Direct-current leakage current sensor based on magnetic modulation

Abstract

The invention discloses a direct-current leakage current sensor based on magnetic modulation. The direct-current leakage current sensor is used for monitoring direct-current insulation condition, and has good performance. The direct-current leakage current sensor comprises an oscillating circuit, a diode, a double magnetic core differential motion unit, a first filter, an instrument amplifier, a phase sensitive detector and a second filter. The direct-current leakage current sensor disclosed by the invention adopts half-wave simulation; compared with a traditional sensor, a frequency multiplier circuit for generating phase-sensitive detector reference signals is eliminated, the circuit structure is simplified, the inference as well as the cost is reduced, and the direct-current leakage current sensor has the characteristic of high sensitivity.

Description

technical field

[0001] The invention belongs to the technical field of insulation monitoring of electronic power equipment, and more specifically relates to a DC leakage sensor based on magnetic modulation. Background technique

[0002] In electronic power equipment, it is necessary to monitor the DC insulation status in real time to prevent leakage, so as to protect electronic equipment and personal safety. At present, DC leakage current sensors are mostly used for monitoring. The DC leakage current sensor in the prior art is mainly based on the principle of magnetic modulation. A coil is wound on a high-permeability annular magnetic core, an excitation signal is passed through the primary coil to excite the magnetic core, and the detected DC current passes through the magnetic core. center. When the measured DC signal is zero, the induced voltage of the secondary coil is a voltage signal with a symmetrical waveform; when the measured DC current signal is not zero, the ma...

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