Method for automatically correcting temperature drift of electrical vortex sensor

Abstract

The invention provides a method for automatically correcting temperature drift of an electrical vortex sensor. According to the method, a certain impedance measuring circuit is utilized to obtain the equivalent inductance and the resistance of a detection coil, the relationship, changing along with temperature and measurement, of the inductance and the resistance of the detection coil is utilized to remove the influence of temperature changes and extract actual measured change information. According to the method, signals of the vortex sensor composed of an impedance measuring module (4) and a rectification calculating module (5) is used for conditioning the circuit, so that to-be-measured information is obtained, rectification is conducted automatically, and the influence of temperature changes is removed at the same time. According to the method, when temperature drift is rectified, no extra probes or coils or temperature sensors are further arranged, and temperature drift rectification effect is remarkable. Moreover, the method has the advantages of being wide in application range, simple in structure, easy to implement and the like. When the method is used for automatically rectifying the temperature drift of a probe of the electrical vortex sensor, temperature drift coefficients can generally be reduced to below 5nm / DEG C from 500nm / DEG C.

Description

technical field [0001] The invention relates to the field of eddy current sensors, in particular to an automatic correction method for temperature drift of the eddy current sensor. Background technique [0002] The eddy current displacement sensor uses an induction coil with high-frequency excitation to generate an induced eddy current in the target conductor, and converts the distance change between the detection coil and the measured target into a change in the impedance (including inductance and resistance) of the induction coil, and the signal conditioning circuit Displacement information is obtained by measuring changes in search coil parameters. Eddy current sensors are very widely used in displacement, vibration, angle and velocity, or thickness, resistivity and temperature measurement in various industrial field and experimental researches. Due to the characteristics of the eddy current sensor itself, it has many advantages such as high stability, insensitivity to e...

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Problems solved by technology

[0004] The current main compensation (correction) measures mainly include: 1. Increase the differential compensation coil. This method increases the volume and complexity of the probe, and is not universal. It cannot perform temperature compensation for different detection targets, except for the compensation coil. In addition, it is also necessary to install a suitable induction conductor surface for the differential coil

2. Add a non-inductive coil with the same resistance value to sense temperature changes to provide compensation. This method can only eliminate the temperature drift caused by the temperature change of the detection coil resistance itself, the temperature drift of the inductor, and the resistivity of the target conductor Drift caused by temperature drift cannot be compensated for

3. Use the temperature measuring element to measure the temperature and realize the correction of temperature drift. Although this method is feasible, due to the inconsistent temperature of different parts of the sensor, many temperature measuring elements are needed, and the added temperature measuring element adds a lot of leads, which not only increases This increases the complexity of the circuit system, and also increases the number of leads of key components such as the probe, reducing the portability of the sensor

On the other hand, this temperature compensation method is not universal

4. The detection coil is wound with a low-resistance temperature-drift alloy material made of precious metals. The structure of this probe is the same as that of an ordinary probe, but it is expensive

Although this method reduces the temperature drift of the detection coil itself, it cannot control the temperature drift caused by the target conductor, and cannot completely eliminate the temperature drift of the probe-target system. Such an eddy current sensor still has a large temperature drift

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