Reconfigurable Photovoltaic Emulator for Differential Diffusion Charge Redistribution Solar Modules

Abstract

Evaluating, validating, testing, and performing research on hardware components that are connected to actual solar photovoltaic systems can be challenging; photovoltaic emulators are a common practical approach. In particular, addressing emulation for the crucial research topics of partial shading and cell mismatch is important. Differential diffusion charge redistribution is a switched-capacitor architecture using differential power processing for performing maximum peak power point tracking with cell-level granularity using only a single module-level converter. Among the prohibitive challenges is preventing damage to the module-embedded integrated circuits for the corner cases during fault and failure testing of connected hardware components including power converters. Emulators not only benefit research, but also product development and manufacturing of hardware components and power converters. This paper investigates a reconfigurable linear emulator with an analog controller for photovoltaic modules configured for differential diffusion charge redistribution. Cell mismatch and partial shading are shown to be equivalent and that the averaged behavior of these switched-capacitor solar photovoltaic modules can be represented by two separate continuous-time circuits that are coupled by feedback and constraints leading to an emulator design that is demonstrated through a hardware prototype.