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Lasarte, Spain

Zito P.,ENEA | Lampasi A.,ENEA | Coletti A.,Fusion for Energy F4E | Novello L.,Fusion for Energy F4E | And 6 more authors.
Fusion Engineering and Design

Fast Plasma Position Control Coils (FPPCC) PSs control the vertical position of the plasma during a plasma shot, to prevent Vertical Displacement Event (VDE), using FPPC coils installed in vacuum vessel for JT-60SA. For this task, the FPPCC PSs have to be very fast for reacting to plasma movements. Further, an open loop feed forward voltage control is adopted in order to achieve a fast control of FPPCC PSs. The main characteristics are: 4-quadrant AC/DC converter 12-pulse with circulating current, DC load voltage ±1000. V and DC load current ±5. kA.The overvoltage induced by FPPC coil during a plasma disruption can reach 10. kV and it is protected by a nonlinear resistor in parallel to the crowbar up to its intervention. All these technical characteristics have strongly influenced the design of the FPPCC converter and transformers which have been validated by simulation model of FPPCC PS. The outcomes of the simulation allowed to finalize the performances and dynamic behavior of voltage response. © 2015 Elsevier B.V. Source

Zulaika M.,JEMA | Ganuza D.,JEMA | Arenal A.,JEMA | De La Fuente J.M.,JEMA | And 2 more authors.
Fusion Engineering and Design

The company JEMA has delivered to the Joint European Torus (JET facility at Culham) the enhanced radial field amplifier (ERFA). This device is a high frequency, high power amplifier aimed at correcting instabilities due to fast plasma disturbances. The system is composed of four identical units connected in series through a connection box delivering up to ±12 kV, ±5 kA (60 MVAr) in four quadrant operation. Each unit is composed of an input converter stage, a DC link energy storage stage, an output inverter and an output bypass (for continuing operation in case of a unit failure). ERFA works as an energy exchanger between the internal DC link capacitors bank and the JET radial field coils. The input converter compensates for power losses in the JET coils and the ERFA during operation. The ERFA control system is fundamental for the amplifier performance to meet the speed of response required with the flexibility to achieve this for an unpredictable reference and for a wide range of load coil configurations. This paper covers the control architecture, the real-time evaluation and high speed response to the system requirements, and the fast exchange rate of data among ERFA units. © 2011 Elsevier B.V. All Rights Reserved. Source

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