超声液位传感器的等效电路模型及其仿真分析

Modelling and simulation of equivalent circuit for ultrasonic liquid level transducer

将电-力-声类比方法应用到超声液位传感器的建模中,建立了超声液位传感器的等效电路模型,并借助傅里叶变换和逆变换推导了传感器的频率响应和瞬态响应关系式.对关键结构参数进行了分析,结果表明:压电元件厚度与谐振频率成反比;机械品质因数会影响超声液位传感器输出电压信号的峰-峰值和余振特性,选用机械品质因数为700左右的压电陶瓷,可以兼顾传感器输出信号峰-峰值与余振特征;通过优化工作间隙,输出电压峰-峰值提高了40%.

The electro-mechanical-acoustic analogy method was investigated in ultrasonic liquid level transducer modeling. The equivalent circuit for ultrasonic liquid level transducer was established. Then following the Fourier transform and its inverse transform, the frequency response function and transient response function of the transducer were derived. The analysis was made for the effects of main parameters. The simulation results show that the thickness of piezoelectric ceramics is reversely proportional to the resonant frequency; the mechanical quality factor is relative to the peak-to peak value and the post-vibration characteristic, with which a good balance can be achieved when mechanical quality factor is 700; the peak-to-peak value of the output voltage can be enhanced by 40% after optimizing the gap between transmitting probe and receiving probe.