Renewable energy is derived from natural processes that are replenished constantly. Included in the definition is electricity and heat generated from solar, wind, ocean, hydropower, biomass, geothermal resources, and bio-fuels and hydrogen derived from renewable resources. Each of these sources has unique characteristics which influence how and where they are used. This paper presents the model...

: Induction generators are gaining the popularity due to its simplicity and no synchronization problem. However the major drawback of this machine is its additional reactive burden on the system, where it is connected. In this paper an attempt is made to explore the performance of a grid connected induction generator (GCIG) due to weak grid conditions i.e. voltage and frequency fluctuations. It...

We prove some new estimates for the convergence of multigrid algorithms applied to nonsymmetric and indefinite elliptic boundary value problems. We provide results for the so-called 'symmetric' multigrid schemes. We show that for the variable 2^-cycle and the ^-cycle schemes, multigrid algorithms with any amount of smoothing on the finest grid converge at a rate that is independent of the numbe...

We provide a maximum norm analysis of an overlapping Schwarz method on nonmatching grids for second-order elliptic obstacle problem. We consider a domain which is the union of two overlapping subdomains where each subdomain has its own independently generated grid. The grid points on the subdomain boundaries need not match the grid points from the other subdomain. Under a discrete maximum princ...

The security issue has become an important concern of grid computing. To prevent the grid resources from being illegally visited, the strong mutual authentication is needed for user and server. In this paper, based on the elliptic curve cryptosystem, we would like to propose an efficient user authentication scheme for grid computing. The proposed scheme only requires a one-way hash function and...

The article discusses application of AC/DC/AC converter cooperating with an induction generator in small hydroelectric power plants. The induction generator works with power grid or a separated group of receivers, enabling to generate power even at low speeds of the turbine. The article provides also results of the investigation concerning the functioning of the generator coupled with AC/DC/AC ...

Solutions Efficient operation of the gas turbine imposes the demand for very high rotational speed of the generator 240,000 rpm. The permanent magnet machine has been chosen as the generator type since this technology is the most promising for high-speed machines: it offers high efficiency and very high power density at low volumes. A high-frequency power converter is required to enable bi-dire...

The infinite grid is the Cayley graph of Z × Z with the usual generators. In this paper, the Ihara zeta function for the infinite grid is computed using elliptic integrals and theta functions. The zeta function of the grid extends to an analytic, multivalued function which satisfies a functional equation. The set of singularities in its domain is finite. The grid zeta function is the first comp...

In order to meet increasing power demand, taking into account economical and environmental factors, wind energy conversion is gradually gaining interest as a suitable source of renewable energy. In this paper, The modeling of the Wind Energy Conversion System (WECS) with Matrix converter i s p r o p o s e d . The matrix converter, as a power electronic converter, is used to interface the induct...

Grid computing is becoming the natural way to aggregate and share large sets of heterogeneous resources. However, grid development and acceptance hinge on proving that grids reliably support real applications. A step in this direction is to combine several grid components into a demonstration and testing framework. This paper presents such an integration effort, in which three research prototyp...