High-precision universal alternative and direct current measuring device

Abstract

A high-precision general-purpose AC and DC current measuring device, including a casing, a magnetic core winding structure, and a circuit board. The magnetic core winding and the circuit board are arranged in the casing. It is made of soft magnetic material with low remanence, and has two measuring heads with consistent performance and opposite directions, completely closed, without air gap, the winding in the magnetic core winding is wound with high withstand voltage enameled wire, the magnetic core Including the measuring head and the mutual inductance magnetic core, all the magnetic cores are placed in the shielding cover to perform the function of strict magnetic shielding. The said shielding cover adopts a multi-layer structure, which not only has the function of shielding the magnetic field but also the function of shielding the electric field , which is extremely important for improving the accuracy of current measurement. The invention has a compensation winding for compensating the magnetic field generated by the measured current at any time, so that only the magnetic field generated by the exciting current exists in the measuring head without other magnetic fields, which is the closed-loop fluxgate principle.

Description

technical field [0001] The invention relates to a current measuring device, in particular to a high-precision general AC and DC current measuring device. Background technique [0002] There are many ways to measure current. For non-contact current measuring devices, magnetic sensitive elements are usually used to measure the magnetic field generated by the current, and then calculate the magnitude of the current. For example, transformers are usually used to measure AC, and Hall principle is usually used to measure current when measuring DC. Among many current measurement schemes, the current measurement method based on the fluxgate principle is a very reliable and highly stable scheme. Because the fluxgate has high sensitivity, it is unmatched by other methods such as the Hall principle. At the same time, because the fluxgate is less affected by temperature, the current measurement device based on the fluxgate principle has good temperature characteristics and high sensiti...

AI Technical Summary

Problems solved by technology

Most of the fluxgate current measuring devices on the market are single measuring heads, with small measuring range and slow response time. They are generally used to measure DC current, but difficult to measure AC current, especially high-frequency AC current.

It is not advisable to simply increase the number of turns of the compensation coil to obtain large current measurement capabilities, because the inherent oscillation frequency of the measuring head will couple a large amount of interference components into the compensation coil, seriously affecting the output of the measurement device

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