SunaPlayer: high-accuracy emulation of solar cells

Abstract

Evaluating and debugging solar panel-driven systems is a cumbersome process. The system must be deployed in the wild, software and hardware bugs identified remotely, and the development cycle must be repeated to build a robust system. Emulation platforms for solar panels offer a plausible remedy, however, existing systems have narrow operating range and are not portable. To address these shortcomings, we design, implement, and evaluate the SunaPlayer, a solar panel emulation platform that supports a wide operating current range (430 micro-amps to 1.89 amps) and voltage range (0.02 V to 9.8 V), and can be powered using batteries. SunaPlayer uses a high gain analog device, a PNP darlington transistor, a multi-scale driving and measurement circuit, and a novel state machine based proportional-integral-differential controller to build an accurate non-linear model of the solar panel. We have implemented a fully functional SunaPlayer prototype, and demonstrate that it can emulate a wide range of solar panels with high accuracy, low latency, high sensitivity, and low power consumption. The design methodology for the SunaPlayer can be used to build systems that model hard to emulate non-linear devices.