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For some industrial applications, an accurate estimation of a light source position is needed. That is the case for a heliostat, a device that projects sunlight onto a focus hundreds of meters away from its aiming point. In this paper, we present a novel sensor design for generating an alignment error signal. Included is a detailed study of its response, which shows that certain geometrical design parameters are necessary to achieve desired accuracy. This sensor has been implemented using microelectromechanical system techniques to achieve a robust structure at low cost and it has been successfully applied to sun-tracking systems. Experimental results obtained in field tests are included. Index Terms--Microelectromechanical system (MEMS), microsensors, power generation, solar energy, sun-tracking control.

Measuring open-circuit voltage (Voc) versus light intensity (Suns) in solar cells permits the access of cell performance without the series resistance effect. This article shows the implementation of a Suns–Voc measurement system that consists of an off-the-shelf photograph flash lamp, a digital oscilloscope, and a specifically designed photodetector board with three silicon photodiodes that covers a light intensity measurement range from 10−5 to 102 suns. The whole system is controlled via universal serial bus (USB) ports from a personal computer allowing the measurement of cell characteristics (pseudo-dark and pseudo-light current density–voltage curves, as well as the pseudo fill factor and pseudo efficiency) automatically in a very short time. [ABSTRACT FROM AUTHOR]

In this work, we report on the fabrication and characterization of n-type c-Si solar cells whose p+ emitters are based on laser processed aluminum oxide/silicon carbide (Al2O3/SiCx) films. The p+ emitter is defined at the rear side of the cell and it consists of point-like laser-diffused p+ regions with a surface charge induced emitter in between based on the high negative charge located at the Al2O3/c-Si interface. These emitters are fabricated at low temperature (< 400 °C) and could be directly compared to silicon heterojunction emitters with the advantage that the deposition of a Transparent Conductive Oxide (TCO) film can be avoided, since they are based on p+/n c-Si homojunctions. Additionally, the involved films are transparent to the IR photons (◻ >1000 nm) that reach the rear surface of the cell resulting in an excellent back reflector. We fabricated solar cells with distance between p+ regions or pitch ranging from 200 to 350 μm with a front surface based on silicon heterojunction technology. Best efficiency (18.1 %) is obtained for a pitch of 250 μm as a consequence of the trade-off between Voc and FF values. [ABSTRACT FROM AUTHOR]

This paper describes the design, fabrication, simulation, and experimental results of an improved miniaturized two-axis sun sensor for industrial applications, created by adapting a technology used previously in satellite applications. The sensor for each axis is composed of six photodiodes integrated in a crystalline-silicon substrate and a layer of cover glass, which is used to protect the silicon and to hold the windows. The high precision is obtained by the subdivision of the field of view, which is \pm 60^\circ, with a resolution of 0.1^\circ. Each region is controlled by an independent high-precision solar sensor. The sensor can be used for sun-tracking applications in a photovoltaic system, heliostat concentration plants, and lighting applications. [ABSTRACT FROM PUBLISHER]

Presents information on a study which described a novel concept of photovoltaic mini array assembly based on a flip-chip Multichip Module technology. Insight on substrate wafer fabrication; Methodology of the study; Results and discussion on the study; Conclusions.

The aim of this work is to study the surface passivation of aluminum oxide/amorphous silicon carbide (Al2O3/a-SiCx) stacks on both p-type and n-type crystalline silicon (c-Si) substrates as well as the optical characterization of these stacks. Al2O3 films of different thicknesses were deposited by thermal atomic layer deposition (ALD) at 200 °C and were complemented with a layer of a-SiCx deposited by plasma-enhanced chemical vapor deposition (PECVD) to form anti-reflection coating (ARC) stacks with a total thickness of 75 nm. A comparative study has been carried out on polished and randomly textured wafers. We have experimentally determined the optimum thickness of the stack for photovoltaic applications by minimizing the reflection losses over a wide wavelength range (300-1200 nm) without compromising the outstanding passivation properties of the Al2O3 films. The upper limit of the surface recombination velocity (S eff,max) was evaluated at a carrier injection level corresponding to 1-sun illumination, which led to values below 10 cm/s. Reflectance values below 2% were measured on textured samples over the wavelength range of 450-1000 nm.