采样保持电路法补偿磁通门传感器背景磁场

A Method of Background Magnetic Field Compensation for Fluxgate Sensors Based on Sample and Hold Circuit

为正确测量目标磁场和提高磁通门传感器的测量精度,背景磁场的补偿至关重要。在分析磁通门常用背景磁场补偿方法基础上,提出一种新的采样保持电路自动补偿方法。运用逻辑脉冲电路为采样保持电路提供固定频率滤除背景磁场信号,并对目标未出现时的信号进行动态跟踪,运用比较电路将目标出现前后的信号进行比较,从而在补偿背景磁场的基础上最大限度地获得目标磁场的信号。设计了实际电路,采用频率为8Hz,占空比为1∶10的采样脉冲,对车速范围为15-60 km/h的车辆磁场信号进行了测量,得到的补偿波形表明了该原理的有效性。该方法可用于磁场的定性测量中,可便于一些特定的外磁场测试。

The compensation of background magnetic field is very important for correct measurement of target magnetic field and accuracy improvement of fluxgate sensors.On the basis of analyzing the common methods of background magnetic field compensation,a new automatic compensation method based on sample and hold circuit is put forward.Detailly,signals of background magnetic field is filtered by fixed frequency of sample and hold circuit which is supplied by logic circuit,and the signals before objects appear are tracked dynamically which are then compared with the ones after objects appear by comparator circuit,in order to furthest obtain the signals of target magnetic field on the basis of background magnetic field compensation.The magnetic field of a vehicle of velocity ranged between 15 km/h and 60 km/h was measured with the sampling pulse of 8Hz frequency and 1：10 duty ratio.The compensation waveforms obtained proved validity of the given method which can be used for observation measurement of magnetic field and some special external magnetic field.