Device and method for measuring AC mutual induction with compensation method

Abstract

The invention provides a new method for precisely measuring AC mutual induction amount by the compensator technology. The mutual induction amount is traced to the source to the measurement of resistance quantity value and frequency, and the uncertainty of two kinds of measurements can both reach 10-9 magnitudes or even more, thus the uncertainty of measurement mutual induction can at least reach 10-8 magnitudes. The most precise method for obtaining standard mutual induction amount, which is published in existing foreign literatures, is 'calculation mutual induction method', i.e. the mutual induction amount is calculated according to the measurement result of the physical dimension of the mutual inductor. Because of the limitation of physical dimension measurement accuracy degree, the uncertainty of foreign methods only can reach 10-6 magnitudes. The invention adopts direct digital synthesis technology to generate multiple paths of AC signals to ensure signal right angle characteristics. A constant current source is adopted to provide excitation for mutual induction to ensure that current flowing in a sampled resistance is always the same as the current flowing in the mutual inductor. The variation of pumping signal voltage does not affect the measuring process. A phase-locked amplifier as a null indicator based on the phase sensitive detection technology only acts on a signal with the same working frequency so as to eliminate noise and harmonic wave influence, and the resolution of the null indicator only reach 1*10-8. The new method provided by the invention can improve magnitude by 10 times compared with the existing foreign methods.

Description

technical field [0001] The invention relates to a new technology for establishing a measurement standard instrument, in particular to a device and method for measuring AC mutual inductance through a compensation method. Background technique [0002] my country is rich in rare earth metal resources, which can be used to produce high-quality magnetic materials. In the past, most of my country's rare earth metals were exported cheaply in the form of raw materials. Foreign countries used these materials to make high-end instruments (such as medical human magnetic resonance imagers, etc.) and then sold them to my country, making a lot of profits. To change this situation, it is necessary to make high-accuracy magnetic measuring instruments to precisely measure the characteristics of magnetic materials, so that my country can also use its own rare earth resources to produce high-quality magnetic materials. The accuracy of magnetic measuring instruments needs to be traced to the m...

AI Technical Summary

Problems solved by technology

Due to the limitation of geometric measurement accuracy, the mutual inductance measurement technology at home and abroad is still at the level of the 1970s, and the uncertainty remains at 2×10 -6 order of magnitude, there has been no new development in recent decades

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