电流模式控制零电压软开关弧焊逆变器

采用具有电流模式的UC3879移相控制芯片 ,研究了一种新型全桥软开关电路的拓扑结构。研究了电流模式移相控制下的驱动电路、过流检测电路和主电路变压器输出波形特点。结合大功率弧焊逆变器的设计 ,分析了领先桥臂和滞后桥臂实现零电压软开关的条件。试验表明 ,无论占空比为何值 ,当功率变压器初级电压为零时 ,初级电流基本维持最大值不变 ;领先桥臂中点电压变换期间 ,变压器初级电流基本保持最大值 ,使得领先桥臂容易实现软开关 ;由于激磁电感参与了滞后桥臂换流 ,滞后桥臂中两只IGBT也实现了零电压软开关

A Study on Zero-Voltage Switch Inverter with Current Mode Control for Arc Welding Inverter

A novel topological circuit with full bridge soft switching is developed by adopting phase shift chip UC3879 with current mode and phase shift control.The output waveform characteristics of driving circuit,detecting over current port and main circuit transformer have been researched by practical experiment.Furthermore,based on designing of a large power inverter for arc welding,the soft switching conditions of leading and lagging legs have been analyzed.Following conclusions have been achieved by experiments.No matter what value of the duty is,the primary current of power transformer keeps the maximum value when its primary voltage equals zero.In the midpoint voltage of leading leg transition,its soft switching is easily realized because of the primary current of transformer keeping the maximum.Two pieces of IGBT of lagging leg also achieve soft switching due to the magnetizing inductance participating in the transition of lagging leg.