다중혈관 관상동맥 환자에서 y-문합을 이용하여 양쪽 내흉동맥만을 사용한 우회술의 조기 성적

Although the concept of variable-speed drives, based on utilization of multiphase machines, dates back to the late 1960s, it was not until the mid- to late 1990s that multiphase drives became serious contenders for various applications. These include electric ship propulsion, locomotive traction, electric and hybrid electric vehicles, ldquomore-electricrdquo aircraft, and high-power industrial applications. As a consequence, there has been a substantial increase in the interest for such drive systems worldwide, resulting in a huge volume of work published during the last ten years. An attempt is made in this paper to provide a brief review of the current state of the art in the area. After addressing the reasons for potential use of multiphase rather than three-phase drives and the available approaches to multiphase machine designs, various control schemes are surveyed. This is followed by a discussion of the multiphase voltage source inverter control. Various possibilities for the use of additional degrees of freedom that exist in multiphase machines are further elaborated. Finally, multiphase machine applications in electric energy generation are addressed.

Multiphase Electric Machines for Variable-Speed Applications

Large-scale deployment of intermittent renewable energy (namely wind energy and solar PV) may entail new challenges in power systems and more volatility in power prices in liberalized electricity markets. Energy storage can diminish this imbalance, relieving the grid congestion, and promoting distributed generation. The economic implications of grid-scale electrical energy storage technologies are however obscure for the experts, power grid operators, regulators, and power producers. A meticulous techno-economic or cost-benefit analysis of electricity storage systems requires consistent, updated cost data and a holistic cost analysis framework. To this end, this study critically examines the existing literature in the analysis of life cycle costs of utility-scale electricity storage systems, providing an updated database for the cost elements (capital costs, operational and maintenance costs, and replacement costs). Moreover, life cycle costs and levelized cost of electricity delivered by electrical energy storage is analyzed, employing Monte Carlo method to consider uncertainties. The examined energy storage technologies include pumped hydropower storage, compressed air energy storage (CAES), flywheel, electrochemical batteries (e.g. lead–acid, NaS, Li-ion, and Ni–Cd), flow batteries (e.g. vanadium-redox), superconducting magnetic energy storage, supercapacitors, and hydrogen energy storage (power to gas technologies). The results illustrate the economy of different storage systems for three main applications: bulk energy storage, T&D support services, and frequency regulation.

Electrical energy storage systems: A comparative life cycle cost analysis

Energy storage technologies and real life applications – A state of the art review

The electric vehicle (EV) technology addresses the issue of the reduction of carbon and greenhouse gas emissions. The concept of EVs focuses on the utilization of alternative energy resources. However, EV systems currently face challenges in energy storage systems (ESSs) with regard to their safety, size, cost, and overall management issues. In addition, hybridization of ESSs with advanced power electronic technologies has a significant influence on optimal power utilization to lead advanced EV technologies. This paper comprehensively reviews technologies of ESSs, its classifications, characteristics, constructions, electricity conversion, and evaluation processes with advantages and disadvantages for EV applications. Moreover, this paper discusses various classifications of ESS according to their energy formations, composition materials, and techniques on average power delivery over its capacity and overall efficiencies exhibited within their life expectancies. The rigorous review indicates that existing technologies for ESS can be used for EVs, but the optimum use of ESSs for efficient EV energy storage applications has not yet been achieved. This review highlights many factors, challenges, and problems for sustainable development of ESS technologies in next-generation EV applications. Thus, this review will widen the effort toward the development of economic and efficient ESSs with a longer lifetime for future EV uses.

Review of energy storage systems for electric vehicle applications: Issues and challenges

Variations of marine current speed can lead to strong fluctuations in the power extracted by a marine current turbine (MCT). During short-time period, swell effect is the main cause for the current speed variations. Conventional tip speed ratio Maximum Power Point Tracking (MPPT) algorithm will require the MCT to accelerate or to decelerate frequently under swell effect, which can cause severe fluctuations in the generator power. This paper focuses on power smoothing control of a PMSG-Based MCT system. A modified MPPT algorithm with filter strategy is proposed in generator-side control to use the system inertia for smoothing the fluctuation of generator power. When the current speed is over rated value, the power limitation control will be applied. In the second step, Supercapacitor (SC) Energy Storage System (ESS) is added to compensate the residual power fluctuations. Simulations of a 1.5 MW direct- driven grid-connected MCT system are carried out. The results demonstrate that the association of the generator-side filter strategy with the SC ESS system achieves a smoothed power injected to the grid in case of swell disturbances.

LISSAGE SUPERCAPACITIF DE LA PUISSANCE PRODUITE PAR UNE HYDROLIENNE CONNECTEE AU RESEAU Power Smoothing Control of a Grid-Connected Marine Current Turbine System Using Supercapacitors

Variations of marine current speed can lead to strong fluctuations in the power extracted by a marine current turbine (MCT). During short-time period, swell effect is the main cause for the current speed variations. Conventional tip speed ratio Maximum Power Point Tracking (MPPT) algorithm will require the MCT to accelerate or to decelerate frequently under swell effect, which can cause severe fluctuations in the generator power. This paper focuses on power smoothing control of a PMSG-Based MCT system. A modified MPPT algorithm with filter strategy is proposed in generator-side control to use the system inertia for smoothing the fluctuation of generator power. When the current speed is over rated value, the power limitation control will be applied. In the second step, Supercapacitor (SC) Energy Storage System (ESS) is added to compensate the residual power fluctuations. Simulations of a 1.5 MW direct-driven grid-connected MCT system are carried out. The results demonstrate that the association of the generator-side filter strategy with the SC ESS system achieves a smoothed power injected to the grid in case of swell disturbances.

https://hal.archives-ouvertes.fr/hal-00874492/document

Power Smoothing Control of a Grid-Connected Marine Current Turbine System Using Supercapacitors

En raison de la previsibilite des courants marins, les hydroliennes apparaissent a priori comme tres attractives en tant que source d’electricite future pour les zones cotieres isolees et les iles eloignees situees a proximite de sites a forts courants comme les iles du Ponant au large du Finistere. Cependant la puissance produite par une hydrolienne varie considerablement avec la vitesse des courants marins pendant une journee. Cet article propose d’utiliser une batterie a circulation ou « flow battery » pour faciliter la gestion quotidienne de la puissance d’une hydrolienne et permettre de fournir ainsi une puissance demandee par les utilisateurs d’un reseau electrique isole. Un generateur diesel de faible puissance est egalement integre pour charger la batterie lorsque l’etat de charge de la batterie est tres bas et que le courant marin est insuffisant pour assurer l’alimentation du reseau et la recharge de la batterie.
L’originalite du travail propose repose ainsi sur l’etude de l’hybridation d’une hydrolienne associee a une batterie a circulation et a un generateur diesel.

https://hal.archives-ouvertes.fr/hal-01065332/document

Intégration d’une batterie à circulation pour lisser la puissance quotidienne fournie par une hydrolienne sur un réseau îloté

Science Arts & Métiers (SAM) is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible.

Franck Scuiller

Papers

LISSAGE SUPERCAPACITIF DE LA PUISSANCE PRODUITE PAR UNE HYDROLIENNE CONNECTEE AU RESEAU Power Smoothing Control of a Grid-Connected Marine Current Turbine System Using Supercapacitors

Power Smoothing Control of a Grid-Connected Marine Current Turbine System Using Supercapacitors

Intégration d’une batterie à circulation pour lisser la puissance quotidienne fournie par une hydrolienne sur un réseau îloté

Science Arts & Métiers (SAM) is an open access repository that collects the work of Arts et Métiers ParisTech researchers and makes it freely available over the web where possible.

Lissage supercapacitif de la puissance produite par une hydrolienne connectee au reseau