Optimized parameters identification and monitoring for piezoelectric transducers under mechanical load and voltage

Accurate identification of the equivalent circuit parameters of the piezoelectric transducers (PT) under complex operating conditions is essential to guide the design and matching of ultrasonic systems. However, the current impedance analyzer can not obtain the equivalent parameters of PT under the actual operating conditions (high voltage and high load). Therefore, a new parameter identification method of PT was proposed, which combines the admittance circle and Nelder-Mead optimization algorithm (NMOA). The initial value of the equivalent parameter was calculated by fitting the admittance circle, and the parameter identification accuracy was improved by NMOA. Through simulation and experimental test, the results show that the accuracy of the proposed method was much higher than that of the admittance circle method, and the accuracy of the NMOA was less affected by the step size, which was conducive to shortening the frequency sweep time. Finally, the identification system of PT under load was built through the combination of hardware and software, and the parameter identification experiment of PT was carried out under mechanical load and high voltage. The results show that both R₁ and f_s increase with the increase of load, and R₁ increases with the increase of voltage, while the frequency f_s decreases. This study demonstrates the dynamic performance changes of the PT under mechanical and voltage loads. The real-time feedback of dynamic parameters is beneficial for monitoring the state of the PT during operation.