Comparison between PI and PR current controllers in grid connected PV inverters

This paper presents a comparison between Proportional Integral (PI) and Proportional Resonant (PR) current controllers used in Grid Connected Photovoltaic (PV) Inverters. Both simulation and experimental results will be presented. A 3kW Grid- Connected PV Inverter was designed and constructed for this research.peer-reviewe

Design of PR current control with selective harmonic compensators using Matlab

This paper presents a procedure to design a Proportional Resonant (PR) current controller with additional PR selective harmonic compensators for Grid Connected Photovoltaic (PV) Inverters. The design of the PR current control and the harmonic compensators will be carried out using Matlab. Testing was carried out on a 3kW Grid- Connected PV Inverter which was designed and constructed for this research. Both simulation and experimental results will be presented.peer-reviewe

Reduction of current harmonics in grid-connected PV inverters using harmonic compensation - conforming to IEEE and IEC standards

This paper deals with the reduction of harmonics generated by Grid-Connected PV Inverters to conform to the harmonic limits set by the IEEE and IEC standards. An analysis of the current harmonics present in the output current of a grid-connected inverter will be presented. The inverter will be current controlled by a Proportional-Resonant (PR) current controller. The design and testing of the PR current controller will be presented. This paper will also deal with the application of harmonic compensation to make the inverter compliant to the standards, by using selective harmonic compensators in addition to the Proportional-Resonant (PR) controller. Both simulation and experimental results will be presented. Testing was carried out on a Grid-Connected PV Inverter which was designed and constructed for this research.peer-reviewe

Paralleling of buck converters for DC microgrid operation

This paper presents the controller design of paralleled Buck converters using Droop Control to obtain common load sharing for DC Microgrid operation. Proportional Integral (PI) controllers are used to provide nested current and voltage control of the Buck converters. Droop control is applied to obtain load sharing between the paralleled converters. Then, a voltage restoration loop is applied utilizing another PI controller to restore the desired voltage in the dc microgrid, correcting any voltage deviations caused by the droop loop. The operation of the controllers is tested by simulating two paralleled Buck converters operated in the continuous current mode while sharing a common resistive load.peer-reviewe

PomBase 2015: updates to the fission yeast database.

PomBase (http://www.pombase.org) is the model organism database for the fission yeast Schizosaccharomyces pombe. PomBase provides a central hub for the fission yeast community, supporting both exploratory and hypothesis-driven research. It provides users easy access to data ranging from the sequence level, to molecular and phenotypic annotations, through to the display of genome-wide high-throughput studies. Recent improvements to the site extend annotation specificity, improve usability and allow for monthly data updates. Both in-house curators and community researchers provide manually curated data to PomBase. The genome browser provides access to published high-throughput data sets and the genomes of three additional Schizosaccharomyces species (Schizosaccharomyces cryophilus, Schizosaccharomyces japonicus and Schizosaccharomyces octosporus)

Evaluating a multi-component intervention to reduce and break up office workers' sitting with sit-stand desks using the APEASE criteria

Objective: Sedentary workplace interventions have had success in reducing excessive sitting time in office workers, but barriers to implementation and uptake remain. This study formally assessed a theory-derived, sit-stand desk intervention using the APEASE (Acceptability, Practicability, Effectiveness, Affordability, Side-effects, Equity) criteria. / Methods: Thirteen adults (eight female, mean age 38 ± 10 years) from the treatment arm of a sedentary behaviour intervention participated in semi-structured interviews. Thematic codes were inductively assigned to data items followed by deductive charting using the APEASE criteria. / Results: The intervention was highly acceptable, practicable, safe to deploy, and helped workers reduce workplace sitting time, though individual preferences and workload mediated engagement. Affordability of sit-stand desks and Equity of access were potential barriers to uptake. / Conclusions: Through the lens of the APEASE criteria, this theory-derived, multi-component sit-stand desk intervention showed acceptability, practicability and effectiveness in reducing and breaking up sedentary time at work with minimal side effects. Using this approach with further tailoring and personalisation may help workers achieve greater reductions in workplace sitting, though affordability and equity should be considered further

Control of buck and boost converters for stand-alone DC microgrids

This paper presents the modelling and control of Buck and Boost converters to be operated in a stand-alone DC Microgrid. The Buck and Boost converters can be considered as the basis of a number of other converters, therefore the control system presented can be extended to other similar applications. The two converters can be used to interface photovoltaic (PV) panels or wind turbine systems to a DC microgrid. In this paper both converters will be modelled in continuous conduction mode (CCM), and the control system needed to operate these converters in a stand-alone DC microgrid will be presented. The inductor current and the output voltage of the converter will be controlled using nested control loops. The droop control method will be utilized to obtain load sharing between the converters when these are paralleled in the microgrid. An outer addition voltage restoration loop will be applied to restore the desired voltage in the dc microgrid, correcting any voltage deviations caused by the droop control method. The operation of the control loops will be tested by simulations. The simulation model will consist of two paralleled Buck converters operated in CCM, while sharing a common resistive load.peer-reviewe

PomBase: a comprehensive online resource for fission yeast.

PomBase (www.pombase.org) is a new model organism database established to provide access to comprehensive, accurate, and up-to-date molecular data and biological information for the fission yeast Schizosaccharomyces pombe to effectively support both exploratory and hypothesis-driven research. PomBase encompasses annotation of genomic sequence and features, comprehensive manual literature curation and genome-wide data sets, and supports sophisticated user-defined queries. The implementation of PomBase integrates a Chado relational database that houses manually curated data with Ensembl software that supports sequence-based annotation and web access. PomBase will provide user-friendly tools to promote curation by experts within the fission yeast community. This will make a key contribution to shaping its content and ensuring its comprehensiveness and long-term relevance