自激振荡磁感应传感器研究

Research on Self-oscillating Magnetic Induction Sensors

摘要:

面向数字式、小体积的磁场传感器应用需求，现有的感应式磁场传感器普遍存在硬件电路复杂， 数字化需要使用模数转换器件，难以实现小型化的问题，需探索一种新原理磁场传感器。因此，提出了一种基于自激振荡磁感应技术的磁场传感器，该传感器测量原理基于激励电压占空比与被测磁场的线性关系。与其他磁场传感器相比较，提出的磁场传感器输出为占空比形式，不需要额外的滤波电路和模数转换电路，硬件电路较为简单，因此有利于实现数字化和小型化。同时，分析了自激振荡产生过程，建立了激励电压占空比与被测磁场的理论方程；制作了原理样机，验证了基于自激振荡磁感应技术的传感器实现的可行性。结果表明，在开环条件下，±100 000 nT 量程下传感器的线性度在 0.98%。

Abstract:

Aiming at the application requirements of digital and small-volume magnetic field sensors，it is necessary to explore a new magnetic field sensor，because existing inductive magnetic field sensors generally have the problems of complex hardware circuits，the need to use analog-to-digital conversion devices for digitalization， and it is difficult to achieve miniaturization. In this paper，a magnetic field sensor based on self-oscillating magnetic induction technology is proposed. Its measurement principle is based on the linear relationship between the duty cycle of the excitation voltage and the measured magnetic field. Compared with other magnetic field sensors，the output of the magnetic field sensor proposed in this paper is in the form of duty cycle，which does not require additional filtering circuits and analog-to-digital conversion circuits，and the hardware circuit is relatively simple， so it is beneficial to digitalization and miniaturization. Besides，the generation process of self-excited oscillation is analyzed，and the theoretical equation of excitation voltage duty cycle and measured magnetic field is established. A prototype is made to verify the feasibility of the magnetic field sensor based on self-excited oscillation magnetic induction technology. The results show that under open-loop conditions，the linearity of the sensor is 0.98% with the range of ±100 000 nT.