Analysis of Potential for Mitigation of Building-Integrated PV Array Shading Losses Through Use of Distributed Power Converters Available to Purchase

Partial shading of building-integrated photovoltaic (BIPV) arrays is very common, as they are limited by building geometry and most often installed in crowded urban or suburban environments. Power losses in shaded BIPV systems tend to be disproportionately large, due in large part to mismatches in operating conditions between panels. Maximum power point tracking at a modular level, which can be achieved through the use of module integrated dc-dc converters (MICs), may be used to mitigate some of these losses. This paper investigates the potential power gain provided by MICs for several representative partially shaded BIPV array scenarios. A flexible, comprehensive simulation model for BIPV systems is developed, which allows for variations in insolation and temperature at the PV cell level, while accurately modeling MICs and their effect on array performance. Shadows from nearby objects are mapped onto the modeled BIPV arrays and simulated on an annual, hourly basis, with varying array configuration as well as object size and placement. Results of these simulations show that the impact of MICs on system power output varies depending on factors such as radiation availability, time shaded throughout the year, shadow size and distribution on the array, and inverter design. Annual power gains of 3–30% are realized for a moderately shaded system with MICs when compared to conventional approaches. Further opportunities for increased energy capture in a BIPV system with MICs are identified and discussed.