Fig. 3. Conventional BHB inverter and proposed two-stage inverter ( (a) conventional BHB topology, (b) proposed two-stage topology,(c) conventional asynchronous PWM modulation method, (d) proposed time-sharing synchronous PWM modulation method, (e)conventional separate dual loop controller, (f) proposed hybrid current controller).A High Efficiency Two-stage Inverter forPhotovoltaic Grid-connected Generation SystemsJiang Liu,Shanmei Cheng ,and Anwen ShenHuazhong University of Science and Technology, Wuhan, China Abstract Conventional boost-full-bridge and boost-hybrid-bridge two-stage inverters are widely applied in order to adapt to the wide dcinput voltage range of photovoltaic arrays. However, the efficiency of the conventional topology is not fully optimized becauseadditional switching losses are generated in the voltage conversion so that the input voltage rises and then falls. Moreover, theelectrolytic capacitors in a dc-link lead to a larger volume combined with increases in both weight and cost. This paper proposesa higher efficiency inverter with time-sharing synchronous modulation. The energy transmission paths, wheeling branches andswitching losses for the high-frequency switches are optimized so that the overall efficiency is greatly improved. In this paper, acontrastive analysis of the component losses for the conventional and proposed inverter topologies is carried out in MATLAB.Finally, the high-efficiency under different switching frequencies and different input voltages is verified by a 3 kW prototype.Keywords: Overall efficiency, Photovoltaic array, Time-sharing synchronous modulation, Two-stage inverterLINK FULL TEXT: http://jpe.or.kr/archives/view_articles.asp?seq=1351 AbstractA Study on Control and Grid Synchronization for a Three-phase GridconnectedInverter in Distributed Generation SystemsLai Ngoc Bao(Supervisor Kim, Kyeong-Hwa)Dept. of Electrical and Information EngineeringThe Graduate SchoolSeoul National University of Science and TechnologyThis thesis presents an improved current control strategy for a three-phase grid-connectedinverter under distorted grid conditions. The primary challenge associated with the gridconnectedinverter in distributed generation (DG) systems is to maintain the harmoniccontents in output current below the specified values even when the grid is subject touncertain disturbances such as harmonic distortion. To address such a challenge, animproved current control scheme is proposed for a grid-connected inverter, in which thefundamental and harmonic currents are independently controlled by a PI decouplingcontroller and a predictive basis controller, respectively. The controller design approach isbased on the model decomposition principle, where the measured inverter currents andgrid voltages are split into the fundamental and harmonic currents using moving averagefilters (MAFs). Furthermore, to detect the grid angular displacement and frequency withbetter accuracy even in the presence of the grid voltage disturbances, the MAF is alsointroduced to construct an enhanced phase-lock loop (PLL) scheme. Theoretical analysesas well as comparative simulations results prove that the proposed control schemeadequately compensates the abnormalities caused by the grid voltage disturbances withfast transient response. To validate the feasibility of the proposed control scheme, theiientirecontrol algorithm is implemented on a 2 kVA three-phase grid-connected invertersystem using 32-bit floating-point DSP TMS320F28335. As a result, the proposedscheme is an attractive way to control a grid-connected inverter under adverse gridconditions.LINKhttp://www.mediafire.com/file/6bwc5529rb2b24u/grid.pdf REFORMA DA PARTE ATIVA DE TRANSFORMADORES DE POTENCIA-DEIWYD MIRANDA SOARESWELLEY FERNANDES VIEIRA-PONTIFICIA UNIVERSIDADE CATOLICA DE GOIASDEPARTAMENTO DE COMPUTACAOGRADUACAO EM ENGENHARIA ELETRICA Trabalho de Conclusao de Curso apresentado por Deiwyd Miranda Soares e Welley Fernandes Vieira, a PONTIFICIA UNIVERSIDADE CATOLICA DE GOIAS - PUC-GO, como requisito parcial para obtencao do grau de titulo de Bacharel