焊接系统中一种新型的逆变器控制方法

摘要

There are two PI links needed to be designed in the traditional double dosed loop controller,so the design is difficult and the control variable is effective in a fixed load range.To resolve this problem,a current hysteresis control is introduced.But the traditional hysteresis control will lead to the switching frequency of inverter unfixed.By introducing the varied hysteresis-band current control,the proposed control retains the benefit of the hysteresis control with fast dynamic response and tackles the drawback of the standard hysteresis control with variable switching frequency.Simulation and experiment is carried out to proof the analysis.%环宽固定的滞环电流控制逆变电源具有电流跟踪精度高、动态响应快和无条件稳定等优点,但其开关频率随输出电压的变化而改变,产生噪声并增加了滤波器设计困难.基于此,设计了一台双闭环控制的单相全桥逆变器,内环以准恒定开关频率的滞环电流控制,PI控制电压作为外环.该逆变器既保留了传统固定环宽滞环电流控制的优点,又保证了逆变器的开关频率恒定,拓宽了滞环控制的应用范围.将该方法应用在弧焊逆变系统中能提高系统的稳定性和可靠性,理论分析、仿真和试验验证了该方法的可行性.