Electrolyzer Power Conditioning
DC-DC Converter Conditioning Bus to Electrolyzer Voltage
Electrolyzer power conditioning is a 3 kg buck DC-DC converter housed in 316L stainless steel that steps down a primary 400 V bus to the 2 to 30 V required by water electrolysis stacks. Delivering up to 25 A at 95 percent efficiency, the unit applies current-mode control and soft-start functions to accommodate cell aging and protect sensitive membranes. In the lunar environment, the absence of a protective magnetosphere necessitates radiation-tolerant gallium nitride switching transistors to achieve a 20-year operational life, while the vacuum requires specialized thermal pathways to reject approximately 25 W of peak waste heat.
DC-DC converter that takes the main 400 V bus and steps it down to the ~2-30 V electrolyzer stack voltage with current-mode control.
Purpose
DC-DC converter that takes the main 400 V bus and steps it down to the ~2-30 V electrolyzer stack voltage with current-mode control.
Context
Child of L2-WTR-ELEC in L1-WTR water processing chain
Principles
- ▸Buck DC-DC converter with current-limited output (electrolyzers are current-driven)
- ▸Variable output voltage tracks stack as it ages
- ▸Soft-start protects membranes from current spikes
- ▸Rad-tolerant SiC/GaN switching components
- ▸Efficiency >95% reduces parasitic load
Typical implementations
- ▸Renesas rad-hard 100V GaN DC-DC family
- ▸VPT rad-hard DC-DC converters
- ▸Industrial electrolyzer power supplies
Lunar considerations
- ▸Rad-tolerant power electronics for long mission
- ▸Heat rejection ~25 W at peak
Specifications
Functional
| primary function | DC-DC converter that takes the main 400 V bus and steps it down to the ~2-30 V electrolyzer stack voltage with current-mode control. |
| output voltage v | 2, 30 |
| output current a | 25 |
| efficiency percent | 95 |
Physical
| mass kg | 3 |
| materials | GaN switching FETs, Ferrite core, 316L SS housing |
| vacuum compatibility | True |
Operational
| power consumption w | 25 |
| thermal range c | -40, 70 |
| lifetime years | 20 |
| mtbf hours | 150000 |
Interfaces
Provides
- Regulated low-voltage current source
Requires
- 400 V bus input
- Heat rejection
Cite this entry
Lunar Ark Codex. "Electrolyzer Power Conditioning" (L3-WTR-ELEC-PWR). Retrieved 10 September 2026, from https://lunarark.com/entry/L3-WTR-ELEC-PWR
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.