Pang Na, Cheng Defu, Wang Yanzhang
College of Instrumentation & Electrical Engineering, Jilin University, No. 938 Ximinzhu Street, Changchun 130026, China.
College of Information Technology and Media, Beihua University, No. 3999 East Binjiang Road, Jilin 132013, China.
Sensors (Basel). 2017 Oct 12;17(10):2325. doi: 10.3390/s17102325.
The performance of Residence Times Difference (RTD)-fluxgate sensors is closely related to the time difference readout technique. The noise of the induction signal affects the quality of the output signal of the following circuit and the time difference detection, so the stability of the sensor is limited. Based on the analysis of the uncertainty of the RTD-fluxgate using the Bidirectional Magnetic Saturation Time Difference (BMSTD) readout scheme, the relationship between the saturation state of the magnetic core and the target (DC) magnetic field is studied in this article. It is proposed that combining the excitation and induction signals can provide the Negative Magnetic Saturation Time (NMST), which is a detection quantity used to measure the target magnetic field. Also, a mathematical model of output response between NMST and the target magnetic field is established, which analyzes the output NMST and sensitivity of the RTD-fluxgate sensor under different excitation conditions and is compared to the BMSTD readout scheme. The experiment results indicate that this technique can effectively reduce the noise influence. The fluctuation of time difference is less than ±0.1 μs in a target magnetic field range of ±5 × 10⁴ nT. The accuracy and stability of the sensor are improved, so the RTD-fluxgate using the readout technique of high stability time difference is suitable for detecting weak magnetic fields.
停留时间差（RTD）磁通门传感器的性能与时间差读出技术密切相关。感应信号的噪声会影响后续电路输出信号的质量以及时间差检测，因此传感器的稳定性受到限制。基于使用双向磁饱和时间差（BMSTD）读出方案对RTD磁通门不确定性的分析，本文研究了磁芯饱和状态与目标（直流）磁场之间的关系。提出将激励信号和感应信号相结合可得到负磁饱和时间（NMST），它是用于测量目标磁场的一个检测量。此外，建立了NMST与目标磁场之间输出响应的数学模型，分析了不同激励条件下RTD磁通门传感器的输出NMST和灵敏度，并与BMSTD读出方案进行了比较。实验结果表明，该技术能有效降低噪声影响。在±5×10⁴ nT的目标磁场范围内，时间差波动小于±0.1 μs。传感器的精度和稳定性得到提高，因此采用高稳定性时间差读出技术的RTD磁通门适用于弱磁场检测。
