A Class AAA Solar Testbed for Reproducible Long-Term Characterization of Energy-Harvesting Systems

TL;DR

This paper introduces a highly controllable, spectrally configurable solar testbed with Class AAA performance, enabling reproducible long-term evaluation of energy-harvesting systems under stable illumination conditions.

Contribution

It presents a novel LED-based solar testbed with active control, spectral configurability, and high stability, facilitating systematic laboratory characterization of solar energy harvesters.

Findings

Achieves Class AAA IEC 60904-9 performance standards.

Provides spectrally configurable illumination from 5.7 mW/m2 to 908 kW/m2.

Demonstrates high repeatability and stability for long-term experiments.

Abstract

Energy harvesting promises maintenance-free operation of wireless sensor nodes but introduces strong dependencies on stochastic and deployment-specific environmental conditions. In particular, solar-powered systems are highly sensitive to variations in irradiance and spectral composition, which complicates system-level design, parameter tuning, and reliable verification. This work presents a solar testbed in which active control via Hardware-in-the-Loop (HIL) enables stable and repeatable illumination conditions for evaluating ultra-low-power energy harvesting systems. The proposed LED-based solar testbed provides spectrally configurable illumination over a wide dynamic range, from 5.7 mW/m2 to 908 kW/m2. It achieves Class AAA performance according to IEC 60904-9, with a spectral match below 1.3% and a spatial non-uniformity below 1.28% over a 16.5 cm x 16.5 cm test area. The long-term irradiance instability remains below 0.6%. Closed-loop control using integrated illuminance and spectral sensors ensures high temporal stability, while a temperature-controlled DUT stage supports long-term experiments. Experimental results demonstrate high repeatability and suitability for systematic laboratory characterization of solar energy harvesting systems.