Overview of the state of technique for PV inverters used in low voltage grid-connected PV systems: Inverters above 10 kW § V. Salas *, E. Olı ´as Electronic Technology Department, Universidad Carlos III de Madrid, Avda. de la Universidad, 30-28911 Legane ´s (Madrid), Spain Contents 1. Introduction .................................................................................................... 1250 2. State of the technique of photovoltaic grid-connected inverters below 10 kW nominal power .................................. 1250 2.1. Output electrical parameters ................................................................................. 1251 2.2. Input electrical parameters .................................................................................. 1252 2.3. Other parameters .......................................................................................... 1255 3. Conclusions .................................................................................................... 1256 Acknowledgements .............................................................................................. 1257 References ..................................................................................................... 1257 1. Introduction Currently the management of energy sources represents a fundamental problem for the development and prosperity of any community. As a result, two major problems exist: diminishing of energy sources and the atmospheric pollution from the residues from conventional sources. Taking both factors into consideration, it can be argued that it is necessary to optimize energy resources through the use of alternative energy sources. The main characteristics of such sources include their renewability and their limited contribution to contamination. Photovoltaic solar energy is in this category and its use has also notably increased in industry over the past few years. In recent decades there has been an increasing interest in the use of low voltage grid-connected PV systems, conditioned by new incentives from different countries [1,2]. An essential element in those systems is the inverter, that is, the element which converts, in an efficient way, sinusoidal AC current waveform at its output so that it may be connected and synchronized to the utility network [3–14]. 2. State of the technique of photovoltaic grid-connected inverters below 10 kW nominal power In order to carry out this study, a list of five hundred models different from the inverter has been compiled. This has been Renewable and Sustainable Energy Reviews 15 (2011) 1250–1257 ARTICLE INFO Article history: Received 26 June 2009 Received in revised form 14 October 2009 Accepted 13 January 2010 Keywords: Grid-connected inverters Efficiency European efficiency MPP ABSTRACT An analysis has been made of the most important electrical parameters related to photovoltaic grid- connected inverters above 10 kW. To achieve this, a compilation of up to fifty manufacturers, various brands and up to five hundred different models has been prepared and updated to February 2009. Datasheet and manuals have been compiled, noting down their electrical output and input characteristics. Different and important aspects with respect to performance of some PV grid- installation have been analyzed: the number of different models for values of power; topology option; operational DC parameters range (such as nominal power, maximum power, nominal current, voltage), operational AC parameter range (such as nominal power, maximum power, nominal current, voltage), inverter conversion efficiency vs. nominal power and normalised inverter size and weight. ß 2010 Elsevier Ltd. All rights reserved. § Related past papers: Overview of the legislation of DC injection in the network for low voltage small grid-connected PV systems in Spain and other countries. Renewable and Sustainable Energy Reviews 2008;12(February (2)):575–83. V. Salas, E. Olı ´as, M. Alonso, F. Chenlo; DC current injection into the network from PV inverters of <5 kW for low-voltage small grid-connected PV systems. Solar Energy Materials and Solar Cells 2007;91(May (9)):801–6. * Corresponding author. Tel.: +34 916249430. E-mail address: vsalas@ing.uc3m.es (V. Salas). Contents lists available at ScienceDirect Renewable and Sustainable Energy Reviews journal homepage: www.elsevier.com/locate/rser 1364-0321/$ – see front matter ß 2010 Elsevier Ltd. All rights reserved. doi:10.1016/j.rser.2010.09.051