A Systematic Method of Interconnection Optimization for Dense‐Array Concentrator Photovoltaic System

Abstract

This paper presents a new systematic approach to analyze all possible array configurations in order to determine the most optimal dense-array configuration for concentrator photovoltaic (CPV) systems. The proposed method is fast, simple, reasonably accurate, and very useful as a preliminary study before constructing a dense-array CPV panel. Using measured flux distribution data, each CPV cells' voltage and current values at three critical points which are at short-circuit, open-circuit, and maximum power point are determined. From there, an algorithm groups the cells into basic modules. The next step is I-V curve prediction, to find the maximum output power of each array configuration. As a case study, twenty different I-V predictions are made for a prototype of nonimaging planar concentrator, and the array configuration that yields the highest output power is determined. The result is then verified by assembling and testing of an actual dense-array on the prototype. It was found that the I-V curve closely resembles simulated I-V prediction, and measured maximum output power varies by only 1.34%.

Performance study of crossed compound parabolic concentrator as secondary optics in non-imaging dish concentrator for the application of dense-array concentrator photovoltaic system

“…The formulas of short-circuit current, I SC , and open-circuit voltage, V OC , of CPV cell are expressed in Eqs. (6) and (7) respectively (Siaw and Chong, 2013;Siaw et al, 2014). Solar irradiance at solar concentration ratio of one sun is equivalent to 1000 W/m 2 .…”

Distributed and self-adaptive microfluidic cell cooling for CPV dense array receivers

“…To study the impact of this cooling approach, the performance of a CPV receiver composed by 6 strings of 8 PV cells in series [8] is predicted when submitted to an average solar concentration (C) of 600 suns and a non-uniform illumination profile (Figure 3; [7]). Two cooling configurations are compared: cooled by conventional microchannels versus cooled by the proposed matrix of microfluidic cells with individually variable coolant flow rate.…”

“…As a consequence, cooling devices with constant and uniform flow rate distributions are overly conservatives and lead to non-uniform temperature distributions and oversized pumping powers. Temperature non uniformities increase the mismatch losses and mechanical stresses throughout the receiver, which causes reliability losses [8]. Furthermore, the pumping power needed to decrease the PV cells temperature and, therefore, to increase the PV efficiency, must be balanced with the PV output in order to find the optimum working point [7].…”

Concentrated photovoltaic thermal (CPVT) solar collector systems: Part I – Fundamentals, design considerations and current technologies

“…Currently, several hotspot analytical and experimental models are available in the literature [26,27]. Mitigation strategies include using parallelconnected, adequately-sized bypass diodes across PV strings to provide an alternative path for the current when a cell is reversebiased due to poor illumination [24,25]; using concentrated flux homogenizers or multiple optical elements to minimize the unavoidable non-uniformity of the resulting image from concentrator optics [62,83,315]; connecting the cells in-parallel when individual cell voltages are adequate since voltage matching is less sensitive to illumination non-homogeneities than current matching [63]; and optimizing the geometrical arrangement and electrical connection of cells and strings in an array in accordance with the solar flux distribution using innovative strategies such as total cross-tied connections [317], strings with different cell widths [318], connecting individual cells with DC/DC converters [319], and using computerized algorithms to estimate the array's current-voltage curve for all possible connection configurations [320].…”