DC-link voltage selection for a multi-MW wind turbine

2014 ◽  
Vol 33 (5) ◽  
pp. 1722-1740
Author(s):  
Poopak Roshanfekr ◽  
Torbjörn Thiringer ◽  
Sonja Lundmark ◽  
Mikael Alatalo
Keyword(s):  
Wind Turbine ◽  
Energy Efficient ◽  
Design Methodology ◽  
Synchronous Generators ◽  
Maximum Torque ◽  
Voltage Level ◽  
Content Type ◽  
Permanent Magnet Synchronous Generators ◽  
Selection For ◽  
Maximum Torque Per Ampere

Purpose – The purpose of this paper is to investigate how the dc-link voltage for the converter of a wind generator should be selected, i.e. to determine the losses in the generator and the converter when using various dc-link voltage levels. Design/methodology/approach – To presents the efficiency evaluation of 5 MW wind turbine generating systems, two 5 MW surface mounted permanent magnet synchronous generators (PMSG) with medium and low rated voltage is designed. A two-level transistor converter is considered for ac/dc conversion. Three different dc-link voltage levels are used. By using these voltage levels the PMSG is utilized in slightly different ways. Findings – It is found that the system with the lower voltage machine has slightly higher annual energy efficiency compare to the higher voltage system. Furthermore, it is shown that the best choice for the dc-link voltage level is a voltage between the minimum voltage which gives the desired torque and the voltage which gives Maximum Torque Per Ampere. Originality/value – A procedure as well as investigations with quantified results on how to find the highest complete drive system efficiency for a wind turbine application. Based on two given PMSG, the most energy-efficient dc-link voltage has been established.

Must attic ventilation be preserved in energy retrofits?

2019 ◽  
Vol 37 (4) ◽  
pp. 461-472
Author(s):  
William Rose
Keyword(s):  
Vapor Pressure ◽  
Energy Efficient ◽  
Design Methodology ◽  
Air Leakage ◽  
Content Type ◽  
Buoyancy Flow ◽  
Spreadsheet Model ◽  
Radiation Exchange ◽  
Moisture Performance ◽  
Ashrae Standards

Purpose The addition of thermal insulation into attics along with air-tightening of the ceiling plane is a common first step in making homes more energy efficient. Attic ventilation was introduced decades ago on the assumption that air leakage across the ceiling was inevitable and not correctible – this was before the era of spray-applied foams. Often attic ventilation is provided at roof eaves, and ensuring good insulation in their location is critical to avoid cold corners in the rooms below. So may vents be blocked in the course of energy retrofits? The paper aims to discuss this issue. Design/methodology/approach This study consists of a simple spreadsheet model of attic performance. The model is built using material from ASHRAE Handbook Fundamentals and ASHRAE Standards. It includes: Glaser calculations for temperature, vapor pressure and vapor pressure excess; radiation exchange – solar and sky; buoyancy flow assumption for leakage from indoors; wind flow assumption for leakage from outdoors; and change in attic air RH as assumed indicator of change in sheathing moisture performance. Findings The model results show that lowered moisture contributions across air-tightened ceilings may compensate effectively for added insulation (which lowers the attic air temperature) and reduced moisture dilution from attic ventilation. Originality/value These results provide support for the policy of allowing attic ventilation reductions that are proportionate to ceiling air leakage reductions as part of weatherization efforts. Given the limitations of the model, continued field observations remain critical.

scholarly journals Comparison of Flux-Switching and Interior Permanent Magnet Synchronous Generators for Direct-Driven Wind Applications Based on Nelder–Mead Optimal Designing

Mathematics ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 732
Author(s):  
Vladimir Prakht ◽  
Vladimir Dmitrievskii ◽  
Vadim Kazakbaev ◽  
Ekaterina Andriushchenko
Keyword(s):  
Wind Turbine ◽  
Permanent Magnet ◽  
Frequency Converter ◽  
Torque Ripple ◽  
Computational Time ◽  
Synchronous Generators ◽  
Advantages And Disadvantages ◽  
Permanent Magnet Synchronous Generators ◽  
Interior Permanent Magnet ◽  
Nelder Mead Algorithm

The permanent magnet flux-switching machine (PMFSM) is one of the most promising machines with magnets inserted into the stator. To determine in which applications the use of PMFSM is promising, it is essential to compare the PMFSM with machines of other types. This study provides a theoretical comparison of the PMFSM with a conventional interior permanent magnet synchronous machine (IPMSM) in the gearless generator of a low-power wind turbine (332 rpm, 51.4 Nm). To provide a fair comparison, both machines are optimized using the Nelder–Mead algorithm. The minimized optimization objectives are the required power of frequency converter, cost of active materials, torque ripple and losses of a generator averaged over the working profile of the wind turbine. In order to reduce the computational time, the substituting profile method is applied. Based on the results of the calculations, the advantages and disadvantages of the considered machines were revealed: the IPMSM has significantly lower losses and higher efficiency than the PMFSM, and the PMFSM requires much less rare-earth magnets and copper and is, therefore, cheaper in mass production.

Energy consultants calculating sustainability for residential buildings

Facilities ◽  
2019 ◽  
Vol 37 (11/12) ◽  
pp. 825-838 ◽  
Author(s):  
Roger Andre Søraa ◽  
Håkon Fyhn ◽  
Jøran Solli
Keyword(s):  
Design Process ◽  
Energy Efficient ◽  
Design Methodology ◽  
Residential Buildings ◽  
Qualitative Interviews ◽  
Implementation Process ◽  
Building Sector ◽  
Content Type ◽  
Practical Implications

PurposeThis paper aims to investigate the role of a particular energy calculator in enhancing the energy efficiency of existing homes by asking how this calculator was developed and how it is domesticated by craftspeople working as energy consultants.Design/methodology/approachThe study is based on qualitative interviews with users and producers of the energy calculator (n= 22), as well as participation in energy consultation training.FindingsThe paper finds that, in the energy calculator, there is a striking lack of connection between the domestication and script because of lack of energy consultants’ involvement in the design and implementation process.Practical implicationsThe enrolment of energy consultants as energy calculator users earlier in and throughout the design process could be valuable in making the transition to an energy-efficient and environmentally friendly building sector.Social implicationsThe paper argues for recognition of the role of energy consultants, especially craftspeople, as participants in the design process for tools of governance. This is a call to acknowledge the value of particular skills and experiences possessed by craftspeople doing home consultation.Originality/valueBy understanding the intricate developer–user synchronicity in tools developed for upgrading the building sector, energy mitigation can be made more effective.

Study on Directly Driven Wind Turbine with Permanent Magnet Synchronous Generators (D-PMSG)

2011 ◽  
Vol 383-390 ◽  
pp. 3528-3534 ◽  
Author(s):  
Zhong Yao Du ◽  
Rong Ju
Keyword(s):  
Wind Turbine ◽  
Wind Power ◽  
Mathematic Model ◽  
Module Structure ◽  
Synchronous Generators ◽  
Simulation Research ◽  
Permanent Magnet Synchronous Generators ◽  
Speed Modulation ◽  
Simulation Results ◽  
Turbine Speed

Recently, the wind power develops rapidly. In this paper, the mathematic model and vector control of D-PMSG are studied. This thesis involves in simulation research of wind turbine, speed modulation, coordinate transformation, SVPWM waves, main loop and the whole system based on module structure under the environment of MATLAB/SIMULINK. The simulation results indicate that PMSM has perfect characteristic and gives practical meanings for the studies of wind power.

Study on pedestrian flow evacuation with individual-guidance mechanism

Kybernetes ◽  
2016 ◽  
Vol 45 (5) ◽  
pp. 772-787 ◽  
Author(s):  
Can Zhong Yao ◽  
Xiao Feng Liu ◽  
Ji Nan Lin
Keyword(s):  
Random Walk ◽  
Majority Rule ◽  
Design Methodology ◽  
Pedestrian Flow ◽  
Content Type ◽  
Optimal Ratio ◽  
Selection For

Purpose – The purpose of this paper is to provide the possible and better selection for pedestrian flow evacuation. Design/methodology/approach – Simulation. Findings – First, according to the model with self-decision agents, the paper figures out that the effect of evacuation guided by the random-walk mechanism exceeds that guided by the inertial mechanism, and specifically, the effect of evacuation could significantly improve if random-walk agents restraint the probability of random walk under 0.4. Besides, on neighborhood reference mechanism, individuals who take neighbors’ average direction as reference tend to achieve better effect of evacuation than that of following majority rule. Furthermore, this paper proposes that an optimal ratio of the proportion of clever individuals and system density exists for evacuation effect improvement. Finally, the evacuating effect with barrier locating in different space is also studied in our research. Originality/value – The effect of evacuation could significantly improve if random-walk agents restraint the probability of random walk under 0.4. On neighborhood reference mechanism, individuals who take neighbors’ average direction as reference tend to achieve better effect of evacuation than that of following majority rule.

A Comparative Analysis of Three-Phase, Multi-Phase and Dual Stator Axial Flux Permanent Magnet Synchronous Generator for Vertical Axis Wind Turbine

2013 ◽  
Vol 446-447 ◽  
pp. 709-715 ◽  
Author(s):  
M. Shahrukh Adnan Khan ◽  
Rajprasad K. Rajkumar ◽  
Rajparthiban K. Rajkumar ◽  
C.V. Aravind
Keyword(s):  
Wind Turbine ◽  
Permanent Magnet ◽  
Synchronous Generator ◽  
Vertical Axis ◽  
Vertical Axis Wind Turbine ◽  
Synchronous Generators ◽  
Permanent Magnet Synchronous Generators ◽  
Wind Turbine System ◽  
Three Phase ◽  
Multi Phase

In this paper, the performances of all the three kinds of Axial type Multi-Pole Permanent Magnet Synchronous Generators (PMSG) namely Three-phase, Multi-phase or Five Phase and Double Stator fixed in Vertical Axis Wind Turbine (VAWT) were investigated and compared in order to get an optimal system. MATLAB/Simulink had been used to model and simulate the wind turbine system together with all the three types Permanent Magnet Generators. It was observed from the result that with the increasing number of pole in both low and high wind speed, the five phase generator produced more power than the other two generators. In general, it was observed that the responses of the Multi-phase generator at both high and low speed wind showed promising aspect towards the system followed by Dual Stator. But with the change of the variables such as wind velocity, turbine height, radius, area together with the generator pole pairs and stator resistance, the optimum system should be chosen by considering the trade-off between different configurations which were firmly analyzed and described in this paper.

Sensory inputs in tourists’ nightlife experiences – a study of Bangkok, Kuala Lumpur and Singapore

2020 ◽  
Vol 14 (2) ◽  
pp. 259-272
Author(s):  
Bình Nghiêm-Phú
Keyword(s):  
Design Methodology ◽  
Kuala Lumpur ◽  
Content Type ◽  
Sensory Inputs ◽  
Tourist Destinations ◽  
Bivariate Correlation ◽  
Sensory Marketing ◽  
Visual Inputs ◽  
Selection For ◽  
Practical Implications

Purpose This study aims to identify the sensory inputs that tourists use to shape their nightlife experiences. Design/methodology/approach The situations in three Southeast Asian cities, Bangkok, Kuala Lumpur and Singapore were examined, using tourist reviews posted on tripadvisor.com. A total of 460 data units concerning Bangkok, 373 data units concerning Kuala Lumpur and 453 data units concerning Singapore were compiled and manually analyzed to reveal the frequency of the primary sensory inputs used by the reviewers. Bivariate correlation analysis was additionally performed to reveal the co-occurrences of the sensory inputs that tourists used to form their impressions of each city. Findings The findings suggest that gustatory inputs were powerful yet unspecific, while visual inputs were vivid and conspicuous. Audio inputs added certain meaningful contributions to some extent for some tourists. However, the distribution of the sensory inputs differed across the three cities. Moreover, the contributions of the olfactory and tactile inputs are largely missing. Practical implications With the management of nightlife businesses (small or micro servicescapes), a thoughtful selection for the drink menu is necessary. When possible, a signature drink should be invented and promoted for each place. With the projection and promotion of tourist destinations as nightlifescapes, a sensory marketing approach should be considered. For example, nightlifescapes could be presented and promoted with unique drinks, good views of the city’s landmarks and interesting local music. Originality/value Prior to this study, little research has been carried out to investigate tourists’ nightlife experiences and their impressions of nightlifescapes. In addition, little has been done to identify the sensory inputs that tourists use to explain their experiences and impressions.

Enabling energy-efficient renovation: the case of vertical extension to buildings

2019 ◽  
Vol 19 (1) ◽  
pp. 2-14 ◽  
Author(s):  
Rikard Sundling ◽  
Åke Blomsterberg ◽  
Anne Landin
Keyword(s):  
Life Cycle ◽  
Environmental Impact ◽  
Energy Efficient ◽  
Design Methodology ◽  
Data Gathering ◽  
Low Energy ◽  
Content Type ◽  
Vertical Extension ◽  
Profit Analysis ◽  
Energy Plus

Purpose This paper is based on a study of six similar buildings built in Gothenburg, Sweden, in 1971, which were in urgent need of renovation. A life cycle profit analysis shows how four competing concepts were evaluated to find a financially viable renovation concept; additionally, the environmental impacts of these renovation concepts using a life cycle assessment are presented. Design/methodology/approach Four renovation concepts are compared to find the most appropriate concept, namely, minimalist, code-compliant, low-energy and low-energy plus vertical extension concepts. The methods used for comparison are life cycle profit analysis and life cycle impact assessment; the methods used for data gathering included site visits, interviews, document study, co-benefits study and energy simulation. Findings The findings show that vertical extension supported the energy-efficient renovation of the buildings and that the combination of low-energy and the vertical extension had the highest return on investment and the lowest environmental impact. The selected concept for renovating the remaining five buildings combined was the low-energy plus vertical extension. Additional benefits from vertical extension include more apartments in central locations for the housing company, a wider variety of apartment layouts and a wider range of tenants. Drawbacks include increased use of infrastructure, green space and common appliances, as well as gentrification. Originality/value This study shows how a vertical extension can financially enable an energy-efficient renovation and further lower its environmental impact. Benefits and drawbacks of densification are also highlighted to better understand the implementation of vertically extending a building.

Grey wolf optimization based parameter selection for support vector machines

2016 ◽  
Vol 35 (5) ◽  
pp. 1513-1523 ◽  
Author(s):  
Sathish Eswaramoorthy ◽  
N. Sivakumaran ◽  
Sankaranarayanan Sekaran
Keyword(s):  
Design Methodology ◽  
Support Vector ◽  
Svm Classifier ◽  
Grey Wolf Optimizer ◽  
Grey Wolf ◽  
Grey Wolf Optimization ◽  
Content Type ◽  
Vector Machines ◽  
Human Perceptions ◽  
Selection For

Purpose The purpose of this paper is to tune support vector machine (SVM) classifier using grey wolf optimizer (GWO). Design/methodology/approach The schema of the work aims at extracting the features from the collected data followed by a SVM classifier and metaheuristic optimization to tune the classifier parameters. Findings The optimal tuning of classifier parameters lowers errors due to manual elucidation and decreases the risk in human perceptions and repeated visual dignosis. Originality/value A novel, GWO based tuning algorithm is used for SVM classifier, which is implemented in classifying the complex and nonlinear biomedical signals like intracranial electroencephalogram.

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