Research Of The STM32-based Ultrasonic Power Supply System

With the development of electric power technology,ultrasonic technology has been widely applied in various fields.The ultrasonic power supply can provide energy for various ultrasonic equipment,and its demand is becoming urgent.This paper combines digital technology with traditional ultrasonic power supply to realize a high performance ultrasonic power supply with digital control.The main research contents of this paper are as follows:(1)The load matching characteristics of ultrasonic transducers was analyzed,the difference of matching parameters between series matching and parallel matching was and compared,and determined the method of series matching,and used MATLAB software to analyze the system coupling oscillation under this matching mode.In view of the defects of static matching mode,two dynamic matching modes of matching inductor dynamic regulation and frequency tracking are proposed,and frequency tracking scheme is selected as the dynamic matching mode of ultrasonic power supply after comparative analysis.(2)The rectification scheme and inverter scheme of the ultrasonic power supply were determined through comparative analysis.In terms of power control,several common power modulation methods were compared,and PS-PWM power modulation technology was adopted as the power control method in this paper.Combined with soft-switching technology to reduce device losses and achieve continuous power adjustment.(3)The structure and mathematical model of phase-locked loop with delay compensation are introduced.Two types of phase-locked loop implementation are analyzed:analog phase-locked loop and digital phase-locked loop.Finally,variable step-length digital phase-locked loop control strategy of the ring.(4)According to the structure of the ultrasonic power supply,the hardware circuits of the system are designed,including the sampling circuit,the drive circuit,the dead-time circuit,the phase detection circuit,and the current RMS detection circuit,etc.,and then the software program of the system is also designed.Including resonance frequency search program and frequency tracking program.Finally,a simulation model of the frequency tracking and power adjustment control strategy of the ultrasonic power system is established in MALAB.The simulation results show that the design can well implement the frequency tracking and adjustment of the system output power.Subsequently,an experimental platform was built using the STM32 chip.The experimental results show that the frequency tracking effect of the system is good,and it also verifies the correctness and feasibility of the variable step size control used in this paper.