基于STM32的超声波电源设计与实现

Design and implementation of ultrasonic power supply based on STM32

压电超声波换能器应用广泛,可用于工业塑焊、测距、探伤、医学成像、碎石等.不同的换能器及负载,其谐振频率不同且会动态变化,所以需要匹配不同的电源,使换能器工作在理想状态.为此,设计一套用于工业塑焊的可自动追踪换能器谐振频率和恒定振幅的超声波电源.该电源以STM32为控制器,输出PWM波控制IGBT实现逆变,并使用LC串联型网络来匹配换能器,将负载端电流电压采集回STM32形成闭环系统,从而实现自动追频和恒定振幅控制.经验证,当换能器谐振频率偏移时,本系统能在500 ms内完成自动追频,振幅误差小于3%,加工成功率及效率提高50%以上,能在一定程度上延长换能器寿命,提升工厂加工效率、提高生产安全性.

Piezoelectric ultrasonic transducer is widely used in industrial plastic welding,ranging,flaw detection,medical imaging,graveling,etc.Different transducers and loads have different resonant frequencies which may change dynamically,so it is necessary to match different power sources to make the transducer work in perfect state.Therefore,a set of ultrasonic power sources was designed for industrial plastic welding that could track the resonant frequency and stabilized the amplitude of the transducer.With STM32 as the controller,the output PWM wave controled IGBT to realize the inverter,and the LC series network was used to match the transducer.The current and voltage of the load end were collected back to STM32 to form a closed-loop system,thus realized control of automatic frequency tracking and amplitude stabilizing.It was proved that the automatic frequency tracing could be completed within 500 milliseconds when the resonant frequency was offset,the amplitude error was less than 3%,and the processing success rate and efficiency were increased by more than 50%.This power supply could greatly prolong the life of the transducer,and improve the factory processing efficiency and production safety.