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IEEE transactions on energy conversion |
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Ajouter le résultat dans votre panierDead time compensation method for voltage-fed PWM inverter / Seon-Hwan Hwang in IEEE transactions on energy conversion, Vol. 25 N° 1 (Mars 2010)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 1 - 10
Titre : Dead time compensation method for voltage-fed PWM inverter Type de document : texte imprimé Auteurs : Seon-Hwan Hwang, Auteur ; Jang-Mok Kim, Auteur Année de publication : 2010 Article en page(s) : pp. 1 - 10 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : PI control; PWM invertors; electric current control; power conversion harmonics Résumé : A new dead time compensation method for a pulsewidth modulation (PWM) inverter is proposed. In the PWM inverter, voltage distortion due to the dead time effects produces fifth and seventh harmonics in the phase currents of the stationary reference frame, and a sixth harmonic in the d- and q-axis currents of the synchronous reference frame, respectively. In this paper, the sixth harmonic of the integrator output of the synchronous d-axis proportional-integral (PI) current regulator is used to compensate the output voltage distortion due to the dead time effects, since the integrator output has ripple corresponding to six times the stator fundamental frequency. The proposed method can be easily implemented by feedforwardly adding compensation voltages to the output reference voltage of the synchronous PI current regulator. The proposed method, therefore, has some significant advantages such as simple implementation without additional hardware, easy mathematical computation, no offline experimental measurements, and application in both the steady state and the transient state. The validity of the proposed compensation algorithm is shown through several experiments. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5308357&sortType%3Das [...] [article] Dead time compensation method for voltage-fed PWM inverter [texte imprimé] / Seon-Hwan Hwang, Auteur ; Jang-Mok Kim, Auteur . - 2010 . - pp. 1 - 10.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 1 - 10
Mots-clés : PI control; PWM invertors; electric current control; power conversion harmonics Résumé : A new dead time compensation method for a pulsewidth modulation (PWM) inverter is proposed. In the PWM inverter, voltage distortion due to the dead time effects produces fifth and seventh harmonics in the phase currents of the stationary reference frame, and a sixth harmonic in the d- and q-axis currents of the synchronous reference frame, respectively. In this paper, the sixth harmonic of the integrator output of the synchronous d-axis proportional-integral (PI) current regulator is used to compensate the output voltage distortion due to the dead time effects, since the integrator output has ripple corresponding to six times the stator fundamental frequency. The proposed method can be easily implemented by feedforwardly adding compensation voltages to the output reference voltage of the synchronous PI current regulator. The proposed method, therefore, has some significant advantages such as simple implementation without additional hardware, easy mathematical computation, no offline experimental measurements, and application in both the steady state and the transient state. The validity of the proposed compensation algorithm is shown through several experiments. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5308357&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 11 - 19
Titre : Identification of the induction motor in sinusoidal mode Type de document : texte imprimé Auteurs : Laroche, E., Auteur ; Boutayeb, M., Auteur Année de publication : 2010 Article en page(s) : pp. 11 - 19 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : induction motors; nonlinear programming; parameter estimation Résumé : This paper presents an original method for estimation of the induction motor parameters, including iron loss, with measurements in the sinusoidal steady-state mode. Based on a change of parameter yielding a model that is linear with respect to the new set of parameters, this method allows parameter estimation with low computation cost and without being concerned by local minima problems. This method is evaluated and compared with two other methods from the literature, which are also based on sinusoidal steady-state measurements: a standard method based on two elementary tests and a method where parameters are estimated through minimization of a nonconvex distance criterion with a nonlinear programming algorithm. For the considered methods, sensitivities to measurement and modeling errors are evaluated, emphasizing the performances of the original method. Experimental results, obtained on a setup of 1.5 kW rated power, are provided. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5356211&sortType%3Das [...] [article] Identification of the induction motor in sinusoidal mode [texte imprimé] / Laroche, E., Auteur ; Boutayeb, M., Auteur . - 2010 . - pp. 11 - 19.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 11 - 19
Mots-clés : induction motors; nonlinear programming; parameter estimation Résumé : This paper presents an original method for estimation of the induction motor parameters, including iron loss, with measurements in the sinusoidal steady-state mode. Based on a change of parameter yielding a model that is linear with respect to the new set of parameters, this method allows parameter estimation with low computation cost and without being concerned by local minima problems. This method is evaluated and compared with two other methods from the literature, which are also based on sinusoidal steady-state measurements: a standard method based on two elementary tests and a method where parameters are estimated through minimization of a nonconvex distance criterion with a nonlinear programming algorithm. For the considered methods, sensitivities to measurement and modeling errors are evaluated, emphasizing the performances of the original method. Experimental results, obtained on a setup of 1.5 kW rated power, are provided. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5356211&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 20 - 24
Titre : Symptoms of winding insulation aging after 37 years of service life in a hydrogenerator Type de document : texte imprimé Auteurs : Weiers, T., Auteur Année de publication : 2010 Article en page(s) : pp. 20 - 24 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : corona; hydroelectric generators; machine insulation Résumé : To gain insight into the aging mechanisms of winding insulations for power generators, the insulation system of an in-service aged winding was assessed. Accordingly, generator bars were dismantled from an 8 kV hydrogenerator that had failed an overpotential test. Since this machine had previously been steam cleaned, it was assumed that its winding insulation could have absorbed water. A loss factor of 9.6% measured at 0.2 UN confirmed this assumption. To investigate the consequences of this finding, voltage endurance tests were carried out: Time to breakdown values of the in-service aged insulation were obtained that were shorter by a factor 27 compared to an unaged replacement bar. Hence, the absorption of water by an in-service aged insulation can significantly deteriorate its remaining life. Apart from the groundwall insulation, oil from the bearings of this machine had partly dissolved the corona protection of the winding. Accordingly, the maximum surface resistance of the corona protection was found to be more than ten times higher compared to its original value. This problem may yield discharges in the slots of the stator which compromise reliable operation. It is therefore recommended to check windings with similar problems for this type of discharge. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5352315&sortType%3Das [...] [article] Symptoms of winding insulation aging after 37 years of service life in a hydrogenerator [texte imprimé] / Weiers, T., Auteur . - 2010 . - pp. 20 - 24.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 20 - 24
Mots-clés : corona; hydroelectric generators; machine insulation Résumé : To gain insight into the aging mechanisms of winding insulations for power generators, the insulation system of an in-service aged winding was assessed. Accordingly, generator bars were dismantled from an 8 kV hydrogenerator that had failed an overpotential test. Since this machine had previously been steam cleaned, it was assumed that its winding insulation could have absorbed water. A loss factor of 9.6% measured at 0.2 UN confirmed this assumption. To investigate the consequences of this finding, voltage endurance tests were carried out: Time to breakdown values of the in-service aged insulation were obtained that were shorter by a factor 27 compared to an unaged replacement bar. Hence, the absorption of water by an in-service aged insulation can significantly deteriorate its remaining life. Apart from the groundwall insulation, oil from the bearings of this machine had partly dissolved the corona protection of the winding. Accordingly, the maximum surface resistance of the corona protection was found to be more than ten times higher compared to its original value. This problem may yield discharges in the slots of the stator which compromise reliable operation. It is therefore recommended to check windings with similar problems for this type of discharge. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5352315&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 25 - 33
Titre : Low-speed and standstill operation of a sensorless direct torque and flux controlled IPM synchronous motor drive Type de document : texte imprimé Auteurs : Foo, G., Auteur ; Sayeef, S., Auteur ; Rahman, M.F., Auteur Année de publication : 2010 Article en page(s) : pp. 25 - 33 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : PI control; closed loop systems; machine vector control; observers; permanent magnet motors; synchronous motor drives; torque control Résumé : This paper investigates a sensorless direct torque and flux control scheme for interior permanent magnet synchronous motor drives at low speeds, including standstill. Closed-loop control of both torque and stator flux linkage are achieved by using two proportional-integral controllers. The reference voltage vectors are generated by a space vector modulation unit. A high-frequency signal injection technique is adopted at low speeds to obtain the rotor position information. A hybrid current-voltage model flux observer with a smooth handover algorithm estimates the stator flux linkage over the whole speed range. Experimental results confirm the effectiveness of the proposed method. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5409657&sortType%3Das [...] [article] Low-speed and standstill operation of a sensorless direct torque and flux controlled IPM synchronous motor drive [texte imprimé] / Foo, G., Auteur ; Sayeef, S., Auteur ; Rahman, M.F., Auteur . - 2010 . - pp. 25 - 33.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 25 - 33
Mots-clés : PI control; closed loop systems; machine vector control; observers; permanent magnet motors; synchronous motor drives; torque control Résumé : This paper investigates a sensorless direct torque and flux control scheme for interior permanent magnet synchronous motor drives at low speeds, including standstill. Closed-loop control of both torque and stator flux linkage are achieved by using two proportional-integral controllers. The reference voltage vectors are generated by a space vector modulation unit. A high-frequency signal injection technique is adopted at low speeds to obtain the rotor position information. A hybrid current-voltage model flux observer with a smooth handover algorithm estimates the stator flux linkage over the whole speed range. Experimental results confirm the effectiveness of the proposed method. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5409657&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 34 - 48
Titre : Development and validation of a comprehensive synchronous machine model for a real-time environment Type de document : texte imprimé Auteurs : A. B. Dehkordi, Auteur ; Neti, P., Auteur ; Gole, A.M., Auteur Année de publication : 2010 Article en page(s) : pp. 34 - 48 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : fault diagnosis; finite element analysis; machine theory; machine windings; synchronous machines Résumé : A comprehensive model of a salient-pole synchronous machine is developed for a real-time environment. By obtaining the effective specific permeance of the machine from simple experimental measurements and the exact geometry of the rotor pole arc, a model is developed that includes the exact distribution of windings and operating-point-dependent saturation. This model offers a superior simulated response of the machine for fault transients, as well as for steady-state harmonic behavior, and is suitable for the closed-loop testing of relays and controls. The inductances of the machine are computed using the modified winding function approach and validated using finite-element analysis. Finally, the performance of the model is validated under healthy and faulted conditions by comparison with tests on an actual machine. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5404394&sortType%3Das [...] [article] Development and validation of a comprehensive synchronous machine model for a real-time environment [texte imprimé] / A. B. Dehkordi, Auteur ; Neti, P., Auteur ; Gole, A.M., Auteur . - 2010 . - pp. 34 - 48.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 34 - 48
Mots-clés : fault diagnosis; finite element analysis; machine theory; machine windings; synchronous machines Résumé : A comprehensive model of a salient-pole synchronous machine is developed for a real-time environment. By obtaining the effective specific permeance of the machine from simple experimental measurements and the exact geometry of the rotor pole arc, a model is developed that includes the exact distribution of windings and operating-point-dependent saturation. This model offers a superior simulated response of the machine for fault transients, as well as for steady-state harmonic behavior, and is suitable for the closed-loop testing of relays and controls. The inductances of the machine are computed using the modified winding function approach and validated using finite-element analysis. Finally, the performance of the model is validated under healthy and faulted conditions by comparison with tests on an actual machine. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5404394&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 49 - 58
Titre : Progress in DC testing of generator stator windings : theoretical considerations and laboratory tests Type de document : texte imprimé Auteurs : David, E., Auteur ; Lamarre, L., Auteur Année de publication : 2010 Article en page(s) : pp. 49 - 58 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : condition monitoring; machine insulation; machine testing; partial discharge measurement; stators; synchronous machines Résumé : The aging due to mechanical, thermal, electrical, and environmental stresses of a stator insulation system inherently involves alterations of the material properties that are detrimental to its service operation. When these properties are deteriorated to the point where the material can no longer operate safely under normal stress conditions, it implies that it has reached the end of its useful life. To prevent such forced outages and improve the useful life, condition-based maintenance and diagnostic tests are periodically conducted on stator insulation systems. Among the tests performed to assess the condition of winding insulation, various methods are commonly used, such as partial discharge measurements, hipot, step voltage, and ramped voltage tests (RTs), to name just a few. DC testing, where the current is continuously monitored, whether during a step voltage test, such as the polarization/depolarization test, or during a linearly increasing voltage test, such as the RT, is commonly used in the field in order to assess the quality of stator winding insulating systems of large synchronous rotating machines. Both of these tests are related to the dielectric response of the insulation system. This paper presents theoretical considerations on the dielectric response of the various types of machine winding insulation systems encounter in the field as well as laboratory results on individual bars and coils. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5357403&sortType%3Das [...] [article] Progress in DC testing of generator stator windings : theoretical considerations and laboratory tests [texte imprimé] / David, E., Auteur ; Lamarre, L., Auteur . - 2010 . - pp. 49 - 58.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 49 - 58
Mots-clés : condition monitoring; machine insulation; machine testing; partial discharge measurement; stators; synchronous machines Résumé : The aging due to mechanical, thermal, electrical, and environmental stresses of a stator insulation system inherently involves alterations of the material properties that are detrimental to its service operation. When these properties are deteriorated to the point where the material can no longer operate safely under normal stress conditions, it implies that it has reached the end of its useful life. To prevent such forced outages and improve the useful life, condition-based maintenance and diagnostic tests are periodically conducted on stator insulation systems. Among the tests performed to assess the condition of winding insulation, various methods are commonly used, such as partial discharge measurements, hipot, step voltage, and ramped voltage tests (RTs), to name just a few. DC testing, where the current is continuously monitored, whether during a step voltage test, such as the polarization/depolarization test, or during a linearly increasing voltage test, such as the RT, is commonly used in the field in order to assess the quality of stator winding insulating systems of large synchronous rotating machines. Both of these tests are related to the dielectric response of the insulation system. This paper presents theoretical considerations on the dielectric response of the various types of machine winding insulation systems encounter in the field as well as laboratory results on individual bars and coils. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5357403&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 59 - 69
Titre : Effect of erroneous position measurements in vector-controlled doubly fed induction generator Type de document : texte imprimé Auteurs : Zhong Wang, Auteur ; Guo-jie Li, Auteur ; Yuanzhang Sun, Auteur Année de publication : 2010 Article en page(s) : pp. 59 - 69 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : asynchronous generators; machine control; phase locked loops; position measurement; rotors; stators Résumé : Vector control of the doubly fed induction generators (DFIGs) depends on accurate information from a stator voltage phase lock loop (PLL) and a rotor position encoder for the reference frame transformations required by theory. The effect of erroneous information due to noise picked up by commonly used hardware PLLs and incremental position encoders was analyzed in this paper. The analysis shows that erroneous information can give rise to destructively large currents due to: 1) the DFIG system wrongfully perceiving very large P and Q references; and 2) system instability. It is shown that instability does not arise from inside the inner current feedback loop, but from the outer feedback loop that regulates the complex power. Simulation and experimental test results validate the analysis. The experimental results are taken from a 1.5-MW DFIG intended for a wind turbine. A simple scheme to protect against the erroneous information has been tested successfully in a brief trial period. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5401075&sortType%3Das [...] [article] Effect of erroneous position measurements in vector-controlled doubly fed induction generator [texte imprimé] / Zhong Wang, Auteur ; Guo-jie Li, Auteur ; Yuanzhang Sun, Auteur . - 2010 . - pp. 59 - 69.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 59 - 69
Mots-clés : asynchronous generators; machine control; phase locked loops; position measurement; rotors; stators Résumé : Vector control of the doubly fed induction generators (DFIGs) depends on accurate information from a stator voltage phase lock loop (PLL) and a rotor position encoder for the reference frame transformations required by theory. The effect of erroneous information due to noise picked up by commonly used hardware PLLs and incremental position encoders was analyzed in this paper. The analysis shows that erroneous information can give rise to destructively large currents due to: 1) the DFIG system wrongfully perceiving very large P and Q references; and 2) system instability. It is shown that instability does not arise from inside the inner current feedback loop, but from the outer feedback loop that regulates the complex power. Simulation and experimental test results validate the analysis. The experimental results are taken from a 1.5-MW DFIG intended for a wind turbine. A simple scheme to protect against the erroneous information has been tested successfully in a brief trial period. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5401075&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 70 - 79
Titre : Application of the finite-element method for the determination of the parameters representing the cross-magnetizing in saturated synchronous machines Type de document : texte imprimé Auteurs : Xiaodong Liang, Auteur ; El-Serafi, A.M., Auteur ; S. O. Faried, Auteur Année de publication : 2010 Article en page(s) : pp. 70 - 79 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : electromagnetic fields; finite element analysis; synchronous machines Résumé : It has been recognized that the cross-magnetizing phenomenon of saturated synchronous machines plays an important role in their analysis using the two-axis frame models. In this paper, the finite-element method (FEM) is applied to determine from 2-D static electromagnetic field solutions the parameters representing this phenomenon. A specially designed synchronous machine that can be excited from both its direct and quadrature axes is used in this study in order that the parameters representing the cross-magnetizing effect could be measured experimentally and, thus, the accuracy of the numerical solution can be verified. The effects of some of the factors that may affect the accuracy of the FEM analysis have also been investigated. The results of these studies have shown that the calculated parameters representing the cross-magnetizing phenomenon using the FEM are consistent with the measured values. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5345872&sortType%3Das [...] [article] Application of the finite-element method for the determination of the parameters representing the cross-magnetizing in saturated synchronous machines [texte imprimé] / Xiaodong Liang, Auteur ; El-Serafi, A.M., Auteur ; S. O. Faried, Auteur . - 2010 . - pp. 70 - 79.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 70 - 79
Mots-clés : electromagnetic fields; finite element analysis; synchronous machines Résumé : It has been recognized that the cross-magnetizing phenomenon of saturated synchronous machines plays an important role in their analysis using the two-axis frame models. In this paper, the finite-element method (FEM) is applied to determine from 2-D static electromagnetic field solutions the parameters representing this phenomenon. A specially designed synchronous machine that can be excited from both its direct and quadrature axes is used in this study in order that the parameters representing the cross-magnetizing effect could be measured experimentally and, thus, the accuracy of the numerical solution can be verified. The effects of some of the factors that may affect the accuracy of the FEM analysis have also been investigated. The results of these studies have shown that the calculated parameters representing the cross-magnetizing phenomenon using the FEM are consistent with the measured values. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5345872&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 80 - 89
Titre : Influence of nonconsecutive bar breakages in motor current signature analysis for the diagnosis of rotor faults in induction motors Type de document : texte imprimé Auteurs : Riera-Guasp, Martin, Auteur ; Cabanas, M. F., Auteur ; Antonino-Daviu, Jose Alfonso, Auteur Année de publication : 2010 Article en page(s) : pp. 80 - 89 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : electric machine analysis computing; fault diagnosis; finite element analysis; rotors; squirrel cage motors Résumé : Studies of rotor asymmetries in squirrel-cage induction motors have traditionally focused on analyses of the effects of the breakage of adjacent bars on the magnetic field and current spectrum. However, major motor manufacturers have reported cases where damaged bars are randomly distributed around the rotor perimeter of large HV machines. In some of these cases, the motors were being monitored under maintenance programs based on motor current signature analysis (MCSA), and the degree of degradation found in the rotor was much greater than that predicted by analysis of their current spectra. For this reason, a complete study was carried out, comprising a theoretical analysis, as well as simulation and tests, to investigate the influence that the number and location of faulty bars has on the traditional MCSA diagnosis procedure. From the theoretical analysis, based on the application of the fault-current approach and space-vector theory, a very simple method is deduced, which enables the left sideband amplitude to be calculated for any double bar breakage, per unit of the sideband amplitude corresponding to a single breakage. The proposed methodology is generalized for the estimation of the sideband amplitude in the case of multiple bar breakages and validated by simulation using a finite-element-based model, as well as by laboratory tests. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5350691&sortType%3Das [...] [article] Influence of nonconsecutive bar breakages in motor current signature analysis for the diagnosis of rotor faults in induction motors [texte imprimé] / Riera-Guasp, Martin, Auteur ; Cabanas, M. F., Auteur ; Antonino-Daviu, Jose Alfonso, Auteur . - 2010 . - pp. 80 - 89.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 80 - 89
Mots-clés : electric machine analysis computing; fault diagnosis; finite element analysis; rotors; squirrel cage motors Résumé : Studies of rotor asymmetries in squirrel-cage induction motors have traditionally focused on analyses of the effects of the breakage of adjacent bars on the magnetic field and current spectrum. However, major motor manufacturers have reported cases where damaged bars are randomly distributed around the rotor perimeter of large HV machines. In some of these cases, the motors were being monitored under maintenance programs based on motor current signature analysis (MCSA), and the degree of degradation found in the rotor was much greater than that predicted by analysis of their current spectra. For this reason, a complete study was carried out, comprising a theoretical analysis, as well as simulation and tests, to investigate the influence that the number and location of faulty bars has on the traditional MCSA diagnosis procedure. From the theoretical analysis, based on the application of the fault-current approach and space-vector theory, a very simple method is deduced, which enables the left sideband amplitude to be calculated for any double bar breakage, per unit of the sideband amplitude corresponding to a single breakage. The proposed methodology is generalized for the estimation of the sideband amplitude in the case of multiple bar breakages and validated by simulation using a finite-element-based model, as well as by laboratory tests. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5350691&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 90 - 99
Titre : Generalized topologies of multiple single-phase motor drives Type de document : texte imprimé Auteurs : Dos Santos, E.C., Auteur ; Jacobina, C.B., Auteur ; Beltrao de Rossiter Correa, M., Auteur Année de publication : 2010 Article en page(s) : pp. 90 - 99 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : AC motor drives; DC-AC power convertors Résumé : This paper investigates multiple single-phase converters for multiple single-phase motor drives from a dc-link voltage. The dc-link voltage is obtained from primary energy sources such as photovoltaic, battery, utility grid, or by a combination of these. This paper points out the best configuration for different scenarios. The proposed systems allow functions such as soft start, independent adjustment of motor speeds, or group of motors operating at different rated frequencies. Furthermore, a control technique has been proposed to maximize the utilization of the dc-link voltage and minimize shared leg currents. Several relevant characteristics of the converters are addressed, such as voltage capability, shared-leg currents, and power ratings. Experimental and simulated results are presented. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5378603&sortType%3Das [...] [article] Generalized topologies of multiple single-phase motor drives [texte imprimé] / Dos Santos, E.C., Auteur ; Jacobina, C.B., Auteur ; Beltrao de Rossiter Correa, M., Auteur . - 2010 . - pp. 90 - 99.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 90 - 99
Mots-clés : AC motor drives; DC-AC power convertors Résumé : This paper investigates multiple single-phase converters for multiple single-phase motor drives from a dc-link voltage. The dc-link voltage is obtained from primary energy sources such as photovoltaic, battery, utility grid, or by a combination of these. This paper points out the best configuration for different scenarios. The proposed systems allow functions such as soft start, independent adjustment of motor speeds, or group of motors operating at different rated frequencies. Furthermore, a control technique has been proposed to maximize the utilization of the dc-link voltage and minimize shared leg currents. Several relevant characteristics of the converters are addressed, such as voltage capability, shared-leg currents, and power ratings. Experimental and simulated results are presented. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5378603&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 100 - 106
Titre : A new criterion for the quantification of broken rotor bars in induction motors Type de document : texte imprimé Auteurs : Boqiang Xu, Auteur ; Liling Sun, Auteur ; Ren Hui, Auteur Année de publication : 2010 Article en page(s) : pp. 100 - 106 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : fault diagnosis; induction motors; rotors Résumé : This paper addresses itself to evaluate quantitatively the severity of broken rotor bar (BRB) fault, i.e., the number of BRBs in induction motors. Sideband components are induced in stator current if BRB fault is present and commonly used for diagnosis purposes. Filippetti criterion has been proposed and developed in the literature to quantify the severity of BRB fault by using sideband components, however, with unsatisfactory universality/accuracy. This paper briefly analyzes Filippetti criterion, and mathematically derives a new criterion for the quantification of BRBs, based on the electromagnetic mechanism of sideband components. Comparing to Filippetti criterion, the universality and accuracy of the new criterion are both improved. Moreover, the new criterion includes the influence from the interbar currents associated with BRB fault. The related experiment on a 3-kW, 380-V, 50-Hz induction motor has been conducted, and results show the superiority of the new criterion over Filippetti criterion. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5340658&sortType%3Das [...] [article] A new criterion for the quantification of broken rotor bars in induction motors [texte imprimé] / Boqiang Xu, Auteur ; Liling Sun, Auteur ; Ren Hui, Auteur . - 2010 . - pp. 100 - 106.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 100 - 106
Mots-clés : fault diagnosis; induction motors; rotors Résumé : This paper addresses itself to evaluate quantitatively the severity of broken rotor bar (BRB) fault, i.e., the number of BRBs in induction motors. Sideband components are induced in stator current if BRB fault is present and commonly used for diagnosis purposes. Filippetti criterion has been proposed and developed in the literature to quantify the severity of BRB fault by using sideband components, however, with unsatisfactory universality/accuracy. This paper briefly analyzes Filippetti criterion, and mathematically derives a new criterion for the quantification of BRBs, based on the electromagnetic mechanism of sideband components. Comparing to Filippetti criterion, the universality and accuracy of the new criterion are both improved. Moreover, the new criterion includes the influence from the interbar currents associated with BRB fault. The related experiment on a 3-kW, 380-V, 50-Hz induction motor has been conducted, and results show the superiority of the new criterion over Filippetti criterion. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5340658&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 107 - 117
Titre : Evaluation of two anti-islanding schemes for a radial distribution system equipped with self-excited induction generator wind turbines Type de document : texte imprimé Auteurs : El-Khattam, W., Auteur ; Sidhu, Tarlochan S., Auteur ; Seethapathy, R., Auteur Année de publication : 2010 Article en page(s) : pp. 107 - 117 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : asynchronous generators; circuit breakers; distributed power generation; optical fibre communication; power distribution protection; power system interconnection; power system measurement; radiocommunication; wind turbines Résumé : Local distribution companies (LDCs) require disconnection of distributed generation (DG) as soon as disturbance events occur to prevent sustainable islanding and damaging DGs and other equipments. In this paper, real-time laboratory testings were carried out to evaluate existing anti-islanding detection schemes. A comprehensive analysis and a testing process are proposed to assess the selection of a fast and reliable scheme for a practical radial distribution system equipped with a group of self-excited induction generator wind turbines (SEIG). Two anti-islanding schemes (passive local detection and communication based) were examined on various commercial relays to disconnect SEIG-DG in case of a main breaker opening due to a fault. The impact of existing recloser timer characteristics on the selection of the proper scheme is illustrated. The selected scheme was verified to disconnect SEIG-DGs in case of a manual main breaker opening in a proper time to protect public safety. A dedicated fiber optic connection and radio frequency communication-based schemes were evaluated and compared with passive local detection scheme performance. Various scenarios of SEIG-DG penetration levels were simulated, and different available commercial relay functions were tested. The obtained results, recommendations, and economic evaluations for choosing a proper scheme are reported and discussed. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5353726&sortType%3Das [...] [article] Evaluation of two anti-islanding schemes for a radial distribution system equipped with self-excited induction generator wind turbines [texte imprimé] / El-Khattam, W., Auteur ; Sidhu, Tarlochan S., Auteur ; Seethapathy, R., Auteur . - 2010 . - pp. 107 - 117.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 107 - 117
Mots-clés : asynchronous generators; circuit breakers; distributed power generation; optical fibre communication; power distribution protection; power system interconnection; power system measurement; radiocommunication; wind turbines Résumé : Local distribution companies (LDCs) require disconnection of distributed generation (DG) as soon as disturbance events occur to prevent sustainable islanding and damaging DGs and other equipments. In this paper, real-time laboratory testings were carried out to evaluate existing anti-islanding detection schemes. A comprehensive analysis and a testing process are proposed to assess the selection of a fast and reliable scheme for a practical radial distribution system equipped with a group of self-excited induction generator wind turbines (SEIG). Two anti-islanding schemes (passive local detection and communication based) were examined on various commercial relays to disconnect SEIG-DG in case of a main breaker opening due to a fault. The impact of existing recloser timer characteristics on the selection of the proper scheme is illustrated. The selected scheme was verified to disconnect SEIG-DGs in case of a manual main breaker opening in a proper time to protect public safety. A dedicated fiber optic connection and radio frequency communication-based schemes were evaluated and compared with passive local detection scheme performance. Various scenarios of SEIG-DG penetration levels were simulated, and different available commercial relay functions were tested. The obtained results, recommendations, and economic evaluations for choosing a proper scheme are reported and discussed. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5353726&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 118-127
Titre : Torque ripple reduction in interior permanent magnet synchronous machines using stators with odd number of slots per pole pair Type de document : texte imprimé Auteurs : Seok-Hee Han, Auteur ; Jahns, Thomas M., Auteur ; Soong, W.L., Auteur Année de publication : 2010 Article en page(s) : pp. 118-127 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : permanent magnet machines; rotors; stators; synchronous machines Résumé : This paper develops analytical principles for torque ripple reduction in interior permanent magnet (IPM) synchronous machines. The significance of slot harmonics and the benefits of stators with odd number of slots per pole pair are highlighted. Based on these valuable analytical insights, this paper proposes coordination of the selection of stators with odd number of slots per pole pair and IPM rotors with multiple layers of flux barriers in order to reduce torque ripple. The effectiveness of using stators with odd number of slots per pole pair in reducing torque ripple is validated by applying a finite-element-based Monte Carlo optimization method to four IPM machine topologies, which are combinations of two stator topologies (even or odd number of slots per pole pair) and two IPM rotor topologies (one- or two-layer). It is demonstrated that the torque ripple can be reduced to less than 5% by selecting a stator with an odd number of slots per pole pair and the IPM rotor with optimized barrier configurations, without using stator/rotor skewing or rotor pole shaping. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5401095&sortType%3Das [...] [article] Torque ripple reduction in interior permanent magnet synchronous machines using stators with odd number of slots per pole pair [texte imprimé] / Seok-Hee Han, Auteur ; Jahns, Thomas M., Auteur ; Soong, W.L., Auteur . - 2010 . - pp. 118-127.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 118-127
Mots-clés : permanent magnet machines; rotors; stators; synchronous machines Résumé : This paper develops analytical principles for torque ripple reduction in interior permanent magnet (IPM) synchronous machines. The significance of slot harmonics and the benefits of stators with odd number of slots per pole pair are highlighted. Based on these valuable analytical insights, this paper proposes coordination of the selection of stators with odd number of slots per pole pair and IPM rotors with multiple layers of flux barriers in order to reduce torque ripple. The effectiveness of using stators with odd number of slots per pole pair in reducing torque ripple is validated by applying a finite-element-based Monte Carlo optimization method to four IPM machine topologies, which are combinations of two stator topologies (even or odd number of slots per pole pair) and two IPM rotor topologies (one- or two-layer). It is demonstrated that the torque ripple can be reduced to less than 5% by selecting a stator with an odd number of slots per pole pair and the IPM rotor with optimized barrier configurations, without using stator/rotor skewing or rotor pole shaping. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5401095&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 128 - 139
Titre : Load-tracking performance of an autonomous SOFC-based hybrid power generation/energy storage system Type de document : texte imprimé Auteurs : Wang, Li, Auteur ; Dong-Jing Lee, Auteur Année de publication : 2010 Article en page(s) : pp. 128 - 139 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : DC-DC power convertors; battery storage plants; diesel-electric generators; hybrid power systems; invertors; solid oxide fuel cells Résumé : This paper focuses on the load-tracking performance of an autonomous hybrid power generation/energy storage system (PG/ESS) with two solid-oxide fuel cells (SOFCs), a diesel-engine generator (DEG), a battery ESS (BESS), two dc-dc converters, and a dc-ac inverter. The system can sustain PG to supply suddenly changed loads, one of which is an emergency load that must have uninterruptible power supply. This paper proposes a control scheme using the output dc current of the SOFC or the current magnitude of the ac load to modulate the hydrogen-flow rate of the SOFC. The PG of the two SOFCs can be adequately coordinated with the generated power of the DEG, the stored/released energy of the BESS, and the output power of the dc-ac inverter to maintain both frequency and voltage of the connected loads at the desired values. Time-domain simulated results of the studied hybrid system under four studied cases are performed and analyzed to validate the good load-tracking characteristics of the proposed SOFC-based hybrid PG/ESS feeding time-varying loads. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5350670&sortType%3Das [...] [article] Load-tracking performance of an autonomous SOFC-based hybrid power generation/energy storage system [texte imprimé] / Wang, Li, Auteur ; Dong-Jing Lee, Auteur . - 2010 . - pp. 128 - 139.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 128 - 139
Mots-clés : DC-DC power convertors; battery storage plants; diesel-electric generators; hybrid power systems; invertors; solid oxide fuel cells Résumé : This paper focuses on the load-tracking performance of an autonomous hybrid power generation/energy storage system (PG/ESS) with two solid-oxide fuel cells (SOFCs), a diesel-engine generator (DEG), a battery ESS (BESS), two dc-dc converters, and a dc-ac inverter. The system can sustain PG to supply suddenly changed loads, one of which is an emergency load that must have uninterruptible power supply. This paper proposes a control scheme using the output dc current of the SOFC or the current magnitude of the ac load to modulate the hydrogen-flow rate of the SOFC. The PG of the two SOFCs can be adequately coordinated with the generated power of the DEG, the stored/released energy of the BESS, and the output power of the dc-ac inverter to maintain both frequency and voltage of the connected loads at the desired values. Time-domain simulated results of the studied hybrid system under four studied cases are performed and analyzed to validate the good load-tracking characteristics of the proposed SOFC-based hybrid PG/ESS feeding time-varying loads. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5350670&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 140 - 147
Titre : Eliminating ground current in a transformerless photovoltaic application Type de document : texte imprimé Auteurs : Lopez, O., Auteur ; Freijedo, F.D., Auteur ; Yepes, A.G., Auteur Année de publication : 2010 Article en page(s) : pp. 140 - 147 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : harmonics; photovoltaic power systems; power system simulation Résumé : For low-power grid-connected applications, a single-phase converter can be used. In photovoltaic (PV) applications, it is possible to remove the transformer in the inverter to reduce losses, costs, and size. Galvanic connection of the grid and the dc sources in transformerless systems can introduce additional ground currents due to the ground parasitic capacitance. These currents increase conducted and radiated electromagnetic emissions, harmonics injected in the utility grid, and losses. Amplitude and spectrum of the ground current depend on the converter topology, the switching strategy, and the resonant circuit formed by the ground capacitance, the converter, the ac filter, and the grid. In this paper, the ground current in a 1.5-kW PV installation is measured under different conditions and used to build a simulation model. The installation includes a string of 16 PV panel, a full-bridge inverter, and an LCL filter. This model allows the study of the influence of the harmonics injected by the inverter on the ground current. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5401088&sortType%3Das [...] [article] Eliminating ground current in a transformerless photovoltaic application [texte imprimé] / Lopez, O., Auteur ; Freijedo, F.D., Auteur ; Yepes, A.G., Auteur . - 2010 . - pp. 140 - 147.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 140 - 147
Mots-clés : harmonics; photovoltaic power systems; power system simulation Résumé : For low-power grid-connected applications, a single-phase converter can be used. In photovoltaic (PV) applications, it is possible to remove the transformer in the inverter to reduce losses, costs, and size. Galvanic connection of the grid and the dc sources in transformerless systems can introduce additional ground currents due to the ground parasitic capacitance. These currents increase conducted and radiated electromagnetic emissions, harmonics injected in the utility grid, and losses. Amplitude and spectrum of the ground current depend on the converter topology, the switching strategy, and the resonant circuit formed by the ground capacitance, the converter, the ac filter, and the grid. In this paper, the ground current in a 1.5-kW PV installation is measured under different conditions and used to build a simulation model. The installation includes a string of 16 PV panel, a full-bridge inverter, and an LCL filter. This model allows the study of the influence of the harmonics injected by the inverter on the ground current. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5401088&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 148 - 160
Titre : Modeling and fault diagnosis of a polymer electrolyte fuel cell using electrical equivalent analysis Type de document : texte imprimé Auteurs : Hernandez, A., Auteur ; Daniel Hissel, Auteur ; Outbib, R., Auteur Année de publication : 2010 Article en page(s) : pp. 148 - 160 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : fault diagnosis; proton exchange membrane fuel cells Résumé : Fuel cell systems are complex systems and a high degree of competence is needed in different areas of knowledge such as thermodynamics, fluid dynamics, electrochemistry, and others, for their comprehension. This paper is a contribution to global modeling and fault diagnosis of these systems. More precisely, the goal of this paper is twofold. First, an electrical equivalent model, which could be used as a unifying approach to fuel cell systems will be resented. Second, a methodology to use the electrical model for fuel cell system diagnosis will be introduced, making special emphasis on fuel cell flooding detection. In order to illustrate the relevance of the proposed approach, experimental validations of the model, and the diagnosis methodology are proposed. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5353706&sortType%3Das [...] [article] Modeling and fault diagnosis of a polymer electrolyte fuel cell using electrical equivalent analysis [texte imprimé] / Hernandez, A., Auteur ; Daniel Hissel, Auteur ; Outbib, R., Auteur . - 2010 . - pp. 148 - 160.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 148 - 160
Mots-clés : fault diagnosis; proton exchange membrane fuel cells Résumé : Fuel cell systems are complex systems and a high degree of competence is needed in different areas of knowledge such as thermodynamics, fluid dynamics, electrochemistry, and others, for their comprehension. This paper is a contribution to global modeling and fault diagnosis of these systems. More precisely, the goal of this paper is twofold. First, an electrical equivalent model, which could be used as a unifying approach to fuel cell systems will be resented. Second, a methodology to use the electrical model for fuel cell system diagnosis will be introduced, making special emphasis on fuel cell flooding detection. In order to illustrate the relevance of the proposed approach, experimental validations of the model, and the diagnosis methodology are proposed. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5353706&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 161 - 167
Titre : A novel method to estimate the O&M costs for the financial planning of the wind power projects based on wind speed : a case study Type de document : texte imprimé Auteurs : Joshi, D.R., Auteur ; Jangamshetti, S.H., Auteur Année de publication : 2010 Article en page(s) : pp. 161 - 167 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : financial management; maintenance engineering; planning; reliability; wind turbines Résumé : A novel analytical method is proposed to find the reliability, the average failure rate, and the operation and maintenance costs (OMCs) of wind turbine generator based on the site wind data. The failure rate function is developed using wind turbine failure frequency distribution, published by Renewable Energy Information System on Internet, Germany. The presented method works computationally fast and does not require large wind data input, which is a requirement of many existing, commercially available simulation methods. The annually increasing OMCs, computed by this method, give better financial assessment of the wind power projects. The method presented is implemented on an Indian wind site. OMCs are obtained for 20 years. Results match the actual field data, for the survey period, barring their warranty period. It is hoped that the proposed method helps financial investors and equity holders for a better financial assessment of the wind power projects at planning stage. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5342492&sortType%3Das [...] [article] A novel method to estimate the O&M costs for the financial planning of the wind power projects based on wind speed : a case study [texte imprimé] / Joshi, D.R., Auteur ; Jangamshetti, S.H., Auteur . - 2010 . - pp. 161 - 167.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 161 - 167
Mots-clés : financial management; maintenance engineering; planning; reliability; wind turbines Résumé : A novel analytical method is proposed to find the reliability, the average failure rate, and the operation and maintenance costs (OMCs) of wind turbine generator based on the site wind data. The failure rate function is developed using wind turbine failure frequency distribution, published by Renewable Energy Information System on Internet, Germany. The presented method works computationally fast and does not require large wind data input, which is a requirement of many existing, commercially available simulation methods. The annually increasing OMCs, computed by this method, give better financial assessment of the wind power projects. The method presented is implemented on an Indian wind site. OMCs are obtained for 20 years. Results match the actual field data, for the survey period, barring their warranty period. It is hoped that the proposed method helps financial investors and equity holders for a better financial assessment of the wind power projects at planning stage. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5342492&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 168 - 180
Titre : High-altitude wind power generation Type de document : texte imprimé Auteurs : Lorenzo Fagiano, Auteur ; Milanese, M., Auteur ; Piga, D., Auteur Année de publication : 2010 Article en page(s) : pp. 168 - 180 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : numerical analysis; wind power plants; wind turbines Résumé : The paper presents the innovative technology of high-altitude wind power generation, indicated as Kitenergy, which exploits the automatic flight of tethered airfoils (e.g., power kites) to extract energy from wind blowing between 200 and 800 m above the ground. The key points of this technology are described and the design of large scale plants is investigated, in order to show that it has the potential to overcome the limits of the actual wind turbines and to provide large quantities of renewable energy, with competitive cost with respect to fossil sources. Such claims are supported by the results obtained so far in the Kitenergy project, undergoing at Politecnico di Torino, Italy, including numerical simulations, prototype experiments, and wind data analyses. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5350676&sortType%3Das [...] [article] High-altitude wind power generation [texte imprimé] / Lorenzo Fagiano, Auteur ; Milanese, M., Auteur ; Piga, D., Auteur . - 2010 . - pp. 168 - 180.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 168 - 180
Mots-clés : numerical analysis; wind power plants; wind turbines Résumé : The paper presents the innovative technology of high-altitude wind power generation, indicated as Kitenergy, which exploits the automatic flight of tethered airfoils (e.g., power kites) to extract energy from wind blowing between 200 and 800 m above the ground. The key points of this technology are described and the design of large scale plants is investigated, in order to show that it has the potential to overcome the limits of the actual wind turbines and to provide large quantities of renewable energy, with competitive cost with respect to fossil sources. Such claims are supported by the results obtained so far in the Kitenergy project, undergoing at Politecnico di Torino, Italy, including numerical simulations, prototype experiments, and wind data analyses. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5350676&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 181 - 190
Titre : Harmonic analysis of a DFIG for a wind energy conversion system Type de document : texte imprimé Auteurs : Lingling Fan, Auteur ; Yuvarajan, S., Auteur ; Kavasseri, R., Auteur Année de publication : 2010 Article en page(s) : pp. 181 - 190 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : asynchronous generators; direct energy conversion; equivalent circuits; harmonic analysis; machine theory; wind power plants Résumé : This paper develops a framework for analysis of harmonics in a doubly fed induction generator (DFIG) caused by nonsinusoidal conditions in rotor and unbalance in stator. Nonsinusoidal rotor voltages are decomposed into harmonic components and their corresponding sequences are identified. Induced harmonics in stator are analyzed and computed, from which the torques produced by these interactions between stator and rotor harmonic components can be found. During unbalanced stator conditions, symmetric component theory is applied to the stator voltage to get positive-, negative-, and zero-sequence components of stator and rotor currents. The steady-state negative-sequence equivalent circuit for a DFIG is derived based on the reference frame theory. Harmonic currents in the rotor are computed based on the sequence circuits. In both scenarios, the harmonic components of the electromagnetic torque are calculated from the interactions of the harmonic components of the stator and rotor currents. Three case studies are considered, namely: 1) nonsinusoidal rotor injection; 2) an isolated unbalanced stator load scenario; and 3) unbalanced grid-connected operation. The analysis is verified with results from numerical simulations in Matlab/Simulink. For illustration, the second case is verified using experiments. The simulation results and experimental results agree well with the results from analysis. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5340615&sortType%3Das [...] [article] Harmonic analysis of a DFIG for a wind energy conversion system [texte imprimé] / Lingling Fan, Auteur ; Yuvarajan, S., Auteur ; Kavasseri, R., Auteur . - 2010 . - pp. 181 - 190.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 181 - 190
Mots-clés : asynchronous generators; direct energy conversion; equivalent circuits; harmonic analysis; machine theory; wind power plants Résumé : This paper develops a framework for analysis of harmonics in a doubly fed induction generator (DFIG) caused by nonsinusoidal conditions in rotor and unbalance in stator. Nonsinusoidal rotor voltages are decomposed into harmonic components and their corresponding sequences are identified. Induced harmonics in stator are analyzed and computed, from which the torques produced by these interactions between stator and rotor harmonic components can be found. During unbalanced stator conditions, symmetric component theory is applied to the stator voltage to get positive-, negative-, and zero-sequence components of stator and rotor currents. The steady-state negative-sequence equivalent circuit for a DFIG is derived based on the reference frame theory. Harmonic currents in the rotor are computed based on the sequence circuits. In both scenarios, the harmonic components of the electromagnetic torque are calculated from the interactions of the harmonic components of the stator and rotor currents. Three case studies are considered, namely: 1) nonsinusoidal rotor injection; 2) an isolated unbalanced stator load scenario; and 3) unbalanced grid-connected operation. The analysis is verified with results from numerical simulations in Matlab/Simulink. For illustration, the second case is verified using experiments. The simulation results and experimental results agree well with the results from analysis. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5340615&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 191 - 198
Titre : Techno-economic comparison of operational aspects for direct drive and gearbox-driven wind turbines Type de document : texte imprimé Auteurs : McMillan, D., Auteur ; Ault, Graham W., Auteur Année de publication : 2010 Article en page(s) : pp. 191 - 198 Note générale : energy concersion Langues : Anglais (eng) Mots-clés : wind turbines; Markov chain Résumé : The majority of wind turbines currently in operation have the conventional Danish concept design-that is, the three-bladed rotor of such turbines is indirectly coupled with an electrical generator via a gearbox. Recent technological developments have enabled direct drive wind turbines to become economically feasible. Potentially, direct drive wind turbines may enjoy higher levels of availability due to the removal of the gearbox from the design. However, this is only a theory: so far not substantiated by detailed analytic calculation. By providing such a calculation, this paper enables us to quantitatively evaluate technical and economic merits of direct drive and gearbox-driven wind turbines. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5416624&sortType%3Das [...] [article] Techno-economic comparison of operational aspects for direct drive and gearbox-driven wind turbines [texte imprimé] / McMillan, D., Auteur ; Ault, Graham W., Auteur . - 2010 . - pp. 191 - 198.
energy concersion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 191 - 198
Mots-clés : wind turbines; Markov chain Résumé : The majority of wind turbines currently in operation have the conventional Danish concept design-that is, the three-bladed rotor of such turbines is indirectly coupled with an electrical generator via a gearbox. Recent technological developments have enabled direct drive wind turbines to become economically feasible. Potentially, direct drive wind turbines may enjoy higher levels of availability due to the removal of the gearbox from the design. However, this is only a theory: so far not substantiated by detailed analytic calculation. By providing such a calculation, this paper enables us to quantitatively evaluate technical and economic merits of direct drive and gearbox-driven wind turbines. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5416624&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 199 - 206
Titre : A form-wound induction machine model for the study of three-phase surge propagation Type de document : texte imprimé Auteurs : Clerici, D., Auteur ; Della Torre, F., Auteur ; Morando, A.P., Auteur Année de publication : 2010 Article en page(s) : pp. 199 - 206 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : asynchronous machines; finite element analysis; stators Résumé : A three-phase model of asynchronous machines operating at medium or high frequencies is presented. It can be used to study the propagation of surge waves along the stator windings of induction form-wound machines. The model is derived from an analogy with a three-phase transmission line. The use of time-space Clarke vectors allows the introduction of mutual coupling between phases. The analytical expressions for voltage waves are derived and the distributed parameters of the model are calculated by means of finite-element method (FEM), considering a specific induction machine that was studied by other authors. Some examples are proposed in order to confirm the model validity and to underline certain fundamental aspects of the project of three-phase stator windings of induction machines. The applications considered leads to numerical results in qualitative agreement with those calculated and/or measured by other authors. In a forthcoming work on the subject, the authors propose to compare the theoretical results presented here with those resulting from an experimental campaign. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5340677&sortType%3Das [...] [article] A form-wound induction machine model for the study of three-phase surge propagation [texte imprimé] / Clerici, D., Auteur ; Della Torre, F., Auteur ; Morando, A.P., Auteur . - 2010 . - pp. 199 - 206.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 199 - 206
Mots-clés : asynchronous machines; finite element analysis; stators Résumé : A three-phase model of asynchronous machines operating at medium or high frequencies is presented. It can be used to study the propagation of surge waves along the stator windings of induction form-wound machines. The model is derived from an analogy with a three-phase transmission line. The use of time-space Clarke vectors allows the introduction of mutual coupling between phases. The analytical expressions for voltage waves are derived and the distributed parameters of the model are calculated by means of finite-element method (FEM), considering a specific induction machine that was studied by other authors. Some examples are proposed in order to confirm the model validity and to underline certain fundamental aspects of the project of three-phase stator windings of induction machines. The applications considered leads to numerical results in qualitative agreement with those calculated and/or measured by other authors. In a forthcoming work on the subject, the authors propose to compare the theoretical results presented here with those resulting from an experimental campaign. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5340677&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 207 - 216
Titre : A novel sensorless MPPT controller for a high-efficiency microscale wind power generation system Type de document : texte imprimé Auteurs : Ching-Tsai Pan, Auteur ; Yu-Ling Juan, Auteur Année de publication : 2010 Article en page(s) : pp. 207 - 216 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : AC-DC power convertors; adaptive control; dynamic response; harmonic distortion; maximum power point trackers; power generation control; power system harmonics; wind power plants Résumé : In this paper, a novel maximum power point tracking (MPPT) controller with an adaptive compensation control is first proposed for a microscale wind power generation system (WPGS). Based on the adaptive control, the dynamic response is improved and more wind energy can be captured during wind velocity variations. For cost and reliability consideration, no mechanical sensors are used in this proposed WPGS. A single-stage ac-to-dc converter is then proposed to replace the traditional two-stage converter and incorporate the MPPT control for achieving higher efficiency and lower total harmonic distortion (THD). To further improve the efficiency of the converter, a quasi-synchronous rectification (QSR) algorithm is proposed to control the active switches for reducing the conduction loss of the body diodes. The analytic closed form duty ratios of the corresponding active switches are also derived for easy implementation. Furthermore, a prototype system is constructed and the proposed MPPT controller and QSR algorithm are both implemented using a DSP, namely, TMS320F2812. Some experimental results are given to verify the validity of the proposed microscale WPGS. It is found that the total output energy can be increased by 13% for the microscale WPGS. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5340657&sortType%3Das [...] [article] A novel sensorless MPPT controller for a high-efficiency microscale wind power generation system [texte imprimé] / Ching-Tsai Pan, Auteur ; Yu-Ling Juan, Auteur . - 2010 . - pp. 207 - 216.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 207 - 216
Mots-clés : AC-DC power convertors; adaptive control; dynamic response; harmonic distortion; maximum power point trackers; power generation control; power system harmonics; wind power plants Résumé : In this paper, a novel maximum power point tracking (MPPT) controller with an adaptive compensation control is first proposed for a microscale wind power generation system (WPGS). Based on the adaptive control, the dynamic response is improved and more wind energy can be captured during wind velocity variations. For cost and reliability consideration, no mechanical sensors are used in this proposed WPGS. A single-stage ac-to-dc converter is then proposed to replace the traditional two-stage converter and incorporate the MPPT control for achieving higher efficiency and lower total harmonic distortion (THD). To further improve the efficiency of the converter, a quasi-synchronous rectification (QSR) algorithm is proposed to control the active switches for reducing the conduction loss of the body diodes. The analytic closed form duty ratios of the corresponding active switches are also derived for easy implementation. Furthermore, a prototype system is constructed and the proposed MPPT controller and QSR algorithm are both implemented using a DSP, namely, TMS320F2812. Some experimental results are given to verify the validity of the proposed microscale WPGS. It is found that the total output energy can be increased by 13% for the microscale WPGS. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5340657&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 217 - 227
Titre : A multirate field construction technique for efficient modeling of the fields and forces within inverter-fed induction machines Type de document : texte imprimé Auteurs : Dezheng, Wu, Auteur ; Pekarek, S.D., Auteur Année de publication : 2010 Article en page(s) : pp. 217 - 227 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : air gaps; asynchronous machines; finite element analysis; invertors; power convertors; power electronics Résumé : In recent research, a field construction technique (FCT) was derived to enable more efficient evaluation of the magnetic fields and forces within induction machines. Using the FCT, the results of two finite-element (FE) solutions are used to establish basis functions for the flux densities in the airgap of the machine. The basis functions are then used to predict the magnetic fields and forces under arbitrary stator excitation. In this paper, a multirate FCT (MRFCT) is proposed to enable efficient FCT modeling of machines that are connected to power electronic converters. Within the MRFCT, the low- and high-frequency components of the stator current are partitioned. The partitioned currents are then used to calculate the flux density and forces at time steps commensurate with the respective low- and high-frequency dynamics. It is shown that applying the MRFCT, the forces and fields of a machine connected to a power electronic circuit can be obtained at a small fraction of the time required for a coupled FE/circuit model. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5350668&sortType%3Das [...] [article] A multirate field construction technique for efficient modeling of the fields and forces within inverter-fed induction machines [texte imprimé] / Dezheng, Wu, Auteur ; Pekarek, S.D., Auteur . - 2010 . - pp. 217 - 227.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 217 - 227
Mots-clés : air gaps; asynchronous machines; finite element analysis; invertors; power convertors; power electronics Résumé : In recent research, a field construction technique (FCT) was derived to enable more efficient evaluation of the magnetic fields and forces within induction machines. Using the FCT, the results of two finite-element (FE) solutions are used to establish basis functions for the flux densities in the airgap of the machine. The basis functions are then used to predict the magnetic fields and forces under arbitrary stator excitation. In this paper, a multirate FCT (MRFCT) is proposed to enable efficient FCT modeling of machines that are connected to power electronic converters. Within the MRFCT, the low- and high-frequency components of the stator current are partitioned. The partitioned currents are then used to calculate the flux density and forces at time steps commensurate with the respective low- and high-frequency dynamics. It is shown that applying the MRFCT, the forces and fields of a machine connected to a power electronic circuit can be obtained at a small fraction of the time required for a coupled FE/circuit model. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5350668&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 228 - 236
Titre : A novel scheme for rapid tracking of maximum power point in wind energy generation systems Type de document : texte imprimé Auteurs : Agarwal, V., Auteur ; Aggarwal, R. K., Auteur ; Patidar, P., Auteur Année de publication : 2010 Article en page(s) : pp. 228 - 236 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : matrix convertors; power grids; wind power Résumé : This paper presents a novel maximum power point (MPP) tracking (MPPT) algorithm for grid-connected wind energy generation systems (WEGS). This is a rapid tracking algorithm that uses the fact that the value of ????,?? an intermediate variable, especially defined for the purpose, remains constant ( =??MPP ) for a given WEGS at the MPP irrespective of the wind velocity. The value of ??MPP is known in advance. The algorithm works in two stages. In the first stage, it uses large steps to quickly drive the operating point to lie within a narrow band with limits ??max and ??min. In the second stage, exact MPP is tracked using the ??perturb and observe?? method. No extra hardware or measurements (sensors) are required compared to the existing algorithms. Hence, the cost is not increased. Application of the proposed algorithm to an example WEGS shows that the time taken by the system to reach MPP is much smaller compared to most of the existing algorithms. A prototype matrix converter has been developed for grid interfacing and the proposed MPPT scheme has been implemented in conjunction with Venturini and space-vector-modulation-based switching schemes. All the results of this study are presented. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5350683&sortType%3Das [...] [article] A novel scheme for rapid tracking of maximum power point in wind energy generation systems [texte imprimé] / Agarwal, V., Auteur ; Aggarwal, R. K., Auteur ; Patidar, P., Auteur . - 2010 . - pp. 228 - 236.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 228 - 236
Mots-clés : matrix convertors; power grids; wind power Résumé : This paper presents a novel maximum power point (MPP) tracking (MPPT) algorithm for grid-connected wind energy generation systems (WEGS). This is a rapid tracking algorithm that uses the fact that the value of ????,?? an intermediate variable, especially defined for the purpose, remains constant ( =??MPP ) for a given WEGS at the MPP irrespective of the wind velocity. The value of ??MPP is known in advance. The algorithm works in two stages. In the first stage, it uses large steps to quickly drive the operating point to lie within a narrow band with limits ??max and ??min. In the second stage, exact MPP is tracked using the ??perturb and observe?? method. No extra hardware or measurements (sensors) are required compared to the existing algorithms. Hence, the cost is not increased. Application of the proposed algorithm to an example WEGS shows that the time taken by the system to reach MPP is much smaller compared to most of the existing algorithms. A prototype matrix converter has been developed for grid interfacing and the proposed MPPT scheme has been implemented in conjunction with Venturini and space-vector-modulation-based switching schemes. All the results of this study are presented. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5350683&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 237 - 244
Titre : Computation of differential inductance and flux linkage positional derivative by a sensitivity approach Type de document : texte imprimé Auteurs : Melgoza, E., Auteur ; Venegas, V., Auteur ; Escarela-Perez, R., Auteur Année de publication : 2010 Article en page(s) : pp. 237 - 244 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : electric machines; finite element analysis; sensitivity analysis Résumé : The differential inductance and flux linkage positional derivative are important parameters in the analysis and simulation of electrical machines where saturation is nonnegligible. A new method for the computation of these quantities for devices with an arbitrary number of windings is presented. The method is based on the determination of the sensitivity of the magnetic vector potential to variations in the input current vector or the rotor position, in the context of finite-element formulations. The implementation of the proposed method for plane Cartesian and axisymmetric cases is considered in detail. The method and its implementation are verified by comparisons against known inductance formulas or results from other computational methods. In the case of the differential inductance, the proposed scheme is an alternative to energy perturbation methods, while the determination of the flux linkage positional derivative is made in one step for the first time. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5350685&sortType%3Das [...] [article] Computation of differential inductance and flux linkage positional derivative by a sensitivity approach [texte imprimé] / Melgoza, E., Auteur ; Venegas, V., Auteur ; Escarela-Perez, R., Auteur . - 2010 . - pp. 237 - 244.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 237 - 244
Mots-clés : electric machines; finite element analysis; sensitivity analysis Résumé : The differential inductance and flux linkage positional derivative are important parameters in the analysis and simulation of electrical machines where saturation is nonnegligible. A new method for the computation of these quantities for devices with an arbitrary number of windings is presented. The method is based on the determination of the sensitivity of the magnetic vector potential to variations in the input current vector or the rotor position, in the context of finite-element formulations. The implementation of the proposed method for plane Cartesian and axisymmetric cases is considered in detail. The method and its implementation are verified by comparisons against known inductance formulas or results from other computational methods. In the case of the differential inductance, the proposed scheme is an alternative to energy perturbation methods, while the determination of the flux linkage positional derivative is made in one step for the first time. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5350685&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 245 - 252
Titre : Virtual models for prediction of wind turbine parameters Type de document : texte imprimé Auteurs : Andrew Kusiak, Auteur ; Wenyan, Li, Auteur Année de publication : 2010 Article en page(s) : pp. 245 - 252 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : data mining; power engineering computing; wind turbines Résumé : In this paper, a data-driven methodology for the development of virtual models of a wind turbine is presented. To demonstrate the proposed methodology, two parameters of the wind turbine have been selected for modeling, namely, power output and rotor speed. A virtual model for each of the two parameters is developed and tested with data collected at a wind farm. Both models consider controllable and noncontrollable parameters of the wind turbine, as well as the delay effect of wind speed and other parameters. To mitigate data bias of each virtual model and ensure its robustness, a training set is assembled from ten randomly selected turbines. The performance of a virtual model is largely determined by the input parameters selected and the data mining algorithms used to extract the model. Several data mining algorithms for parameter selection and model extraction are analyzed. The research presented in the paper is illustrated with computational results. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5340659&sortType%3Das [...] [article] Virtual models for prediction of wind turbine parameters [texte imprimé] / Andrew Kusiak, Auteur ; Wenyan, Li, Auteur . - 2010 . - pp. 245 - 252.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 245 - 252
Mots-clés : data mining; power engineering computing; wind turbines Résumé : In this paper, a data-driven methodology for the development of virtual models of a wind turbine is presented. To demonstrate the proposed methodology, two parameters of the wind turbine have been selected for modeling, namely, power output and rotor speed. A virtual model for each of the two parameters is developed and tested with data collected at a wind farm. Both models consider controllable and noncontrollable parameters of the wind turbine, as well as the delay effect of wind speed and other parameters. To mitigate data bias of each virtual model and ensure its robustness, a training set is assembled from ten randomly selected turbines. The performance of a virtual model is largely determined by the input parameters selected and the data mining algorithms used to extract the model. Several data mining algorithms for parameter selection and model extraction are analyzed. The research presented in the paper is illustrated with computational results. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5340659&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 253 - 261
Titre : Assessments of energy capacity and energy losses of supercapacitors in fast charging–discharging cycles Type de document : texte imprimé Auteurs : Yonghua, Cheng, Auteur Année de publication : 2010 Article en page(s) : pp. 253 - 261 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : stability; supercapacitors Résumé : In order to safely operate the supercapacitor (SuperCap) energy storages as peak power units until the end of their lifetime in the real applications, identifying the electrical characteristics of SuperCaps and assessing the energy capacity and energy losses in fast energy conversion are the essential procedures. Until now, most methods are based on the international standard IEC 62391. However, the detected parameters (capacitance and series resistance) are not suitable enough, to precisely represent the energy capacity of the SuperCaps at different voltage levels and to estimate the power losses at different power levels. Therefore, the enhanced methods of characterizing SuperCaps in the fast charging-discharging cycles are developed. Furthermore, the energy losses due to the variation of capacitance during the charging and discharging states are evaluated, and the electrical stability of the SuperCap modules is also observed with respect to the variation of capacitance. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5350682&sortType%3Das [...] [article] Assessments of energy capacity and energy losses of supercapacitors in fast charging–discharging cycles [texte imprimé] / Yonghua, Cheng, Auteur . - 2010 . - pp. 253 - 261.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 253 - 261
Mots-clés : stability; supercapacitors Résumé : In order to safely operate the supercapacitor (SuperCap) energy storages as peak power units until the end of their lifetime in the real applications, identifying the electrical characteristics of SuperCaps and assessing the energy capacity and energy losses in fast energy conversion are the essential procedures. Until now, most methods are based on the international standard IEC 62391. However, the detected parameters (capacitance and series resistance) are not suitable enough, to precisely represent the energy capacity of the SuperCaps at different voltage levels and to estimate the power losses at different power levels. Therefore, the enhanced methods of characterizing SuperCaps in the fast charging-discharging cycles are developed. Furthermore, the energy losses due to the variation of capacitance during the charging and discharging states are evaluated, and the electrical stability of the SuperCap modules is also observed with respect to the variation of capacitance. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5350682&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 262 - 264
Titre : A new algorithm to photovoltaic power point tracking problems with quadratic maximization Type de document : texte imprimé Auteurs : Pai, Fu-Sheng, Auteur ; Ru-Min Chao, Auteur Année de publication : 2010 Article en page(s) : pp. 262 - 264 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : optimisation; photovoltaic power systems Résumé : One of critical concerns in the operation of the photovoltaic system is the maximum power point (MPP) tracking problem that increases the economical feasibility of the system. This letter presents a tracking method using the quadratic polynomial to perform a MPP tracker of a given photovoltaic array. With the method, the maximum power calculation is made from a quadratic manner that it convergences significantly accelerated. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5340544&sortType%3Das [...] [article] A new algorithm to photovoltaic power point tracking problems with quadratic maximization [texte imprimé] / Pai, Fu-Sheng, Auteur ; Ru-Min Chao, Auteur . - 2010 . - pp. 262 - 264.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 262 - 264
Mots-clés : optimisation; photovoltaic power systems Résumé : One of critical concerns in the operation of the photovoltaic system is the maximum power point (MPP) tracking problem that increases the economical feasibility of the system. This letter presents a tracking method using the quadratic polynomial to perform a MPP tracker of a given photovoltaic array. With the method, the maximum power calculation is made from a quadratic manner that it convergences significantly accelerated. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5340544&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 265 - 267
Titre : Analysis of a self-excited induction generator with P –Q load model Type de document : texte imprimé Auteurs : Haque, M.H., Auteur Année de publication : 2010 Article en page(s) : pp. 265 - 267 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : asynchronous generators; numerical analysis Résumé : A simple method for analyzing the steady-state performance of a self-excited induction generator with P-Q load model is described in this letter. First, the basic operating equations of the generator are derived from its equivalent circuit, and then solved using a numerical-based routine. The proposed method is then tested on a 1.5-kW induction generator and the simulation results obtained are compared with the corresponding experimental values. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5350686&sortType%3Das [...] [article] Analysis of a self-excited induction generator with P –Q load model [texte imprimé] / Haque, M.H., Auteur . - 2010 . - pp. 265 - 267.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 265 - 267
Mots-clés : asynchronous generators; numerical analysis Résumé : A simple method for analyzing the steady-state performance of a self-excited induction generator with P-Q load model is described in this letter. First, the basic operating equations of the generator are derived from its equivalent circuit, and then solved using a numerical-based routine. The proposed method is then tested on a 1.5-kW induction generator and the simulation results obtained are compared with the corresponding experimental values. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5350686&sortType%3Das [...]
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 268 - 270
Titre : A flux-based expression of induction machine magnetizing inductance Type de document : texte imprimé Auteurs : Lupsa-Tataru, L., Auteur Année de publication : 2010 Article en page(s) : pp. 268 - 270 Note générale : energy conversion Langues : Anglais (eng) Mots-clés : asynchronous machines; inductance Résumé : Tending toward the adaptive modeling of main flux saturation in induction machine, this brief discloses the induction machine magnetizing inductance as an expression in terms of only d -q axis winding flux linkages. It will be shown that such an expression considerably facilitates the inclusion of main flux saturation effects in internal structure of the well-established winding flux linkage state-space model. The derivation procedure will be carried out without altering the structural equations of the generalized d- q axis mathematical model of the induction machine. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5416623&sortType%3Das [...] [article] A flux-based expression of induction machine magnetizing inductance [texte imprimé] / Lupsa-Tataru, L., Auteur . - 2010 . - pp. 268 - 270.
energy conversion
Langues : Anglais (eng)
in IEEE transactions on energy conversion > Vol. 25 N° 1 (Mars 2010) . - pp. 268 - 270
Mots-clés : asynchronous machines; inductance Résumé : Tending toward the adaptive modeling of main flux saturation in induction machine, this brief discloses the induction machine magnetizing inductance as an expression in terms of only d -q axis winding flux linkages. It will be shown that such an expression considerably facilitates the inclusion of main flux saturation effects in internal structure of the well-established winding flux linkage state-space model. The derivation procedure will be carried out without altering the structural equations of the generalized d- q axis mathematical model of the induction machine. En ligne : http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5416623&sortType%3Das [...]
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