用于网格状金属切割的等离子切割电源控制策略研究

摘要

For solving the problem that how to control arc current accurately in the process of cutting grid plates, an arc current reference feedforward composite control strategy was proposed, which was based on the analysis of arc transfer process and arc model. The external loop of control strategy is current loop, which can control arc current and achieve the precise control of arc energy. Arc current reference feedforward compensation based on load model was introduced into voltage inner loop. The voltage loop can quickly establish the arc voltage, which maintains the arc stable. Simulations and experimental results were given to verify that the proposed control method can respond quickly between non⁃transferred arc and transferred arc when cutting grid plates,and can achieve the precise control of arc current simultaneously.%为解决金属网格切割过程中精确控制弧电流的问题，在分析金属网格切割弧转移过程、建立电弧模型的基础上，提出一种基于电弧负载模型的弧电流指令前馈的复合控制策略。控制策略外环为电流环，实现等离子电弧电流及能量控制；在电压内环引入基于电弧负载模型的弧电流指令前馈控制，通过前馈控制的快速性迅速建立弧柱电压，达到维持电弧稳定的目的。仿真和实验结果表明，提出的控制策略能够快速响应网格状金属切割时引弧过程及非转移弧和转移弧之间的快速切换需求，实现弧电流的快速精确控制。