The Experts below are selected from a list of 669 Experts worldwide ranked by ideXlab platform
Makoto Takizawa - One of the best experts on this subject based on the ideXlab platform.
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An extended improved Redundant Power consumption laxity-based (EIRPCLB) algorithm for energy efficient server cluster systems
World Wide Web, 2015Co-Authors: Tomoya Enokido, Dilawaer Duolikun, Makoto TakizawaAbstract:In cloud computing systems, server cluster systems are used to provide flexible, scalable, and fault-tolerant application services. One way to provide a fault-tolerant application service is that multiple replicas of each application process are performed on multiple servers in a server cluster. However, a large amount of electric energy is consumed in a server cluster. Hence, it is critical to discuss how to make information systems not only fault-tolerant but also energy-efficient. In our previous studies, the extended improved Redundant Power consumption laxity-based (EIRPCLB) algorithm is proposed to reduce the total energy consumption of a server cluster to Redundantly perform application processes. Once a replica successfully terminates on one server, replicas being or to be performed on other servers are meaningless. In the EIRPCLB algorithm, the total energy consumption of a server cluster can be reduced by forcing meaningless replicas to terminate and differentiating the starting time of each replica. In this paper, we evaluate the EIRPCLB algorithm in terms of total energy consumption and the average response time in homogeneous and heterogeneous clusters. We make clear how the total energy consumption of a server cluster and response time of each process change according to the change of inter-arrival time of request processes, inter-request time of replicas, redundancy of each process, and delay time between servers.
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evaluation of the extended improved Redundant Power consumption laxity based eirpclb algorithm
Advanced Information Networking and Applications, 2014Co-Authors: Tomoya Enokido, Ailixier Aikebaier, Makoto TakizawaAbstract:Application processes have to be not only fault-tolerantly but also energy-efficiently performed in presence of server faults in a cluster of servers. In our previous studies, the extended improved Redundant Power consumption laxity-based (EIRPCLB) algorithm is proposed where a process is actively replicated on multiple servers. While the cluster can be fault-tolerant, the larger amount of electric Power is consumed than non-Redundant execution. In order to reduce the total Power consumption of servers, the total computation time of the replicas has to be reduced. We discuss an EIRPCLB algorithm for force termination and late restart of replicas. Here, as long as one replica successfully terminates, only a smaller part of every other replica is performed. In this paper, we evaluate the EIRPCLB algorithm in terms of total Power consumption and the average response time in homogeneous and heterogeneous clusters. We make clear how the total Power consumption of a cluster and response time of each process change according to the redundancy of each process and delay time between servers.
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AINA - Evaluation of the Extended Improved Redundant Power Consumption Laxity-Based (EIRPCLB) Algorithm
2014 IEEE 28th International Conference on Advanced Information Networking and Applications, 2014Co-Authors: Tomoya Enokido, Ailixier Aikebaier, Makoto TakizawaAbstract:Application processes have to be not only fault-tolerantly but also energy-efficiently performed in presence of server faults in a cluster of servers. In our previous studies, the extended improved Redundant Power consumption laxity-based (EIRPCLB) algorithm is proposed where a process is actively replicated on multiple servers. While the cluster can be fault-tolerant, the larger amount of electric Power is consumed than non-Redundant execution. In order to reduce the total Power consumption of servers, the total computation time of the replicas has to be reduced. We discuss an EIRPCLB algorithm for force termination and late restart of replicas. Here, as long as one replica successfully terminates, only a smaller part of every other replica is performed. In this paper, we evaluate the EIRPCLB algorithm in terms of total Power consumption and the average response time in homogeneous and heterogeneous clusters. We make clear how the total Power consumption of a cluster and response time of each process change according to the redundancy of each process and delay time between servers.
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the evaluation of the improved Redundant Power consumption laxity based irpclb algorithm in homogeneous and heterogeneous clusters
Complex Intelligent and Software Intensive Systems, 2013Co-Authors: Tomoya Enokido, Ailixier Aikebaier, Makoto TakizawaAbstract:In a server cluster, one server is usually selected to perform a request process from a client. Once the server stops by fault, the client is suspended to wait for a reply. Even if the request is performed on another server on detection of fault of the server, some QoS requirement like response time may not be satisfied. Hence, each request is Redundantly performed on multiple servers to be tolerant of server faults. Here, more number of servers a request process is Redundantly performed, the more reliable but the more amount of electric Power is consumed. Thus, it is critical to discuss how to realize a reliable and energy-aware server cluster in presence of server faults. The Redundant Power consumption laxity-based (RPCLB) algorithm is proposed to Redundantly and energy-efficiently perform a request process in our previous studies. In this paper, we newly discuss an improved RPCLB (IRPCLB) algorithm where once a process successfully terminates on one server, meaningless Redundant processes are forced to terminate on the other servers. We show the total Power consumption of servers and response time of each process can be reduced in the IRPCLB algorithm than the RPCLB and round-robin (RR) algorithms in both heterogeneous and homogeneous clusters.
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CISIS - The Evaluation of the Improved Redundant Power Consumption Laxity-Based (IRPCLB) Algorithm in Homogeneous and Heterogeneous Clusters
2013 Seventh International Conference on Complex Intelligent and Software Intensive Systems, 2013Co-Authors: Tomoya Enokido, Ailixier Aikebaier, Makoto TakizawaAbstract:In a server cluster, one server is usually selected to perform a request process from a client. Once the server stops by fault, the client is suspended to wait for a reply. Even if the request is performed on another server on detection of fault of the server, some QoS requirement like response time may not be satisfied. Hence, each request is Redundantly performed on multiple servers to be tolerant of server faults. Here, more number of servers a request process is Redundantly performed, the more reliable but the more amount of electric Power is consumed. Thus, it is critical to discuss how to realize a reliable and energy-aware server cluster in presence of server faults. The Redundant Power consumption laxity-based (RPCLB) algorithm is proposed to Redundantly and energy-efficiently perform a request process in our previous studies. In this paper, we newly discuss an improved RPCLB (IRPCLB) algorithm where once a process successfully terminates on one server, meaningless Redundant processes are forced to terminate on the other servers. We show the total Power consumption of servers and response time of each process can be reduced in the IRPCLB algorithm than the RPCLB and round-robin (RR) algorithms in both heterogeneous and homogeneous clusters.
Tomoya Enokido - One of the best experts on this subject based on the ideXlab platform.
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An extended improved Redundant Power consumption laxity-based (EIRPCLB) algorithm for energy efficient server cluster systems
World Wide Web, 2015Co-Authors: Tomoya Enokido, Dilawaer Duolikun, Makoto TakizawaAbstract:In cloud computing systems, server cluster systems are used to provide flexible, scalable, and fault-tolerant application services. One way to provide a fault-tolerant application service is that multiple replicas of each application process are performed on multiple servers in a server cluster. However, a large amount of electric energy is consumed in a server cluster. Hence, it is critical to discuss how to make information systems not only fault-tolerant but also energy-efficient. In our previous studies, the extended improved Redundant Power consumption laxity-based (EIRPCLB) algorithm is proposed to reduce the total energy consumption of a server cluster to Redundantly perform application processes. Once a replica successfully terminates on one server, replicas being or to be performed on other servers are meaningless. In the EIRPCLB algorithm, the total energy consumption of a server cluster can be reduced by forcing meaningless replicas to terminate and differentiating the starting time of each replica. In this paper, we evaluate the EIRPCLB algorithm in terms of total energy consumption and the average response time in homogeneous and heterogeneous clusters. We make clear how the total energy consumption of a server cluster and response time of each process change according to the change of inter-arrival time of request processes, inter-request time of replicas, redundancy of each process, and delay time between servers.
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evaluation of the extended improved Redundant Power consumption laxity based eirpclb algorithm
Advanced Information Networking and Applications, 2014Co-Authors: Tomoya Enokido, Ailixier Aikebaier, Makoto TakizawaAbstract:Application processes have to be not only fault-tolerantly but also energy-efficiently performed in presence of server faults in a cluster of servers. In our previous studies, the extended improved Redundant Power consumption laxity-based (EIRPCLB) algorithm is proposed where a process is actively replicated on multiple servers. While the cluster can be fault-tolerant, the larger amount of electric Power is consumed than non-Redundant execution. In order to reduce the total Power consumption of servers, the total computation time of the replicas has to be reduced. We discuss an EIRPCLB algorithm for force termination and late restart of replicas. Here, as long as one replica successfully terminates, only a smaller part of every other replica is performed. In this paper, we evaluate the EIRPCLB algorithm in terms of total Power consumption and the average response time in homogeneous and heterogeneous clusters. We make clear how the total Power consumption of a cluster and response time of each process change according to the redundancy of each process and delay time between servers.
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AINA - Evaluation of the Extended Improved Redundant Power Consumption Laxity-Based (EIRPCLB) Algorithm
2014 IEEE 28th International Conference on Advanced Information Networking and Applications, 2014Co-Authors: Tomoya Enokido, Ailixier Aikebaier, Makoto TakizawaAbstract:Application processes have to be not only fault-tolerantly but also energy-efficiently performed in presence of server faults in a cluster of servers. In our previous studies, the extended improved Redundant Power consumption laxity-based (EIRPCLB) algorithm is proposed where a process is actively replicated on multiple servers. While the cluster can be fault-tolerant, the larger amount of electric Power is consumed than non-Redundant execution. In order to reduce the total Power consumption of servers, the total computation time of the replicas has to be reduced. We discuss an EIRPCLB algorithm for force termination and late restart of replicas. Here, as long as one replica successfully terminates, only a smaller part of every other replica is performed. In this paper, we evaluate the EIRPCLB algorithm in terms of total Power consumption and the average response time in homogeneous and heterogeneous clusters. We make clear how the total Power consumption of a cluster and response time of each process change according to the redundancy of each process and delay time between servers.
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the evaluation of the improved Redundant Power consumption laxity based irpclb algorithm in homogeneous and heterogeneous clusters
Complex Intelligent and Software Intensive Systems, 2013Co-Authors: Tomoya Enokido, Ailixier Aikebaier, Makoto TakizawaAbstract:In a server cluster, one server is usually selected to perform a request process from a client. Once the server stops by fault, the client is suspended to wait for a reply. Even if the request is performed on another server on detection of fault of the server, some QoS requirement like response time may not be satisfied. Hence, each request is Redundantly performed on multiple servers to be tolerant of server faults. Here, more number of servers a request process is Redundantly performed, the more reliable but the more amount of electric Power is consumed. Thus, it is critical to discuss how to realize a reliable and energy-aware server cluster in presence of server faults. The Redundant Power consumption laxity-based (RPCLB) algorithm is proposed to Redundantly and energy-efficiently perform a request process in our previous studies. In this paper, we newly discuss an improved RPCLB (IRPCLB) algorithm where once a process successfully terminates on one server, meaningless Redundant processes are forced to terminate on the other servers. We show the total Power consumption of servers and response time of each process can be reduced in the IRPCLB algorithm than the RPCLB and round-robin (RR) algorithms in both heterogeneous and homogeneous clusters.
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CISIS - The Evaluation of the Improved Redundant Power Consumption Laxity-Based (IRPCLB) Algorithm in Homogeneous and Heterogeneous Clusters
2013 Seventh International Conference on Complex Intelligent and Software Intensive Systems, 2013Co-Authors: Tomoya Enokido, Ailixier Aikebaier, Makoto TakizawaAbstract:In a server cluster, one server is usually selected to perform a request process from a client. Once the server stops by fault, the client is suspended to wait for a reply. Even if the request is performed on another server on detection of fault of the server, some QoS requirement like response time may not be satisfied. Hence, each request is Redundantly performed on multiple servers to be tolerant of server faults. Here, more number of servers a request process is Redundantly performed, the more reliable but the more amount of electric Power is consumed. Thus, it is critical to discuss how to realize a reliable and energy-aware server cluster in presence of server faults. The Redundant Power consumption laxity-based (RPCLB) algorithm is proposed to Redundantly and energy-efficiently perform a request process in our previous studies. In this paper, we newly discuss an improved RPCLB (IRPCLB) algorithm where once a process successfully terminates on one server, meaningless Redundant processes are forced to terminate on the other servers. We show the total Power consumption of servers and response time of each process can be reduced in the IRPCLB algorithm than the RPCLB and round-robin (RR) algorithms in both heterogeneous and homogeneous clusters.
Martin H L Chow - One of the best experts on this subject based on the ideXlab platform.
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practical design and evaluation of a 1 kw pfc Power supply based on reduced Redundant Power processing principle
IEEE Transactions on Industrial Electronics, 2008Co-Authors: Martin K. H. Cheung, Martin H L ChowAbstract:Using the reduced Redundant Power processing (R2P2) principle, a single-phase Power-factor correction (PFC) Power supply can achieve a higher overall efficiency as a result of the use of a noncascading structure that involves less repeated processing of the input Power. This paper investigates a single-phase noncascading PFC Power supply based on the R2P2 principle. The circuit employs a current-fed full-bridge converter as the PFC preregulator, and a buck-boost converter as the voltage regulator. This paper addresses the design of this noncascading PFC Power supply and in particular the relationships between the gained efficiency, the transient response and the size of the energy storage. Experimental results obtained from a 1 kW laboratory prototype are presented.
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Design of a 1 kW PFC Power supply based on reduced Redundant Power processing principle
37th IEEE Power Electronics Specialists Conference, 2006Co-Authors: Martin K. H. Cheung, Martin H L ChowAbstract:This paper presents a single phase Power factor correction (PFC) Power supply topology based on a non-cascading connection of a current-fed full-bridge converter and a buck-boost converter, both converters being operated in continuous conduction mode (CCM). Due to the reduced Redundant processing of Power, the non-cascading structure can inherently achieve a higher overall efficiency compared to the classical two-stage cascade structure. An analysis of the reduced Redundant Power processing (R 2 P 2 ) principle is given and the associated practical problems discussed. Experimental results verify the effectiveness of the non-cascading structure of the proposed topology as an appropriate solution for increasing the overall efficiency.
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a family of pfc voltage regulator configurations with reduced Redundant Power processing
IEEE Transactions on Power Electronics, 2001Co-Authors: Martin H L Chow, M K H CheungAbstract:This paper discusses a systematic method for deriving basic converter configurations that achieve Power factor correction (PFC) and voltage regulation. The discussion begins with a general three-port representation of Power supplies that provide PFC and voltage regulation. Based on this representation and a Power flow consideration, a systematic procedure is derived to generate all possible minimal configurations. Among these configurations, only a few have been known previously and used in practice. It is found that the efficiency of PFC voltage regulators can be improved by reducing the amount of Redundant Power to be processed by the constituent converters. A systematic circuit synthesis procedure is proposed for creating PFC voltage regulators with reduced Redundant Power processing. Experimental measurements verify the improved efficiency.
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Reduced Redundant Power processing (R/sup 2/P/sup 2/) PFC voltage regulators: circuit synthesis and control
2000 IEEE 31st Annual Power Electronics Specialists Conference. Conference Proceedings (Cat. No.00CH37018), 2000Co-Authors: Martin H L Chow, Martin K. H. CheungAbstract:High input Power factor is becoming a mandatory requirement, in addition to tight output regulation, of DC Power supplies that derive Power directly from the AC mains. In principle, the Power factor correction (PFC) and output regulation functions are separately achieved by two Power stages. This paper addresses the amalgamation of the two Power stages to form a PFC voltage regulator. The focus is the noncascading structure that allows a higher overall efficiency to be achieved. Unlike the conventional cascade configuration, the circuits discussed in this paper allow part of the input Power to be processed by only one stage, thereby reducing the amount of Power Redundantly processed by the two constituent Power stages. This paper describes in particular a systematic synthesis method and some important issues related to the control of such converter circuits.
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An efficient PFC voltage regulator with reduced Redundant Power processing
30th Annual IEEE Power Electronics Specialists Conference. Record. (Cat. No.99CH36321), 1999Co-Authors: Martin H L ChowAbstract:Conventional PFC Power supplies employ two cascading stages that deal separately with PFC and voltage regulation. Since Power is processed serially by two Power stages, the efficiency is limited. In this paper a PFC Power supply with improved efficiency is proposed. This circuit makes use of a parallel configuration that reduces unnecessary processing of all Power by two stages serially. The circuit is derived from consideration of the Power flow between the input, the load and the storage capacitor. A specific circuit implementation is described and the test results are reported.
Ailixier Aikebaier - One of the best experts on this subject based on the ideXlab platform.
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evaluation of the extended improved Redundant Power consumption laxity based eirpclb algorithm
Advanced Information Networking and Applications, 2014Co-Authors: Tomoya Enokido, Ailixier Aikebaier, Makoto TakizawaAbstract:Application processes have to be not only fault-tolerantly but also energy-efficiently performed in presence of server faults in a cluster of servers. In our previous studies, the extended improved Redundant Power consumption laxity-based (EIRPCLB) algorithm is proposed where a process is actively replicated on multiple servers. While the cluster can be fault-tolerant, the larger amount of electric Power is consumed than non-Redundant execution. In order to reduce the total Power consumption of servers, the total computation time of the replicas has to be reduced. We discuss an EIRPCLB algorithm for force termination and late restart of replicas. Here, as long as one replica successfully terminates, only a smaller part of every other replica is performed. In this paper, we evaluate the EIRPCLB algorithm in terms of total Power consumption and the average response time in homogeneous and heterogeneous clusters. We make clear how the total Power consumption of a cluster and response time of each process change according to the redundancy of each process and delay time between servers.
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AINA - Evaluation of the Extended Improved Redundant Power Consumption Laxity-Based (EIRPCLB) Algorithm
2014 IEEE 28th International Conference on Advanced Information Networking and Applications, 2014Co-Authors: Tomoya Enokido, Ailixier Aikebaier, Makoto TakizawaAbstract:Application processes have to be not only fault-tolerantly but also energy-efficiently performed in presence of server faults in a cluster of servers. In our previous studies, the extended improved Redundant Power consumption laxity-based (EIRPCLB) algorithm is proposed where a process is actively replicated on multiple servers. While the cluster can be fault-tolerant, the larger amount of electric Power is consumed than non-Redundant execution. In order to reduce the total Power consumption of servers, the total computation time of the replicas has to be reduced. We discuss an EIRPCLB algorithm for force termination and late restart of replicas. Here, as long as one replica successfully terminates, only a smaller part of every other replica is performed. In this paper, we evaluate the EIRPCLB algorithm in terms of total Power consumption and the average response time in homogeneous and heterogeneous clusters. We make clear how the total Power consumption of a cluster and response time of each process change according to the redundancy of each process and delay time between servers.
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the evaluation of the improved Redundant Power consumption laxity based irpclb algorithm in homogeneous and heterogeneous clusters
Complex Intelligent and Software Intensive Systems, 2013Co-Authors: Tomoya Enokido, Ailixier Aikebaier, Makoto TakizawaAbstract:In a server cluster, one server is usually selected to perform a request process from a client. Once the server stops by fault, the client is suspended to wait for a reply. Even if the request is performed on another server on detection of fault of the server, some QoS requirement like response time may not be satisfied. Hence, each request is Redundantly performed on multiple servers to be tolerant of server faults. Here, more number of servers a request process is Redundantly performed, the more reliable but the more amount of electric Power is consumed. Thus, it is critical to discuss how to realize a reliable and energy-aware server cluster in presence of server faults. The Redundant Power consumption laxity-based (RPCLB) algorithm is proposed to Redundantly and energy-efficiently perform a request process in our previous studies. In this paper, we newly discuss an improved RPCLB (IRPCLB) algorithm where once a process successfully terminates on one server, meaningless Redundant processes are forced to terminate on the other servers. We show the total Power consumption of servers and response time of each process can be reduced in the IRPCLB algorithm than the RPCLB and round-robin (RR) algorithms in both heterogeneous and homogeneous clusters.
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CISIS - The Evaluation of the Improved Redundant Power Consumption Laxity-Based (IRPCLB) Algorithm in Homogeneous and Heterogeneous Clusters
2013 Seventh International Conference on Complex Intelligent and Software Intensive Systems, 2013Co-Authors: Tomoya Enokido, Ailixier Aikebaier, Makoto TakizawaAbstract:In a server cluster, one server is usually selected to perform a request process from a client. Once the server stops by fault, the client is suspended to wait for a reply. Even if the request is performed on another server on detection of fault of the server, some QoS requirement like response time may not be satisfied. Hence, each request is Redundantly performed on multiple servers to be tolerant of server faults. Here, more number of servers a request process is Redundantly performed, the more reliable but the more amount of electric Power is consumed. Thus, it is critical to discuss how to realize a reliable and energy-aware server cluster in presence of server faults. The Redundant Power consumption laxity-based (RPCLB) algorithm is proposed to Redundantly and energy-efficiently perform a request process in our previous studies. In this paper, we newly discuss an improved RPCLB (IRPCLB) algorithm where once a process successfully terminates on one server, meaningless Redundant processes are forced to terminate on the other servers. We show the total Power consumption of servers and response time of each process can be reduced in the IRPCLB algorithm than the RPCLB and round-robin (RR) algorithms in both heterogeneous and homogeneous clusters.
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ITCS - Improved Redundant Power Consumption Laxity-Based Algorithm for Server Clusters
Lecture Notes in Electrical Engineering, 2013Co-Authors: Tomoya Enokido, Ailixier Aikebaier, Makoto TakizawaAbstract:A client usually issues a request to one server in a cluster of servers and the server sends a reply to the client. Once the server stops by fault, the client is suspended to wait for a reply. In order to be tolerant of server faults, each request is Redundantly performed on multiple servers. Here, the more number of servers a request process is Redundantly performed, the more reliable but the more amount of electric energy is consumed. Thus, it is critical to discuss how to realize energy-aware, robust clusters of servers. In this paper, we newly propose the improved Redundant Power consumption laxity-based (IRPCLB) algorithm where once a process successfully terminates on one server, meaningless Redundant processes are not performed on the other servers. We show the total Power consumption of servers is reduced in the IRPCLB algorithm.
Martin K. H. Cheung - One of the best experts on this subject based on the ideXlab platform.
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practical design and evaluation of a 1 kw pfc Power supply based on reduced Redundant Power processing principle
IEEE Transactions on Industrial Electronics, 2008Co-Authors: Martin K. H. Cheung, Martin H L ChowAbstract:Using the reduced Redundant Power processing (R2P2) principle, a single-phase Power-factor correction (PFC) Power supply can achieve a higher overall efficiency as a result of the use of a noncascading structure that involves less repeated processing of the input Power. This paper investigates a single-phase noncascading PFC Power supply based on the R2P2 principle. The circuit employs a current-fed full-bridge converter as the PFC preregulator, and a buck-boost converter as the voltage regulator. This paper addresses the design of this noncascading PFC Power supply and in particular the relationships between the gained efficiency, the transient response and the size of the energy storage. Experimental results obtained from a 1 kW laboratory prototype are presented.
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Design of a 1 kW PFC Power supply based on reduced Redundant Power processing principle
37th IEEE Power Electronics Specialists Conference, 2006Co-Authors: Martin K. H. Cheung, Martin H L ChowAbstract:This paper presents a single phase Power factor correction (PFC) Power supply topology based on a non-cascading connection of a current-fed full-bridge converter and a buck-boost converter, both converters being operated in continuous conduction mode (CCM). Due to the reduced Redundant processing of Power, the non-cascading structure can inherently achieve a higher overall efficiency compared to the classical two-stage cascade structure. An analysis of the reduced Redundant Power processing (R 2 P 2 ) principle is given and the associated practical problems discussed. Experimental results verify the effectiveness of the non-cascading structure of the proposed topology as an appropriate solution for increasing the overall efficiency.
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Reduced Redundant Power processing (R/sup 2/P/sup 2/) PFC voltage regulators: circuit synthesis and control
2000 IEEE 31st Annual Power Electronics Specialists Conference. Conference Proceedings (Cat. No.00CH37018), 2000Co-Authors: Martin H L Chow, Martin K. H. CheungAbstract:High input Power factor is becoming a mandatory requirement, in addition to tight output regulation, of DC Power supplies that derive Power directly from the AC mains. In principle, the Power factor correction (PFC) and output regulation functions are separately achieved by two Power stages. This paper addresses the amalgamation of the two Power stages to form a PFC voltage regulator. The focus is the noncascading structure that allows a higher overall efficiency to be achieved. Unlike the conventional cascade configuration, the circuits discussed in this paper allow part of the input Power to be processed by only one stage, thereby reducing the amount of Power Redundantly processed by the two constituent Power stages. This paper describes in particular a systematic synthesis method and some important issues related to the control of such converter circuits.