Current transformer

Abstract

The invention provides a current transformer. The current transformer comprises a magnetic core, a first primary winding, a second primary winding and a first secondary winding, wherein the magnetic core comprises a first closed magnetic circuit and a second closed magnetic circuit; the first closed magnetic circuit is formed by the connection of a first magnetic core structure and a second magnetic core structure, the second closed magnetic circuit is formed by the connection of the first magnetic core structure and a third magnetic core structure, and the first magnetic core structure is a common magnetic core structure of the first closed magnetic circuit and the second closed magnetic circuit; the first primary winding penetrates through the first closed magnetic circuit, and the second primary winding penetrates through the second closed magnetic circuit; the first secondary winding is wound on the first magnetic core structure; magnetic flow generated by differential mode currents which passes through the first primary winding and the second primary winding overlaps with one another on the first magnetic core structure, and magnetic flow generated by common mode currents which passes through the first primary winding and the second primary winding cancels one another out on the first magnetic core structure. According to the current transformer, independent measurements of the differential mode currents and the common mode currents can be achieved.

Description

technical field [0001] This application relates to electronic components, and more particularly to current transformers. Background technique [0002] Photovoltaic power generation system refers to a power generation system that uses solar cells to directly convert solar energy into electrical energy. In the process of using photovoltaic power generation system to generate electricity, there will be a risk of DC arcing. Arc-fault circuit interrupter (AFCI) is usually used to identify the presence of DC arcing in photovoltaic power systems, so as to eliminate the risk. AFCI needs to accurately capture the differential mode current noise signal generated during the arcing process . [0003] In the circuit, by connecting the primary winding of the current transformer in series in the energized line that needs to measure the current, according to the detected magnitude of the current flowing through the secondary winding of the current transformer, the current flowing through t...

AI Technical Summary

Problems solved by technology

Current transformers can be used to detect the differential mode current and common mode current in the energized line, however, in the actual circuit, the differential mode current and the common mode current coexist in the energized line, because the differential mode current and the common mode current flow through the same line , the existence of the common mode current affects the output differential mode current of the current transformer, it is difficult to realize the independent measurement of the differential mode current, and the capture of the differential mode current is not accurate enough

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