Design considerations and topology selection for dc-module-based building integrated photovoltaic system

The photovoltaic modules using in the building integrated photovoltaic system generally have different installation orientations and angles, moreover these modules are easy to be affected by partial shadows and mismatch of their electrical parameters. Consequently the conventional power configurations based on centralized, string and multi-string technology is difficulty to obtain high energy conversion efficiency, in severe cases, the hot-spot problem can arise and the photovoltaic modules can be irreversibly damaged. A novel power configuration based on dc module technology is proposed to improve the reliability and maximize the output capability of the photovoltaic power system, and it is of potential interest in residential generation system utilizing multiple sustainable energy sources. The dc-module-based system integrates a high step-up dc-dc converter with a photovoltaic module into one electrical device, then assigned to a common inverter, and a compact and cost effective solution is achieved. This paper investigates the design criterion of photovoltaic module integrated dc-dc converter according demands and specifications of the system. The performance and characteristic of the suitable converter topologies is evaluated. Based on the evaluation results, a current-fed half bridge topology is selected for this application, and an experimental prototype was built and tested in the laboratory to verify the results.