Series Balancing Capacitor-Integrated String of PV Modules Connected to DC Grid for BIPV Applications

In a world of ever increasing energy demand, the necessity of renewable energy sources (RES) have become all the more important. Among the various RES available, solar photovoltaics have proved to be a very promising solution. One innovative approach within this field is Building Integrated Photovoltaic (BIPV) systems, which combine energy generation with architectural functionality. They are designed to produce electricity through PV modules seamlessly incorporated into building architecture, paving the way for the realization of zero-energy buildings in the future. Such systems, even though have several advantages, may still suffer from non-uniform operating conditions, which if not taken care, can drastically reduce power yield of the system. To address this concern, a novel Series Balancing Capacitor (SBC) integrated Distributed Maximum Power Point Tracking (DMPPT) architecture is proposed in this paper. Compared to the schemes reported in the literature, it has the following salient features: the proposed system can be directly connected to a fixed voltage DC grid without the need for an intermediate Full Power Processing (FPP) converter, while allowing all PV modules connected in a string to operate at their respective MPPs. The system also has Non-MPP mode functionality to handle varying loading demands. A suitable control strategy is devised to operate the system in MPP and non-MPP mode. Subsequently, a laboratory prototype is developed and detailed experimental validation of the system is carried out to confirm the viability of the system.