Analysis and design of LLC resonant converter for electron beam welding filament power supply

In order to solve the power consumption problem of the filament supply in the Electron beam welding system, 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 is utilized. As a result, a full-bridge LLC resonant converter, in combination with pulse frequency modulation control method is presented in this paper. Then, a soft-switching type, DC input 48V, 0~.15A DC output adjustable by setting the filament power supply prototype is designed. The power supply design process and the experimental results show that the power supply prototype solves the heat problem of inverter well and also improves the inverter´s efficiency. Finally, some means are introduced to handle the problem of inflated load voltage.