Rearch of Dynamic Resistance Characteristics of Liquefied Transducers under Different Loads
For the problem of different heat generation of the transducer caused by the operation of the ultrasonic vibrator under different loads in liquefied ultrasound,the dynamic resistance change and heat generation of the transducer working in series resonant frequency under different load environments are studied from theoretical and experimental aspects.The mapping relationship between the dynamic resistance change and the heat generation of the transducer in the transducer equivalent circuit model is obtained for different liquid load variations such as liquid temperature,liquid viscosity,immersion depth,liquid density,etc.For the transducer at series resonant frequen-cy,the dynamic resistance versus voltage and current is obtained by theoretical calculation.In view of the drawback that the impedance analyzer has low driving power and cannot accurately test the dynamic resistance change trend when the transducer is loaded,a scheme is designed to test the dynamic resistance change trend when the transducer is loaded.A series resonant point frequency tracking circuit based on frequency-tracking chip is implemented to ensure that the ultrasonic power output frequency is always at the transducer series resonant point.This research can provide a reference for improving reliability of ultrasonic power working in complex load environment.