Estatística das aplicações de métodos multicritério nas áreas da engenharia de produção

Currently, the decision analysis in production processes involves a level of detail, in which the problem is subdivided to analyze it in terms of different and conflicting points of view. The multi-criteria analysis has been an important tool that helps assertive decisions related to the production process. This process of analysis has been incorporated into various areas of production engineering, by applying multi-criteria methods in solving the problems of the productive sector. This research presents a statistical study on the use of multi-criteria methods in the areas of Production Engineering, where 935 papers were filtered from 20.663 publications in scientific journals, considering a level of the publication quality based on the impact factor published by the JCR between 2010 and 2015. In this work, the descriptive statistics is used to represent some information and statistical analysis on the volume of applications methods. Relevant results were found with respect to the "amount of advanced methods that are being applied and in which areas related to Production Engineering." This information may provide support to researchers when preparing a multi-criteria application, whereupon it will be possible to check in which issues and how often the other authors have used multi-criteria methods.

Projeto, implementação e análise de um conversor CC-CC de alto ganho e alto rendimento para aplicações fotovoltaicas

In recent years the photovoltaic generation has had greater insertion in the energy mix of the most developed countries, growing at annual rates of over 30%. The pressure for the reduction of pollutant emissions, diversification of the energy mix and the drop in prices are the main factors driving this growth. Grid tied systems plays an important role in alleviating the energy crisis and diversification of energy sources. Among the grid tied systems, building integrated photovoltaic systems suffers from partial shading of the photovoltaic modules and consequently the energy yield is reduced. In such cases, classical forms of modules connection do not produce good results and new techniques have been developed to increase the amount of energy produced by a set of modules. In the parallel connection technique of photovoltaic modules, a high voltage gain DC-DC converter is required, which is relatively complex to build with high efficiency. The current-fed isolated converters explored in this work have some desirable characteristics for this type of application, such as: low input current ripple and input voltage ripple, high voltage gain, galvanic isolation, feature high power capacity and it achieve soft switching in a wide operating range. This study presents contributions to the study of a high gain and high efficiency DC-DC converter for use in a parallel system of photovoltaic generation, being possible the use in a microinverter or with central inverter. The main contributions of this work are: analysis of the active clamping circuit operation proposing that the clamp capacitor connection must be done on the negative node of the power supply to reduce the input current ripple and thus reduce the filter requirements; use of a voltage doubler in the output rectifier to reduce the number of components and to extend the gain of the converter; detailed study of the converter components in order to raise the efficiency; obtaining the AC equivalent model and control system design. As a result, a DC-DC converter with high gain, high efficiency and without electrolytic capacitors in the power stage was developed. In the final part of this work the DC-DC converter operation connected to an inverter is presented. Besides, the DC bus controller is designed and are implemented two maximum power point tracking algorithms. Experimental results of full system operation connected to an emulator and subsequently to a real photovoltaic module are also given.