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弧焊逆变电源是一个非线性、离散的病态系统，理论上很难得到精确的解析解。本文利用状态空间分析法建立系统的平均状态方程，经线性化后得出逆变器的数学模型，该模型为一二阶振荡环节。根据弧焊逆变器中参数配置满足（１ＲＣ）２＞＞４ＬＣ的情况，对该数学模型进行简化，将该数学模型简化成一个积分环节和一个一阶惯性环节相串联的结构。在此基础上用频域法进行分析和校正，在理论校正参数附近取多组实际校正参数，分别进行电阻负载实验和焊接工艺实验。实验结果与理论分析结果相符。本文还对负载突然开路、短路以及开机、停机等大信号过程进行了模型的实用性分析。研究表明，弧焊逆变电源系统在工程中可用频域分析法进行分析和校正。推导的小信号平均频域数学模型反应了系统的基本特性，模型由系统的结构参数Ｒ、Ｌ、Ｃ及静态导通比Ｄ决定。推导的小信号频率数学模型简单明了，关系清楚，可以用来对弧焊逆变电源系统进行分析和设计以及指导动特性调试。
Arc welding inverter is a non-linear, discrete pathological system, in theory it is difficult to get accurate analytical solution. In this paper, the state space analysis method is used to establish the average state equation of the system, and the mathematical model of the inverter is obtained after linearization. The model is a second-order oscillation part. The mathematical model is simplified according to the parameter configuration of (1RC) 2 >> 4LC in the arc welding inverter. The mathematical model is simplified into a structure in which an integral part and a first-order inertial part are connected in series. On the basis of this, frequency domain analysis and correction are carried out. Several sets of actual calibration parameters are taken in the vicinity of the theoretical correction parameters. Resistive load tests and welding process experiments are carried out respectively. The experimental results are consistent with the theoretical analysis. The paper also analyzes the practicality of the model when the load is suddenly open, short-circuited and large signal processes such as power-on and power-off. The research shows that the arc welding inverter power system can be analyzed and corrected by the frequency domain analysis method in the project. The derived small-signal average frequency-domain mathematical model reflects the basic characteristics of the system. The model is determined by the structural parameters R, L, C and the static conduction ratio D of the system. The deduced mathematical model of small signal frequency is simple and clear, and has a clear relationship. It can be used to analyze and design the arc welding inverter power system and guide the debugging of the dynamic characteristics.