直流电流比较仪解调方式的研究

为提升直流电流比较仪的灵敏度和准确度、降低噪声,对其关键环节解调方式开展研究。阐述直流电流比较仪两种解调方式的工作原理,设计相应的电路并搭建仿真模型。结果表明,两种解调方式都能实现将检测绕组输出信号转换为对应直流电压的功能。峰差解调的重要优点是能解调出所有的偶次谐波信号,从而获得很高的检波增益,有利于提高灵敏度和准确度。但二次电流的纹波较大。相敏解调的窄带特性有利于减小系统的噪声电平,二次电流的纹波很小。由于只解调二次谐波,需满足最佳条件才能达到高灵敏度。

Research on the demodulation methods of DC current comparator

In order to improve the sensitivity and accuracy and reduce the noise of DC current comparator, the key link demodulation method was researched. Describe the working principle of two demodulation methods of DC current comparator; design the corresponding circuit and build the simulation model. The result shows that both methods can realize the function of converting the output signal of detection winding to the corresponding DC voltage. The important advantage of peak difference demodulation is that it can demodulate all even harmonic signals. A high detection gain will be obtained accordingly, which is favorable to increase sensitivity and accuracy. But the ripple of secondary current is large. Narrow band characteristics of phase sensitive demodulation are beneficial for reducing the system noise level; the ripple of secondary current is very small. As only second harmonics are demodulated, it is necessary to satisfy the best condition to achieve high sensitivity.