放电能量实时控制的双极性电火花加工脉冲电源

通过观测电火花放电现象对加工的影响,发现可控的双极性电火花加工能用更低的加工刀具磨损率获得比传统单极性电火花加工更高的材料去除率和效率,因此基于先进的电力电子技术,提出了一种双极性通用型电火花加工用脉冲电源,并给出相应的能量控制策略,还采用可提供连续正负脉冲输出的全桥电路作为该脉冲电源的主电路,并引入间隙电压和间隙电流的和作为唯一的控制量,在引弧阶段采用电压控制,在放电阶段采用电流控制。用一个电路完成放电间隙的击穿和放电能量的控制,减小脉冲电源系统的体积,同时在单个放电过程的各个阶段,对脉冲电压、放电电流、放电持续时间和消电离时间等参数进行合理灵活的调整,在维持放电频率一定的情况下,保证加工过程中单次放电能量的一致,从而实现高效均匀的电火花加工。

Bipolar Pulse Power Generator for EDM with Real-time Discharge Energy Control

Based on the researches of alternating arcing phenomena and their influences on the machining performance,a controlled bipolar pulse machining can achieve larger material removal and efficient machining with limited tool wear than unipolar in the same condition.A new type bipolar universal pulse power generator with discharge energy control strategy for EDM,using advanced power electronics technology,was proposed.A full bridge circuit,which instinctively combined a polarity selection circuit (as bridge circuit) and a pulse power circuit (as buck converter),was used as the main power circuit.A voltage control was used during the gap ionizing phase and a current control was used in the discharge phase,respectively.Hence,the breakdown of discharge gap and the control of discharge current and energy can be completed by one circuit,which reduced the volume of pulse power supply and increased the energy efficiency in machining.Furthermore,machining parameters,such as pulse open voltage,discharge current amplitude,discharge duration time,and de-ionization time can be adjusted reasonably and flexibly in different stages during one discharge process.Thus,a fixed discharge frequency with constant energy consumption in each discharge cycle can be achieved,which means efficient and uniform processing.