基于串联谐振的电子束焊机灯丝电源的研究

Research on series resonant electron beam welding filament power supply

传统的电子束焊机阴极灯丝加热电源采用PWM硬开关逆变,存在着开关管损耗过大、发热严重的问题。为了减小开关管的损耗,利用串联谐振变换器在开关频率小于1/2谐振频率的情况下具有恒流线性输出和软开关的特性,研制了一台基于全桥串联谐振结构的PFM调制型灯丝电源样机。实验结果表明,该电源样机输出电流0~15 A可调,实现了开关管的零电流开启和准零电流/电压关断,提高了逆变器的效率。最后提出了一些解决灯丝电源灯丝断路时电压虚高的改进方案。

Traditional electron beam welder cathode filament heating power commonly adopt PWM inverter hard switching technology. It has a problem of high switch loss and large heat dissipation. In order to reduce the loss, the character of series resonant converter at a switching frequency of less than 1/2 of the resonant frequency with a constant current output and the feature of soft switch was utilized. As a result, a full-bridge series resonant converter,in combination with PFM control method was presented in this paper. The experimental results show that the 0~15 A DC output current adjustable power supply prototype, realize the zero current switch turn-on and quasi-zero current/voltage turn-off and improve the inverter＇s efficiency. Finally, some means were introduced to handle the problem of inflated load voltage the case of load breakdown.