Key Points for Anti-Impact Design of High-Voltage Power Supplies for Electron Beams

The application of electron beam technology is increasingly widespread in fields such as material surface modification, low-temperature food sterilization, and semiconductor lithography. The high-voltage power supply for electron beams, as its core power source, needs to operate stably in environments with high voltage (typically in the range of kilovolts to megavolts) and wide load fluctuations. In actual working conditions, impact events such as instantaneous load short-circuiting/open-circuiting, power grid voltage surges, and external electromagnetic pulses occur frequently. Insufficient anti-impact capability of the power supply will not only lead to unstable beam current and reduced process accuracy but also may cause serious failures such as breakdown of high-voltage components and burnout of power devices. Therefore, the anti-impact design of high-voltage power supplies for electron beams must focus on the four core goals of energy buffering, rapid regulation, interference isolation, and structural tolerance and conduct systematic optimization from circuit topology, component selection, control algorithms to mechanical structures.
The anti-impact adaptability of the circuit topology is the foundation of the design. Traditional linear regulated topologies have low efficiency and weak anti-impact capability in high-voltage scenarios, so topologies with bidirectional energy flow capability should be preferred. For example, the phase-shifted full-bridge topology achieves wide-range output regulation by adjusting the conduction phase of switching tubes, and its built-in freewheeling diode can quickly discharge transient current during load impact; the LLC resonant topology utilizes the energy buffering characteristics of the resonant cavity to limit voltage fluctuations during impact within the resonant frequency bandwidth, reducing stress on power devices. Meanwhile, a transient energy absorption branch should be added to the topology, using a series structure of varistors and ultra-fast recovery diodes, which can absorb excess energy from overvoltage impacts at the input/output terminals within microseconds to avoid high-voltage breakdown.
The selection and layout of energy storage components directly affect the impact buffering effect. For high-voltage side energy storage, metallized film capacitors with low equivalent series resistance (ESR) should be selected, as they have strong ripple current tolerance and are less prone to thermal breakdown under high-frequency impacts; supercapacitors can be used on the low-voltage side to quickly compensate for current gaps caused by power grid surges or load mutations by leveraging their high power density. The layout adopts a combination of distributed + centralized modes: small-capacity capacitors are placed close to power devices to reduce voltage spikes caused by parasitic inductance; large-capacity capacitors are installed at the bus to achieve global energy buffering and prevent component damage due to local energy concentration.
A fast-response feedback control strategy is the key to anti-impact performance. The transience of impact events requires the control system to have microsecond-level response capability. Traditional PI controllers are prone to overshoot or lag, so an adaptive PID control algorithm should be introduced. By real-time detecting the rate of change of output voltage and current, control parameters are dynamically adjusted to avoid voltage dips or overshoots at the initial stage of impact. For predictable impacts such as process switching, a feedforward control module can be added to output compensation signals in advance to offset the impact. At the same time, a hardware-level overcurrent/overvoltage protection circuit is indispensable. Current transformers and voltage Hall sensors are used for real-time sampling, and when abnormal signals are detected, power devices are directly triggered to turn off, shortening the protection response time to the nanosecond level.
Electromagnetic compatibility (EMC) and mechanical structure protection should be advanced simultaneously. External electromagnetic impacts (such as lightning strikes and electromagnetic pulses from equipment startup/shutdown) can interfere with internal circuits through conduction or radiation. Multi-level EMC filters should be installed at the input port, using a combination of common-mode inductors and X/Y capacitors to suppress differential-mode and common-mode interference; high-voltage leads should use shielded twisted pairs wrapped with metal braids to reduce the impact of electric field radiation on the control circuit. In terms of mechanical structure, high-voltage components should be fixed with insulating brackets to prevent component displacement or reduced insulation gaps caused by vibration impacts; at the same time, heat dissipation design should be optimized, using a combination of heat pipes and cooling fans to reduce the transient temperature rise of power devices during impact and avoid performance degradation caused by thermal stress.
The anti-impact design of high-voltage power supplies for electron beams is a systematic engineering project involving multi-dimensional collaboration, which requires balancing circuit performance, component characteristics, control accuracy, and mechanical reliability. Only through comprehensive optimization of topology adaptation, precise energy storage, fast control, and multi-faceted protection can the power supply operate stably under complex impact conditions, providing reliable power support for the industrial application of electron beam technology.