Novel Approach Immune to Partial Shading for Photovoltaic Energy Harvesting from Building Integrated PV (BIPV) Solar Roofs

The rapid development of solar photovoltaic (PV) technology facilitates implementation of building integrated PV (BIPV) as a key technology for energy efficient buildings. This study addresses parallel grid integration of micro strings composed of BIPV modules. Existing BIPV products are reviewed. A low number of PV cells per module suggests their series connection to be compatible with microinverters. A concept of a shade tolerant microinverter called Optiverter was applied to BIPV microstrings and compared experimentally to a high-end and a low-end commercial microinverters. Several shading scenarios for three BIPV element types were considered. The Optiverter was compared to several commercial micro inverters in terms of maximum power point tracking under unshaded and shaded conditions, power conversion efficiency, maximum power point tracking efficiency, and overall efficiency combining these two parameters.