Numerical Simulation Of Radially Polarized Piezoelectric Cylindrical Tube Ultrasonic Transducer And The Study Of Ultrasonic Power Supply

Power ultrasound is an important branch of ultrasonics.With the rapid development of electronic technology and computer technology, power ultrasound has been widely used in industry、agriculture、national defense and biomedical. Ultrasonic wave is useful in ultrasonic cleaning,ultrasonic medicine extraction and ultrasonic atomization in the aspect of biomedical applications. Ultrasonic cleaning used in medical instruments cleaning and infusion bottle cleaning has the advantages of high cleaning degree 、 safe and reliable. Ultrasonic drug extraction can improve the extraction from 50% to 500% than traditional extraction methods.All above are based on ultrasonic transducer that produce strong ultrasonic wave and the realization of the power ultrasonic power.Ultrasonic transducer is extremely important in the field of ultrasonic.Piezoelectric ultrasonic transducer is the most widely used in the power ultrasonic transducer. To give direction for the design of a new type of radially polarized piezoelectric cylindrical tube ultrasonic transducer that can produce an uniform ultrasonic field and provide certain basis for subsequent research,radially polarized piezoelectric cylindrical tube ultrasonic transducer was numerical simulated.A ultrasonic power supply with adjustable frequency and power was designed for piezoelectric ultrasonic transducer. The frequency of the ultrasonic power system is range from 20 KHz to 60 KHz.And the power of the system can be adjusted in some degree.This subject has two parts:Radially polarized piezoelectric cylindrical tube ultrasonic transducerswas numerical simulated and ultrasonic power supply was designed. Concrete content is as follows:(1)The numerical simulation of radially polarized piezoelectric cylindrical tube ultrasonic transducers has been conducted. Firstly, the first threevibration modals of piezoelectric cylindrical tube was simulated by frequency respond analysis. Then,the relationships between the first-order resonant frequency and tube size and the change of excitation voltage were analyzed. Finally, the ultrasonic fields produced by radially polarized piezoelectric cylindrical tube in air and in water were simulated.The influence of air and water on piezoelectric cylindrical tube was analyzed. A radially polarized piezoelectric cylindrical tube ultrasonic transducer was made.The admittance was measured by Precision Impedance Analyzer and was compared with the numerical simulation result. It is shown that the experimental result is in good agreement with the simulated result. Therefore the results of numerical simulation can give important direction for the actual application of radially polarized piezoelectric ultrasonic transducer and the further research.(2)An ultrasonic power supply for the piezoelectric ultrasonic transducer is designed.It including ultrasonic power supply main circuit、 digital control circuit and power supply circuit.The inverter circuit is the core of the power circuit. The required driving waveform of the inverter circuit is provided by microcontroller and the corresponding drive circuit.The frequency and power of ultrasonic power supply can be adjusted by modulating the PWM driving wave. Finally,the ultrasonic power supply was tested when carrying the load of ultrasonic transducer. The result shows that system can output the correct waveform to excite ultrasonic transducer. All the above provides a basis for subsequent study of this kind ultrasonic power supply.