IC IDRM2: 18 May 2011 P. Dumortier et al. Slide 1 Validation of the Electrical Properties of the...

IC IDRM2: 18 May 2011IC IDRM2: 18 May 2011P. Dumortier et al.P. Dumortier et al. Slide Slide 11CYCLECYCLEPOLITECNICO

DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

CYCLECYCLEPOLITECNICO

DI TORINOPOLITECNICO

DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

Validation of the Electrical Properties of the ITER ICRF Antenna using Reduced-Scale Mock-Ups

P. Dumortier, F. Durodié, D. Grine, V. Kyrytsya, F. Louche, A. Messiaen, M. Vervier, M. Vrancken

LPP-ERM/KMS, Brussels, Belgium, CYCLE

Work supported by F4E-2009-GRT-026 grant


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

1919thth RF Top Conf: 3 June 2011 RF Top Conf: 3 June 2011P Dumortier et alP Dumortier et al Slide Slide 22

Outline ITER ICRH antenna - RF requirements Actual reference antenna

Design choices & features Optimization of the antenna Frequency response

Reduced-scale mock-ups Rationale for the use of reduced-scale mock-ups Phase 1: Optimization of one triplet

Validation of antenna box optimization Phase 2: Validation of optimized model

Validation of optimized front face and 4-port junction Broadbanding by service stub

Phase 3: Mock-up of full antenna Performance evaluation Grounding

Matching and Decoupling system test Conclusions


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


What does IO request ? ITER ICRH antenna - RF requirements Actual reference antenna







ITER ICRH antenna - RF requirements Actual reference antenna








DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


ITER ICRH antenna – key RF requirements Nominal power: 20 MW per antenna (2 antennas) Frequency range: 40 – 55 MHz Phased antenna array (6 poloidal x 4 toroidal array) for radiated

power spectrum control: Control of toroidal phase differences Control of current ratio between columns of straps

Maximum allowed voltage: Vmax=45kV Maximum allowed electric field:

Torus vacuum:Emax=2kV/mm perpendicular to Btor ; Emax=3kV/mm parallel to Btor

Private vacuum: Emax=3kV/mm Quasi CW operation Location: equatorial port plug


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


What is the ITER antenna looking like ? Why ? ITER ICRH antenna - RF requirements Actual reference antenna















DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Short currentstraps

Short circuit

24 straps grouped in triplets → 6x4 array

Port Plug FlangeRF grounding

Port plug wall

Antenna boxNeutron shield

3640

2160

1708

Actual Reference Design – ICRH Antenna

B17 M. Nightingale

Faraday

screen

4-Port Junction(arms: Z01=15Ω)

RF vacuum windows

Feeding line(Z02=20Ω)

Service stub (Z0SSt=15Ω)


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Design choices and features Short low-inductance straps

Lower voltage on straps, better radiation efficiency → high power density

Z0F=15Ω Trade-off between maximizing coupling, minimizing VSWR and

minimizing Emax Segmentation (3 straps)

Minimizing Emax and Vmax Passive 4-port junction (4PJ)

Connects 3 straps in parallel to one feeding line Reduction of the number of feeding lines No active/moving component in the antenna Currents are in phase

→ triplet of straps is seen as a long strap with uniform current by plasma Service stub

Broad-banding of the RF response curve Outside antenna:

20Ω-50Ω transition at Vmax to reduce VSWR Decoupling and matching network (Double Stub Tuner)

Reduction of mutual coupling effects Control current distribution of array to impose required current spectrum


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


In all regions: and

Assumption for optimization: critical parameter is Vmax

Improve achievable Vmax by design (rounding edges,…)

For given Vmax and Imax,lines → Maximize Gmin

to maximize P and minimize S (SWR) for given Z0

Example: if Gmin ↑ by 20% → S by 20%

201

2F

1maxF

ZX

VI

FF R

P2I

0min ZS

1G

2

VGP

2max

min

For given |Vmax|:

→ P ↑ by 20%→ same |Imax, lines| and

For given P:

→ Vmax by 10%→ |Imax, lines| by 10% and

Antenna triplet RF model


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Triplet frequency response

Gmin1 determined by ZF and Z01

If ideal TL 4PJ is at Vanti-node for all frequencies: Gmin2,max = 3Gmin1

)(for 2F

2F

201

2F

F1min

XR

ZX

RG


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



4PJ fixed in space → acts as a single frequency filter Maximum at fopt, when electrical junction point is at Vanti-node

Tune response by choosing Z01, <l1>, Z02

Gmin2,max = 3 Gmin1

fopt solution of tan(β<l1>)= Z01/XF

Bandwidth function of Z01/XF and Z02/Z01

fopt


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



Broad-banding → Band-pass filter response in feeding line Gmin3 response shape determined by Z0SSt, L4PJ-SSt and LSSt

Gmin3 response curve turns around a turning point and its slope is determined by LSSt

fTP determined by L4PJ-SSt

(Turning point remains on Gmin2 curve)

Turningpoint

fTP


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


By acting on front face geometry of the antenna (↔ Gmin1)→ Strap width, box depth, vertical septum recess, profiling…

But |IF| ↑ when XF ↓ because

Trade-off between Iant,max and Vmax

Modeling (MWS, Topica, Antiter II) + Mock-Up Phase 1

By acting on the 4-port junction (↔ Gmin2)

→ Optimal frequency solution of tan(β<l>)= Z01/XF

→ Bandwidth function of Z01/XF and Z02/Z01

→ Optimize 4PJ geometry By acting on Service Stub: Z0SSt, L4PJ-SSt and LSSt (↔ Gmin3)

Modeling (MWS, TL) + Mock-Up Phase 2

201

2F

F1min

ZX

RG

Mainly due to antenna box geometry, weak dependence on plasma conditions

Partly due to external medium and partly due to antenna box geometry

F

F

F

FF X

V

Z

VI

Pre

mat

chin

g

No

imp

act

on

I an

t

Co

up

ling

Imp

act

on

I an

t

Frequency response can be optimized…

B14 – F. Louche

B16 – F. Durodié


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


RF properties validation using RF mock-ups ITER ICRH antenna - RF requirements Actual reference antenna















DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Why using reduced-scale RF mock-ups ? Relatively cheap way to validate the RF simulations results Same impedances as full scale model if ratio between dimensions

and vacuum wavelength kept constant (except for skin effect losses)

→ Operating frequency needs to be multiplied by reduction scale factor

Realistic plasma-like load conditions obtained by putting a medium with a large dielectric constant, such as water, in front of the antenna

→ Load variations obtained by moving water load in front of antenna mock-up

No need for large water load

→ Small concentration of salt added to water allows wave absorption (avoid reflections on walls leading to standing waves)


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Phase 1 – RF optimization validation Based on October 2007 design (1 strap triplet and triangular 4PJ)

Measurements/simulations performed: Scan in distance mock-up – water load Scan in strap width and antenna box depth

3 different strap widths 3 different box depths

→ 9 sets of straps Impact of Faraday screen Impact of vertical septum recess


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Phase 1 – Set-up


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Scan in load conditions

2

VGP

2max

min

Good agreement with simulations (except when load against the antenna) but MWS: importance of BC and meshing to obtain quantitative agreement Measurements: importance of correct de-embedding of 20Ω-50Ω transition

Expected frequency response - not centered in ITER band because fixed 4PJ Only slight frequency shift with change in loading


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Scan in strap width and antenna box depth Scan in strap width W : XF ↓ when W ↑ → shift towards higher f

Scan in antenna box depth D : XF ↑ when D ↑ → shift towards lower f

Good agreement with numerical simulations


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Numerical optimization Optimization of strap width and antenna box depth

Not very sensitive to W and D when close to optimum


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Phase 2 – Optimized geometry and service stub Optimized geometry (reference June 2008)

Measurement/simulations performed: Set of spacers to scan:

4-port junction arms length Service stub insertion point

Scan in 15Ω service stub length Scan in distance mock-up – water load No Faraday screen


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Scan in 4-port junction arms’ length

Frequency response can be centered in band by acting on 4PJ arms’ lengths

But this affects Gmin2 as Gmin2,max = 3 Gmin1 (in case of ideal TL 4PJ)


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Scan in 4-port junction arms’ length Comparison Measurements – MWS and TL simulations


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Broad-banding by service stub


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Comparison measurement – TL model Excellent representation of service stub insertion by

Transmission Line modeling


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Impact of service stub insertion point

Change LSSt → Turn around “turning point”

Change L4PJ-SSt → Move “turning point” along Gmin curve


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


40MHz 55MHz

Voltage pattern

For Vmax in the MTL of Vmax3 = 45 kV the voltage can be higher: in 4PJ in section between 4PJ and SSt in SSt

→ Need to operate at Vmax3 < 45kV for some frequency ranges


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Power limitation

Active power for 1 triplet and given experimental load condition Power from Gmin and Vmax=45kV in all regions of antenna Infinite extent regions

2

VGP

2max

min


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Power limitation

But regions 1, 2 and service stub of finite extent

→ Vmax corresponding to Gmin may not be reached

→ Voltage margin Power constrained to Vmax=45kV reached in every region


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Power limitation

Active power for 1 triplet and given experimental load condition Maximum power constrained to Vmax=45kV in all regions of antenna Other power limitations exist (electric fields, current) Very sensitive to LSSt, less to L4PJ and rather insensitive to L4PJ-SSt

= Minimum of dotted lines

B16 – F. Durodié


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Phase 3: Full antenna RF characterization RF characterization of full array Impact of Faraday Screen on coupling Effect of vertical septa recess Effect of grounding


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


RF performance – Preliminary measurement Expected RF frequency response (relative) Skew in 0π0π response due to too low KD,water for low f

Total radiated power for Vmax3=45kV in feeding line and fixed water load position

B18 – S. Champeaux


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Power distribution amongst triplets Array currents controlled but strong variation in active radiated power to

straps for the different triplets due to mutual coupling Active radiated power can be negative for some triplets

Crucial importance of good decoupling network


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Comparison with modeling

Preliminary analysis show fair agreement between measurements and modeling


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Impact of vertical septum recess

Significant gain in coupling by recessing further the vertical septa Less gain for dipole (0π0π)

Mutual coupling between strap triplets increased→ check whether level is tolerable by decoupling network→ evaluate impact on tuning elements (range, current rating, …)

Frequency shift towards lower frequencies→ coupling will increase further when centering in the frequency band

Different positions of service stub for internal and external triplets Note: slight uncertainty on exact position on temporary set-up Note: full VS recess, i.e. all vertical septa recessed

Reference Reference + 20mm Reference + 40mm


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Effect of Faraday Screen Limited decrease of coupling observed Slight shift of towards higher frequencies


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Effect of grounding on RF frequency response

A54 – V. Kyrytsya

Mind the gap: 20mm clearance gap between the antenna plug and the vacuum vessel may lead to mode excitation in the gap

Frequency response is essentially affected for monopole phasing

→ avoid monopole excitation due to unequal anti-node voltage distribution


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Performed on design 2003 mock-up at present CT option (back-up)

Adjacent poloidal triplets are connected in shunt in the circuit via a T-junction Matching stubs to adjust the conjugate pairs 6 Toroidal decouplers are preset (vacuum load) capacitors 11 feedback actuators for phase control of voltage anti-nodes (other parameters

preset) Tuning stubs: 8 Generator relative phase: 3

Fully simulated, implemented and tested on mock-up Hybrid option (reference)

Adjacent poloidal triplets are connected to 3dB hybrid splitter Double stub tuning on each triplet line 23 active feedback actuators for full antenna (other parameters preset)

Double Stub Tuners: 8 x 2 = 16 actuators Poloidal decouplers: 4 actuators Toroidal (CD phasings) or Poloidal-Toroidal (Heating phasings) decouplers: 3 actuators

Fully simulated, implemented and tested (CD case) on mock-up Decoupler tuning by voltage anti-node on adjacent lines comparison Starting conditions important for stability

→ in practice, starting from the vacuum conditions is OK

Phase 5: Matching and Decoupling

B15 – D. Grine

D. Grine – RF2009


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Left: 10 decouplers (green) between the ports A-H and 16 matching stubs (red) on the 8 heating lines;

Right: feedback system with software-based controller and associated hardware

Mock-up of the ITER antenna and the 3dB hybrid matching circuit

Straparray

Decouplers

DoubleStubTuners

3dB Hybrids& DST probes

Water load(removed)

Voltage anti-node ports

3dB Hybrid Mock-up Implementation


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Impedance tuning is done via one of three developed algorithms: Bang-Bang: same as CT. Fast Bang-Bang: improves on former by simultaneously steering the

two tuning stubs. Real/Imag: steers the double stub tuner using analytically derived

formulas based on the measured reflection coefficient at the hybrid outputs, both in magnitude and in phase.

Resilience study started

3dB Hybrid

Simulation of RA,eff excursion from 2.25Ω/m to 5Ω/m and current drive. |HO| for the heating lines A-H as a function of the normalized iterations n/NBB,

where NBB is the number of iterations required for the Bang-Bang algorithm to converge

B15 – D. Grine

Bang-Bang Fast Bang-Bang Real/Imag


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Experimental measurements on mock-up validated simulation results Gain confidence in design optimization and expected

performance Frequency response and broad-banding by service stub confirmed Coupling loss due to presence of Faraday screen is limited Coupled power very sensitive to vertical septum position

Beneficial to recess further the vertical septum Need integration with decoupling and matching network

Vital importance of decoupling network confirmed Grounding

Importance of correct grounding (essentially for monopole) Matching and decoupling

Suitable algorithms found and implemented Tested on CT and hybrid options on full array (CD case only for

hybrid option)

Conclusions


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Some related contributions R02 – R. D’Inca – Arc detection for the ICRF system on ITER I06 – R. Maggiora – Mitigation of parallel RF potentials by an appropriate antenna design

using TOPICA I17 – E. Lerche – ICRF scenarios for ITER’s half field phase A54 – V. Kyrytsya – Detailed modeling of grounding solutions for the ITER ICRH antenna B11 – A. Mukherjee – Status of R&D activity for ITER ICRF power source B12 – D. Rasmussen – ITER ICH transmission line and matching system prototype

development B14 – F. Louche – 3D modeling and optimization of the ITER ICRH antenna B15 – D. Grine – Results of the implementation on a mock-up of the full 3dB hybrid

matching option of the ITER ICRH system B16 – F. Durodié – Optimization of the layout of the CYCLE ITER antenna port plug and

its performance assessment B17 – M. Nightingale – Design of the ITER ICRF Antenna B18 – S. Champeaux – High dielectric dummy loads for ITER ICRH antenna laboratory

testing: numerical simulation of one triplet loading by ferroelectric ceramics B19 – JM. Bernard – TITAN: a test bed facility for ICRH antenna and components of

ITER B25 – D. Rathi – A simple coaxial ceramic based vacuum window for Vacuum

transmission line of ICRF system B30 – A. Messiaen – Influence of the edge plasma profile and parameters on the

coupling of an ICRH antenna. Application to ITER. B31 – D. Milanesio – Analysis of the impact of antenna and plasma models on RF

potentials evaluation


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Scan in load conditions Estimate of strap input impedance

Effective strap input resistance significantly varies with load (distance mock-up – water load)

Effective strap input reactance almost insensitive to load (distance mock-up – water load)


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


4-port junction passive distribution Estimate of input strap voltage and current on the 3

straps of one triplet

Excellent passive power distribution operated by 4-port junction


DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h



DI TORINO

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h

i

a ca

r mf

c ar ed h


Impedance tuning for the CT is done via the Bang-Bang algorithm: an ad-hoc (trial&error) approach using the magnitude of the reflections after the T and steering only one stub at a time for each CT

Phase feedback

on mock-up

Matching feedback on

mock-up

Simulation of load-resilience at the generators for RA,eff ≈ 2.25Ω/m and

Current Drive

Measurement of load-resilience at the generators for RA,eff ≈ 2.25Ω/m and Current

Drive

Initial wrong decisions

Conjugate-T

IC IDRM2: 18 May 2011 P. Dumortier et al. Slide 1 Validation of the Electrical Properties of the...

Documents

Transcript of IC IDRM2: 18 May 2011 P. Dumortier et al. Slide 1 Validation of the Electrical Properties of the...