Research On Ultrasonic Generator With Intelligent Frequency Control

Ultrasonic cleaning technology is an important development direction of power ultrasonic technology.Because of its advantages of good cleaning effect,no pollution and low cost,it is gradually replacing the traditional cleaning method and widely used in the actual production and life.Ultrasonic generator is the core part of ultrasonic cleaning machine,the frequency and power of its output signal are the key indicators of ultrasonic cleaning technology.Ultrasound transducer will aging and produce mechanical loss in harsh working environment,which will cause its resonance frequency to drift.If the output signal frequency of the ultrasonic generator does not match the resonance frequency of the transducer,it will reduce the transducer's working efficiency and affect the safe operation of the ultrasonic cleaner.In order to solve the problem of transducer resonance frequency drift,an ultrasonic generator based on STM32 single-chip computer,with adjustable output power and automatic tracking of transducer resonance frequency has been developed after the analysis of transducer impedance characteristics.The main power circuit of the ultrasonic generator consists of three parts:rectifier filter circuit,inverter circuit and high frequency transformer.The output power of the signal is adjusted by using phase shifting PWM control technology.The control system circuit uses STM32F407ZGT6 as processing chip,uses digital phase-locked technology to track the resonant frequency of the transducer,and designs the corresponding phase difference information acquisition circuit and signal driving circuit.In the software aspect,the control system program of the ultrasonic generator is designed by using keil compiler.In the control algorithm,the fuzzy PI control is used,and the fuzzy controller is designed.Finally,each circuit module is tested,and the simulation model of the ultrasonic generator is built on MATLAB/Simulink to verify.The results show that the designed ultrasonic generator can better track the resonant frequency of the transducer.