汽车转速传感器信号稳定性的研究和分析

The Research and Analysis for Output Signal Stability on Automotive Speed Sensor

为了满足汽车转速传感器在极限工况下的磁场要求,提高传感器的输出信号可靠性,本文通过Comsol磁场仿真计算转速传感器在全气隙工况下的磁场强度和磁场峰峰值的变化,利用最小二乘法求解出传感器随着温度升高输出信号出现不稳定的原因,采用在芯片和磁体之间增加聚磁片并增加磁体长度的方式使得传感器在全温度以及极限工作气隙范围内的磁场强度和磁场峰峰值均满足芯片要求.测试结果表明:设计优化后的转速传感器在极限工况下输出信号稳定,未发生信号波动异常.传感器同时增加聚磁片和磁体长度为转速传感器的信号稳定性提供了新的解决方案.

In order to meet the magnetic field requirement at worst case working conditions for automotive speed sensor and improve its reliability for output signal,The speed sensor's magnetic field intensity and peak-peak value is calculated under full air gap conditions based on Comsol field simulation in this paper,use the least square method to get the cause for speed sensor output signal instability while temperature increased,by adding polymagnetic between hall chip and magnet with increasing the length of magnet to ensure magnetic field intensity and peak-peak value of the sensor met with hall chip requirements in the whole temperature and limit working air gap range.The test result shows that the output signal of improved speed sensor is stable under the extreme conditions,there is no signal fluctuation.It provides a new solution for output signal stability of speed sensor by simultaneously adding polymagnetic shee and length of magnet.