We present a real-time parameter estimation method to extract cell-level parameters based on a one-diode model formulation during active shading. Active shading is accomplished by a custom fabricated Polymer Dispersed Liquid Crystal (PDLC) screen controlled via relays and precicely timed to work in conjunction with a curve tracer and data acquisition system. Parameters are rapidly extracted and can be used to infer cell degradation and propensity to hot-spot generation. The parameter estimation method leverages an efficient initialization scheme using the Lambert-W function and asymptotic methods. Simulation and preliminary experimental results are provided.

Degradation of photovoltaic (PV) modules remains an important area of research. This paper focuses on degradation due to partial shading caused by controlled dust deposition of medium-sized sand. The sand was deposited in a controlled manner to simulate a dust clumping effect often caused by rainfall on a tilted module. While a number of studies have analyzed dustinduced reduction in power output, its impact on thermal variability during operation has neither been reported, nor quantified to date. Data is presented from four strings of an array in which two strings have been subjected to a dusting protocol and two strings are clean. Thermal statistics of the four strings are presented and compared. In addition, a number of thermal images recorded during IV curve traces are presented which depict dynamic hot spot evolution.