AC/DC zero-flux fluxgate current sensor and program control configuration and calibration method thereof

Abstract

The invention discloses an AC / DC zero-flux fluxgate current sensor, which comprises a fluxgate current sensor body and a configuration and calibration circuit for configuring and calibrating the fluxgate current sensor body. The fluxgate current sensor body comprises a first iron core, a second iron core, an excitation winding, a feedback winding and a measurement winding. The configuration and calibration circuit comprises a processor, a crystal oscillator, an RS232 interface circuit, an excitation source amplification drive circuit, a programmable compensation signal tracker, a programmablefilter, a phase-sensitive demodulation circuit, a PI control circuit and a power amplifier. The invention discloses a program control configuration and calibration method of an AC / DC zero-flux fluxgate current sensor. According to the invention, the offset current caused by inconsistent parameters of the two iron cores can be automatically matched, the requirement on the process consistency of thetwo fluxgate iron cores can be greatly reduced, the optimal performance of the fluxgate sensor can be realized, the practicability is strong, and the popularization and use values are high.

Description

technical field [0001] The invention belongs to the technical field of intelligent sensors, and in particular relates to an AC / DC zero-flux fluxgate current sensor and a program-controlled configuration and calibration method thereof. Background technique [0002] Fluxgate current sensor plays an important role in the field of high-performance current measurement because of its fast response time, good temperature characteristics, high sensitivity, simultaneous measurement of DC and AC currents, and wide measurement range. However, because the fluxgate current sensor has high requirements on the consistency of the core material and manufacturing process, the parameters of the two cores and the winding of the fluxgate are completely consistent, resulting in high cost, complicated process, difficult debugging, and The offset voltage and offset current of the source electronic components will also cause the fluxgate secondary current to have an offset current output. [0003] ...

AI Technical Summary

Problems solved by technology

In particular, the frequency of the excitation signal greatly affects the performance of the sensor. If the frequency is too high, the noise will increase; if the frequency is too low, the sensitivity of the sensor will be reduced. The frequency is fixed between hundreds and thousands of hertz, and the bandpass frequency of the second harmonic filter cannot be changed.

[0004] At present, the typical foreign countries are the IT series AC and DC fluxgate current sensors of LEM Electronics (LEM), and the domestic Shenzhen Hangzhi Precision IIT series AC and DC fluxgate current sensors. These companies produce and develop AC and DC fluxgate current sensors based on the principle of fluxgates. The sensor can achieve ppm-level linearity, but due to the high requirements on the parameters of the fluxgate iron core and winding, the iron core process is complex, the cost is high, and the zero offset cannot be calibrated by digital program control technology. Currently, 60A to 2000A The price of the current fluxgate current sensor is between several thousand yuan and tens of thousands of yuan, which greatly limits its application range, and there are also the following defects:

[0005] (1) High requirements on iron core material and process, and high cost;

[0006] (2) For different applications, it is impossible to achieve the best application effect by configuring the parameters of the current transformer;

[0007] (3) Unable to factory calibrate the inherent zero offset current

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