Polar scientific research constitutes a core academic field for global climate change studies, polar resource exploration, geophysical observation and astronomical monitoring. The Arctic, Antarctic and high-altitude polar regions feature extreme conditions: ultra-low temperatures, strong winds, blizzards, low atmospheric pressure, intense ultraviolet radiation, unmanned operation and limited energy supply. High‑voltage power supplies serve as critical power components for polar research equipment, delivering stable high‑voltage bias, power driving and signal amplification for ice-core detection radars, atmospheric monitors, aurora observation systems, seismic detectors, unmanned polar observatories, under-ice robots and satellite communication terminals. They convert energy from storage batteries or renewable power into regulated high‑voltage DC power for scientific instruments. Their cold-start capability at extreme low temperatures, operational stability, ultra-low power consumption, long-term reliability and environmental adaptability directly determine continuous equipment runtime, valid data acquisition and overall mission success. Polar applications impose extreme technical requirements far beyond conventional industrial power supplies: 1. Cold-start and stable operation at ultra-low temperatures. Inland polar winter temperatures drop to −80 ℃, with annual averages below −40 ℃. Conventional electronics suffer severe parameter drift: semiconductor threshold shifts, sharp rises in on-resistance, capacitor capacity decay and excessive ESR, magnetic core permeability collapse, insulation embrittlement and cracking, leading to startup failure, breakdown and permanent damage. Power supplies must achieve cold startup at −80 ℃ without external preheating and maintain stable operation across −55 ℃ to +55 ℃ with output voltage drift below ±1%. 2. Ultra-low standby power and high full-range efficiency. Unmanned polar stations rely heavily on solar, wind and battery energy; total battery-only endurance can extend to six months during polar nights. Static power consumption severely limits mission duration. Requirements include static power below 5 mW and peak conversion efficiency ≥90%, maintaining high efficiency from 10% to 100% load. Traditional high‑voltage supplies consume hundreds of milliwatts at standby and perform poorly under light loads. 3. Extreme long-term reliability for unattended deployment. Research systems typically operate continuously for one to two years without maintenance; unexpected shutdown causes data loss and permanent equipment risk. Standards demand MTBF ≥ 1×10⁵ hours and design life ≥ five years with robust automatic fault recovery. 4. Comprehensive resistance to harsh polar environments. Conditions include snowstorms, condensation icing, strong UV radiation, coastal salt corrosion, transportation vibration/shock and low pressure. Power units require full environmental protection: anti-UV treatment, vibration hardness, anti-icing sealing and low-pressure insulation reinforcement. 5. Extremely wide input voltage tolerance. Lithium, lead-acid and fuel-cell batteries experience dramatic voltage drop at ultra-low temperatures. Input coverage must span 30%–150% of nominal voltage, ensuring reliable startup even at severely depleted battery levels. 6. Low electromagnetic interference and complete protection. High-precision weak-signal scientific sensors are highly sensitive to noise. Power supplies must deliver minimal radiated and conducted interference while integrating comprehensive overvoltage, overcurrent, short-circuit, overtemperature, reverse-polarity and surge protection. This methodology establishes a complete framework covering ultra-low-temperature topology adaptation, full-temperature performance tuning, ultra-low-power high-efficiency design, polar environmental protection and unattended operational assurance. It provides standardized guidelines for high‑voltage power supplies deployed in Antarctic, Arctic and high-altitude cold-region observation systems. Addressing core challenges including −80 ℃ cold startup, ultra-low standby consumption and multi-year unattended reliability, the universal architecture adopts wide-input isolated flyback topology + linear post-regulation + fully digital low-power control, enhanced by adaptive temperature compensation and full environmental sealing. This eliminates traditional limitations of poor cold-start performance, high standby loss and insufficient long-term stability. The flyback topology offers simplicity, low component count, compact size, high step-up ratio and inherent galvanic isolation, ideal for miniaturized low-power polar systems. Combined with linear post-regulation, switching ripple is eliminated for ultra-low noise suitable for precision scientific instrumentation. Seven core design principles are defined: 1. Ultra-low-temperature optimized flyback transformer design. Magnetic cores adopt wide-temperature nanocrystalline or amorphous alloy material to maintain stable permeability and saturation flux density from −80 ℃ to +85 ℃ without catastrophic performance collapse. Multi-strand Litz wire reduces skin/proximity losses; interleaved winding minimizes leakage inductance, eliminating the need for additional RCD snubbers and reducing fixed losses. Ample flux derating prevents core saturation at extreme low temperatures. Polyimide insulation withstands cold embrittlement and cracking. 2. Ultra-wide input voltage adaptation. Mixed PWM/PFM peak-current control accommodates severe battery voltage fluctuation from 30% to 150% nominal input, enabling startup and full-load operation even at deeply depleted low-temperature battery voltage. Integrated under-voltage lockout, reverse-polarity protection and surge suppression safeguard fragile components. 3. Fully digital ultra-low-power control architecture. Ultra-low-power industrial MCU features static current<1 μA and active current <50 μA. Four optimized operating modes ensure minimal energy use: • Normal PWM mode maintains precision and dynamic response. • Light-load PFM mode reduces switching frequency to minimize light-load losses. • Standby mode disables power conversion with standby power <1 mW. • Deep sleep mode retains only wake logic with total consumption <5 μA for multi-month polar-night dormancy. Adaptive temperature algorithms dynamically adjust switching frequency, current limits and loop compensation to compensate semiconductor, magnetic and capacitor drift across the full temperature range, stabilizing output within ±0.5%. Factory calibrated temperature-based voltage correction ensures total drift below ±1%. Low-power high-impedance sampling minimizes static losses while preserving accuracy. 4. Low-ripple linear post-regulation. A high‑voltage linear regulator eliminates switching ripple entirely, achieving peak-to-peak ripple <0.05%, critical for sensitive scientific measurement circuits. Independent overcurrent and short-circuit protection further enhance safety while optimizing dropout voltage to balance efficiency and noise performance. 5. Full extreme-low-temperature component grading. All components qualify for −85 ℃ to +125 ℃ military/industrial ranges. Low-temperature-stable MOSFETs and diodes prevent threshold drift and rising on-resistance. Electrolytic capacitors are eliminated; only ceramic and PPS film capacitors ensure ≤10% capacity decay and ≤50% ESR increase at −80 ℃. Precision metal-film resistors maintain stability with temperature coefficients <25 ppm/℃. All parts undergo temperature cycling and low-temperature burn-in screening to eliminate early failure risks. 6. Redundancy and automatic recovery for unattended operation. Dual redundant control power, sampling circuits and reference sources enable seamless failover without system shutdown. Multi-level fault protection automatically recovers from transient overvoltage, overcurrent, short-circuit and overtemperature events. Hardware/software watchdog reset prevents system lockup. Intelligent battery under-voltage dormancy protects cells from deep discharge with automatic wake-up upon solar recharge recovery. 7. Full polar environmental protection design. Fully sealed aluminum alloy housings achieve IP67 against snow, moisture and salt fog. Reinforced mechanical construction withstands impact and under-ice vibration. Full vacuum epoxy potting eliminates internal air gaps to prevent condensation icing and insulation failure while improving thermal uniformity. UV-resistant exterior coatings prevent aging and cracking under intense solar radiation. High-altitude low-pressure insulation reinforces creepage distances to avoid corona discharge. All components and connectors are mechanically secured against vibration loosening. Ultra-low-power high-efficiency optimization runs throughout the entire design: simplified flyback architecture reduces component losses; minimized transformer leakage removes snubber losses; mixed PWM/PFM guarantees high efficiency across all loads; multi-mode power gating suppresses standby consumption; carefully selected low-loss semiconductors, low-ESR capacitors and ultra-low-power auxiliary circuits achieve static power <5 mW and peak efficiency ≥90%. Extreme cold-start stability is ensured through micro-power pre-warm auxiliary circuits for critical control and magnetic components without excessive energy consumption, combined with soft-start ramps to avoid inrush and core saturation at −80 ℃. Real-time adaptive parameter tuning compensates temperature drift across semiconductors, magnetics and capacitors. Passive thermal insulation plus mild self-heating from controlled switching losses maintains internal temperature without dedicated heaters. This methodology fundamentally solves traditional weaknesses such as failed ultra-low-temperature startup, high standby consumption and poor long-term reliability. It enables −80 ℃ preheat-free cold startup, full-temperature stable output, ultra-low static power below 5 mW and efficiency above 90%, supporting five-plus years of unattended polar operation. Widely applicable to Arctic/Antarctic research stations, high-altitude cold-region monitoring, glacier detection and unmanned meteorological systems, it delivers core technical support for domestic high‑voltage power supply localization and performance breakthroughs in extreme cold scientific exploration.