114 research outputs found
One-Cycle Zero-Integral-Error Current Control for Shunt Active Power Filters
[EN] Current control has, for decades, been one of the more challenging research fields in the development of power converters. Simple and robust nonlinear methods like hysteresis or sigma-delta controllers have been commonly used, while sophisticated linear controllers based on classical control theory have been developed for PWM-based converters. The one-cycle current control technique is a nonlinear technique based on cycle-by-cycle calculation of the ON time of the converter switches for the next switching period. This kind of controller requires accurate measurement of voltages and currents in order achieve a precise current tracking. These techniques have been frequently used in the control of power converters generating low-frequency currents, where the reference varies slowly compared with the switching frequency. Its application is not so common in active power filter current controllers due to the fast variation of the references that demands not only accurate measurements but also high-speed computing. This paper proposes a novel one-cycle digital current controller based on the minimization of the integral error of the current. Its application in a three-leg four-wire shunt active power filter is presented, including a stability analysis considering the switching pattern selection. Furthermore, simulated and experimental results are presented to validate the proposed controller.Orts-Grau, S.; Balaguer-Herrero, P.; Alfonso-Gil, JC.; MartĂnez-MĂĄrquez, CI.; Gimeno Sales, FJ.; Segui-Chilet, S. (2020). One-Cycle Zero-Integral-Error Current Control for Shunt Active Power Filters. Electronics. 9(12):1-16. https://doi.org/10.3390/electronics9122008S116912Orts-Grau, S., Gimeno-Sales, F. J., Abellan-Garcia, A., Segui-Chilet, S., & Alfonso-Gil, J. C. (2010). Improved Shunt Active Power Compensator for IEEE Standard 1459 Compliance. IEEE Transactions on Power Delivery, 25(4), 2692-2701. doi:10.1109/tpwrd.2010.2049033Orts-Grau, S., Gimeno-Sales, F. J., Segui-Chilet, S., Abellan-Garcia, A., Alcaniz-Fillol, M., & Masot-Peris, R. (2009). Selective Compensation in Four-Wire Electric Systems Based on a New Equivalent Conductance Approach. IEEE Transactions on Industrial Electronics, 56(8), 2862-2874. doi:10.1109/tie.2009.2014368Trinh, Q.-N., & Lee, H.-H. (2013). An Advanced Current Control Strategy for Three-Phase Shunt Active Power Filters. IEEE Transactions on Industrial Electronics, 60(12), 5400-5410. doi:10.1109/tie.2012.2229677Bosch, S., Staiger, J., & Steinhart, H. (2018). Predictive Current Control for an Active Power Filter With LCL-Filter. IEEE Transactions on Industrial Electronics, 65(6), 4943-4952. doi:10.1109/tie.2017.2772176Balasubramanian, R., Parkavikathirvelu, K., Sankaran, R., & Amirtharajan, R. (2019). Design, Simulation and Hardware Implementation of Shunt Hybrid Compensator Using Synchronous Rotating Reference Frame (SRRF)-Based Control Technique. Electronics, 8(1), 42. doi:10.3390/electronics8010042Imam, A. A., Sreerama Kumar, R., & Al-Turki, Y. A. (2020). Modeling and Simulation of a PI Controlled Shunt Active Power Filter for Power Quality Enhancement Based on P-Q Theory. Electronics, 9(4), 637. doi:10.3390/electronics9040637Panigrahi, R., Subudhi, B., & Panda, P. C. (2016). A Robust LQG Servo Control Strategy of Shunt-Active Power Filter for Power Quality Enhancement. IEEE Transactions on Power Electronics, 31(4), 2860-2869. doi:10.1109/tpel.2015.2456155Herman, L., Papic, I., & Blazic, B. (2014). A Proportional-Resonant Current Controller for Selective Harmonic Compensation in a Hybrid Active Power Filter. IEEE Transactions on Power Delivery, 29(5), 2055-2065. doi:10.1109/tpwrd.2014.2344770Panigrahi, R., & Subudhi, B. (2017). Performance Enhancement of Shunt Active Power Filter Using a Kalman Filter-Based Control Strategy. IEEE Transactions on Power Electronics, 32(4), 2622-2630. doi:10.1109/tpel.2016.2572142Jiang, W., Ding, X., Ni, Y., Wang, J., Wang, L., & Ma, W. (2018). An Improved Deadbeat Control for a Three-Phase Three-Line Active Power Filter With Current-Tracking Error Compensation. IEEE Transactions on Power Electronics, 33(3), 2061-2072. doi:10.1109/tpel.2017.2693325Buso, S., Caldognetto, T., & Brandao, D. (2015). Dead-Beat Current Controller for Voltage Source Converters with Improved Large Signal Response. IEEE Transactions on Industry Applications, 1-1. doi:10.1109/tia.2015.2488644Tarisciotti, L., Formentini, A., Gaeta, A., Degano, M., Zanchetta, P., Rabbeni, R., & Pucci, M. (2017). Model Predictive Control for Shunt Active Filters With Fixed Switching Frequency. IEEE Transactions on Industry Applications, 53(1), 296-304. doi:10.1109/tia.2016.2606364Kumar, M., & Gupta, R. (2017). Sampled-Time-Domain Analysis of a Digitally Implemented Current Controlled Inverter. IEEE Transactions on Industrial Electronics, 64(1), 217-227. doi:10.1109/tie.2016.2609840Ho, C. N.-M., Cheung, V. S. P., & Chung, H. S.-H. (2009). Constant-Frequency Hysteresis Current Control of Grid-Connected VSI Without Bandwidth Control. IEEE Transactions on Power Electronics, 24(11), 2484-2495. doi:10.1109/tpel.2009.2031804Wu, F., Feng, F., Luo, L., Duan, J., & Sun, L. (2015). Sampling period online adjusting-based hysteresis current control without band with constant switching frequency. IEEE Transactions on Industrial Electronics, 62(1), 270-277. doi:10.1109/tie.2014.2326992Holmes, D. G., Davoodnezhad, R., & McGrath, B. P. (2013). An Improved Three-Phase Variable-Band Hysteresis Current Regulator. IEEE Transactions on Power Electronics, 28(1), 441-450. doi:10.1109/tpel.2012.2199133Komurcugil, H., Bayhan, S., & Abu-Rub, H. (2017). Variable- and Fixed-Switching-Frequency-Based HCC Methods for Grid-Connected VSI With Active Damping and Zero Steady-State Error. IEEE Transactions on Industrial Electronics, 64(9), 7009-7018. doi:10.1109/tie.2017.2686331Chang, C.-H., Wu, F.-Y., & Chen, Y.-M. (2012). Modularized Bidirectional Grid-Connected Inverter With Constant-Frequency Asynchronous SigmaâDelta Modulation. IEEE Transactions on Industrial Electronics, 59(11), 4088-4100. doi:10.1109/tie.2011.2176693Mertens, A. (1994). Performance analysis of three-phase inverters controlled by synchronous delta-modulation systems. IEEE Transactions on Industry Applications, 30(4), 1016-1027. doi:10.1109/28.297919Morales, J., de Vicuna, L. G., Guzman, R., Castilla, M., & Miret, J. (2018). Modeling and Sliding Mode Control for Three-Phase Active Power Filters Using the Vector Operation Technique. IEEE Transactions on Industrial Electronics, 65(9), 6828-6838. doi:10.1109/tie.2018.2795528Guzman, R., de Vicuna, L. G., Morales, J., Castilla, M., & Miret, J. (2016). Model-Based Control for a Three-Phase Shunt Active Power Filter. IEEE Transactions on Industrial Electronics, 63(7), 3998-4007. doi:10.1109/tie.2016.2540580Pichan, M., & Rastegar, H. (2017). Sliding-Mode Control of Four-Leg Inverter With Fixed Switching Frequency for Uninterruptible Power Supply Applications. IEEE Transactions on Industrial Electronics, 64(8), 6805-6814. doi:10.1109/tie.2017.2686346E. S., S., E. K., P., Chatterjee, K., & Bandyopadhyay, S. (2014). An Active Harmonic Filter Based on One-Cycle Control. IEEE Transactions on Industrial Electronics, 61(8), 3799-3809. doi:10.1109/tie.2013.2286558Wang, L., Han, X., Ren, C., Yang, Y., & Wang, P. (2018). A Modified One-Cycle-Control-Based Active Power Filter for Harmonic Compensation. IEEE Transactions on Industrial Electronics, 65(1), 738-748. doi:10.1109/tie.2017.2682021Jin, T., & Smedley, K. M. (2006). Operation of One-Cycle Controlled Three-Phase Active Power Filter With Unbalanced Source and Load. IEEE Transactions on Power Electronics, 21(5), 1403-1412. doi:10.1109/tpel.2006.880264Hirve, S., Chatterjee, K., Fernandes, B. G., Imayavaramban, M., & Dwari, S. (2007). PLL-Less Active Power Filter Based on One-Cycle Control for Compensating Unbalanced Loads in Three-Phase Four-Wire System. IEEE Transactions on Power Delivery, 22(4), 2457-2465. doi:10.1109/tpwrd.2007.893450Qiao, C., Smedley, K. M., & Maddaleno, F. (2004). A Single-Phase Active Power Filter With One-Cycle Control Under Unipolar Operation. IEEE Transactions on Circuits and Systems I: Regular Papers, 51(8), 1623-1630. doi:10.1109/tcsi.2004.832801Qiao, C., Jin, T., & MaSmedley, K. (2004). One-Cycle Control of Three-Phase Active Power Filter With Vector Operation. IEEE Transactions on Industrial Electronics, 51(2), 455-463. doi:10.1109/tie.2004.82522
Galaxy clusters and groups in the ALHAMBRA Survey
We present a catalogue of 348 galaxy clusters and groups with
selected in the 2.78 ALHAMBRA Survey. The high precision of our
photometric redshifts, close to , and the wide spread of the seven
ALHAMBRA pointings ensure that this catalogue has better mass sensitivity and
is less affected by cosmic variance than comparable samples.
The detection has been carried out with the Bayesian Cluster Finder (BCF),
whose performance has been checked in ALHAMBRA-like light-cone mock catalogues.
Great care has been taken to ensure that the observable properties of the mocks
photometry accurately correspond to those of real catalogues. From our
simulations, we expect to detect galaxy clusters and groups with both
completeness and purity down to dark matter halo masses of
for . Cluster redshifts are
expected to be recovered with precision for . We also expect
to measure cluster masses with
precision down to , masses which are
smaller than those reached by similar work.
We have compared these detections with previous optical, spectroscopic and
X-rays work, finding an excellent agreement with the rates reported from the
simulations. We have also explored the overall properties of these detections
such as the presence of a colour-magnitude relation, the evolution of the
photometric blue fraction and the clustering of these sources in the different
ALHAMBRA fields. Despite the small numbers, we observe tentative evidence that,
for a fixed stellar mass, the environment is playing a crucial role at lower
redshifts (z0.5).Comment: Accepted for publication in MNRAS. Catalogues and figures available
online and under the following link:
http://bascaso.net46.net/ALHAMBRA_clusters.htm
Estrategia marina demarcaciĂłn marina levantino-balear parte IV. Descriptores del buen estado ambiental. Descriptor 1: biodiversidad evaluaciĂłn inicial y buen estado ambiental
El descriptor 1 de la Ley 41/2010 de protecciĂłn del medio marino, trasposiciĂłn a la ley española de la Directiva Marco sobre la Estrategia Marina (DMEM: 2008/56/CE) dice textualmente "Se mantiene la biodiversidad. La calidad y la frecuencia de los hĂĄbitats y la distribuciĂłn y abundancia de las especies estĂĄn en consonancia con las condiciones fisiogrĂĄficas, geogrĂĄficas y climĂĄticas". SegĂșn el Convenio sobre la Diversidad BiolĂłgica (UNCED, 1992), Ă©sta se define como: "La variabilidad de organismos vivos de cualquier fuente, incluidos, entre otras cosas, los ecosistemas terrestres y marinos y otros ecosistemas acuĂĄticos y los complejos ecolĂłgicos de los que forman parte; comprende la diversidad dentro de cada especie, entre especies y de los ecosistemas"
Quercus pyrenaica coppices II : Degradation takes roots on its historical management
Physiological performance of Quercus pyrenaica in relation to clonal structure and traditional us
The Fourteenth Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the extended Baryon Oscillation Spectroscopic Survey and from the second phase of the Apache Point Observatory Galactic Evolution Experiment
The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) has been in
operation since July 2014. This paper describes the second data release from
this phase, and the fourteenth from SDSS overall (making this, Data Release
Fourteen or DR14). This release makes public data taken by SDSS-IV in its first
two years of operation (July 2014-2016). Like all previous SDSS releases, DR14
is cumulative, including the most recent reductions and calibrations of all
data taken by SDSS since the first phase began operations in 2000. New in DR14
is the first public release of data from the extended Baryon Oscillation
Spectroscopic Survey (eBOSS); the first data from the second phase of the
Apache Point Observatory (APO) Galactic Evolution Experiment (APOGEE-2),
including stellar parameter estimates from an innovative data driven machine
learning algorithm known as "The Cannon"; and almost twice as many data cubes
from the Mapping Nearby Galaxies at APO (MaNGA) survey as were in the previous
release (N = 2812 in total). This paper describes the location and format of
the publicly available data from SDSS-IV surveys. We provide references to the
important technical papers describing how these data have been taken (both
targeting and observation details) and processed for scientific use. The SDSS
website (www.sdss.org) has been updated for this release, and provides links to
data downloads, as well as tutorials and examples of data use. SDSS-IV is
planning to continue to collect astronomical data until 2020, and will be
followed by SDSS-V.Comment: SDSS-IV collaboration alphabetical author data release paper. DR14
happened on 31st July 2017. 19 pages, 5 figures. Accepted by ApJS on 28th Nov
2017 (this is the "post-print" and "post-proofs" version; minor corrections
only from v1, and most of errors found in proofs corrected
Chronic Oral Anticoagulation Therapy and Prognosis of Patients Admitted to Hospital for COVID-19: Insights from the HOPE COVID-19 Registry
BackgroundMost evidence regarding anticoagulation and COVID-19 refers to the hospitalization setting, but the role of oral anticoagulation (OAC) before hospital admission has not been well explored. We compared clinical outcomes and short-term prognosis between patients with and without prior OAC therapy who were hospitalized for COVID-19.MethodsAnalysis of the whole cohort of the HOPE COVID-19 Registry which included patients discharged (deceased or alive) after hospital admission for COVID-19 in 9 countries. All-cause mortality was the primary endpoint. Study outcomes were compared after adjusting variables using propensity score matching (PSM) analyses.Results7698 patients were suitable for the present analysis (675 (8.8%) on OAC at admission: 427 (5.6%) on VKAs and 248 (3.2%) on DOACs). After PSM, 1276 patients were analyzed (638 with OAC; 638 without OAC), without significant differences regarding the risk of thromboembolic events (OR 1.11, 95% CI 0.59-2.08). The risk of clinically relevant bleeding (OR 3.04, 95% CI 1.92-4.83), as well as the risk of mortality (HR 1.22, 95% CI 1.01-1.47; log-rank p valueâ=â0.041), was significantly increased in previous OAC users. Amongst patients on prior OAC only, there were no differences in the risk of clinically relevant bleeding, thromboembolic events, or mortality when comparing previous VKA or DOAC users, after PSM.ConclusionHospitalized COVID-19 patients on prior OAC therapy had a higher risk of mortality and worse clinical outcomes compared to patients without prior OAC therapy, even after adjusting for comorbidities using a PSM. There were no differences in clinical outcomes in patients previously taking VKAs or DOACs. This trial is registered with NCT04334291/EUPAS34399
Impact of the first wave of the SARS-CoV-2 pandemic on the outcome of neurosurgical patients: A nationwide study in Spain
Objective To assess the effect of the first wave of the SARS-CoV-2 pandemic on the outcome of neurosurgical patients in Spain. Settings The initial flood of COVID-19 patients overwhelmed an unprepared healthcare system. Different measures were taken to deal with this overburden. The effect of these measures on neurosurgical patients, as well as the effect of COVID-19 itself, has not been thoroughly studied. Participants This was a multicentre, nationwide, observational retrospective study of patients who underwent any neurosurgical operation from March to July 2020. Interventions An exploratory factorial analysis was performed to select the most relevant variables of the sample. Primary and secondary outcome measures Univariate and multivariate analyses were performed to identify independent predictors of mortality and postoperative SARS-CoV-2 infection. Results Sixteen hospitals registered 1677 operated patients. The overall mortality was 6.4%, and 2.9% (44 patients) suffered a perioperative SARS-CoV-2 infection. Of those infections, 24 were diagnosed postoperatively. Age (OR 1.05), perioperative SARS-CoV-2 infection (OR 4.7), community COVID-19 incidence (cases/10 5 people/week) (OR 1.006), postoperative neurological worsening (OR 5.9), postoperative need for airway support (OR 5.38), ASA grade =3 (OR 2.5) and preoperative GCS 3-8 (OR 2.82) were independently associated with mortality. For SARS-CoV-2 postoperative infection, screening swab test <72 hours preoperatively (OR 0.76), community COVID-19 incidence (cases/10 5 people/week) (OR 1.011), preoperative cognitive impairment (OR 2.784), postoperative sepsis (OR 3.807) and an absence of postoperative complications (OR 0.188) were independently associated. Conclusions Perioperative SARS-CoV-2 infection in neurosurgical patients was associated with an increase in mortality by almost fivefold. Community COVID-19 incidence (cases/10 5 people/week) was a statistically independent predictor of mortality. Trial registration number CEIM 20/217
Association Between Preexisting Versus Newly Identified Atrial Fibrillation and Outcomes of Patients With Acute Pulmonary Embolism
Background Atrial fibrillation (AF) may exist before or occur early in the course of pulmonary embolism (PE). We determined the PE outcomes based on the presence and timing of AF. Methods and Results Using the data from a multicenter PE registry, we identified 3 groups: (1) those with preexisting AF, (2) patients with new AF within 2 days from acute PE (incident AF), and (3) patients without AF. We assessed the 90-day and 1-year risk of mortality and stroke in patients with AF, compared with those without AF (reference group). Among 16 497 patients with PE, 792 had preexisting AF. These patients had increased odds of 90-day all-cause (odds ratio [OR], 2.81; 95% CI, 2.33-3.38) and PE-related mortality (OR, 2.38; 95% CI, 1.37-4.14) and increased 1-year hazard for ischemic stroke (hazard ratio, 5.48; 95% CI, 3.10-9.69) compared with those without AF. After multivariable adjustment, preexisting AF was associated with significantly increased odds of all-cause mortality (OR, 1.91; 95% CI, 1.57-2.32) but not PE-related mortality (OR, 1.50; 95% CI, 0.85-2.66). Among 16 497 patients with PE, 445 developed new incident AF within 2 days of acute PE. Incident AF was associated with increased odds of 90-day all-cause (OR, 2.28; 95% CI, 1.75-2.97) and PE-related (OR, 3.64; 95% CI, 2.01-6.59) mortality but not stroke. Findings were similar in multivariable analyses. Conclusions In patients with acute symptomatic PE, both preexisting AF and incident AF predict adverse clinical outcomes. The type of adverse outcomes may differ depending on the timing of AF onset.info:eu-repo/semantics/publishedVersio
Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2
The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality
The 13th Data Release of the Sloan Digital Sky Survey: First Spectroscopic Data from the SDSS-IV Survey Mapping Nearby Galaxies at Apache Point Observatory
The fourth generation of the Sloan Digital Sky Survey (SDSS-IV) began observations in July 2014. It pursues three core programs: APOGEE-2,MaNGA, and eBOSS. In addition, eBOSS contains two major subprograms: TDSS and SPIDERS. This paper describes the first data release from SDSS-IV, Data Release 13 (DR13), which contains new data, reanalysis of existing data sets and, like all SDSS data releases, is inclusive of previously released data. DR13 makes publicly available 1390 spatially resolved integral field unit observations of nearby galaxies from MaNGA,the first data released from this survey. It includes new observations from eBOSS, completing SEQUELS. In addition to targeting galaxies and quasars, SEQUELS also targeted variability-selected objects from TDSS and X-ray selected objects from SPIDERS. DR13 includes new reductions ofthe SDSS-III BOSS data, improving the spectrophotometric calibration and redshift classification. DR13 releases new reductions of the APOGEE-1data from SDSS-III, with abundances of elements not previously included and improved stellar parameters for dwarf stars and cooler stars. For the SDSS imaging data, DR13 provides new, more robust and precise photometric calibrations. Several value-added catalogs are being released in tandem with DR13, in particular target catalogs relevant for eBOSS, TDSS, and SPIDERS, and an updated red-clump catalog for APOGEE.This paper describes the location and format of the data now publicly available, as well as providing references to the important technical papers that describe the targeting, observing, and data reduction. The SDSS website, http://www.sdss.org, provides links to the data, tutorials and examples of data access, and extensive documentation of the reduction and analysis procedures. DR13 is the first of a scheduled set that will contain new data and analyses from the planned ~6-year operations of SDSS-IV.PostprintPeer reviewe
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