基于DSP控制的超声金属焊接电源

Research on ultrasonic metal welding power supply based on DSP

关键词:  超声金属焊接电源  频率跟踪  压电换能器  增量式PI控制算法

Key words:  ultrasonic welding power supply  frequency tracking  piezoelectric transducer  incremental PI algorithm

摘要:

为了进一步提高超声金属焊接的可靠性与稳定性,针对现有模拟超声焊接电源频率跟踪性能差、焊接过程振幅不可调的缺陷,文中提出了基于数字信号处理器(DSP)控制的超声电源方案.通过采集压电换能器两端电压、电流相位差,利用增量式PI控制算法实现了焊接过程的频率跟踪;采用脉冲宽度调节的方式实现了焊接过程超声振幅大小的调节.结果表明,采用数字控制的超声电源,实现了焊接过程振幅的连续可调;负载突变时,0.32 ms时间内可以实现频率跟踪过程.

Abstract:

The analog power supply of ultrasonic welding has the shortages of inaccurate frequency tracking and unadjustable amplitude in the process of welding, which make the welding process unstable, sometimes even lead to failure.The design scheme based on digital signal processor(DSP) was proposed to improve the reliability and stability of ultrasonic metal welding.Frequency tracking was realized by using incremental PI algorithm through gathering phase difference signal between voltage and current of piezoelectric transducer(PZT).The method of pulse width modulate(PWM) was used to control and adjust the amplitude of ultrasonic vibration.The results indicated the ultrasonic welding power supply based on DSP could adjust the amplitude continuously and track the resonant frequency in 0.32 ms during the welding process.