Showing papers by "Juan Manuel Campos Carrasco published in 2014"

Adaptive Vectorial Filter for Grid Synchronization of Power Converters Under Unbalanced and/or Distorted Grid Conditions

Abstract: This paper presents a new synchronization scheme for detecting multiple positive-/negative-sequence frequency harmonics in three-phase systems for grid-connected power converters. The proposed technique is called MAVF-FLL because it is based on the use of multiple adaptive vectorial filters (AVFs) working together inside a harmonic decoupling network, resting on a frequency-locked loop (FLL) which makes the system frequency adaptive. The method uses the vectorial properties of the three-phase input signal in the αβ reference frame in order to obtain the different harmonic components. The MAVF-FLL is fully designed and analyzed, addressing the tuning procedure in order to obtain the desired and predefined performance. The proposed algorithm is evaluated by both simulation and experimental results, demonstrating its ability to perform as required for detecting different harmonic components under a highly unbalanced and distorted input grid voltage.

Siberian elm responses to different culture conditions under short rotation forestry in Mediterranean areas

Abstract: This work explores the possibilities of biomass production, for energy purposes, of Siberian elm in Mediterranean areas, including marginal lands with poor soil and low water availability. To achieve this, the influence of soil type, planting density, and water availability on biomass production were analyzed after the first 3 years of the growing cycle in 2 different locations. Moreover, a method to estimate biomass production as a function of some morphological parameters of the trees, as well as the use of leaf water potential as a good indicator of trees' water status, are discussed. The analysis of parameters having an influence on elm growth showed that soil type is the most important factor to obtain a good yield. In soils with enough nutrients and higher water-holding capacity, biomass productions in the range 13-14 Mg DM ha-1 were achieved even under rainfed conditions. In irrigated plots, Siberian elm production was more than double the production of biomass under rainfed conditions; however, significant differences were not found between the 2 different irrigation doses under study. Biomass yield was greater for the highest planting density (6666 plants ha-1). Leaf water potential has been shown to be a useful tool for finding out plant water status. Tree growth showed a direct relationship to midmorning leaf water potential, and it was equal to 0 for leaf water potentials lower than -1.83 MPa; this value indicates a great resistance to drought by the species.