Documents disponibles écrits par cet auteur

Direct self-control for BLDC motor drives based on three-dimensional coordinate system / Jin, Gao in IEEE transactions on industrial electronics, Vol. 57 N° 8 (Août 2010) 

Public ISBD [article]  in IEEE transactions on industrial electronics > Vol. 57 N° 8 (Août 2010) . - pp. 2836 - 2844 Titre : Direct self-control for BLDC motor drives based on three-dimensional coordinate system Type de document : texte imprimé Auteurs : Jin, Gao, Auteur ; Yuwen, Hu, Auteur Année de publication : 2011 Article en page(s) : pp. 2836 - 2844 Note générale : Génie électrique Langues : Anglais (eng) Mots-clés : Brushless  dc  (BLDC)  Motor  drive  Direct  self-control  (DSC)  Sensorless  Three-dimensional  coordinate  Torque  transient  response Index. décimale : 621.38 Dispositifs électroniques. Tubes à électrons. Photocellules. Accélérateurs de particules. Tubes à rayons X Résumé : In this paper, a new control algorithm for brushless dc (BLDC) motor drives is presented. Direct self-control, which has been widely applied on induction motor drives in high-power low-frequency traction, is introduced to BLDC drives. The Cartesian coordinate system is selected with three coordinate axes X, Y, and Z mutually at right angle to each other with three phase axes a, b, and c being movable. A two-phase conduction scheme is selected with the axis of the exciting phase located in the X-Y plane or, otherwise, along the direction of the Z -axis during unexcited (i.e., the unexcited phase axis is always directed along the Z-axis). The tracks of stator flux and voltage vectors are all three-dimensional, as a result of a variable voltage of unexcited phase and commutation every 60 electrical degrees. However, projections on the X-Y plane of these three-dimensional tracks are concise. The projection of flux vector is a hexagonal path, whereas the voltage vector projections are six active vectors. The projection of stator flux is controlled by the projections of voltage vectors. The newly proposed algorithm can be implemented with relatively low cost hardware and concise software, presenting fast torque transient response in 0.1 ms. The sensorless control is also implemented by flux estimation once in one sector. The validity and effectiveness of the proposed scheme are verified with simulated and experimental results. DEWEY : 621.38 ISSN : 0278-0046 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5332310 [article] Direct self-control for BLDC motor drives based on three-dimensional coordinate system [texte imprimé] / Jin, Gao, Auteur ; Yuwen, Hu, Auteur . - 2011 . - pp. 2836 - 2844. Génie électrique Langues : Anglais (eng) in IEEE transactions on industrial electronics > Vol. 57 N° 8 (Août 2010) . - pp. 2836 - 2844 Mots-clés : Brushless  dc  (BLDC)  Motor  drive  Direct  self-control  (DSC)  Sensorless  Three-dimensional  coordinate  Torque  transient  response Index. décimale : 621.38 Dispositifs électroniques. Tubes à électrons. Photocellules. Accélérateurs de particules. Tubes à rayons X Résumé : In this paper, a new control algorithm for brushless dc (BLDC) motor drives is presented. Direct self-control, which has been widely applied on induction motor drives in high-power low-frequency traction, is introduced to BLDC drives. The Cartesian coordinate system is selected with three coordinate axes X, Y, and Z mutually at right angle to each other with three phase axes a, b, and c being movable. A two-phase conduction scheme is selected with the axis of the exciting phase located in the X-Y plane or, otherwise, along the direction of the Z -axis during unexcited (i.e., the unexcited phase axis is always directed along the Z-axis). The tracks of stator flux and voltage vectors are all three-dimensional, as a result of a variable voltage of unexcited phase and commutation every 60 electrical degrees. However, projections on the X-Y plane of these three-dimensional tracks are concise. The projection of flux vector is a hexagonal path, whereas the voltage vector projections are six active vectors. The projection of stator flux is controlled by the projections of voltage vectors. The newly proposed algorithm can be implemented with relatively low cost hardware and concise software, presenting fast torque transient response in 0.1 ms. The sensorless control is also implemented by flux estimation once in one sector. The validity and effectiveness of the proposed scheme are verified with simulated and experimental results. DEWEY : 621.38 ISSN : 0278-0046 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=5332310

Effects of bending moments and pretightening forces on the flexural stiffness of contact interfaces in rod-fastened rotors / Jin, Gao in Transactions of the ASME . Journal of engineering for gas turbines and power, Vol. 134 N° 10 (Octobre 2012) 

Public ISBD [article]  in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 134 N° 10 (Octobre 2012) . - 08 p. Titre : Effects of bending moments and pretightening forces on the flexural stiffness of contact interfaces in rod-fastened rotors Type de document : texte imprimé Auteurs : Jin, Gao, Auteur ; Qi Yuan, Auteur ; Li Pu, Auteur Année de publication : 2012 Article en page(s) : 08 p. Note générale : gas turbines Langues : Anglais (eng) Mots-clés : rod-fastened  rotor  (RFR);  stiffness;  rotor  dynamic  performance  analysis Résumé : The rod-fastened rotor (RFR) is comprised of a series of discs clamped together by a central tie rod or several tie rods on the pitch circle diameter. The equivalent flexural stiffness of contact interfaces Kc in the RFR is the key concern for accurate rotor dynamic performance analysis. Each contact interface was modeled as a bending spring with a stiffness of Kc and a hinge in this study. The contact states of the contact interfaces, which depend on the pretightening forces and bending moments (static), have effects on Kc. The approach to calculating Kc in two contact states is presented. The first contact state is that the whole zone of the contact interface is in contact; Kc is determined by the contact layer, which consists of asperities of the contact surfaces. Hertz contact theory and the Greenwood and Williamson (GW) statistical model are used to calculate the equivalent flexural stiffness of the contact layer Kcc. The second contact state is that some zones of the contact interface are separated (when the bending moment is relatively large); the equivalent flexural stiffness of the rotor segment Ksf (not including Kcc) decreases, as the material in the separated zone has no contribution to the bending load-carrying capacity of the rotor. The strain energy, which is calculated by the finite element method (FEM), is used to determine Ksf. The stiffness Ksf is equivalent to the series stiffness of the discs of the rotor segment with flexural stiffness of Kd and a spring with bending stiffness of Kcf in the location of the contact interface, so Kc is equal to the series stiffness of Kcc and Kcf in the second contact state. The results of a simplified RFR indicate that, for a fixed pretightening force, Kcc decreases with bending moments in the first contact state, whereas increases with bending moments in the second contact state. In addition, Kcf and Kc decrease abruptly with the increase of bending moments in the second contact state when the rotor is subjected to a relatively large pretightening force. Finally, the multipoint exciting method was used to measure the modal parameters of the experimental RFR. It is found that the experimental modal frequencies decrease as the pretightening force decreases. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000134000010 [...] [article] Effects of bending moments and pretightening forces on the flexural stiffness of contact interfaces in rod-fastened rotors [texte imprimé] / Jin, Gao, Auteur ; Qi Yuan, Auteur ; Li Pu, Auteur . - 2012 . - 08 p. gas turbines Langues : Anglais (eng) in Transactions of the ASME . Journal of engineering for gas turbines and power > Vol. 134 N° 10 (Octobre 2012) . - 08 p. Mots-clés : rod-fastened  rotor  (RFR);  stiffness;  rotor  dynamic  performance  analysis Résumé : The rod-fastened rotor (RFR) is comprised of a series of discs clamped together by a central tie rod or several tie rods on the pitch circle diameter. The equivalent flexural stiffness of contact interfaces Kc in the RFR is the key concern for accurate rotor dynamic performance analysis. Each contact interface was modeled as a bending spring with a stiffness of Kc and a hinge in this study. The contact states of the contact interfaces, which depend on the pretightening forces and bending moments (static), have effects on Kc. The approach to calculating Kc in two contact states is presented. The first contact state is that the whole zone of the contact interface is in contact; Kc is determined by the contact layer, which consists of asperities of the contact surfaces. Hertz contact theory and the Greenwood and Williamson (GW) statistical model are used to calculate the equivalent flexural stiffness of the contact layer Kcc. The second contact state is that some zones of the contact interface are separated (when the bending moment is relatively large); the equivalent flexural stiffness of the rotor segment Ksf (not including Kcc) decreases, as the material in the separated zone has no contribution to the bending load-carrying capacity of the rotor. The strain energy, which is calculated by the finite element method (FEM), is used to determine Ksf. The stiffness Ksf is equivalent to the series stiffness of the discs of the rotor segment with flexural stiffness of Kd and a spring with bending stiffness of Kcf in the location of the contact interface, so Kc is equal to the series stiffness of Kcc and Kcf in the second contact state. The results of a simplified RFR indicate that, for a fixed pretightening force, Kcc decreases with bending moments in the first contact state, whereas increases with bending moments in the second contact state. In addition, Kcf and Kc decrease abruptly with the increase of bending moments in the second contact state when the rotor is subjected to a relatively large pretightening force. Finally, the multipoint exciting method was used to measure the modal parameters of the experimental RFR. It is found that the experimental modal frequencies decrease as the pretightening force decreases. DEWEY : 620.1 ISSN : 0742-4795 En ligne : http://asmedl.org/getabs/servlet/GetabsServlet?prog=normal&id=JETPEZ000134000010 [...]