Searched for: department:"Electrical%5C%2BSustainable%5C%2BEnergy"
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Khan, R.U.A. (author), Silva, S.R.P. (author), Van Swaaij, R.A.C.M.M. (author)
Amorphous carbon (a-C) has been shown to be intrinsically p-type, and polymeric a-C (PAC) possesses a wide Tauc band gap of 2.6 eV. We have replaced the p-type amorphous silicon carbide layer of a standard amorphous silicon solar cell with an intrinsic ultrathin layer of PAC. The thickness of the p layer had to be reduced from 9 to 2.5 nm in...
journal article 2003
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Klaver, A. (author), Nádaždy, V. (author), Zeman, M. (author), Swaaiij, R.A.C.M.M. (author)
We present a study of changes in the defect density of states in hydrogenated amorphous silicon (a-Si:H) due to high-energy electron irradiation using charged deep-level transient spectroscopy. It was found that defect states near the conduction band were removed, while in other band gap regions the defect-state density increased. A similar...
journal article 2006
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Van den Brom, H.E. (author), Houtzager, E. (author), Brinkmeier, B.E.R. (author), Chevtchenko, O.A. (author)
AJosephson arbitrary waveform synthesizer (JAWS) has been developed in order to generate quantum-based ac voltage signals. The key component of this JAWS is a modified commercial 30-Gb/s pattern generator that can generate ternary patterns (containing the values +1, 0, and ?1, resulting in bipolar pulses). The new pulse-drive electronics have...
journal article 2008
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Verboomen, J. (author), Van Hertem, D. (author), Schavemaker, P.H. (author), King, W.L. (author), Belmans, R. (author)
Analytical expressions are derived to gain insight in the operating principles of phase shifting transformers (PSTs) in a highly meshed grid. To this extent, the dc load flow algorithm is adapted to account for such devices. This leads to a linear expression for the relation between PST settings and the active power flow in the lines. Based on...
journal article 2008
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Papaefthymiou, G. (author), Klöckl, B. (author)
This paper contributes a Markov chain Monte Carlo (MCMC) method for the direct generation of synthetic time series of wind power output. It is shown that obtaining a stochastic model directly in the wind power domain leads to reduced number of states and to lower order of the Markov chain at equal power data resolution. The estimation quality of...
journal article 2008
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Kumar, P. (author), Bauer, P. (author)
This work focuses on a design methodology that aids in design and development of complex engineering systems. This design methodology consists of simulation, optimization and decision making. Within this work a framework is presented in which modelling, multi-objective optimization and multi criteria decision making techniques are used to design...
journal article 2008
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Kumar, P. (author), Bauer, P. (author)
In this paper, we develop a comprehensive model of a permanent-magnet brushless DC (BLDC) motor. An analytical model for determining instantaneous air-gap field density is developed. This instantaneous field distribution can be further used to determine the cogging torque, induced back electromotive force, and iron losses in the motor. The...
journal article 2008
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Gulski, E. (author), Cichecki, P. (author), Wester, F. (author), Smit, J.J. (author), Bodega, R. (author), Hermans, T.J.W.H. (author), Seitz, P.P. (author), Quak, B. (author), De Vries, F. (author)
In addition to after-laying of new-installed high voltage (HV) power cables the use of on-site non-destructive on-site testing and diagnosis of service aged power cables is becoming an important issue to determine the actual condition of the cable systems and to determine the future performances. In this paper based on field experience an...
journal article 2008
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Cichecki, P. (author), Jongen, R.A. (author), Gulski, E. (author), Smit, J.J. (author), Quak, B. (author), Petzold, F. (author), De Vries, F. (author)
journal article 2008
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De Jong, E.C.W. (author), Ferreira, B.J.A. (author), Bauer, P. (author)
A means for power electronics to exploit the level of 3-D packaging already being implemented in compact consumer products, such as digital cameras, is investigated in order to increase its power density. The increase in functionality and usage of printed circuit board (PCB) in power electronic converters is highlighted and improvements proposed...
journal article 2008
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Papaefthymiou, G. (author), Kurowicka, D. (author)
The increasing penetration of renewable generation in power systems necessitates the modeling of this stochastic system infeed in operation and planning studies. The system analysis leads to multivariate uncertainty analysis problems, involving non-Normal correlated random variables. In this context, the modeling of stochastic dependence is...
journal article 2009
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Zhao, D. (author), Ferreira, J.A. (author), Roc'h, A. (author), Leferink, F. (author)
Filters used in electromagnetic interference suppression are often described in literature on drive systems and have become a standard solution in industry. The effect of the commercial off-the-shelf filter depends significantly on how it is installed. A model that includes the installation parameters is made first and then the parameters of the...
journal article 2009
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Pieters, B.E. (author), Stiebig, H. (author), Zeman, M. (author), Van Swaaij, R.A.C.M.M. (author)
Microcrystalline silicon (?c-Si:H) is a promising material for application in multijunction thin-film solar cells. A detailed analysis of the optoelectronic properties is impeded by its complex microstructural properties. In this work we will focus on determining the mobility gap of ?c-Si:H material. Commonly a value of 1.1?eV is found, similar...
journal article 2009
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Zhou, Y. (author), Bauer, P. (author), Ferreira, J.A. (author), Pierik, J. (author)
Doubly fed induction generator (DFIG) still shares a large part in today's wind power market. It provides the benefits of variable speed operation cost-effectively, and can control its active and reactive power independently. Crowbar protection is often adopted to protect the rotor-side voltage source converter (VSC) from transient overcurrent...
journal article 2009
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Bang, D. (author), Polinder, H. (author), Shrestha, G. (author), Ferreira, J.A. (author)
conference paper 2009
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Shrestha, G. (author), Polinder, H. (author), Bang, D. (author), Jassal, A.K. (author), Ferreira, J.A. (author)
A direct drive generator used in wind turbine has high energy yield compared to other drivetrain topologies and low maintenance is expected as the technology matures. On the other hand direct drive generator weight and size increases rapidly when scaled up to larger units. This paper will investigate the possibility of weight reduction of large...
conference paper 2009
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Krc, J. (author), Zeman, M. (author), Luxembourg, S.L. (author), Topic, M. (author)
A concept of a modulated one-dimensional photonic-crystal (PC) structure is introduced as a back reflector for thin-film solar cells. The structure comprises two PC parts, each consisting of layers of different thicknesses. Using layers of amorphous silicon and amorphous silicon nitride a reflectance close to 100% is achieved over a broad...
journal article 2009
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Jarolimek, K. (author), De Groot, R.A. (author), De Wijs, G.A. (author), Zeman, M. (author)
We use a molecular-dynamics simulation within density-functional theory to prepare realistic structures of hydrogenated amorphous silicon. The procedure consists of heating a crystalline structure of Si64H8 to 2370 K, creating a liquid and subsequently cooling it down to room temperature. The effect of the cooling rate is examined. We prepared a...
journal article 2009
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Xyngi, I. (author), Ishchenko, A. (author), Popov, M. (author), Van der Sluis, L. (author)
This letter describes the transient stability analysis of a 10-kV distribution network with wind generators, microturbines, and CHP plants. The network being modeled in Matlab/Simulink takes into account detailed dynamic models of the generators. Fault simulations at various locations are investigated. For the studied cases, the critical...
journal article 2009
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Veldman, E. (author), Geldtmeijer, D.A.M. (author), Slootweg, J.G. (author)
The transition towards a more sustainable energ y supply system causes changes in the supply and demand of energ y. It requires a more flexible and efficient operation of the electricity distribution grids. It calls for a smart grid with intelligent control embedded in the grids to incorporate electricity storage and controllable loads. This...
conference paper 2009
Searched for: department:"Electrical%5C%2BSustainable%5C%2BEnergy"
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