Abstract:In the building integrated photovoltaic (BIPV) system, the influence of partial shading on the energy efficiency of the BIPV system is large in certain circumstance. Energy efficiency of the centralized system and multi string type system are researched in four typical shading conditions. Results show that, when the shading is not serious, whether the system is in weak light or bright light condition, the energy conversion efficiency of the centralized system and multi string system is high and the difference is small. When the shading is serious, whether the system is in weak light or bright light condition, the system energy efficiency difference of two kinds of energy conversion structure is very big. In general, multi string systems is more higher than centralized system in energy efficiency, so the choice of a better energy conversion structure is the key factor to reduce the shading effect and improve the system energy efficiency.