基于弧控制的等离子切割电源新型复合控制策略

A novel composite control strategy for plasma cutting power supply based on arc control

关键词:  等离子切割电源  弧控制  前馈补偿  前馈补偿双闭环复合控制

Key words:  plasma cutting power supply  arc control  feed-forward compensator  feed-forward composite control of double closed-loop

摘要:

根据非高频引弧技术在等离子切割电源中的应用,分析了等离子电弧的静态特性,推导出了等离子电弧数学模型,并结合电源在非高频引弧、弧转移及弧能量突变过程中的控制需求.提出了一种新型复合控制策略,该策略的内环是由前馈补偿的电弧电压与反馈电弧电压构成电压闭环复合控制,外环则以电流闭环对等离子弧柱能量进行控制,形成了一种前馈补偿双闭环复合控制方式,以满足电源在非高频引弧负载条件下对快速性和稳定性的控制需求.结果表明,文中所提控制策略不仅可以提高系统的快速性和鲁棒性,还具有优异的动态响应能力,电源的非线性适应能力强,有效的解决了等离子切割电源的控制需求.

Abstract:

This paper analyzes static characteristics of plasma arc with the derivation of plasma arc mathematical model according to the application of low-frequency(LF) pilot arc technology in the plasma cutting power supply,and integrates with the control requirements in low-frequency (LF) pilot arc,arc transferring and arc energy transferring,and proposes a novel composite control strategy. In order to meet the power's control requirements of rapidity and stability with the load of low-frequency(LF) pilot arc,the inner loop of this strategy builds up voltage loop composite control with feed-forward arc voltage and feedback arc voltage,and the current outer loop controls the energy of plasma arc,forming a control method of feed-forward composite control of double closed-loop. Simulations and experiments were given to verify that the mentioned control strategy not only improved system's stability and robustness,but also had excellent dynamic responsibility. The power had well non-liner resilience, meeting requirements for plasma cutting power supply.