Maximum Power Point Tracker
Multi-String Solar Array MPPT Controller
A multi-string maximum power point tracker is a power conversion controller utilizing radiation-hardened microcontrollers and gallium nitride FETs to continuously adjust solar array operating voltages for optimal power extraction. Lunar surface conditions complicate this regulation; the 336-hour day-night cycle restricts active tracking to the roughly 168-hour lunar day, during which solar cell temperature variations continuously shift the optimal operating point. Over decades, progressive solar cell degradation and dust accumulation continuously alter current-voltage characteristics, requiring adaptive perturb-and-observe or incremental conductance algorithms to track each string independently under partial shading.
Maximum power point tracking system extracting optimal power from solar array strings
Purpose
Continuously adjust solar array operating point to maximize power extraction as conditions change
Context
Child of L2-PWR-CONV within the Lunar Ark power generation system
Principles
- ▸Perturb-and-observe algorithm adjusts operating voltage to find maximum power point
- ▸Incremental conductance method provides faster convergence than P&O for rapid changes
- ▸Multi-string MPPT tracks each string independently for partial shading optimization
- ▸Digital MPPT with microcontroller enables adaptive algorithm selection
Typical implementations
- ▸Emcore MPPT charge controllers for space solar arrays
- ▸Morningstar TriStar MPPT (terrestrial, adapted concept for space)
- ▸GaN-based high-efficiency MPPT converters (>98% efficiency)
- ▸JAXA solar array power regulator with integrated MPPT
Lunar considerations
- ▸Solar cell degradation over decades shifts MPP continuously requiring adaptive tracking
- ▸Dust accumulation changes I-V curve characteristics over time
- ▸336-hour day/night cycling means MPPT only active during ~168-hour lunar day
- ▸Temperature variation of solar cells during day affects optimal operating point
Specifications
Functional
| primary function | Maximum power point tracking system extracting optimal power from solar array strings |
Physical
| materials | Rad-hard microcontroller, GaN FETs, Current/voltage sensors, Ceramic capacitors |
Interfaces
Provides
- MPPT-optimized DC power from solar arrays
Requires
- Raw solar array string outputs
Cite this entry
Lunar Ark Codex. "Maximum Power Point Tracker" (L3-PWR-CONV-MPPT). Retrieved 10 September 2026, from https://lunarark.com/entry/L3-PWR-CONV-MPPT
Licensed CC-BY-SA 4.0. You may reuse and adapt this entry with attribution, under the same licence.