为了提高微电弧焊接过程中的电流控制精度和小电流稳定性，设计了一种精密微电弧焊接逆变电源． 该电源在传统钨极氩弧焊电源的基础上加入了基于数字信号处理器的全数字化控制系统，采用有限双极性控制方法实现了全桥逆变电路的软开关． 文中还介绍了电弧负载的电特性，分析了焊接工艺对电源电气特性的要求，设计了直流和脉冲两种波形控制方案，阐述了电源系统的软件流程及控制算法． 结果表明:通过精确控制电流、时间、频率、脉宽等输出参数，可实现对输出能量的精密控制，且波形一致性较好;采用积分分离 PID 控制算法，可实现电弧“起弧 － 燃烧 － 收弧”过程的柔顺过渡，提高小电流输出时的电弧稳定性．

In order to improve the control precision of welding current and the stability of arc with low current du-ring the micro arc welding，a precision inverter power supply is designed． In this power supply，a digital control system based on the digital signal processor is introduced into the traditional argon tungsten arc welding inverter，and the limited bipolar control method is used to realize the soft switching of the full-bridge inverter． In addition，the electrical characteristics of the arc load are introduced，the requirements of welding process for the power su-pply are analyzed，two kinds of waveform control schemes respectively for direct current and pulse are designed，and the software procedure of the power system and the corresponding control algorithm are expounded． It is de-monstrated that both the precise control of output energy and the nice consistency of waveforms can be achieved by accurately controlling such output parameters as current，time，frequency and pulse width; and that the integral separation PID control algorithm helps to realize a smooth transition of the arc from arcing to breakdown and then to annihilation，thus improving the stability of arc with low current．