一种开关驱动的电涡流式位移传感器的原理与实验研究

Fundamental and experimental research on a switch-driven eddy-current displacement sensor

从能量损耗角度出发,对一种开关电路驱动的电涡流位移传感器的工作原理进行了分析。该传感器利用气隙与工作电流间的对应关系实现对目标位移的检测,且仅需一次低通滤波即可完成信号调理,系统结构简单。作者以铁、铝和无磁不锈钢作为被测目标在不同开关频率下进行了实验研究,并对实验结果进行了分析。结果表明:对3种被测目标,随着频率的变化,系统灵敏度经历了相似的变化过程,且在谐振频率附近,灵敏度达到负向最大值;在0.5与1.5倍谐振频率的两个频率附近,系统灵敏度达到两个正向极大值;在谐振频率附近,当被测目标为铁时,系统灵敏度最大,而目标为铝时次之。

The fundamental of a switch-driven eddy-current displacement sensor is analyzed based on the eddy current power loss. The sensor achieves target displacement detection based on the relationship between the gas gap and the working current; and only one low pass filtering is needed for the signal conditioning. A series of experiments were carried out at different switching frequencies with iron, aluminum and nonmagnetic stainless steel as the targets; and the experiment data were analyzed. Analysis results show that as the switching frequency changes the detection sensitivity experiences a similar variation process for different targets; and the sensitivity reaches a negative maximal value around the resonance frequency, the sensitivity reaches two positive maximal values at approximately half and 1.5 times the resonance frequency; the sensitivity for iron has its largest value around the resonance frequency, and the sensitivity for aluminum takes the second place.