Direct current sensor

Abstract

The present invention discloses a DC curren sensor. In said sensor a detection coil is added, said sensor adopts single-core three-winding structure, when a DC bias magnet is existed in the magnetic core, the induced potential obtained by detection coil can produce positive-negative half-wave unsmmetrical waveforms, said waveforms can be converted into the voltage signal of difference of positive-negative half-wave effective values, after voltage / current conversio, said signal can be fed into feedback winding, said feedback winding cap produce the DC magnetic potential whose direction is opposite to that of magnetic patential produced by detected direct current to balance the bias magnetic potential produced by detected direct current to form 'null-flux' state, so that it can obtain the detected direct current intensity so as to implement the detection of direct current.

Description

technical field [0001] The invention relates to a direct current sensor, which is suitable for detecting direct current including the following aspects: such as used in power electronic equipment for current feedback, cut-off control, steady current regulation, direct current side overcurrent, power system and electrolysis industry, etc. DC current signal detection. Background technique [0002] In DC transmission system, frequency conversion speed control device, UPS power supply, inverter welding machine, electrolytic plating, CNC machine tool, microcomputer monitoring system, power grid monitoring system and various fields that need to isolate and detect DC current, it is necessary to accurately detect and control DC current. The fundamental guarantee for the safe and reliable operation of the equipment and the first problem to be solved. [0003] Current measurement equipment such as DC current comparators, DC transformers, and shunts have been developed; some measureme...

AI Technical Summary

Problems solved by technology

This amplifier has serious disadvantages: when the number of turns of the DC winding is large, according to the principle of transformer effect, the AC voltage in the excitation winding will induce an alternating voltage in the DC winding. In order to effectively suppress the induced voltage in the DC control loop, it is necessary to Putting an inductor in series in the circuit or having to use a double core structure will make its structure complex, bulky and heavy

In order to obtain the excellent performance of the magnetic modulator, the performance of the ferromagnetic material must be improved. Therefore, the magnetic core material with high magnetic permeability and low coercive force should be selected, such as 1J85 or 1J86 Permalloy, and a magnetic core with a high squareness ratio and Strict pairing of magnetic cores requires that the waveform of the excitation power supply is strictly symmetrical and the amplitude and frequency of the output voltage must be stable to ensure that the magnetic modulator core works in a fully saturated state. Because of these characteristics, the application and promotion of the magnetic modulator are limited.

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