Global energy demand and environmental concerns are the driving force for use of alternative, sustainable, and clean energy sources. Solar energy is the inexhaustible and CO2-emission-free energy source worldwide. The Sun provides 1.4 � 10 5 TW power as received on the surface of the Earth and about 3.6 � 10 4 TW of this power is usable. In 2012, world power consumption was 17 TW, which is less than 3.6 � 10 4 TW. Photovoltaic (PV) cells are the basic element for converting solar energy into electricity. PV cell technologies, energy conversion efficiency, economic analysis, energy policies, environmental impact, various applications, prospects, and progress have been comprehensively reviewed and presented in this paper. This work compiles the latest literature (i.e. journal articles, conference proceedings, and reports, among others) on PV power generation, economic analysis, environmental impact, and policies to increase public awareness. From the review, it was found that PV is an easy way to capture solar energy where PV based power generation has also rapidly increased.

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Global Prospects, Progress, Policies and Environmental Impact of Solar Photovoltaic Power Generation

This paper reviews the history of fuel cells. Its follows the path from the invention of the fuel cell up to present days. Fuel cell types as well as their advantages, disadvantages and principal applications nowadays are explained. History teaches once again that devices perceived by the public as recent inventions, are actually the product of many years (almost two centuries in this case) of arduous research.

Fuel cells: History and updating. A walk along two centuries

Identification of PV solar cells and modules parameters using the genetic algorithms: Application to maximum power extraction

This paper presents a maximum power point tracking approach for a photovoltaic system using the dividing rectangles algorithm. The new approach overcomes some weaknesses of the existing methods such as the perturb and observe method as it is capable of searching for global maximum. This is particularly important for a system that is partially shaded. To validate the performance of the proposed scheme, experimental studies have been conducted. The results have shown that the proposed approach is robust and possesses a fast tracking speed.

A Global Maximum Power Point Tracking Scheme Employing DIRECT Search Algorithm for Photovoltaic Systems

Photovoltaic (PV) is a fast growing segment among renewable energy (RE) systems, whose development is owed to depleting fossil fuel and climate-changing environmental pollution. PV power output capacity, however, is still low and the associated costs still high, so efforts continue to develop PV converter and its controller, aiming for higher power-extracting efficiency and cost effectiveness. Different algorithms have been proposed for Maximum Power Point Tracking (MPPT). Since the choice of right converter for different application has an important influence in the optimum performance of the photovoltaic system, this paper reviews the state-of-the-art in research works on non-isolated DC–DC buck, boost, buck–boost, Cuk and SEPIC converters and their characteristics, to find a solution best suiting an application with Maximum Power Point Tracking. Review shows that there is a limitation in the system's performance according to the type of converter used. In can be concluded that the best selection of DC–DC converter which is really suitable and applicable in the PV system is the buck–boost DC–DC converter since it is capable of achieving optimal operation regardless of the load value with negotiable performance efficiency and price issue.

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A current and future study on non-isolated DC–DC converters for photovoltaic applications

Theoretical assessment of the maximum power point tracking efficiency of photovoltaic facilities with different converter topologies

In order to characterize photovoltaic devices a procedure to measure I–V curves is required. The main methods used to perform this task are reviewed. It is shown that at least six distinct methods have been reported in the literature with many variations in implementation. A detailed comparison taking into account typical parameters for measuring systems is accomplished. This paper could be used as a reference for future work on photovoltaic module characterization.

Different methods to obtain the I–V curve of PV modules: A review

A high-flexibility DC load for fuel cell and solar arrays power sources based on DC–DC converters

In this paper, the usefulness of several topologies of DC-DC converters for measuring the characteristic curves of photovoltaic (PV) modules is theoretically analyzed. Eight topologies of DC-DC converters with step-down/step-up conversion relation (buck-boost single inductor, CSC (canonical switching cell), Cuk, SEPIC (single-ended primary inductance converter), zeta, flyback, boost-buck-cascaded, and buck-boost-cascaded converters) are compared and evaluated. This application is based on the property of these converters for emulating a resistor when operating in continuous conduction mode. Therefore, they are suitable to implement a system capable of measuring the I-V curve of PV modules. Other properties have been taken into account: input ripple, devices stress, size of magnetic components and input-output isolation. The study determines that SEPIC and Cuk converters are the most suitable for this application mainly due to the low input current ripple, allow input-output insulation and can be connected in parallel in order to measure PV modules o arrays with greater power. CSC topology is also suitable because it uses fewer components but of a larger size. Experimental results validate the comparative analysis.

Comparative analysis of buck-boost converters used to obtain I–V characteristic curves of photovoltaic modules

The achievement of I-V and P-V curves of photovoltaic modules gives the possibility of obtaining their characteristic parameters: the short-circuit current (I/sub sc/), the open-circuit voltage (V/sub oc/), the maximum power point (MPP) and the fill factor (FF). These values are significant for the design of a photovoltaic system. These curves depend on the global irradiance (G), the temperature (T) and the spectral distribution of the solar irradiation. In this paper, a new methodology to determine the afore mentioned curves by using DC-DC converters is proposed. This methodology allows carrying out the complete sweep of the voltage and the current (including V/sub oc/ and I/sub sc/). Regarding the traditional methods, this new one provides the following advantages: a) minimum power loss with regard to the systems that operate in lineal zone (active zone); this implies several advantages in size and cost; and b) this new method allows an automatic adaptation of the interpolation interval.

E. Duran

Papers

Theoretical assessment of the maximum power point tracking efficiency of photovoltaic facilities with different converter topologies

Different methods to obtain the I–V curve of PV modules: A review

A high-flexibility DC load for fuel cell and solar arrays power sources based on DC–DC converters

Comparative analysis of buck-boost converters used to obtain I–V characteristic curves of photovoltaic modules

A new approach to obtain I-V and P-V curves of photovoltaic modules by using DC-DC converters