压电器件阻抗测试系统的研制

基于压电器件的等效电路模型,利用导纳圆理论图测量压电器件阻抗特性参数及过零检测相位差测量原理,构建了一套完整的压电器件性能参数阻抗测试系统。通过单片机控制信号产生幅值固定、频率可变的正弦信号,经功率放大后驱动压电器件产生超声高频振动,并采集压电器件两端的电压、电流及相位差信号,通过串口传给上位机。上位机采用基于Labview人机交互界面,实现压电器件阻抗特性参数计算和图形显示。实验结果表明,本测试系统能测量压电器件各主要相关参数,并动态显示阻抗特性曲线,可用于压电器件的参数测试与性能评估。

Development of Impedance Measurement System of Piezoelectric Devices

Based on the equivalent circuit model of piezoelectric devices, using the theory of admittance circle diagram to measure the transducer impedance parameter and the theory of zero cross detection to measure the phase difference, an impedance measuring system of piezoelectric devices performance parameters is developed. In the developed system, a sine wave with fixed amplitude and variable frequency is generated by a microcontroller. After being amplified by power amplifier, the piezoelectric device is driven to vibrate by the generated sine wave at high frequency. Then, the microcontroller collects the voltage, current and phase difference during the working process of piezoelectric devices. The collected signals are transmitted to PC by the serial port. Based on the man machine interactive interface of Labview, the impedance characteristic parameters and graphics of piezoelectric devices can be displayed. The experimental results show that the developed system is capable of measuring the main parameters of piezoelectric devices and of displaying the dynamic characteristic impedance curves. The developed impedance measurement system can also be used for the parameters testing and performance evaluation of piezoelectric devices.