Experiments with real-time controlled ECW

Transcription

1 Experiments with real-time controlled ECW on the TCV Tokamak Experiments with real-time controlled ECW on the TCV Tokamak S. Alberti 1, G. Arnoux 2, J. Berrino 1, Y.Camenen 1, S. Coda 1, B.P. Duval 1, T.P. Goodman 1, J-M. Moret 1, J.I. Paley 1, L. Porte 1 and TCV team 1 Centre de Recherches en Physique des Plasmas CRPP EPFL Association EURATOM-Confédération Suisse Station 13 CH-11 Lausanne, Switzerland 2 Départment de Recherches sur la Fusion Contrôlée, Association EURATOM-CEA, CEA/Cadarache, 1318 Saint Paul-lez-Durance Cédex, France S. Alberti, CRPP-EPFL 1

2 OUTLINE TCV Tokamak ECW system X2 LFS & X3 top-launch X3 real-time control results Real-time control of plasma current with X2 ECCD Real-time control of plasma elongation with X2 Advanced Digital Plasma Control System Conclusions S. Alberti, CRPP-EPFL 2

3 ECW system on TCV X3-Cluster C 3 Gyrotrons 118GHz/.MW/2s X3 Top-launcher TCV Tokamak X2-Cluster A 3 Gyrotrons 82.7GHz/.MW/2s X2-Cluster B 3 Gyrotrons 82.7GHz/.MW/2s 6 X2 Launchers LFS injection in red: real-time (RT) controlled actuators in these experiments S. Alberti, CRPP-EPFL 3

4 X2 LFS-launch Actuator: RT control on θ with dθ/dt max = 96 deg/s Toroidal launcher angle φ adjusted from shot to shot S. Alberti, CRPP-EPFL 4

5 X3 top-launch z θ l = θ l (t) X3 TOP z θ l R θ l R X2 LFS X3 cold resonance Actuator: mirror angle θ l, RT control with dθ l /dt max = 2 /s. Mirror radial position R: adjusted from shot to shot. S. Alberti, CRPP-EPFL

6 Analogue Real-time control of X3 launcher Sinusoidal perturbation f = 13 Hz Mirror angle modulation at 13Hz Phase shifter Reference signal Synchronous demodulator R(s) + - G 1 (s) PID G 2 (s) Mirror + motor Plasma: I X PB Filter 13± Hz Demodulator G 3 (s) Low pass filter External function generator Observable: I x, Soft X-ray emissivity signal proportional to di X/dθ PID controller G 2 (s) [db] Transfer function G 2 (s): Mirror + motor Te-X [kev] δθ mes =1.4 o 4 P abs [%] 2 Mirror + motorization transfer function can be approximated by a 2 nd order pole with a strongly damped resonance at 13Hz φ [deg] 1 1 Frequency [Hz] θ l [deg] δθ toray =1. o S. Alberti, CRPP-EPFL 6

7 X3 Real-time control experiments Open loop Closed loop, P-term Linear sweep of θ l accross optimum angle θ l (t) = θ lopt reg. [deg] PB T -X [kev] θ [deg] out [V] e 47 a) <n b) e > L = [m -3 ] c) d) 2717 θ [deg] T e -X [kev] reg. [deg] a) b) c) 2741 τ <n e > L = [m -3 ] Time [s] t 1 t Time [s] S. Alberti, CRPP-EPFL 7

8 X3 Real-time control experiments: conclusions Real-time control of mirror angle successfully used on a wide variety of L-mode plasmas. It has been an essential element for studying the X3 properties in TCV in the top-launch configuration. G. Arnoux et al, PPCF, 47, 29 (2) S. Alberti et al., Nuclear Fusion, 4, 1224 (2) Improvement needed for operating the real-time control of the X3 top-launch on H-mode plasmas. S. Alberti, CRPP-EPFL 8

9 TCV Hybrid controller (analogue) Observables Plasma current Elongation error signals Launcher Gyrotron HV-PS Hybrid all coefficients of matrices A, M, G and gains loaded digitally PID is an analogue controller Actuators X2 gyrorton PS X2 launchers S. Alberti, CRPP-EPFL 9

10 RT control of I p with X2 ECCD in fully non-inductive discharge X2-ECCD launching configuration T eo = 4keV, n e = m -3 I p 1kA 6 gyrotrons (paired) Constant angles for the 6 X2 launchers #33981 S. Alberti, CRPP-EPFL 1

11 RT control of I p with X2 ECCD in fully non-inductive discharge PI controller Time constant τ = L/R Error signal = Iref - Ip I OH = constant, demonstrating fully EC driven plasma current RT actuator P RF via gyrotron cathode voltage (V k ) control J. Paley et al., submitted to PPCF, paper at EPS-27 (Varsaw, Poland) S. Alberti, CRPP-EPFL 11

12 RT elongation control with X2 B2 C2 D2 F κ = j φ B q Elongation, κ, controlled via: F κ = j φ B q E8 E7 E6 E A1 E4 E3 E2 E1 B1 G G6 4 G F8 F7 F6 F F4 F3 F2 F1 Possible actuators: B q : quadrupole field component from E-F coils and/or j φ = σ[τ e (ρ)] Ε φ : toroidal current den- Actuator: ECH deposition localised at ρ dep = const but ρ dep = const => r dep (κ(t)) Previous experiments performed with r dep = const, Y. Camenen et al., to be published in Nuclear Fusion, June S. Alberti, CRPP-EPFL 12

13 Elongation observable and ρ dep tracking a Shot Time n/d/l P(%) I(A/W) P N /2/ e /2/ e P N 2 P N 3 P N 4 P N P N 6 4 c d P EC (W/m 3 W) b δρ dep a,b,c,d : fixed points in poloidal cross-section from magnetic probes the poloidal-flux Ψ(t), at fixed positions is available in real-time RT observable for κ: δκ RT (t) = f(ψ a + Ψ b - Ψ c - Ψ d ); f, monotonic function κ(t) = κ + δκ RT (t) Deposition tracking: θ launch (κ(t)) ρ dep = θ + α δκ RT (t) S. Alberti, CRPP-EPFL 13

14 Relative effect of j φ and B q actuators Constant B q j φ actuator B q actuator τ L/R S. Alberti, CRPP-EPFL 14

15 Closed loop application of ECRH under constant quadrupole field RT control of elongation for κ step-down Elongation error signal PI controller RT actuator P ECRH via control of HV-PS (2 gyrotrons on same cluster) RT tracking of ρ dep with two launchers Δρ dep with RT tracking significantly lower than without tracking J. Paley et al., submitted to PPCF, paper at EPS-27 (Varsaw, Poland) S. Alberti, CRPP-EPFL 1

16 Preliminary experiments with DPCS 1 Digital PID 24 channels DSP Based, Clock 1 khz (Max 2 khz) 1 B.P. Duval et al. IEEE Trans. on Nuclear Science, 3, 2179(26) in collaboration with Association Euratom/IST Portugal S. Alberti, CRPP-EPFL 16

17 Comparison analogue - digital PID output 1 first channels of PID output #34313 DAC/PID sampling rate digital: 1kHz time [s] time [s] time [s] sampling rate analogue: 1kHz S. Alberti, CRPP-EPFL 17

18 First digitally controlled TCV plasma shot # th IAEA-TCM on ECRH Physics and Technology for ITER, Vienna, 6-8 June 27 S. Alberti, CRPP-EPFL 18

19 Final DPCS configuration 12 ch ch 24 ch A + G 196 signals ch 24 ch, 1kHz 4 ch., fast 1-2kHz 4+4 ch. from very slow to 2kHz Digital PID (DSP Based) 24 ch M 12 ch S. Alberti, CRPP-EPFL 19

20 Conclusions 3 applications of analogue RT control ECW on TCV: - X3 top launch observable: <T e > L, actuator: θ X3 launching angle - Plasma current control observable: I p, actuator: P RF on 2 clusters via V cathode - Elongation control observable: κ, actuators: P RF on 2 gyrotrons via V cathode θ X2 on 2 independent launchers First demonstration of digital RT control on ohmic plasma RT control ECW on TCV with multi-observables and multi-actuators will be performed with the new DPCS during the next TCV experimental campaign (28). S. Alberti, CRPP-EPFL 2