67 research outputs found

    Real-time plasma state monitoring and supervisory control on TCV

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    In ITER and DEMO, various control objectives related to plasma control must be simultaneously achieved by the plasma control system (PCS), in both normal operation as well as off-normal conditions. The PCS must act on off-normal events and deviations from the target scenario, since certain sequences (chains) of events can precede disruptions. It is important that these decisions are made while maintaining a coherent prioritization between the real-time control tasks to ensure high-performance operation. In this paper, a generic architecture for task-based integrated plasma control is proposed. The architecture is characterized by the separation of state estimation, event detection, decisions and task execution among different algorithms, with standardized signal interfaces. Central to the architecture are a plasma state monitor and supervisory controller. In the plasma state monitor, discrete events in the continuous-valued plasma state are modeled using finite state machines. This provides a high-level representation of the plasma state. The supervisory controller coordinates the execution of multiple plasma control tasks by assigning task priorities, based on the finite states of the plasma and the pulse schedule. These algorithms were implemented on the TCV digital control system and integrated with actuator resource management and existing state estimation algorithms and controllers. The plasma state monitor on TCV can track a multitude of plasma events, related to plasma current, rotating and locked neoclassical tearing modes, and position displacements. In TCV experiments on simultaneous control of plasma pressure, safety factor profile and NTMs using electron cyclotron heating (ECH) and current drive (ECCD), the supervisory controller assigns priorities to the relevant control tasks. The tasks are then executed by feedback controllers and actuator allocation management. This work forms a significant step forward in the ongoing integration of control capabilities in experiments on TCV, in support of tokamak reactor operation

    The design of gradient-index lenses using analytical and optimization techniques

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    Imperial Users onl

    Near-field coupling of wireless devices and long communications cables

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    A comprehensive investigation of the coupling between mobile devices and communication/control cables in several environments is described here. Both experimental and numerical results are shown and compared using a number of different methods in different laboratories. Results indicate a good level of agreement between the different approaches thus giving confidence that predictive studies based on simulation can give a good quantitative assessment of coupling. Moreover, the studies show that varying the configuration of the coupled systems does not significantly affects the maximum coupling thus making it possible to obtain a reasonable worst case estimate of coupling from a small number of generic studies.Electromagnetic compatibility in diffused communications system

    Time Domain Measure for Power Flow of Thin Wire Electromagnetic Field

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    The influence of the fuel stratification on the IC engine working cycle with the compressed natural gas

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    Abstract The gaseous fuels are very convenient from the economic aspect as well as from the ecology aspect. Fuel stratification allows the engine work with the globally lean mixture and in this way increase the engine efficiency and reduces the pump losses. The separation of the engine working space, on the area where the mixture will be always rich, and on the area where the mixture will be always lean, allows the spark ignition engine work with the globally lean mixture. In the paper it was investigated, how the fuel stratification ratio influences on the combustion process of the compressed natural gas in the spark ignition engine. It was found that the stratification ratio has a great influence on the combustion process, as well as on the engine performances and the efficiency. Based on the research it was identified the optimal combustion process from the aspect of the performances and the efficiency.</jats:p
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