针对传统CO2 焊接电源的单环控制、动态特性不好、工作不可靠等缺点 ,介绍了一种采用全桥逆变电路作为主电路 ,分别以电压反馈和变压器原边电流反馈作为外环、内环双环控制的恒压大电流弧焊逆变电源装置 ,阐明了它的工作原理 ,分析了这种基于PI调节的、以PWM控制器UC3846为核心的控制系统。实验证明 ,该逆变电源装置具有快速性和稳定性好、可靠性高和功率较大的优点。 Aiming at the disadvantages of single-loop control of traditional CO2 welding power supply, poor dynamic characteristics and unreliable work, a full-bridge inverter circuit is introduced as the main circuit. Voltage feedback and primary current feedback of transformer are taken as outer ring and inner Loop double-loop control of constant current high-current arc welding inverter power supply unit, clarified its working principle, analyzed based on PI regulation, PWM control system UC3846 as the core of the control system. Experiments show that the inverter has the advantages of fastness and stability, high reliability and high power.