TCV Advanced Plasma Control System SoftwareArchitecture andResults

A newAdvanced PlasmaControl Systemforthe TCV tokamakhasbeenimplemented basedonan in-house developed highperformance DSPs-based VME system, specially designed forreal-time plasmacontrol andeventdetection on fusion experiments. Thispaperdescribes thesoftware architecture ofthedigital systemaswellastheintegration ofthephysicists control algorithms intheDSPssoftware. Theintegration conditions on theTCV control systemandthefirst results ofthereal-time control operation arealso presented. Finally, acritical analysis of thesystem performance andtheexperimental operation ofTCV APCSisdiscussed. I.INTRODUCTION R EAL-TIME plasma control isakeyissue fortheadvanced operation ofmagnetic confinement fusion devices. However, existing control systems arenotwellsuited for magnetic-confinement fusionexperiments suchas the Tokamak 'aConfiguration Variable (TCV)oftheAssociation EURATOMISwiss Confederation. Theseexperiments require newcontrol systems withhigher performance which arehard tofind inexisting equipments and impossible toimplement inconventional control systems. The complex operations that havetobeperformed during plasma confinement, like controlling oftheplasma duration andshape areonly possible withamodemreal-time control system. This iswhy successful development ofadvanced operational regimes depends somuchonthearchitecture andprocessing capacity oftheinstalled control system. Infact, plasma control mustbeextremely fast, demanding considerable computation powerandneeds areally intelligent strategy forreal-time decision making, whichcanonlybe achieved through a digitally programmable system. These features becomeespecially relevant inTCV,whichhasasits maingoalthestudy ofdifferent plasma configurations and shapes obtained byvarying alarge setoftokamak parameters. Aiming atsolving this problem thenewAdvanced Plasma Control System (APCS) ofTCVwasdeveloped. TheAPCSis a dedicated real-time control anddataacquisition system based onanin-house developed VME intelligent module (IM) (1)(Figs. 1 and2),withparallel processing capabilities provided by foursynchronized floating point operation TMS320C44 Digital Signal Processors (DSP). Thismodule, originally developed forother real-time control applications in fusion (2), isindeed thebest solution because itgathers all the features neededforthisproject: floating point operations, timingsynchronisms, parallel processing features, the Cl~~~~~ ~~~1-~~~~r) \O ~~~~~~~-00 ~ 0