Documents disponibles écrits par cet auteur

A complex space vector approach to rotor temperature estimation for line-connected induction machines with impaired cooling / Zhi Gao in IEEE transactions on industrial electronics, Vol. 56 N°1 (Janvier 2009) 

Public ISBD [article]  in IEEE transactions on industrial electronics > Vol. 56 N°1 (Janvier 2009) . - pp. 239 - 247 Titre : A complex space vector approach to rotor temperature estimation for line-connected induction machines with impaired cooling Type de document : texte imprimé Auteurs : Zhi Gao, Auteur ; Habetler, Thomas G, Auteur ; Harley, R.G., Auteur Année de publication : 2009 Article en page(s) : pp. 239 - 247 Note générale : electronics Langues : Anglais (eng) Mots-clés : asynchronous  machines;  condition  monitoring;  cooling;  fast  Fourier  transforms;  overvoltage  protection;  relay  protection;  relays;  rotors;  vectors Résumé : Thermal models used in overload protection relays often fail to predict the rotor temperature for motors with impaired cooling conditions. In this case, the temperature estimated from the rotor resistance can be used as an indicator of the motor's cooling capability. However, this estimated rotor temperature is often corrupted by estimation error due to the asymmetry in the power supply. A detailed analysis of the trajectories of the complex current and voltage space vectors in a synchronous reference frame is presented in this paper, and the negative sequence fundamental frequency components are identified as the major cause of the estimation error. Based on this analysis, a fast and efficient algorithm is proposed to calculate the rotor temperature for line-connected induction machines. By applying the Goertzel algorithm to the complex current and voltage space vectors, constructed directly from the motor terminal measurements, the positive sequence fundamental frequency components are extracted, and the rotor temperature is then estimated with significantly reduced estimation error. Compared to the conventional scheme based on the fast Fourier transform, the proposed algorithm is faster and more efficient, and is therefore more suitable for implementation on a low-cost hardware platform. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=4675302&sortType%3Das [...] [article] A complex space vector approach to rotor temperature estimation for line-connected induction machines with impaired cooling [texte imprimé] / Zhi Gao, Auteur ; Habetler, Thomas G, Auteur ; Harley, R.G., Auteur . - 2009 . - pp. 239 - 247. electronics Langues : Anglais (eng) in IEEE transactions on industrial electronics > Vol. 56 N°1 (Janvier 2009) . - pp. 239 - 247 Mots-clés : asynchronous  machines;  condition  monitoring;  cooling;  fast  Fourier  transforms;  overvoltage  protection;  relay  protection;  relays;  rotors;  vectors Résumé : Thermal models used in overload protection relays often fail to predict the rotor temperature for motors with impaired cooling conditions. In this case, the temperature estimated from the rotor resistance can be used as an indicator of the motor's cooling capability. However, this estimated rotor temperature is often corrupted by estimation error due to the asymmetry in the power supply. A detailed analysis of the trajectories of the complex current and voltage space vectors in a synchronous reference frame is presented in this paper, and the negative sequence fundamental frequency components are identified as the major cause of the estimation error. Based on this analysis, a fast and efficient algorithm is proposed to calculate the rotor temperature for line-connected induction machines. By applying the Goertzel algorithm to the complex current and voltage space vectors, constructed directly from the motor terminal measurements, the positive sequence fundamental frequency components are extracted, and the rotor temperature is then estimated with significantly reduced estimation error. Compared to the conventional scheme based on the fast Fourier transform, the proposed algorithm is faster and more efficient, and is therefore more suitable for implementation on a low-cost hardware platform. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=4675302&sortType%3Das [...]

Feed-forward transient current control for low-voltage ride-through enhancement of DFIG wind turbines / Jiaqi Liang in IEEE transactions on energy conversion, Vol. 25, N° 3 (Septembre 2010) 

Public ISBD [article]  in IEEE transactions on energy conversion > Vol. 25, N° 3 (Septembre 2010) . - pp. 836 - 843 Titre : Feed-forward transient current control for low-voltage ride-through enhancement of DFIG wind turbines Type de document : texte imprimé Auteurs : Jiaqi Liang, Auteur ; Qiao, Wei, Auteur ; Harley, R.G., Auteur Année de publication : 2011 Article en page(s) : pp. 836 - 843 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : Asynchronous  generators;  electric  current  control;  fault  diagnosis;  feedforward;  power  grids;  transient  analysis;  wind  turbines Résumé : High penetration of wind power requires reliable wind energy generation. A successful low-voltage ride-through (LVRT) scheme is a key requirement to achieve reliable and uninterrupted electrical power generation for wind turbines equipped with doubly fed induction generators (DFIGs). This paper proposes a feed-forward transient current control (FFTCC) scheme for the rotor side converter (RSC) of a DFIG to enhance its LVRT capability. This new control scheme introduces additional feed-forward transient compensations to a conventional current regulator. When three phase faults occur, these compensation terms correctly align the RSC ac-side output voltage with the transient-induced voltage, resulting in minimum transient rotor current and minimum occurrence of crowbar interruptions. With little additional computational effort, the proposed control scheme helps relieve the transient current stress on the RSC and helps maintain an uninterrupted active and reactive power supply from the wind turbines to the power grid. Simulation results are shown to demonstrate the effectiveness of the proposed FFTCC scheme in suppressing transient rotor currents. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5552142&sortType%3Das [...] [article] Feed-forward transient current control for low-voltage ride-through enhancement of DFIG wind turbines [texte imprimé] / Jiaqi Liang, Auteur ; Qiao, Wei, Auteur ; Harley, R.G., Auteur . - 2011 . - pp. 836 - 843. energy conversion Langues : Anglais (eng) in IEEE transactions on energy conversion > Vol. 25, N° 3 (Septembre 2010) . - pp. 836 - 843 Mots-clés : Asynchronous  generators;  electric  current  control;  fault  diagnosis;  feedforward;  power  grids;  transient  analysis;  wind  turbines Résumé : High penetration of wind power requires reliable wind energy generation. A successful low-voltage ride-through (LVRT) scheme is a key requirement to achieve reliable and uninterrupted electrical power generation for wind turbines equipped with doubly fed induction generators (DFIGs). This paper proposes a feed-forward transient current control (FFTCC) scheme for the rotor side converter (RSC) of a DFIG to enhance its LVRT capability. This new control scheme introduces additional feed-forward transient compensations to a conventional current regulator. When three phase faults occur, these compensation terms correctly align the RSC ac-side output voltage with the transient-induced voltage, resulting in minimum transient rotor current and minimum occurrence of crowbar interruptions. With little additional computational effort, the proposed control scheme helps relieve the transient current stress on the RSC and helps maintain an uninterrupted active and reactive power supply from the wind turbines to the power grid. Simulation results are shown to demonstrate the effectiveness of the proposed FFTCC scheme in suppressing transient rotor currents. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5552142&sortType%3Das [...]