Papers by Keyword: Grid Distortion

Abstract: In this paper, the performance of three different phase locked loop (PLL) algorithms is experimentally evaluated in a grid connected photovoltaic inverter. Robust PLL is a key requirement for ensuring system compatibility with existing grid codes. The double second order generalized integrator (DSOGI) and the decoupled double synchronous reference frame (DDSRF) PLL are compared against the conventional synchronous reference frame (SRF) PLL under grid disturbances. All synchronization algorithms are initially simulated in Matlab and subsequently transformed in discrete time for implementation in the digital controller. Grid distortions, such as phase voltage sags, frequency fluctuations and voltage harmonic distortion are emulated via a controllable three phase generator.

Abstract: The modeling of extrusion of various Al alloys and their particulate metal matrix composites was conducted by DEFORM™ finite element analysis to develop strain rate, stress and temperature distributions through the peak load and into steady state following development of the hot zone. The hot strength and ductility, constitutive constants and microstructural evolution had been determined by hot torsion. The relative load-stroke curves were determined for several billet temperatures, extrusion ratios and ram speeds. The grid distortion and distributions of important internal parameters define the evolution of microstructure. The extrudability was estimated on the basis of load, ductility and the potential for modeling the microstructure developed.