The existence of failures in photovoltaic systems causes energy losses, security problems, and damage to its components. Therefore, it is necessary to develop monitoring systems to improve their productivity, reliability, efficiency, and safety. This work proposes a method for detecting and indicating short-circuit failure and partial shading present in grid-connected photovoltaic modules. The novelty of this proposal is the processing of voltage and current signals generated (ripple signals) by the electrical interaction between the photovoltaic string, the photovoltaic inverter, the condition of the modules, temperature, and irradiance. The magnitudes of specific frequency components are obtained from these electrical signals using DFT, and Cartesian coordinates are formed in a three-dimensional plane. Coordinates belonging to each of the string conditions are mostly located in different octants from this plane. This distribution allows an assessment of the modules state. Certain scattering is solved with a K-nearest neighbors algorithm. The effectiveness of the methodology was experimentally validated in two PVG with different characteristics. In each test case, the method was adaptable to the real conditions of the photovoltaic system. The results show effectiveness greater than 90% in the first evaluation levels, there is a slightly lower detection certainty in anomalous conditions with coordinates that are very close to each other. However, the system has 100% certainty detecting the presence of an abnormal condition. The method allows adaptation to different conditions, and takes advantage of the electrical signals derived from the actual performance of the used devices.

The effect of annealing atmosphere on indium-gallium-zinc-oxide (IGZO) thin film transistors (TFTs) fabricated on a deformable softening polymer substrate is presented in this work. Different annealing conditions—ambient, oxygen, vacuum and forming gas—are employed in the fabrication of IGZO TFTs and the changes in electrical characteristics are examined. Fabricated devices exhibit shape memory properties due to thiol-ene/acrylate substrates allowing the softening of bioelectronics to demonstrate modulus changes in aqueous conditions at body temperature. Gold (Au) is used as the contact metal for the gate, drain and source for its good adherence and malleability required for this polymer. It is found that annealing treatments at 250 °C can improve the field effect mobility of the TFTs from 10-2 up to 30 cm2/V-s. These improvements are attributed to the reduction of oxygen concentration in the active film of the TFTs. The contact resistance is also reduced by the annealing treatments from approximately 1 MΩ to 20 kΩ, indicating improvement in physical contact at the IGZO-Au interface. In addition, the contributions of contact resistance and channel resistance to other electrical parameters are analyzed. This study will pave the way for the development and optimization of high-performance bioelectronic devices on smart polymers.

In the present work, a methodology that allows optimizing the permanent magnet synchronous generator (PMSG) design by establishing limit values of magnet radius and length that maximize efficiency for the nominal parameters of the wind turbine is developed. The methodology consists of two fundamental models. One model calculates the generator parameters from the radius of the magnet base, and the other optimization model determines two optimum generators according to the optimization criteria of maximum efficiency and maximum efficiency with minimum weight starting from the axial length and the radius of the magnet base. For the optimization, the numerical method of the golden section was used. The model was validated from a 10 kW PMSG and the results of two optimum generators are presented according to the optimization criteria. In addition, when the obtained results are compared with the reference electric generator, an increase in efficiency of 1.15% and 0.81% and a reduction in weight of 30.79% and 39.15% of the optimized generators are obtained for maximum efficiency and minimum weight, respectively. Intermediate options between the maximum efficiency generator and the minimum weight generator allows for the selection of the optimum dimensioning for the electric generator as a function of the parameters from the wind turbine design.