New architecture for high efficiency DC-DC converter dedicated to photovoltaic conversion

Abstract

Abstract The latest researches on photovoltaic energy conversion clearly show that the next generation systems will be both smarter and efficient, with insurance of greater security and modularity. They are clearly oriented nowadays on the multi-point conversion, based on a parallel high voltage bus, with photovoltaic panels owner of their individual Maximum Power Point Tracker (MPPT) connected to an integrated DC-DC converter managing a global Maximum Power Point. This structure allows to avoid shadowing problems. We have studied in this paper the possibility to have a small universal DC-DC converter able to work in a large input voltage range (10 - 40 volts), and producing an output voltage up to around 300 volts with a global efficiency better than 96%. In this paper we describe an original Step-Up converter architecture tested on a standard inverter i.e. including its own MPPT. We also discuss the possibility to use high voltage parallel bus to improve the electro-magnetic compatibility and electro-magnetic pulse robustness by the low surface of wirer loops, which also represents an interesting way to decrease wiring prices. The global efficiency improvement of this architecture has been estimated for + 15 to 20% compared to classic ones. This structure allows the use of numerous technologies (amorphous, poly, mono.. . cells) working together on a single HVDC bus in an optimal efficiency. Finally, it is possible to migrate sequentially and progressively from an old standard technology towards this new one as described before.