| Flux-gate sensor is a kind of weak magnetic field detection sensor based on the principle of magnetic saturation; it occupies a great advantage in the field of weak magnetic field detection with its unique high sensitivity, wide measurement range and other outstanding properties,But on the temperature sensitivity and reliable stability still has certain defects.Therefore,the flux-gate sensor is widely used in geomagnetic research, geological exploration, petroleum logging, magnetic navigation, magnetic material testing and nondestructive testing of materials and other fields. In recent years,with the rapid development of science and the emergence of new materials, Flux-gate sensor in the magnetic core material and digital direction of progress. This paper uses Co-based amorphous band and DSP to handle the flux-gate signal, which can improves temperature performance and sensitivity of flux-gate sensor, and also has the advantages of high integration, good stability, and low power dissipation.This paper firstly analyzes the domestic and foreign present research situation as well as the principle of flux-gate technology, designs a digital flux-gate sensor based on TMS320F2812 DSP. Then we introduce the structure of the flux-gate sensor probe and the core material selection. The parallel structure of double core and Co-based amorphous band used as the core is adopted in this paper. In the signal processing circuit, we select the second harmonic test and in crystal resonance circuit for signal source, as a driving signal after frequency division and power amplification. For sensor output signal sensors, we designed the band-pass filter circuit to get second harmonic signal and it will be digital processed through TMS320F2812 DSP. Thirdly,it introduces flux-gate sensor’s digital signal processing theory, software design,debugging.Finally displayed on the LCD; measures and debugs each part of the sensor through the experiment, completing debugging of the overall performance of the sensor, and giving the static characteristic of the sensor. Finally, we make a PCB according to the result of debugging, which strengthens the practical circuit’s reliability.This paper focuses on the production of flux-gate sensor probe, hardware design and software algorithms design of the DSP module. The production of the flux-gate sensor probe should ensure that probe’s structure and core material is symmetrical parallel and distribution of the coil is symmetrical,Otherwise will form the noiseimpact.sensor’s hardware circuit design includes exciting circuit and a band-pass filter circuit, the excitation circuit needs to ensure that the core stays saturation incentive,while the band-pass filter circuit need guarantee its band-width reliable. The software algorithm design of the DSP module includes A/D conversion, the phase-sensitive detector, a low-pass filter,a liquid crystal display.The results show that: when the excitation signal is 11.719 KHz, the amplitude of the sinusoidal signal is 6V, excitation coil is 600 turns, the induction coil is 100 turns,the digital flux-gate sensor which takes Co-based amorphous as core can possess linearity, sensitivity and better stability, among them the sensitivity can reach22.47 m V/Am-1, which is able to meet the need of magnetic field measurement, has some practical value. |
