Start-up system design for small scale autonomous DFIG wind turbine

2021 ◽  
pp. 0309524X2110287
Author(s):  
Meriem Ghodbane-Cherif ◽  
Sondes Skander-Mustapha ◽  
Ilhem Slama-Belkhodja
Keyword(s):  
Power Flow ◽  
Fast Response ◽  
System Component ◽  
Small Scale ◽  
Start Up ◽  
System Functioning ◽  
Current Value ◽  
Doubly Fed ◽  
And Control ◽  
Predictive Controllers

Autonomous wind systems are becoming promising since they provide new and innovative solutions to non-electrified areas. Start-up procedures for this wind systems requires some care to ensure electricity availability, to ovoid overloads and to reduce electrical and mechanical stress that affect lifetime of system components. In this context, this paper deals with an enhanced start-up system for small scale autonomous wind systems based on doubly fed induction generator. With the proposed start-up system, transient magnetizing current value is maintained under rated rotor current value to ensure smooth start-up process. Start-up algorithm guarantees the reach of a stable system functioning. Suggested topology, that includes a supercapacitor as a supplementary source, can be disconnected once wind system boots. Predictive controllers are used to ensure fast response. An energy management system is developed to monitor power flow. Considered model and control strategy of each system component, as well as start-up process are presented. Simulation results prove the effectiveness of the proposed start-up system.

scholarly journals Sustainable Water Resources Using Corner Pivot Lateral, A Novel Sprinkler Irrigation System Layout for Small Scale Farms

2018 ◽  
Vol 8 (12) ◽  
pp. 2601 ◽  
Author(s):  
Saeed Rad ◽  
Lei Gan ◽  
Xiaobing Chen ◽  
Shaohong You ◽  
Liangliang Huang ◽  
...  
Keyword(s):  
Water Distribution ◽  
Large Scale ◽  
Irrigation System ◽  
Sprinkler Irrigation ◽  
Cost Effective ◽  
System Component ◽  
Small Scale ◽  
Can Technique ◽  
Distribution Uniformity ◽  
And Control

Sprinkler irrigation systems are widely used in medium and large scale farms in different forms. However less types are available to apply in small farms due to their high costs. The current study was done according to a novel cost effective design for a semi-permanent sprinkler irrigation system for small farm owners. The new layout known as Corner Pivot Lateral (CPL) was examined in irrigation test center at Lijian Scientific and Technological Demonstration Park, at Nanning city, China. CPL was implemented without a main/sub mainline pipe, by applying a single pivoting lateral at the corner of the plot that directly connected to the resource to convey water from the pump. The lateral moves around the corner using a rotating elbow in a quadrant pattern manually to cover the entire farm. A conventional semi-permanent system was applied for the same farm as reference. A cost analysis on the required components as well as annual operational costs was carried out for comparison and control. Results showed that a lower system component would be needed for the CPL method. Overall, more than a 15% capital cost reduction with 7% annual cost decrement was achieved for CPL in this experiment comparatively. The Catch can technique was applied to examine the CPL system’s efficiency and 79% water distribution uniformity around the sprinkler was obtained. This new method can encourage small estate holders to switch from traditional to pressurized systems which optimizes water application costs.

scholarly journals Starting of induction motor fed with stand-alone DFIG

2021 ◽  
Vol 10 (5) ◽  
pp. 2414-2423
Author(s):  
M. Sharawy ◽  
Adel A. Shaltout ◽  
Naser Abdel- Rahim ◽  
Mahmoud A. Al-Ahmar ◽  
O. E. M. Youssef
Keyword(s):  
Voltage Sag ◽  
Doubly Fed Induction Generator ◽  
System Behavior ◽  
Starting Current ◽  
Start Up ◽  
On Line ◽  
Indirect Field Oriented Control ◽  
Doubly Fed ◽  
Rotor Side Converter ◽  
And Control

This paper presents dynamic simulation and control of stand-alone doubly fed induction generator (DFIG) loaded with 3-phase induction motors (IMs). The study reveals that direct on-line starting of large IMs causes a large voltage sag across the generator terminals as the starting current drawn reaches up to 8-9 times the rated load current. Traditionally, this problem has tackled by oversizing of the generator or employment of special starters, under the pretext of mitigating voltage sag. This work explores ways that the starting current can be reduced economically by applying constant V/f control side by side with indirect field-oriented control (FOC) applied on the rotor side converter of the DFIG. This methodology enables starting of larger IMs and mitigation of voltage sag that occurs during the start-up period. Two different rating of IMs loaded with speed-squared mechanical torque are mainly considered. Simulation results of the system behavior under study confirm the capability of the proposed control.

Präzisions-Forstwirtschaft – was ist das? | Precision forestry – what's that?

2007 ◽  
Vol 158 (8) ◽  
pp. 235-242 ◽  
Author(s):  
Hans Rudolf Heinimann
Keyword(s):  
Business Processes ◽  
Spatial Scales ◽  
Supply Chain Coordination ◽  
Sensor Technology ◽  
Small Scale ◽  
Soil Physics ◽  
Coordination Problem ◽  
Precision Engineering ◽  
Precision Forestry ◽  
And Control

The term «precision forestry» was first introduced and discussed at a conference in 2001. The aims of this paper are to explore the scientific roots of the precision concept, define «precision forestry», and sketch the challenges that the implementation of this new concept may present to practitioners, educators, and researchers. The term «precision» does not mean accuracy on a small scale, but instead refers to the concurrent coordination and control of processes at spatial scales between 1 m and 100 km. Precision strives for an automatic control of processes. Precision land use differs from precision engineering by the requirements of gathering,storing and managing spatio-temporal variability of site and vegetation parameters. Practitioners will be facing the challenge of designing holistic, standardized business processes that are valid for whole networks of firms,and that follow available standards (e.g., SCOR, WoodX). There is a need to educate and train forestry professionals in the areas of business process re-engineering, computer supported management of business transactions,methods of remote sensing, sensor technology and control theory. Researchers will face the challenge of integrating plant physiology, soil physics and production sciences and solving the supply chain coordination problem (SCCP).

Money Code Space

2020 ◽  
Author(s):  
Jack Parkin
Keyword(s):  
Open Source Software ◽  
Global Economy ◽  
Research Problem ◽  
Blockchain Technology ◽  
Distributed Ledger ◽  
Start Up ◽  
Challenging Research ◽  
Digital Politics ◽  
Financial Transactions ◽  
And Control

Newly emerging cryptocurrencies and blockchain technology present a challenging research problem in the field of digital politics and economics. Bitcoin—the first widely implemented cryptocurrency and blockchain architecture—seemingly separates itself from the existing territorial boundedness of nation-state money via a process of algorithmic decentralisation. Proponents declare that the utilisation of cryptography to advance financial transactions will disrupt the modern centralised structures by which capitalist economies are currently organised: corporations, governments, commercial banks, and central banks. Allegedly, software can create a more stable and democratic global economy; a world free from hierarchy and control. In Money Code Space, Jack Parkin debunks these utopian claims by approaching distributed ledger technologies as a spatial and social problem where power forms unevenly across their networks. First-hand accounts of online communities, open-source software governance, infrastructural hardware operations, and Silicon Valley start-up culture are used to ground understandings of cryptocurrencies in the “real world.” Consequently, Parkin demonstrates how Bitcoin and other blockchains are produced across a multitude of tessellated spaces from which certain stakeholders exercise considerable amounts of power over their networks. While money, code, and space are certainly transformed by distributed ledgers, algorithmic decentralisation is rendered inherently paradoxical because it is predicated upon centralised actors, practices, and forces.

The Artificial Pancreas in Cyborg Bodies

2020 ◽  
pp. 412-430
Author(s):  
Anthony Ryan Hatch ◽  
Julia T. Gordon ◽  
Sonya R. Sternlieb
Keyword(s):  
Glucose Sensor ◽  
Social Inequalities ◽  
Infusion Pump ◽  
Artificial Pancreas ◽  
Small Scale ◽  
Glucose Levels ◽  
Loop Design ◽  
Access To Health ◽  
Do It Yourself ◽  
And Control

The new artificial pancreas system includes a body-attached blood glucose sensor that tracks glucose levels, a worn insulin infusion pump that communicates with the sensor, and features new software that integrates the two systems. The artificial pancreas is purportedly revolutionary because of its closed-loop design, which means that the machine can give insulin without direct patient intervention. It can read a blood sugar and administer insulin based on an algorithm. But, the hardware for the corporate artificial pancreas is expensive and its software code is closed-access. Yet, well-educated, tech-savvy diabetics have been fashioning their own fully automated do-it-yourself (DIY) artificial pancreases for years, relying on small-scale manufacturing, open-source software, and inventive repurposing of corporate hardware. In this chapter, we trace the corporate and DIY artificial pancreases as they grapple with issues of design and accessibility in a content where not everyone can become a diabetic cyborg. The corporate artificial pancreas offers the cyborg low levels of agency and no ownership and control over his or her own data; it also requires access to health insurance in order to procure and use the technology. The DIY artificial pancreas offers patients a more robust of agency but also requires high levels of intellectual capital to hack the devices and make the system work safely. We argue that efforts to increase agency, radically democratize biotechnology, and expand information ownership in the DIY movement are characterized by ideologies and social inequalities that also define corporate pathways.

Miniature Bioreactors for Rapid Bioprocess Development of Mammalian Cell Culture

2012 ◽  
Vol 59 (1) ◽  
Author(s):  
Mohd Helmi Sani ◽  
Frank Baganz
Keyword(s):  
Cell Culture ◽  
Mammalian Cell ◽  
Process Development ◽  
Mammalian Cell Culture ◽  
Small Scale ◽  
Cell Culture Process ◽  
Deep Wells ◽  
Working Volume ◽  
Culture Process ◽  
And Control

At present, there are a number of commercial small scale shaken systems available on the market with instrumented controllable microbioreactors such as Micro–24 Microreactor System (Pall Corporation, Port Washington, NY) and M2P Biolector, (M2P Labs GmbH, Aachen, Germany). The Micro–24 system is basically an orbital shaken 24–well plate that operates at working volume 3 – 7 mL with 24 independent reactors (deep wells, shaken and sparged) running simultaneously. Each reactor is designed as single use reactor that has the ability to continuously monitor and control the pH, DO and temperature. The reactor aeration is supplied by sparging air from gas feeds that can be controlled individually. Furthermore, pH can be controlled by gas sparging using either dilute ammonia or carbon dioxide directly into the culture medium through a membrane at the bottom of each reactor. Chen et al., (2009) evaluated the Micro–24 system for the mammalian cell culture process development and found the Micro–24 system is suitable as scaledown tool for cell culture application. The result showed that intra-well reproducibility, cell growth, metabolites profiles and protein titres were scalable with 2 L bioreactors.

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