Ultrasonic Power Supply Design Based On Frequency Automatic Tracking And Power Adjustment Technology

As a high-tech,ultrasonic technology is widely used in the fields of ultrasonic cleaning,ultrasonic welding,and ultrasonic processing devices.The use of these ultrasonic equipment cannot be separated from the support of ultrasonic power supply.The ultrasonic power system is divided into two parts: drive power and load.Its function is to convert electrical energy into high-frequency alternating current signals that match the load.The load is usually an ultrasonic transducer,which is composed of a single crystal material.The internal parameters are easily affected by many factors and change,resulting in the system working in a non-resonant state,resulting in increased system loss and unstable output power.Based on the above problems,the thesis designs an ultrasonic power supply with stable work,high efficiency,automatic frequency tracking and adjustable output power.Firstly,the main circuit of the ultrasonic power supply is studied.The main circuit topology structure composed of single-phase bridge rectifier filter circuit,BUCK chopper circuit,single-phase full-bridge inverter circuit,and load matching network circuit is designed,and the parameters of the main circuit components are calculated and selected.In terms of frequency matching,the series resonance frequency is selected as the working frequency of the transducer,and an improved digital inductance matching network circuit is designed on this basis.In terms of impedance matching,a high-frequency transformer is used to achieve impedance transformation,and the structural parameters of the transformer are designed in detail.Secondly,the control algorithm of the ultrasonic power supply is researched.In terms of frequency automatic tracking technology,a resonant frequency automatic identification algorithm based on Fuzzy-PI-DDS technology is proposed,which solves the problems of frequency drift and slow tracking response of traditional ultrasonic power supplies.In terms of phase difference detection technology,the zero-crossing comparison method is selected as the phase difference detection method to improve the detection accuracy.In terms of power control technology,the second-order sliding mode variable structure algorithm is used to automatically control the duty cycle of the BUCK drive signal to achieve stable power regulation.A simulation model was built through Matlab-Simulink to verify the effectiveness and superiority of the above algorithms.Thirdly,design the software and hardware of the ultrasonic power control system.In terms of hardware,the selected main control chip model is STM32F103RCT6,and the chip peripheral circuit,sampling circuit,phase detection circuit,drive circuit,DDS signal generation circuit,and protection circuit are designed respectively.In terms of software,the thesis adopts C language as the development language of the control system to design the main program and various functional subprograms respectively.Finally,the actual design of the ultrasonic power supply is tested to verify the overall function of the ultrasonic power supply and the stability of related control algorithms.