Nuclear fusion energy represents the ultimate clean energy for humanity, featuring unlimited fuel reserves, zero pollution, intrinsic safety and ultra-high energy density. It is the core strategic solution to global energy crises and climate change. Tokamak, stellarator and inertial confinement fusion facilities are flagship experimental devices for controlled nuclear fusion. The high-energy high-voltage pulse power supply acts as the core power subsystem, delivering large-energy, high-amplitude, precisely synchronized pulsed power for toroidal field coils, poloidal field coils, neutral beam injection systems, ion cyclotron heating and electron cyclotron heating systems. It performs critical functions including plasma generation & confinement, heating plasma to fusion temperature and maintaining stable plasma operation. Its pulse energy, amplitude accuracy, waveform fidelity, synchronous triggering and long-term reliability directly determine plasma confinement performance, temperature, density, stability, and ultimately the success of fusion experiments and energy gain achievement.
Fusion facilities impose extreme requirements far beyond conventional power systems: 1.Ultra-large energy & high-current pulsed output: Tens to hundreds of kV output, single-pulse energy up to tens or hundreds of MJ, peak current ranging from tens to hundreds of kA, pulse width from tens of ms to several seconds. Customizable flat-top, slope and multi-segment waveforms with pulse droop ≤1% and waveform accuracy ≤±0.5%. Traditional pulse supplies cannot support such enormous energy output and precision waveform control. 2.Sub-microsecond multi-system synchronization: Dozens to hundreds of pulse power units operate cooperatively for plasma confinement, heating and current drive. Full-system synchronization ≤1 μs, and ≤100 ns for large reactor-scale facilities. Minor timing deviations cause plasma instability, disruption or permanent device damage. 3.Highest reliability & redundant architecture: Fusion facilities involve massive investment and long experimental preparation cycles. Unexpected faults lead to experiment failure or catastrophic damage. Required MTBF ≥100,000 hours with comprehensive fault tolerance and redundant operation to avoid interruption. 4.Extreme electromagnetic environment resilience: Intense electromagnetic pulses, high-magnetic fields and plasma radiation exist during operation; high-power pulsed outputs also generate severe EMI. Power systems must maintain stable operation under extreme interference while avoiding disturbance to plasma diagnostics and precision control systems. 5.Long lifecycle & cyclic endurance: Long-term repeated operation with tens of thousands of annual pulses; capable of enduring hundreds of thousands to millions of high-energy pulse cycles with a design lifespan ≥30 years and maintain easy maintainability. 6.Multi-level safety interlock & protection: Operating under ultra-high voltage, huge current and massive stored energy; faults release destructive energy. Full protection against overvoltage, overcurrent, short circuit, overtemperature, grounding faults and arcing; fault response<1 μs with safe energy discharge and system interlock to protect equipment and personnel. 7.Grid compatibility & power quality control: Single-pulse power reaches hundreds of MW to GW level, generating severe grid impact. Integrated grid surge suppression, reactive power compensation and harmonic mitigation ensure compliance with strict power quality standards.
This methodology establishes a full-process technical framework covering large-energy pulse topology, high-precision waveform control, nanosecond synchronization, strong EMI resilience and multi-layer redundant reliability design. It supports Tokamak, stellarator, inertial confinement fusion and other fusion devices, providing standardized design principles for core domestic substitution and performance upgrading of China’s fusion power equipment. Targeting ultra-large energy output, high-fidelity waveform control and ultra-high synchronization, the universal architecture adopts modular PFN (Pulse Forming Network) + multi-unit series/parallel superposition + fully distributed fiber-optic synchronous control, combined with high-power semiconductor switches and energy buffer units. It overcomes traditional limitations in delivering huge energy, precise shaping and nanosecond synchronization. Modular superposition increases voltage via series connection and boosts current/energy via parallel connection; independent per-module control enables flexible complex waveform generation while reducing single-unit stress and enhancing scalability, maintainability and reliability. Eight core design principles are defined.
1.Standardized modular pulse power unit design: Each module adopts full-bridge inverter + pulse transformer isolation + series IGBT/IGCT switches; parallel IGBT for high current and series IGBT for high voltage. Output range per module: 10–50 kV, 1–10 kA with full interchangeability for flexible series/parallel configuration from small experimental platforms to GW-scale fusion reactors. Key rules: active voltage sharing ≤±3% for series switches; master-slave current sharing ≤±2% for parallel branches; resonant soft switching minimizes losses and EMI; independent ultra-fast hardware protection<1 μs enables isolated bypass without system shutdown during single-module faults.
2.Optimized Pulse Forming Network (PFN): Multi-stage LC low-pass networks generate flat-top, slope and composite custom pulses with suppressed overshoot, oscillation and droop. Time-domain & circuit simulation matches inductive/resistive plasma loads to achieve droop ≤0.8% and waveform accuracy ≤±0.5%. Low-loss air-core or low-saturation inductors and long-life high-energy pulse capacitors with ultra-low ESR/ESL endure millions of cycles over 30 years. Integrated modular PFN enables flexible waveform reconfiguration without overall system redesign.
3.Energy buffering & grid adaptation system: A three-stage architecture—pulse capacitor bank + flywheel energy storage + rectifier isolation—decouples massive pulsed loads from the grid. Flywheels recharge capacitor banks during inter-pulse intervals, eliminating grid impact. Redundant capacitor banks reserve ≥20% capacity; active PFC ensures grid PF ≥0.99 and THD ≤5%; bidirectional energy recovery feeds residual energy back into storage to improve efficiency and suppress load shock.
4.Fully distributed nanosecond synchronous control: A three-layer hierarchy—central master controller + regional sub-controllers + local module controllers—transmits all clock & trigger signals via single-mode fiber to eliminate galvanic interference. Atomic clock-based global timing achieves stability ≤±0.01 ppm with system clock synchronization ≤50 ns. High-resolution programmable delay chips (≤10 ns step) adjust turn-on timing per module, achieving overall switching synchronization ≤100 ns for precise waveform shaping. Dual redundant fiber ring networks ensure uninterrupted communication under severe EMI.
5.High-fidelity closed-loop waveform control: Feedforward + multi-point real-time feedback adopts ≥10 MSPS high-speed ADC sampling to dynamically adjust module timing & pulse width during discharge, correcting waveform deviation and maintaining overall accuracy ≤±0.5%. Load-adaptive feedforward compensation rapidly responds to inductive/resistive variation for stable plasma excitation.
6.Extreme EMC & anti-interference design: Layered shielding with inner permalloy magnetic shielding and outer aluminum electric shielding provides ≥60 dB attenuation; independent shielded cavities isolate inter-module crosstalk. Full fiber isolation between high-voltage power stages and low-voltage control eliminates coupled interference. Optimized star single-point grounding separates power, analog, digital and shielding grounds; low-impedance stacked busbars reduce loop area and suppress radiated EMI at the source.
7.Three-level full lifecycle redundancy: Component-level dual redundancy for critical chips, drivers and sampling circuits; module-level N+1 redundant configuration with fast bypass isolation; system-level hot standby with seamless 1 ms failover for major faults. All key components apply strict long-term derating: voltage ≤50%, current ≤40%, temperature ≤70% of rated values; core capacitors and switches pass massive cycle aging validation to guarantee ≥30 years stable operation.
8.Multi-tier safety interlock & energy discharge protection: Four-layer protection includes ultra-fast hardware fault shutdown (<1 μs), software intelligent monitoring, full fusion-system interlock for plasma disruption/vacuum faults, and independent on-site emergency stop & door interlock. Redundant dedicated energy discharge loops safely release all stored energy within tens of milliseconds under any fault condition, preventing catastrophic damage and ensuring personnel safety.
In summary, this integrated framework resolves core bottlenecks of conventional pulse power technology, achieving hundreds of MJ to GJ-level energy output, system synchronization within 100 ns, waveform accuracy ≤±0.5%, and 30-year long-life reliable operation with full safety interlock. Widely applicable to Tokamak, stellarator, inertial confinement fusion and Z-pinch facilities, it delivers core independent controllable technologies for domestic breakthroughs and localization of key fusion energy equipment.