The power Supply Unit is the fundamental equipment in telecom industry to power RF equipment and other necessary equipment in base stations and cell towers. Power electronics are of three types depending on the voltage conversion requirement. These are AC to DC, DC to AC, and DC to DC converters. The power electronics units are designed for operating up to 4000 m above sea level. However, the limitation in network range covered by cell towers has put forward the need for a high-altitude platform system (HAPS).  The platform is expected to operate 18-24 km above sea level. The design of power electronics for such altitude poses various challenges. The challenges include the effects of environment on electronic unit, compliance with standards and regulatory requirements which should be fulfilled at that altitude.

The thesis explores and investigates regulatory requirements, electrical standards, and avionics. Electrical standards for airborne equipment are researched in terms of electrical characteristics i.e., voltage, current, transient nature of voltage, overvoltage, undervoltage and electromagnetic compatibility. In addition, creepage, clearance and related breakdown voltage for conducting trace on PCB are also researched. Furthermore, the choice of component i.e., capacitor in terms of environmental characteristics such as temperature and pressure are also researched. Lastly, the heating and cooling solution affected by environmental conditions at high altitude for the power electronics unit is investigated.