A simple control strategy to increase the total efficiency of multi-converter systems

This paper presents a simple control strategy that is employed together with an optimization methodology to achieve optimal efficiency in systems composed by multiple parallel converters. An external loop is responsible for regulating the dc bus voltage and providing a current reference that is weighted in function of the power processed by the system, and then generating optimal current references for each converter. This enable the system to operate with optimal efficiency for all its load range. Experimental results demonstrate th e superior performance of the proposed strategy, improving the efficiency of the system in almost 10 % under light load operation in comparison with the conventional strategy of equal power sharing among convertersPeer ReviewedPostprint (author’s final draft

Factors for Measuring Photovoltaic Adoption from the Perspective of Operators

The diffusion of photovoltaic distributed generation is relevant for addressing the political, economic, and environmental issues in the electricity sector. However, the proliferation of distributed generation brings new administrative and operational challenges for the sustainability of electric power utilities. Electricity distributors operate in economies of scale, and the high photovoltaic penetration means that these companies have economic and financial impacts, in addition to influencing the migration of other consumers. Thus, this paper aims to systematically identify and evaluate critical factors and indicators that may influence electricity distributors in predicting their consumers’ adoption of photovoltaic technology, which were subjected to the analysis of 20 industry experts. Results show that the cost of electricity, generation capacity, and cost of the photovoltaic systems are the most relevant indicators, and it is possible to measure a considerable part of them using the internal data of the electricity distributors. The study contributes to the understanding of the critical factors for the forecast of the adoption of consumers to distributed photovoltaic generation, to assist the distribution network operators in the decision making, and the distribution sustainability. Also, it establishes the theoretical, political, and practical implications for the Brazilian scenario and developing countries.This research was funded by the Conselho Nacional de Desenvolvimento Científico e Tecnológico [grant numbers 311926/2017-7, 142448/2018-4, 310594/2017-0 and 465640/2014-1], Coordenação de Aperfeiçoamento de Pessoal de Nível Superior [grant numbers 1773252/2018, 1845395/2019 and 23038.000776/2017–54] and Fundação de Amparo à Pesquisa do Estado do Rio Grande do Sul [grant number 17/2551-0000517-1].info:eu-repo/semantics/publishedVersio

A new method to improve the total efficiency of parallel converters

This paper proposes a new methodology for efficiency optimization in systems composed by parallel converters. The proposed methodology takes into account the individual efficiency curves and determines the optimum operating point for each converter such that the maximum efficiency of the arrangement is achieved for the entire load range. Due to the nonlinearity of the problem and the complexity of the solution hyperplane, the optimization process is divided into stages of global optimization, local optimization and ambiguity resolutio n. This latter verifies the existence of multiple global minima and selects the most appropriate in function of previous power distributions. Case studies demonstrates the validity of the proposed methodology for different systems configurations.Peer Reviewe

Induction tutor briefing programme

Added t.p. in Welsh: Rhaglen briffio i diwtoriaid sefydlu. Two CD-ROMs in pockets attached to ring binder. In ring binder. Parallel text in English Welsh printed tete becheAvailable from British Library Document Supply Centre- DSC:Vm03/50419 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

A simple control strategy to increase the total efficiency of multi-converter systems

This paper presents a simple control strategy that is employed together with an optimization methodology to achieve optimal efficiency in systems composed by multiple parallel converters. An external loop is responsible for regulating the dc bus voltage and providing a current reference that is weighted in function of the power processed by the system, and then generating optimal current references for each converter. This enable the system to operate with optimal efficiency for all its load range. Experimental results demonstrate th e superior performance of the proposed strategy, improving the efficiency of the system in almost 10 % under light load operation in comparison with the conventional strategy of equal power sharing among convertersPeer Reviewe

LCL Filter Parameter and Hardware Design Methodology for Minimum Volume Considering Capacitor Lifetimes

A design methodology for minimum volume of LCL filters applied to grid connected converters is proposed. It combines the determination of filter parameter values (inductances and capacitances) to hardware design (component technology and inductor construction). Using the proposed strategy, different combinations of L-C-L that meet standard restrictions are determined. The influence of the harmonic content that results from filter design is considered in order to estimate component losses, and filter and bus capacitor lifetimes. Results are presented for filters that lead to the smallest volume, highest capacitor lifetime, or a compromise between both. A case study with three different magnetic material technologies and two types of capacitors is done. The design methodology is experimentally validated for a 1 kW converter. Step-by-step procedures for the determination of filter parameters and inductor hardware design are provided

<i>LCL</i> Filter Parameter and Hardware Design Methodology for Minimum Volume Considering Capacitor Lifetimes

A design methodology for minimum volume of LCL filters applied to grid connected converters is proposed. It combines the determination of filter parameter values (inductances and capacitances) to hardware design (component technology and inductor construction). Using the proposed strategy, different combinations of L-C-L that meet standard restrictions are determined. The influence of the harmonic content that results from filter design is considered in order to estimate component losses, and filter and bus capacitor lifetimes. Results are presented for filters that lead to the smallest volume, highest capacitor lifetime, or a compromise between both. A case study with three different magnetic material technologies and two types of capacitors is done. The design methodology is experimentally validated for a 1 kW converter. Step-by-step procedures for the determination of filter parameters and inductor hardware design are provided