Amplitude Identification for Ultrasonic Transducer Based on Instantaneous Current

In industrial applications, the amplitude of piezoelectric ceramic transducers directly affects the quality and reliability of production. The vibration amplitude of the ultrasonic transducer is related to its own impedance of frequency-dependent. To maximize vibration amplitude and energy transfer efficiency, it is necessary to control the frequency of the ultrasonic transducer. However, the amplitude is difficult to obtain in actual industry. To address this issue, an electromechanical coupling model of the ultrasonic transducer is introduced, and it is proven in the BVD equivalent model that the amplitude is proportional to the amplitude of the dynamic branch current. A new ultrasonic transducer amplitude identification is proposed based on this model. Firstly, the driving voltage and current of the transducer are obtained. By utilizing the static capacitance characteristics, the instantaneous value of the dynamic branch current is derived. The extracted instantaneous current is proven to be directly proportional to the vibration amplitude, which successfully identifies the vibration amplitude of the transducer.