A detailed model of wind power station, including Double Fed Induction Generator, DFIG is presented in this paper. Two control mechanisms are included in the model. The inner control system uses stator flux oriented control for the rotor side converter and grid voltage vector control for the grid side converter. The outer control system is used for wind turbine pitch angle. PSCAD/EMTDC is us...

a detailed model of wind power station, including double fed induction generator, dfig is presented in this paper. two control mechanisms are included in the model. the inner control system uses stator flux oriented control for the rotor side converter and grid voltage vector control for the grid side converter. the outer control system is used for wind turbine pitch angle. pscad/emtdc is used ...

the objectives of this study were (a) to examine the writing performance of l2 learners on the level-specific tasks based on common european framework of reference (cefr) and (b) to investigate whether there was any difference between the students' self-assessed level of writing and the writing level reported by the raters. this study was conducted with 138 iranian students at ba and ma levels ...

this paper proposes a flexible power electronic transformer (fpet) for the application in the micro-grids. the low frequency transformer is usually used at the point of common coupling (pcc) to connect the low voltage grid and utility network to each other. the conventional 50hz transformer results in enhanced low voltage-grid power management system during grid-connected operation. in this pap...

The single-phase transformerless grid-connected photovoltaic (PV) systems, mainly the low-power single-phase systems, require high efficiency, small size, lightweight, and low-cost grid-connected inverters. However, problems such as leakage current, the DC current injection and safety issues are incorporated with transformerless grid-connected PV inverters. Besides, the new standards such as Lo...

Making an initial tetrahedral grid for complex geometry can be a tedious and time consuming task. This paper describes a novel procedure for generation of starting tetrahedral cells using hexahedral block topology. Hexahedral blocks are arranged around an aerodynamic body to form a flow domain. Each of the hexahedral blocks is then decomposed into six tetrahedral elements to obtain an initial t...