变压器参数对电容式位移传感器影响的研究

Study on influence of transformer parameters on capacitive displacement sensor

在已有传感电桥电路的数学模型和噪声模型的基础上,针对变压器参数对应用于空间引力波探测的电容式位移传感器的影响进行研究。仿真分析表明,采用品质因数为197、电感值为4.4 mH的变压器1和品质因数为395、电感值为4.37 mH的变压器2时,电桥等效输出阻抗相差约0.5倍,输出电压噪声相差约1.4倍。在此基础上,使用2种变压器进行实验。在0.1 Hz频点处对电路输出电压噪声和电容传感噪声进行了测量,电路输出电压噪声分别约为29,24.7μV/√Hz,电容传感噪声分别约为1.1,0.95aF/√Hz。电感值相近时,采用品质因数较高的变压器2时,电路输出电压噪声更低,电容传感噪声更低。该测试结果为后续实验中提升传感器系统性能提供研究方向。

On the basis of mathematical model and noise model of the existing bridge circuit,the influence of transformer parameters on capacitive displacement sensor used for space gravitational wave detection is studied.The simulation analysis shows that when transformer 1 with quality factor of 197 and inductance value of 4.4mH and transformer 2 with quality factor of 395 and inductance value of 4.37mH are used,the difference of equivalent output impedance of the bridge is about 0.5 times,and the difference of output voltage noise is 1.4 times.On this basis,two transformers are used for the experiment.The output voltage noise and capacitive sensing noise of the circuit are measured at the frequency point of 0.1 Hz,the circuit output noise is 29 and 24.7μV/√Hz,and the capacitive sensing noise is 1.1 and 0.95aF/√Hz.When the inductance value is similar,transformer 2 with higher quality factor is used,the circuit output voltage noise is lower,and the capacitive sensing noise is lower.The test results provide a research direction for improving the performance of sensor system in subsequent experiments.