精细等离子电源输出电流纹波抑制研究

Research on Output Current Ripple Suppression of Fine Plasma Cutting Power Supply

针对等离子电源输出电流中的纹波问题,设计两相交错并联的Buck DC/DC拓扑结构。分析了单个开关周期内电感上的电流波动,得到主电路参数对于输出电流纹波的影响,并对主电路元器件进行选型。在电流平均法的基础上对电流连续模式下的主电路进行小信号建模,在电流闭环控制基础上,针对响应速度较慢和低频段增益平缓两个问题采用补偿网络进行优化,从补偿网络传递函数离散化得到数字化滤波器,提高了系统稳态特性及响应速度。通过实验验证了该方案对输出电流纹波的抑制效果及工件切割质量提升的可行性。

Aimed at the problem caused by current ripple,two phase interleaving Buck DC/DC topology is applied.The current ripple in a single switching cycle is analyzed and the influence of main circuit parameters on the output current rippled is calculated,based on which the main circuit components are selected.The small signal model of the main circuit in the continuous current mode is established based on the current averaging method.On the basis of the current closed loop control,the compensation network is used to optimize the slow response speed and slow gain in the low frequency band.The digital filter is achieved from the discretization of the transfer function of the compensation network,which improves the stability of the system.State characteristics and response speed.Experiments verify that the scheme can suppress the ripple of output current and improve the cutting quality.