大电流比较仪电磁屏蔽的研究

The Electromagnetic Compatibility of Comparators

AC,DC以及AC/DC大电流比较仪都具有高精度,线性特性好,低漂移等特点。但是用于工业现场的大电流比较仪,由于工作环境恶劣,存在着严重的电磁干扰,如果比较仪的电磁兼容性不好,其精度和稳定性将大受影响。目前传统的电流比较仪均采用了铜屏蔽和磁屏蔽,这种方案自Moore提出以来,一直在比较仪的设计中得到了广泛的应用。但实践表明,在工业现场传统的屏蔽方法是不能够完全满足需要的。本文结合我们多年的研究,提出了一系列新的屏蔽设计方案。

All kinds of comparators including ac、dc and ac/dc comparators possess the notable performance of high accuracy, low drift, high linearity, and good immunity to extend magnetic fields. But the comparator, which is used for on-site test and calibration, will experience a very strong influence from external electromagnetic fields. If the electromagnetic compatibility of the comparator is not well enough, the comparator' s accuracy and stability will decline. The copper shield and magnetic shield have been applied in conventional comparators for many years since they were introduced by Moore. But the conventional method can not reach the requirements of on-site test. In this paper, we will give a series of new shielding methods depending on our study, including a notable double-copper shielding method, the segment shielding method and the new design method of magnetic shield using computer.