Photodiode sensor array design for photovoltaic system inter-row spacing optimization-calculating module performance during in-situ testing / simulated shading

Abstract

Data currently published in the literature provides estimates of photovoltaic (PV) module performance under essentially two standard test conditions. However, real design optimization by electrical and PV engineers working to achieve maximum production for systems they are responsible for requires additional knowledge as to how these modules can be expected to perform under all expected field conditions and in the presence of real obstructions; often including necessary inter-row shading. This work provides, for the first time, detailed field calculations of module performance for two types of PV modules illustrating the detrimental production impact of inter-row shading. The research indicates that using photodiode sensors to provide critical solar data from dispersed locations on the modules could aid in the development of an optimization procedure for minimizing the negative aspects of this common phenomenon. Extension of this work to cover the majority of the many module types will enable engineers to adequately address inter-row shading when they attempt to maximize the size of a PV system for a given roof or ground mounted project. It is clear from these research results that the impacts of inter-row shading on module output and energy production performance are more significant than originally anticipated by current PV design software models and must be considered in future design programs. The research provides a PV module shading test protocol, proposed sensor array layout design and results of the analysis of inter-row module shading (up to one cell row) and cell row coverage (20% through 100% in 20% increments) showing how important and worthwhile this sensor system can be to forwarding the design efforts of engineers working with high voltage photovoltaic power modules.