Documents disponibles écrits par cet auteur

An FPGA-based novel digital PWM control scheme for BLDC motor drives / Sathyan, Anand in IEEE transactions on industrial electronics, Vol. 56 N° 8 (Août 2009) 

Public ISBD [article]  in IEEE transactions on industrial electronics > Vol. 56 N° 8 (Août 2009) . - pp. 3040 - 3049 Titre : An FPGA-based novel digital PWM control scheme for BLDC motor drives Type de document : texte imprimé Auteurs : Sathyan, Anand, Auteur ; Milivojevic, Nikola, Auteur ; Young-Joo Lee, Auteur Article en page(s) : pp. 3040 - 3049 Note générale : Génie électrique Langues : Anglais (eng) Mots-clés : Brushless  dc  (LLDC)  motor  drives  Converters  Field-programmable  gate  arrays  (FPGAs)  Inverters  Motion  control  Pulsewidth  modulation  (PWM) Index. décimale : 621.38 Dispositifs électroniques. Tubes à électrons. Photocellules. Accélérateurs de particules. Tubes à rayons X Résumé : Development of advanced motor drives has yielded increases in efficiency and reliability. Residential and commercial appliances such as refrigerators and air conditioning systems use conventional motor drive technology. The machines found in these applications are characterized by low efficiency and high maintenance. A brushless dc (BLDC) motor drive is characterized by higher efficiency, lower maintenance, and higher cost. In a market driven by profit margins, the appliance industry is reluctant to replace the conventional motor drives with the advanced motor drives (BLDC) due to their higher cost. Therefore, it is necessary to have a low-cost but effective BLDC motor controller. This paper lays the groundwork for the development of a new low-cost IC for control of BLDC motors. A simple novel digital pulsewidth-modulation control has been implemented for a trapezoidal BLDC motor drive system. Due to the simplistic nature of this control, it has the potential to be implemented in a low-cost application-specific integrated circuit. The novel controller is modeled and verified using simulations. Experimental verification is carried out using field-programmable gate arrays to validate the claims presented. DEWEY : 621.38 ISSN : 0278-0046 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=4926182 [article] An FPGA-based novel digital PWM control scheme for BLDC motor drives [texte imprimé] / Sathyan, Anand, Auteur ; Milivojevic, Nikola, Auteur ; Young-Joo Lee, Auteur . - pp. 3040 - 3049. Génie électrique Langues : Anglais (eng) in IEEE transactions on industrial electronics > Vol. 56 N° 8 (Août 2009) . - pp. 3040 - 3049 Mots-clés : Brushless  dc  (LLDC)  motor  drives  Converters  Field-programmable  gate  arrays  (FPGAs)  Inverters  Motion  control  Pulsewidth  modulation  (PWM) Index. décimale : 621.38 Dispositifs électroniques. Tubes à électrons. Photocellules. Accélérateurs de particules. Tubes à rayons X Résumé : Development of advanced motor drives has yielded increases in efficiency and reliability. Residential and commercial appliances such as refrigerators and air conditioning systems use conventional motor drive technology. The machines found in these applications are characterized by low efficiency and high maintenance. A brushless dc (BLDC) motor drive is characterized by higher efficiency, lower maintenance, and higher cost. In a market driven by profit margins, the appliance industry is reluctant to replace the conventional motor drives with the advanced motor drives (BLDC) due to their higher cost. Therefore, it is necessary to have a low-cost but effective BLDC motor controller. This paper lays the groundwork for the development of a new low-cost IC for control of BLDC motors. A simple novel digital pulsewidth-modulation control has been implemented for a trapezoidal BLDC motor drive system. Due to the simplistic nature of this control, it has the potential to be implemented in a low-cost application-specific integrated circuit. The novel controller is modeled and verified using simulations. Experimental verification is carried out using field-programmable gate arrays to validate the claims presented. DEWEY : 621.38 ISSN : 0278-0046 En ligne : http://ieeexplore.ieee.org/xpl/freeabs_all.jsp?arnumber=4926182

Risk analysis of fatigue - induced sequential failures by branch - and - bound method employing system reliability bounds / Young-Joo Lee in Journal of engineering mechanics, Vol. 137 N° 12 (Decembre 2011) 

Public ISBD [article]  in Journal of engineering mechanics > Vol. 137 N° 12 (Decembre 2011) Titre : Risk analysis of fatigue - induced sequential failures by branch - and - bound method employing system reliability bounds Type de document : texte imprimé Auteurs : Young-Joo Lee, Auteur ; Junho Song, Auteur Année de publication : 2012 Note générale : Mécanique appliquée Langues : Anglais (eng) Mots-clés : Risk  management  Fatigue  Structural  systems  Structural  failures Résumé : Various types of structural systems are often subjected to the risk of fatigue-induced failures. If a structure does not have an adequate level of structural redundancy, local failures may initiate sequential failures and cause exceedingly large damage. For the risk-informed design and maintenance of such structural systems, it is thus essential to quantify the risk of fatigue-induced sequential failure. However, such risk analysis is often computationally intractable because one needs to explore innumerable failure sequences, each of which demands component and system reliability analyses in conjunction with structural analyses to account for various uncertainties and the effect of load redistributions. To overcome this computational challenge, many research efforts have been made to identify critical failure sequences with the highest likelihood and to quantify the overall risk by system reliability analysis based on the identified sequences. One of the most widely used approaches is the so-called “branch-and-bound” method. However, only the lower bound on the system risk is usually obtained because of challenges in system reliability analysis, while the changes of the lower bound by newly identified sequences are not diminishing monotonically. This paper aims to improve the efficiency and accuracy of risk analysis of fatigue-induced sequential failures by developing a new branch-and-bound method employing system reliability bounds (termed the B3 method). On the basis of a recursive formulation of the limit-state functions of fatigue-induced failures, a system failure event is formulated as a disjoint cut-set system event. A new search scheme identifies critical fatigue-induced failure sequences in the decreasing order of their probabilities while it systematically updates both lower and upper bounds on the system failure probability without additional system reliability analyses. As a result, the method can provide reasonable criteria for terminating the branch-and-bound search without missing critical failure sequences and reduce the number of computational simulations required to obtain reliable estimates on the system risk. The B3 method is tested and demonstrated by numerical examples of a multilayer Daniels system and a three-dimensional offshore structure. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.org/emo/resource/1/jenmdt/v137/i12/p807_s1?isAuthorized=no [article] Risk analysis of fatigue - induced sequential failures by branch - and - bound method employing system reliability bounds [texte imprimé] / Young-Joo Lee, Auteur ; Junho Song, Auteur . - 2012. Mécanique appliquée Langues : Anglais (eng) in Journal of engineering mechanics > Vol. 137 N° 12 (Decembre 2011) Mots-clés : Risk  management  Fatigue  Structural  systems  Structural  failures Résumé : Various types of structural systems are often subjected to the risk of fatigue-induced failures. If a structure does not have an adequate level of structural redundancy, local failures may initiate sequential failures and cause exceedingly large damage. For the risk-informed design and maintenance of such structural systems, it is thus essential to quantify the risk of fatigue-induced sequential failure. However, such risk analysis is often computationally intractable because one needs to explore innumerable failure sequences, each of which demands component and system reliability analyses in conjunction with structural analyses to account for various uncertainties and the effect of load redistributions. To overcome this computational challenge, many research efforts have been made to identify critical failure sequences with the highest likelihood and to quantify the overall risk by system reliability analysis based on the identified sequences. One of the most widely used approaches is the so-called “branch-and-bound” method. However, only the lower bound on the system risk is usually obtained because of challenges in system reliability analysis, while the changes of the lower bound by newly identified sequences are not diminishing monotonically. This paper aims to improve the efficiency and accuracy of risk analysis of fatigue-induced sequential failures by developing a new branch-and-bound method employing system reliability bounds (termed the B3 method). On the basis of a recursive formulation of the limit-state functions of fatigue-induced failures, a system failure event is formulated as a disjoint cut-set system event. A new search scheme identifies critical fatigue-induced failure sequences in the decreasing order of their probabilities while it systematically updates both lower and upper bounds on the system failure probability without additional system reliability analyses. As a result, the method can provide reasonable criteria for terminating the branch-and-bound search without missing critical failure sequences and reduce the number of computational simulations required to obtain reliable estimates on the system risk. The B3 method is tested and demonstrated by numerical examples of a multilayer Daniels system and a three-dimensional offshore structure. DEWEY : 620.1 ISSN : 0733-9399 En ligne : http://ascelibrary.org/emo/resource/1/jenmdt/v137/i12/p807_s1?isAuthorized=no