基于复合控制数字化弧焊逆变电源的仿真分析

在分析了传统控制方法优缺点的基础上,提出了一种基于重复控制和双闭环控制相结合的复合控制弧焊数字化逆变电源控制方案.重复控制利用扰动的重复性特点,逐周期地修正输出电压可以较好地改善系统的稳态特性,双闭环控制利用电流内环快速、及时的抗扰性来有效地抑制负载扰动的影响,可以较好地改善系统的动态特性.在对弧焊的飞溅及焊缝成形影响因素分析的基础上,利用复合控制的数字化系统,在短路阶段通过实时调整di/dt及峰值电流,短路电流采用适当的外拖回拐量,在燃弧阶段,保持燃弧电压稳定的同时,提高再引弧电流,以改善焊接工艺性能.结果分析表明,采用该方式控制的焊接电源,可以减少飞溅,使焊接过程稳定,焊缝成形变好.

Emulation analysis of digital arc welding inverter with combined control

A novel control strategy of repetitive control and double closed-loop control is presented based on analysis of the merits and demerits of traditional control.Repetitive control uses the repetition trait of interferer,periodically correct output voltage to improve preferably the steady state characteristics of the system,and double closed-loop control uses the current inner-loop to restrain interferer fast to improve preferably the dynamic state characteristics of the system.Based on the analysis of influencing fator of arc welding characteristic,a DSP based whole digital combined control system was established to improve arc welding technics characteristic.During the "short" phase,di/dt and the peak value of current are adjusted properly,and the current of short circuit uses return round outer-drag.During the "arc" phase,the burning-arc voltage stable is kept,and the anew striking arc current is increased.The analysis result shows that by this digital waveform control inverter power source,the welding characteristic can be improved greatly,such as reducing the splash clearly,good appearance of weld and the stability of welding process.