Industrial irradiation technology adopts ionizing radiation from high‑energy electron beams or gamma rays to realize advanced industrial applications including material modification, food sterilization, medical device disinfection, environmental treatment and chemical synthesis. Featuring high efficiency, environmental friendliness, zero residue and continuous production capability, it is widely applied in cable cross‑linking, heat‑shrinkable material manufacturing, food preservation, medical sterilization and waste gas/water treatment. The high‑voltage DC power supply serves as the core power component of industrial irradiation electron accelerators, delivering stable high‑amplitude DC high voltage for electron guns and accelerating tubes. It converts grid power into high‑voltage DC required for high‑energy electron acceleration. Its energy efficiency, long‑term stability, radiation tolerance and output accuracy directly determine electron energy, beam intensity, beam quality and operational efficiency of accelerators, as well as the productivity, processing quality and operational cost of entire irradiation production lines.
Continuous industrial operation imposes extremely strict technical challenges beyond conventional power supplies: 1.Ultra‑high energy efficiency & low power consumption: Irradiation lines run 24/7 with over 8,000 operating hours annually. Power efficiency directly determines electricity costs. For a 100 kW accelerator, each 1% efficiency improvement saves nearly 10,000 kWh per year while reducing cooling load. Required peak efficiency ≥96% and average full‑load efficiency ≥94%, far exceeding 80%–85% of traditional industrial frequency high‑voltage supplies. 2.Long‑term resilience under intense radiation: Accelerators continuously generate high‑energy electrons, X‑rays and gamma rays. Power supplies installed close to acceleration tubes endure severe total ionizing dose (TID) up to 1 Mrad(Si), which causes semiconductor drift, insulation aging, high‑voltage breakdown and system malfunction. Full‑lifetime radiation hardness is mandatory. 3.Extra‑long service life & ultra‑high reliability: Unplanned shutdowns lead to massive product rejection and economic losses. Required MTBF ≥1×10⁵ hours with a 20‑year design lifespan, minimal failure rate and support for non‑stop online maintenance. 4.High‑power ultra‑step‑up topology challenge: Output ranges from 100 kV to 5 MV with power 10 kW–500 kW. Based on 380 V three‑phase input, the maximum voltage gain exceeds 13,000 times, requiring advanced cascaded insulation, multi‑module current/voltage sharing and sophisticated thermal management impossible for single‑stage topologies. 5.High stability & ultra‑low ripple: Uniform irradiation quality demands strict beam stability. Long‑term voltage stability ≤±0.5%, short‑term stability ≤±0.2%, and peak‑to‑peak ripple<1%. Excessive ripple causes energy dispersion, uneven dosage and defective products. 6.Rugged industrial adaptability & comprehensive protection: Harsh on‑site conditions include severe grid fluctuation, heavy EMI, dust, humidity and corrosive gas. The power supply must support strong grid immunity, EMC performance, three‑proof environmental protection and full fault protection against overvoltage, overcurrent, short circuit, overheating, arcing and high‑voltage sparking.
This methodology establishes a full‑process technical framework covering high‑efficiency topology design, full‑chain loss optimization, radiation hardening, long‑lifetime reliability and industrial environmental adaptation. It supports all energy and power grades of industrial electron irradiation accelerators, providing standardized design principles for domestic core‑component localization and performance upgrading. Targeting high step‑up ratio, high power, extreme efficiency and radiation tolerance, the universal three‑stage modular architecture is adopted: three‑phase PFC rectifier + multi‑module parallel full‑bridge LLC resonant isolation + symmetric Cockcroft‑Walton (CW) voltage multiplier. By functional separation and modularization, it solves grid power factor correction, high‑efficiency isolated step‑up and ultra‑high‑voltage output simultaneously, overcoming traditional limitations of low efficiency, bulky size and poor radiation resistance.
1.Front‑stage three‑phase PFC rectifier: A Vienna rectifier achieves unity power factor with low switching stress, low conduction loss and excellent EMI performance. It maintains PF ≥0.99 and THD ≤5% across 20%–120% load, complying with GB/T 14549. Wide input tolerance covers ±20% grid fluctuation with feedforward compensation for stable DC bus voltage. Dual parallel N+1 redundancy guarantees continuous operation during single‑path faults.
2.Middle‑stage multi‑module parallel full‑bridge LLC resonant converter: Standardized identical modules adopt parallel input and series output for flexible scalability from 100 kV to 5 MV. All modules operate near optimal resonant points to achieve ZVS for primary switches and ZCS for secondary rectifiers, eliminating switching losses completely. The resonant frequency is optimized within 20 kHz–50 kHz to balance power density, magnetic loss and EMI. Master‑slave voltage/current sharing ensures deviation ≤±1% with fiber synchronous driving to eliminate circulating current. Planar/matrix transformers with interleaved winding reduce leakage inductance and high‑frequency AC loss, adopting radiation‑resistant composite insulation. N+1 modular redundancy enables automatic bypass and non‑stop online maintenance.
3.Rear‑stage symmetric CW voltage multiplier: Dual‑input symmetric topology reduces ripple by over 50% and distributes voltage stress evenly across stages, significantly simplifying ultra‑high‑voltage insulation and suppressing radiation‑accelerated aging. Radiation‑hardened fast‑recovery HV diodes or SiC Schottky devices minimize rectifier loss; radiation‑resistant polystyrene or polypropylene film capacitors maintain stable capacitance and ESR under prolonged irradiation. Grading rings and shielding optimize electric field distribution to prevent corona discharge, while independent grading resistors ensure uniform voltage distribution stage by stage.
4.Full adoption of wide‑bandgap semiconductors: SiC MOSFETs replace conventional silicon devices, reducing switching loss by over 70% with stable high‑temperature performance and stronger radiation tolerance. SiC Schottky rectifiers eliminate reverse recovery loss and cut rectifier loss by more than 80%, ideal for high‑frequency high‑voltage applications to maximize system efficiency.
5.Dual closed‑loop control architecture: The front PFC adopts inner current loop + outer voltage loop for stable bus voltage and unity power factor. The rear high‑voltage output realizes fully digital precision regulation via high‑precision resistive voltage dividers and fiber‑isolated feedback, achieving voltage stability ≤±0.2%. Feedforward control compensates grid and load variations to enhance dynamic response speed.
6.Integrated layered design: Independent shielding cavities for PFC, LLC and multiplier stages enhance radiation protection and EMI suppression. Optimized layout shortens power loops to reduce parasitic parameters and losses. Compared with traditional industrial frequency high‑voltage power supplies, volume is reduced by over 60% and weight by more than 50%.
Full‑chain efficiency optimization runs through the entire design: resonant soft switching eliminates hard‑switch losses; three‑stage voltage division reduces single‑stage step‑up stress and transformer leakage inductance; SiC devices minimize conduction and switching losses; low‑loss magnetic materials and Litz winding reduce core and winding AC loss; intelligent digital control implements dynamic frequency tuning, adaptive dead‑time adjustment, module sleeping under light load and synchronous rectification optimization, ensuring peak efficiency ≥96% and excellent light‑load performance.
A three‑level radiation hardening system guarantees long‑term stability under 1 Mrad(Si): —Component‑level screening: Radiation‑tolerant SiC power devices, rad‑hard ICs (≥100 krad(Si), high single‑event immunity), non‑electrolytic capacitors, precision metal foil resistors and radiation‑resistant insulation materials with double derating margins. —Circuit‑level reinforcement: Real‑time adaptive compensation offsets TID‑induced parameter drift; triple modular redundancy (TMR) and ECC eliminate single‑event upsets; fast current limiting prevents single‑event latchup burnout; strict electrical/thermal derating slows radiation‑accelerated aging. —System‑level shielding: Thick steel main shielding attenuates primary radiation; independent high‑density lead/tungsten alloy cavities protect sensitive control circuits; optimized mechanical layout places low‑voltage electronics far from radiation sources for additional structural shielding.
Long‑lifetime reliability & industrial environmental adaptation adopt water cooling with uniform thermal distribution to control component temperature within safe limits; dual redundant cooling ensures continuous heat dissipation; full sealing with IP54 rating, conformal coating, corrosion‑proof connectors and slight positive dry air protection resist dust, humidity and corrosive gas; dual redundancy for cooling, control, driving and sampling eliminates single‑point failure; wide grid tolerance with sag ride‑through prevents unexpected shutdowns caused by grid instability.
Comprehensive condition monitoring & protection realize full‑parameter remote telemetry, 10‑year data traceability and full fault coverage including over/under voltage, overcurrent, short circuit, overtemperature, beam overlimit and high‑voltage arcing. Hardware protection responds within 1 μs with dual hardware/software redundancy. Interlock linkage with accelerator and irradiation safety systems ensures absolute equipment and personnel safety, while embedded self‑diagnosis accelerates maintenance and minimizes downtime.
In summary, this integrated framework resolves core weaknesses of traditional irradiation power supplies. The three‑stage modular topology achieves peak efficiency above 96%; comprehensive radiation hardening ensures over 20 years of stable operation under intense irradiation; full‑life reliability supports 24/7 continuous production. Widely applicable to electron beam irradiation accelerators and high‑voltage acceleration systems, it delivers core independent technologies for domestic substitution and performance upgrading of China’s industrial irradiation equipment.