A Study on Impedance Temperature Compensation of Ultrasonic Transducers.

Ultrasonic transducers are a commonly used device for converting electrical energy into sound energy or converting sound energy into electrical energy. It has extensive applications in medical imaging, non-destructive testing, distance measurement, and other fields. However, temperature changes may lead to issues such as ultrasound signal distortion, measurement errors, impedance changes, and system instability, which can have a negative impact on performance and results. This article aims to explore the influence of temperature on the parameters of the equivalent circuit of an energy converter. Starting from the dynamic capacitor, a varactor diode is connected to compensate for its impedance, and PWM is combined with the output voltage of the operational amplifier to drive the varactor diode. The test results indicate that even when the temperature rises, the compensation capacitance and impedance remain basically stable. The relative error of the compensation capacitor is below 1%. The relative error of ultrasonic velocity in 32.5% concentration urea solution is as low as 0.66%.