A new design methodology for multipulse rectifiers with Delta auto-connected transformers and a retrofit application in Adjustable Speed Drives (ASDs)

Multipulse rectifiers can replace a conventional six pulse three-phase rectifier (diode bridge) providing a DC voltage with low ripple, low Total Harmonic Distortion of current (THDi) and a high Power Factor (PF). In this context is presented a multipulse rectifier with generalized Delta-differential autotransformer topology, which can provide any level of DC output voltage for any level of three-phase AC input voltage. This paper presents all the possible configurations for Delta topology in order to choose, through graphics, one configuration that presents reduced weight and volume. The average voltage on the DC bus must be compatible with the DC voltage in the six pulse rectifier used in commercial ASDs. Therefore, it is possible to apply the retrofit technique to replace the conventional bridge rectifier by the proposed multipulse rectifier. Based on mathematic models and simulation results, an 18-pulse rectifier with Delta topology, 220 V of line voltage, 315 V of DC output, and rating 2.5 kW of power was designed, implemented and applied for three different commercial ASDs. Experimental results as voltage and current waveforms and results about PF and THDi will be presented. © 2012 IEEE.

Epidemiologia da mancha de phaeosphaeria e da cercosporiose em milho

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Efeito da ausência de passividade no sistema coroa-implante-parafuso de retenção por meio do MEF-2D

Pós-graduação em Odontologia - FOA

Análise da influência dos sistemas de retenção para overdentures implanto-retidas na distribuição interna das tensões, através do método de elementos finitos

Pós-graduação em Odontologia - FOA

Aspectos da produtividade do feijoeiro correlacionados com atributos do solo sob sistemas de manejo de elevado nível tecnológico

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Sistemas de filtragem aplicados em processos fabris automotivos

The present work resulted from a study about coolant filtration systems in industries with metalworking process in large scale. The filtration and element filter world markets move billions of Reais per year and have a promissory future considering that with the global requirements of sustainable economic development, many companies invest in new filtering technology. Either known as coolant or cutting fluid, it is used to lubricate e cool parts during machining and is necessary due to the high volume demanded in the several machining operations and to the high cost of the product. Therefore, there is the need for recycling the product after its use. The work shows the technology and fundamentals of filtration as well as different filtering elements, filtration systems and scale contamination used in the industry. Also, there is a differentiation between filtration of the surface type (cake) and depth filtration and shows the basic theory of filtration by mathematic models in different operational conditions. Ultimately, project criteria for a coolant filtration system selection is shown followed by technical-operational details of a real vacuum filtration system and a case study aiming the operational cost reduction of the system

Aplicação da equação de Fokker-Planck no estudo de canais iônicos

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Análise dos indicadores biométricos e nutricionais da cultura da alface (Lactuca sativa L.) irrigada com água tratada magneticamente utilizando modelagem fuzzy

Pós-graduação em Agronomia (Irrigação e Drenagem) - FCA

Práticas algébricas no contexto da modelagem compreendida como proposta pedagógica

Pós-graduação em Educação Matemática - IGCE