Method and Application of Air-core Coil Mutual Inductance Coefficient Error Elimination Based on Rotating Cancellation Principle

Abstract

The invention discloses an air core coil mutual inductance coefficient error elimination method and application based on a rotation cancellation principle. The method comprises steps of enabling a rotating disc to rotate by 360 DEG / n relative to a current carrying lead, measuring a voltage of an air core coil, rotating the rotating disc by the same degree and measuring a voltage, and performing n times of rotation; obtaining mutual inductance coefficients according to voltage and current values; and performing weighted average of the mutual inductance coefficients to obtain the accurate mutual inductance coefficient value of the air core coil. The invention discloses an air core coil current measurement method. The air core coil mutual inductance coefficient error elimination method is used for obtaining the mutual inductance coefficient, the rotating disc is rotated at the same degree by many times to obtain multiple groups of voltages of the air core coil, currents are obtained according to the mutual inductance coefficients and the voltages, and the accurate value of a tested current is obtained by weighted average of the multiple groups of currents. Under a precondition that factors of the air core coil symmetry, the current carrying lead cross section, the tested current central position and the like are unknown, the instability of the mutual inductance coefficient is reduced, influences on currents can be eliminated, and the measurement accuracy of the air core coil is improved.

Description

technical field [0001] The invention relates to an error elimination method of a current sensor, in particular to an air-core coil mutual inductance error elimination method based on the principle of rotation cancellation and its application. Background technique [0002] The air-core coil has the advantages of no magnetic saturation, large measurement range, good linearity, and wide frequency bandwidth. It is a very competitive new type of current sensor. The air-core coil is an inductive sensor that measures current based on magnetic induction. , the mutual inductance coefficient is its most critical parameter. [0003] In the air-core coil, the secondary winding is wound on a non-magnetic skeleton, and there is no ferromagnetic material, so that the sensor still has excellent linearity in the range of a few amps to hundreds of kiloamperes. Unlike traditional CT, because it is not directly Measuring current, even if the measured current contains a large DC component, it w...

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Problems solved by technology

[0008] In view of the above-mentioned defects, the present invention provides an air-core coil mutual inductance error elimination method based on the principle of rotation cancellation, aiming to solve the problems in the prior art due to the incorrect structure of the air-core coil and the shape of the current-carrying wire in the process of calibrating the mutual inductance of the air-core coil The technical problem that the calibration results are inaccurate due to the influence of factors such as location and current distribution on the mutual inductance coefficient of the air-core coil

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