Title :
The COMPASS Tokamak Plasma Control Software Performance
Author :
Valcárcel, Daniel F. ; Neto, André ; Carvalho, Ivo S. ; Carvalho, Bernardo B. ; Fernandes, Horácio ; Sousa, Jorge ; Janky, Filip ; Havlicek, Josef ; Beno, Radek ; Horacek, Jan ; Hron, Martin ; Pánek, Radomir
Author_Institution :
Lab. Associado, Associacao EURATOM, Lisbon, Portugal
Abstract :
The COMPASS tokamak has began operation at the IPP Prague in December 2008. A new control system has been built using an ATCA-based real-time system developed at IST Lisbon. The control software is implemented on top of the MARTe real-time framework attaining control cycles as short as 50 μs, with a jitter of less than 1 μs. The controlled parameters, important for the plasma performance, are the plasma current, position of the plasma current center, boundary shape and horizontal and vertical velocities. These are divided in two control cycles: slow at 500 μs and fast at 50 μs. The project has two phases. First, the software implements a digital controller, similar to the analog one used during the COMPASS-D operation in Culham. In the slow cycle, the plasma current and position are measured and controlled with PID and feedforward controllers, respectively, the shaping magnetic field is preprogrammed. The vertical instability and horizontal equilibrium are controlled with the faster 50-μs cycle PID controllers. The second phase will implement a plasma-shape reconstruction algorithm and controller, aiming at optimized plasma performance. The system was designed to be as modular as possible by breaking the functional requirements of the control system into several independent and specialized modules. This splitting enabled tuning the execution of each system part and to use the modules in a variety of applications with different time constraints. This paper presents the design and overall performance of the COMPASS control software.
Keywords :
Tokamak devices; digital control; electric current control; feedforward; fusion reactor instrumentation; plasma boundary layers; plasma instability; plasma toroidal confinement; plasma transport processes; position control; three-term control; velocity control; ATCA based real time system; COMPASS control software performance; COMPASS tokamak; IPP Prague; IST Lisbon; MARTe real time framework; PID controller; digital controller; feedforward controller; horizontal plasma equilibrium; plasma boundary shape; plasma current center position; plasma horizontal velocity; plasma performance; plasma shape controller; plasma shape reconstruction algorithm; plasma vertical velocity; preprogrammed shaping magnetic field; time 50 mus; time 500 mus; tokamak plasmas; vertical plasma instability; Compass; Current measurement; Feedforward neural networks; Plasma measurements; Plasmas; Real time systems; Software; Control systems; data acquisition; real-time software systems;
Journal_Title :
Nuclear Science, IEEE Transactions on
DOI :
10.1109/TNS.2011.2143726