A new defected ground structure (DGS) with tunable working frequency and reconfigurable bandwidth is proposed in this paper. The prototype combines the conventional DGS with T-shaped patch featuring narrow bandwidth and two such units located symmetrically featuring wide bandwidth. The proposed structure is designed, simulated and measured. By embedding two reversely-set PIN diodes and four var...

A compact (0.16 g × 0.08 g) and wide stopband lowpass filter design using open complementary split ring resonator (OCSRR) and defected ground structure (DGS) is presented in this paper. Low pass filter is constructed using two cascaded stages of OCSRR. Since the rejection bandwidth of the OCSRR is narrow, tapered dumbbell shaped DGS section is placed under the OCSRR to enhance the bandwidth. Th...

It is proposed that the application of defected ground structures (DGS) and electromagnetic bandgap (EBG) reduce the phase velocity, increase effective permittivity of microstrips and reduce the effective the wavelength which eventually lead to the reduction of overall length of Wilkinson power dividers. Furthermore, the adjacent strip lines may approach each other, which cause coupling problem...

In this paper, the concept of secondary control is applied for voltage unbalance compensation in an islanded microgrid. The aim of the proposed control approach is to enhance the voltage quality at the point of common coupling (PCC). Unbalance compensation is achieved by proper control of distributed generators (DGs). The DGs control structure mainly consists of active and reactive power contro...

The distribution loads, output of distributed generations (DGs) and dynamic power price present obvious time-sequence property, the typical property is studied in this paper. The model of microgrid (including adjustable load, DGs, storage and dynamic power price) is studied. A multi-timescale collaborative optimization model is built towards microgrid; main measures in different timescale optim...

This paper highlights on the active power sharing of manifold distributed generators (DGs) in a microgrid. The microgrid can be functioned in two modes 1) a grid-connected mode and 2) An autonomous mode. In the course of islanded operation, one DG unit should share its output power with other DG units in exact accordance with the load. Unit output power control (UPC) is introduced to control th...

Multigrid methods have proven to be eecient methods for solving partial diier-ential equations (especially those of elliptic type). There is also growing experience with multigrid solvers for uids problems, e.g., the Stokes and Navier-Stokes equations (using both nite element and nite diierence discretizations). It is also well known that at the heart of any multigrid method is the smoother. In...

ABSTRACT: Installation of many distributed generations (DGs) could be detrimental to the power quality of utility grids. Micro grids facilitate effortless installation of DGs in conventional power systems. In recent years, DC microgrid have gained popularity because DC output sources such as photovoltaic systems, fuel cells, and batteries can be interconnected without ac/dc conversion, which co...

This paper describes an inverter-interfaced distributed generation system that is interconnected with the electric power system. This system has two main goals: to serve customers with reliable electric power and to improve power quality. This system is interfaced through inverters because they are effective to control output voltage and current. Because DGs are interconnected with the electric...

Although OWL 2 is widely used to describe complex objects such as chemical molecules, it cannot represent ‘structural’ features of chemical entities (e.g., having a ring). A combination of rules and description graphs (DGs) has been proposed as a possible solution, but it still exhibits several drawbacks. In this paper we present a radically different approach that we call Description Graph Log...