Research On Automatic Frequency Tracking Technology Of Ultrasonic Generator Based On Labview

Power ultrasonic processing is a widely used advanced processing method in recent years,the method has increasingly high requirements for processing accuracy and output power,the ultrasonic generator as an important part of ultrasonic processing,directly affecting the effect of vibration and the quality of processing.Due to factors such as changes in load and external environment,the output frequency of the ultrasonic generator and the resonant frequency of the piezoelectric transducer do not match,thus affecting the quality of ultrasonic processing.Aiming at the frequency drift of the piezoelectric transducer during ultrasonic processing,this paper designs a Labview-based ultrasonic generator frequency automatic tracking system with STM32 as the control core,and the main research contents are as follows:1.The load analysis and matching study of the ultrasonic generator is carried out.The equivalent circuit characteristics of the piezoelectric transducer are analyzed.Through the analysis and calculation of the electromechanical characteristics of the series resonance point and the parallel resonance point,the parallel resonance point is determined as the driving frequency point of the ultrasonic generator.According to several common matching forms,which determines the series inductance matching.2.The principle introduction and design analysis of the main circuit of the ultrasonic generator are carried out.The principle of the rectification and voltage regulation module,the Buck chopper module and the high frequency inverter module is mainly expounded,and the parameter design and device selection of the three major modules of the main circuit are carried out according to their principles.3.Design the hardware and software of the ultrasonic generator tracking circuit.First,the main control chip commonly used in the tracking circuit is introduced.According to the requirements,the main control chip is determined as STM32,and then the overall design of the tracking circuit is carried out,and the working state of the transducer is judged by the collected voltage and current signals.At the same time,the main program and subprograms of automatic frequency tracking are compiled,and a simple human-computer interaction interface is designed.4.Build the main circuit simulation model in Matlab/Simulink to verify the rationality of the main circuit structure design.Build the DDS simulation model for the PWM modulation technology in the tracking circuit,and perform the PWM module test.The human-machine interface designed by Labview is used to debug and test the whole system.Finally,the circuit experimental platform of ultrasonic generator is built,and the output test is conducted in the laboratory,and the output waveform is analyzed.