This paper presents a new circuit topology of a phase-locked loop that can be used for synchronising a singlephase wind turbine generator (WTG) with the low voltage utility grid. The circuit is based on the time-delay digital tanlock loop (TDTL) architecture and was modelled and simulated using Simulink/MATLAB. The results presented demonstrate the ability of the circuit not only to synchronise...

In this paper, we discuss the vertex space domain decomposition method (VSDDM) for solving the algebraic system of equations which arise from the discretization of symmetric and positive de nite elliptic boundary value problems via nite element methods on general unstructured meshes. Our theory does not require that the subdomains are shape regular and coarse grid is nested to the ne grid. Furt...

We construct monotone numerical schemes for a class of nonlinear PDE for elliptic and initial value problems for parabolic problems. The elliptic part is closely connected to a linear elliptic operator, which we discretize by monotone schemes, and solve the nonlinear problem by iteration. We assume that the elliptic differential operator is in the divergence form, with measurable coefficients s...

With the explosion of networks and the huge amount of data transmitted along, securing data content is becoming more and more important. Data encryption is widely used to ensure security in open networks such as the Internet. With the fast development of cryptography research and computer technology, the capabilities of cryptosystems such as of RSA and Diffie-Hellman are inadequate due to the r...

We describe the R.eeursilJe Subdivision (RS) grid adaption method-an efficient and effective adaptive grid scheme for two-dimensional, elliptic partial differential equations (PDEs). The RS method generates a new grid by recursively subdividing a rectangular domain. We use a heuristic approach which attempts to equidistribute a given density function over the domain. The resulting grid is used ...

We describe and analyze certain V-cycle multigrid algorithms with forms deened by numerical quadrature applied to the approximation of symmetric second order elliptic boundary value problems. This approach can be used for the eecient solution of nite element systems resulting from numerical quadrature as well as systems arising from nite diierence discretizations. The results are based on a reg...

Multiscale methods can in many cases be viewed as special types of domain decomposition preconditioners. The localisation approximations introduced within the multiscale framework are dependent upon both the heterogeneity of the reservoir and the structure of the computational grid. While previous works on multiscale control volume methods have focused on heterogeneous elliptic problems on regu...

Considering a grid cell with a single central point the solution of the discretized Laplace equation may be conceived as a weighted average of points on the cell boundary. Our grid control method is based on a local perturbation of the numerical solution to the Laplace equation by specifying line-wise central target points relative to the orientation of and the distance from the cell’s bounding...

In this paper we propose a cascadic algorithm for nonlinearly perturbed elliptic Dirichlet problems. The nonlinear equations arising from certain nite element discretizations are solved by Newton's method. The cascadic algorithm starts on a comparatively coarse grid where the number of unknowns is small enough to obtain an approximate solution within suu-ciently high precision without substanti...

MODELING AND CONTROL OF A DOUBLY-FED INDUCTION GENERATOR FOR WIND TURBINE-GENERATOR SYSTEMS Xin Jing, M.S.E.E Marquette University, 2012 Wind energy plays an increasingly important role in the world because it is friendly to the environment. During the last decades, the concept of a variable-speed wind turbine (WT) has been receiving increasing attention due to the fact that it is more controll...