, the receiver including:
- an electrically conductive receiver coil;
- a high-voltage receiver channel, HVRC;
- a low-voltage receiver channel, LVRC;
- and
- an over-voltage protection circuit, OVP, connected between the receiver coil and the LVRC, the OVP including:
- a bias circuit;
- a diode connected between the receiver coil and the bias circuit;
- and
- a capacitor connected between the bias circuit and the LVRC;
- wherein the bias circuit is configured for providing a bias threshold for forward biasing or reverse biasing the diode depending on a voltage induced in the receiver coil;
- and
- wherein the capacitor is configured for preventing the LVRC from seeing a bias voltage or current of the bias circuit.
A method of determining a thickness of the object by means of the PEC system comprising a transmitter configured to generate a changing electromagnetic field which induces eddy currents in an object of an electrically conductive material arranged within the electromagnetic field;
- and
- a receiver for a Pulsed Eddy Current, PEC, system configured to detect a changing electromagnetic field generated by eddy currents induced in an object of an electrically conductive material, the receiver including:
- an electrically conductive receiver coil;
- a high-voltage receiver channel, HVRC;
- a low-voltage receiver channel, LVRC;
- and
- an over-voltage protection circuit, OVP, connected between the receiver coil and the LVRC, the OVP including:
- a bias circuit;
- a diode connected between the receiver coil and the bias circuit;
- and
- a capacitor connected between the bias circuit and the LVRC;
- wherein the bias circuit is configured for providing a bias threshold for forward biasing or reverse biasing the diode depending on a voltage induced in the receiver coil;
- and
- wherein the capacitor is configured for preventing the LVRC from seeing a bias voltage or current of the bias circuit;
- the method comprising:
- by means of the transmitter, inducing eddy currents in the object;
- by means of the receiver measuring, as a function of time, a voltage induced in the receiver coil by the changing electromagnetic field generated by the induced eddy currents, wherein:
- for a voltage induced in the receiver coil which is above a bias threshold provided by the bias circuit, the OVP prevents the induced voltage from being seen by the LVRC, and
- for a voltage induced in the receiver coil which is below the bias threshold, the OVP allows the induced voltage to be seen by the LVRC;
- and
- based on the measurement of the voltage, determining the thickness of the object.
Dependencies are inferred from the claim text.