Dynamic Regulation Method of High-Voltage Power Supply for Electron Beam Melting

During the electron beam melting additive process, the real-time changes in the material melting state put forward dynamic regulation requirements for the output of the high-voltage power supply. When the molten pool temperature fluctuates, the powder feed rate changes, or the electron gun scanning speed is adjusted, if the power supply output parameters cannot respond in time, it is easy to cause insufficient melting or over-melting, affecting the mechanical properties of the component. Therefore, the dynamic regulation method needs to realize the fast and accurate adaptation of output parameters.
At the hardware level, SiC MOSFET power devices are used to build a high-frequency conversion circuit, the switching frequency is increased to more than 100kHz, the parameter adjustment delay is shortened, so that the voltage adjustment response time is ≤ 30μs and the current adjustment response time is ≤ 20μs; at the same time, a multi-channel sampling module is introduced to collect signals such as molten pool temperature (through infrared temperature measurement), beam current intensity, and acceleration voltage in real time, with a sampling frequency of 1kHz, providing data support for dynamic regulation.
The software algorithm is the core of dynamic regulation, and an adaptive PID regulation algorithm is designed: a load change prediction model is established based on historical sampling data. When an upward trend of the molten pool temperature is detected, the acceleration voltage is reduced in advance (adjustment range 0.5-2kV) to avoid over-melting; when the powder feed rate increases, the beam current is automatically increased (adjustment range 1-5mA) to ensure melting efficiency. For sudden load disturbances, such as instantaneous load increase caused by powder agglomeration, a fuzzy control strategy is introduced to quickly match adjustment parameters through the fuzzy rule base, suppress output fluctuations, and control the voltage fluctuation range within ±0.2%.
In addition, a linkage mechanism between dynamic regulation and process parameters is constructed: process parameters such as electron beam scanning path and layer thickness are incorporated into the regulation logic. When the printing layer thickness increases from 0.1mm to 0.3mm, the acceleration voltage is automatically increased from 18kV to 22kV, and the beam current is increased from 20mA to 35mA, realizing the "process-power supply" collaborative regulation. Experimental verification shows that after adopting this dynamic regulation method, the density of printed parts is increased to 99.2%, and the fluctuation range of tensile strength is reduced to ±5MPa, which significantly improves the process stability of melt additive manufacturing.