Spectral CT represents the core development direction of high-end medical imaging today. Featuring material decomposition, monoenergetic image reconstruction, virtual non-contrast scanning and other advanced clinical functions, it breaks the limitation of traditional CT that only supports anatomical imaging. It enables accurate identification of lesion composition and possesses irreplaceable value in early tumor diagnosis, cardiovascular screening, urinary stone component analysis, gout crystal detection and other clinical scenarios. The high‑voltage generator is an essential power component of spectral CT, supplying stable DC high voltage to the X‑ray tube. Its dual‑energy fast switching capability, output voltage stability and ripple suppression directly determine X‑ray spectral purity, material decomposition accuracy, image signal‑to‑noise ratio and overall diagnostic performance. The fundamental principle of spectral CT is to rapidly switch between high and low X‑ray tube voltages within an extremely short time, acquiring tissue attenuation data at different photon energies to achieve precise material characterization. Current mainstream high‑end spectral CT systems require the high‑voltage power supply to complete 80 kV / 140 kV dual‑energy switching within hundreds of microseconds, with voltage overshoot below 0.5 %, output ripple lower than 0.1 %, and tube voltage control accuracy better than ±0.5 %. Failure to meet these criteria causes spectral broadening, severe beam‑hardening artifacts, degraded material decomposition accuracy, and even invalid spectral imaging. Conventional mains‑frequency and ordinary high‑frequency high‑voltage generators suffer from slow switching speed, large voltage overshoot, high output ripple and unstable tube current during dual‑energy transitions, making them incapable of satisfying the stringent requirements of advanced spectral CT. All designs must strictly comply with IEC 60601‑1 general medical electrical safety standards, GB 9706.3 safety requirements for medical diagnostic X‑ray equipment, and relevant technical specifications for Class III medical device registration issued by the NMPA. Addressing the core clinical demands and technical challenges of high‑voltage generators for spectral CT, this methodology establishes a comprehensive framework covering topology design, dual‑energy fast switching control, spectral purity optimization and safety compliance. It supports high‑voltage power supply requirements for various high‑end spectral CT devices and provides standardized design guidelines for domestic substitution of premium medical imaging equipment. Focusing on fast dual‑energy switching and high stability for spectral CT applications, this methodology adopts a dual independent high‑frequency resonant inverter architecture integrated with a unified high‑voltage transformer. The two inverter channels correspond to high‑energy and low‑energy output control respectively, sharing the same high‑voltage transformer and X‑ray filament power supply. This ensures independent controllability of dual‑energy outputs while maintaining high system integration, fundamentally overcoming the slow response and low precision limitations of traditional single‑topology dual‑energy designs. A full‑bridge LLC resonant topology is selected to achieve zero‑voltage switching (ZVS) on primary power devices and zero‑current switching (ZCS) on secondary rectifiers across wide load ranges, delivering ultra‑low switching loss, minimal electromagnetic interference and fast dynamic response ideal for high‑speed spectral switching. Four core design principles are implemented. First, resonant parameters are optimized via fundamental harmonic analysis with a resonant frequency of 150 kHz~250 kHz, maintaining continuous soft switching throughout the full voltage range of 80 kV~140 kV and full power range of 10 kW~100 kW. This eliminates hard‑switching losses and EMI, raises overall efficiency above 96 %, reduces thermal stress, and establishes a stable power foundation for rapid dual‑energy transitions. Second, fully symmetrical circuit design with a shared high‑precision reference source ensures identical control accuracy and response speed for both channels, preventing output imbalance during switching. Third, the integrated high‑voltage transformer adopts dual primary windings corresponding to the two inverters and a unified secondary high‑voltage winding to guarantee consistent coupling, with enhanced insulation meeting medical double‑isolation standards. Fourth, integrated input EMI filtering, soft start and inrush current limiting ensure electromagnetic compatibility and avoid interference with other sensitive hospital equipment. Fast dual‑energy switching control forms the core of this methodology. To achieve microsecond‑level transitions required by spectral CT, an FPGA‑based fully digital feedforward plus closed‑loop composite control eliminates the slow response and large overshoot inherent in conventional PID regulation. Three key principles are followed. First, feedforward control acts as the primary strategy with closed‑loop feedback for fine correction. Pre‑stored drive parameters, reference voltages and filament current compensation values for both energy levels are instantly applied upon switching commands, eliminating integral saturation and drastically improving response speed. Second, high‑speed closed‑loop calibration adopts 24‑bit high‑precision ADC sampling at 1 MHz to perform microsecond‑level voltage correction during transitions, ensuring zero overshoot and rapid stabilization. Third, dual closed‑loop linkage of tube voltage and filament current compensates for space‑charge effects in real time, maintaining linear matching between voltage and current and stabilizing X‑ray dosage throughout switching. With this algorithm, full‑range 80 kV to 140 kV switching can be completed within 80 μs with overshoot controlled below 0.3 % and settling time shorter than 50 μs, significantly exceeding the mainstream 150 μs industry standard. Tube current fluctuation is maintained within ±1 % during transitions, fully satisfying clinical spectral imaging requirements. Spectral purity optimization ensures reliable diagnostic performance by suppressing spectral broadening and beam hardening. Systematic improvements cover ripple reduction, long‑term spectral stability and rectifier optimization. Ultra‑low ripple performance is achieved through three measures: an 8‑stage symmetrical voltage multiplier reducing ripple by more than 60 % while lowering component voltage stress; cascaded π‑type high‑voltage filtering using stable polystyrene film capacitors and low‑drift resistors to suppress peak‑to‑peak ripple below 0.08 %; and active ripple cancellation that dynamically injects compensation signals to eliminate residual fluctuations, ensuring total ripple remains below 0.1 % across all power levels. Long‑term spectral stability is maintained via temperature compensation algorithms that dynamically adjust reference voltages according to real‑time thermal data from transformers, rectifiers and capacitors, restricting 8‑hour continuous drift below 0.2 %. Grid fluctuation feedforward correction stabilizes input power, achieving tube voltage accuracy better than ±0.3 % and tube current precision within ±0.8 %. Secondary rectification adopts silicon carbide Schottky diodes to eliminate reverse recovery noise and voltage spikes, while optimized high‑voltage layout shortens power loops and minimizes parasitic distortion, preserving spectral linearity and preventing beam hardening artifacts. Medical safety compliance fulfills strict Class III device regulations through comprehensive electrical safety, EMC and interlock protection designs. Electrical safety adheres fully to IEC 60601‑1 with reinforced double insulation exceeding 20 kV withstand, patient leakage current below 10 μA and equipment leakage under 100 μA. Independent protective grounding, operational grounding and shielding grounding eliminate ground‑loop risks. EMC performance complies with complete GB/T 18268.1 medical standards using multi‑stage EMI filtering, double shielding enclosure, and full physical separation between power and control circuits, achieving Grade 4 immunity against ESD, EFT and radiated interference. A six‑level redundant protection system including over/under voltage, overcurrent/short circuit, overtemperature, arcing and filament open‑circuit protection adopts dual hardware‑software redundancy with fault response faster than 1 μs. Safety interlocks for door status, emergency stop and key switches instantly cut high voltage during faults to ensure absolute safety for patients, operators and equipment. In summary, this methodology delivers a complete technical solution for spectral CT high‑voltage generators, covering topology innovation, fast dual‑energy switching, spectral purity enhancement and full safety compliance. It resolves traditional bottlenecks such as slow transitions, high ripple and poor spectral stability. Feedforward‑closed‑loop control realizes overshoot‑free microsecond dual‑energy switching; multi‑stage ripple suppression achieves ultra‑low ripple below 0.08 %; and comprehensive safety design meets Class III medical device certification requirements. Widely applicable to high‑end spectral CT systems, it provides core technical support for the independent development and domestic replacement of premium Chinese medical imaging equipment.