Optimal PID controller tunning for a boost DC-DC converter using grey wolf optimization algorithm

[ES] Los convertidores de potencia son dispositivos electrónicos que permiten regular niveles de voltaje y, por lo tanto, sus aplicaciones en el ámbito de las energías renovables son importantes. Una de las principales problemáticas de los controladores Proporcional-Integral-Derivativo (PID) es que deben ser sintonizados correctamente para reducir el error entre la señal de salida y la señal de referencia. En este trabajo se presenta la sintonización de un controlador PID para un convertidor CC-CC tipo recortador-elevador empleando un algoritmo de Grey Wolf Optimizer (GWO). El sistema se simula mediante MATLAB/Simulink. Los resultados de la sintonización del controlador PID con el GWO es comparado contra un método clásico de sintonización midiendo el error cuadrático medio y tiempos de respuesta. El desempeño del controlador PID sintonizado a través del GWO mostró tener mejor tiempo de respuesta y menor raíz de error cuadrático medio (RMSE, root mean square error) que el controlador sintonizado por el método clásico.[EN] Power converters are electronic devices that regulate voltage levels and therefore their applications in the field of renewable energies are important. One of the main problems of PID controllers is that they must be tuned correctly to reduce the error between output and reference signal. This work presents the tuning of a PID controller for a DC-DC converter using a GWO Grey Wolf Optimizer (GWO) algorithm. The system is simulated through MATLAB/Simulink. The results of the TUNING of the PID controller with the GWO is compared against a classic tuning method by measuring the mean quadratic error and response times. The performance of the PID controller tuned through the GWO showed better response time and lower root mean square error (RMSE) than the controller tuned by the classic method.Aguila-Leon, J.; Chiñas-Palacios, C.; Vargas-Salgado, C.; Sotelo, J.; Hurtado-Perez, E.; García, EXM. (2020). Sintonización óptima de un controlador PID para un convertidor recortador-elevador CC-CC utilizando un algoritmo de optimización de manada de lobo gris. e-Gnosis. 18:1-8. http://hdl.handle.net/10251/161037S181

Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum

Rarity of monodominance in hyperdiverse Amazonian forests.

Tropical forests are known for their high diversity. Yet, forest patches do occur in the tropics where a single tree species is dominant. Such "monodominant" forests are known from all of the main tropical regions. For Amazonia, we sampled the occurrence of monodominance in a massive, basin-wide database of forest-inventory plots from the Amazon Tree Diversity Network (ATDN). Utilizing a simple defining metric of at least half of the trees ≥ 10 cm diameter belonging to one species, we found only a few occurrences of monodominance in Amazonia, and the phenomenon was not significantly linked to previously hypothesized life history traits such wood density, seed mass, ectomycorrhizal associations, or Rhizobium nodulation. In our analysis, coppicing (the formation of sprouts at the base of the tree or on roots) was the only trait significantly linked to monodominance. While at specific locales coppicing or ectomycorrhizal associations may confer a considerable advantage to a tree species and lead to its monodominance, very few species have these traits. Mining of the ATDN dataset suggests that monodominance is quite rare in Amazonia, and may be linked primarily to edaphic factors

Measurement of the cosmic ray spectrum above 4×10184{\times}10^{18} eV using inclined events detected with the Pierre Auger Observatory

A measurement of the cosmic-ray spectrum for energies exceeding $4{\times}10^{18}$ eV is presented, which is based on the analysis of showers with zenith angles greater than $60^{\circ}$ detected with the Pierre Auger Observatory between 1 January 2004 and 31 December 2013. The measured spectrum confirms a flux suppression at the highest energies. Above $5.3{\times}10^{18}$ eV, the "ankle", the flux can be described by a power law $E^{-\gamma}$ with index $\gamma=2.70 \pm 0.02 \,\text{(stat)} \pm 0.1\,\text{(sys)}$ followed by a smooth suppression region. For the energy ($E_\text{s}$) at which the spectral flux has fallen to one-half of its extrapolated value in the absence of suppression, we find $E_\text{s}=(5.12\pm0.25\,\text{(stat)}^{+1.0}_{-1.2}\,\text{(sys)}){\times}10^{19}$ eV.Comment: Replaced with published version. Added journal reference and DO

Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory

The Auger Engineering Radio Array (AERA) is part of the Pierre Auger Observatory and is used to detect the radio emission of cosmic-ray air showers. These observations are compared to the data of the surface detector stations of the Observatory, which provide well-calibrated information on the cosmic-ray energies and arrival directions. The response of the radio stations in the 30 to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of the incoming electric field. For the latter, the energy deposit per area is determined from the radio pulses at each observer position and is interpolated using a two-dimensional function that takes into account signal asymmetries due to interference between the geomagnetic and charge-excess emission components. The spatial integral over the signal distribution gives a direct measurement of the energy transferred from the primary cosmic ray into radio emission in the AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air shower arriving perpendicularly to the geomagnetic field. This radiation energy -- corrected for geometrical effects -- is used as a cosmic-ray energy estimator. Performing an absolute energy calibration against the surface-detector information, we observe that this radio-energy estimator scales quadratically with the cosmic-ray energy as expected for coherent emission. We find an energy resolution of the radio reconstruction of 22% for the data set and 17% for a high-quality subset containing only events with at least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO