1. CSCM Project Powering cycle and results of the PSpice simulations Emmanuele Ravaioli Thanks to H. Thiesen, A. Verweij TE-MPE-TM 14-07-2011

2. CSCM Project – Powering cycle and results of the PSpice simulations Emmanuele Ravaioli TE-MPE-TM 14-07-2011 RB circuit Schematic of the circuit Powering cycle Power converter behavior Opening of the switches Diode behavior Monte Carlo analysis RQ circuit Conclusions and further work 2

3. RB circuit – Standard configuration Emmanuele Ravaioli TE-MPE-TM 14-07-2011 3 Power converterFilter Switch1 Switch 2 77 Magnets PCs in parallel f_filter ~ 28.5 Hz Extraction system present L_dipole = 98 mH

4. RB circuit – CSCM configuration Emmanuele Ravaioli TE-MPE-TM 14-07-2011 4 Power converterFilter Switch1 Switch 2 77 Magnets PCs in series f_filter ~ 14.2 Hz ( L_filter x4 ) Extraction system present ? L_dipole = 98 mH R_dipole = 43 mΩ (at 20 K) L_cabling = 4 mH U_diode > 1.6 V (at 20 K)

5. Emmanuele Ravaioli TE-MPE-TM 14-07-2011 5 RB circuit – CSCM Powering cycle No opening of the extraction switches dV PC /dt = 20 V/s I DFB = 150 A dI DFB /dt = 1 kA/s I DFB = 6 kA Fast Power Abort 1 2 3 4 5 12345

6. Emmanuele Ravaioli TE-MPE-TM 14-07-2011 6 RB circuit – CSCM Powering cycle (Zoom) No opening of the extraction switches

7. Emmanuele Ravaioli TE-MPE-TM 14-07-2011 7 RB circuit – CSCM Powering cycle (Zoom) – Switches Both RB extraction switches opened without delay at the same time

8. Emmanuele Ravaioli TE-MPE-TM 14-07-2011 8 RB circuit – Diode opening No opening of the extraction switches

9. Emmanuele Ravaioli TE-MPE-TM 14-07-2011 9 RB circuit – Diode opening – Monte Carlo simulation Random distribution of a number of parameters within realistic range N_diode ±20% (opening voltage) R_dipole ±20% R_busbar ±20% L_busbar ±20% C_ground ±5% L_aperture ±0.1%

10. CSCM Project – Powering cycle and results of the PSpice simulations Emmanuele Ravaioli TE-MPE-TM 14-07-2011 RB circuit RQ circuit Schematic of the circuit Powering cycle Power converter behavior Opening of the switch(es) Diode behavior Conclusions and further work 10

11. RQ circuit – CSCM configuration Emmanuele Ravaioli TE-MPE-TM 14-07-2011 11 Power converterFilter Switch1 Switch 2 51 Magnets PCs in series (same PCs of RB) f_filter ~ 14.2 Hz ( L_filter x4 ) Extraction system present ? 1? 2? L_quadrupole = 5.6 mH R_quadrupole = 6.3 mΩ (at 20 K) L_cabling = 2x 4 mH U_diode > 1.6 V (at 20 K) Schematic to be edited

12. Emmanuele Ravaioli TE-MPE-TM 14-07-2011 12 RQ circuit – CSCM Powering cycle No opening of the extraction switches dV PC /dt = 20 V/s I DFB = 500 A dI DFB /dt = 400 A/s I DFB = 6 kA Fast Power Abort 1 2 3 4 5 12345

13. Emmanuele Ravaioli TE-MPE-TM 14-07-2011 13 RQ circuit – CSCM Powering cycle (Zoom) No opening of the extraction switches

14. Emmanuele Ravaioli TE-MPE-TM 14-07-2011 14 RQ circuit – CSCM Powering cycle (Zoom) – 1 Switch One RQ extraction switch opened without delay

15. Emmanuele Ravaioli TE-MPE-TM 14-07-2011 15 RQ circuit – CSCM Powering cycle (Zoom) – 2 Switches Both RQ extraction switches opened without delay at the same time

16. Emmanuele Ravaioli TE-MPE-TM 14-07-2011 16 RQ circuit – Diode opening No opening of the extraction switches

17. CSCM Project – Powering cycle and results of the PSpice simulations Emmanuele Ravaioli TE-MPE-TM 14-07-2011 RB circuit RQ circuit Conclusions and further work 17

18. The analysis of the CSCM powering cycle in the dipole and quadrupole circuit has been carried out by means of a complete PSpice model. The modeling of the diode behavior and the control of the power converter have been challenging and required the developing of dedicated models. The simulated powering cycle comprises a voltage ramp until all the diodes are conducting (current flowing through the DFB larger than a set value), a current plateau, a high-rate current ramp, another plateau at maximum current and the switching-off of the power converter with the eventual opening of the extraction switch(es). The voltage transients and the current decaying have been simulated and the results have been compared with theoretical calculations. The influence of the opening of one or both of the extraction switches have been analyzed. The simulation results suggest that the extraction system is required for the quadrupole circuit but not for the dipole circuit. The model of the diode needs to be improved in order to include the heating effect which causes a decrease of the voltage drop across it. (work in progress) Emmanuele Ravaioli TE-MPE-TM 14-07-2011 18 Conclusions and further work

19. Emmanuele Ravaioli TE-MPE-TM 14-07-2011

20. Annex 20 Emmanuele Ravaioli TE-MPE-TM 14-07-2011

21. 21 Time required for discharging the circuit Simulations and (simple) theoretical calculations CircuitNo switch1 switch2 switches RB – Simulation (U_diode = 1.88 V)110 ms---50 ms RQ – Simulation (U_diode = 1.88 V)450 ms300 ms250 ms RB – Simulation (U_diode = 1.2 V)to be done---to be done RQ – Simulation (U_diode = 1.2 V)to be done RB – Theory (U_diode = 1.88 V)110 ms---~25 ms RQ – Theory (U_diode = 1.88 V)290 ms~150 ms~100 ms RB – Theory (U_diode = 1.2 V)170 ms---~30 ms RQ – Theory (U_diode = 1.2 V)450 ms~180 ms~120 ms The model of the diode needs to be improved in order to include the heating effect which causes a decrease of the voltage drop across it. (work in progress)

22. Emmanuele Ravaioli TE-MPE-TM 14-07-2011 22 RB circuit – Fast Power Abort – Details No opening of the extraction switches

23. Emmanuele Ravaioli TE-MPE-TM 14-07-2011 23 RB circuit – Fast Power Abort – Details Both RB extraction switches opened without delay at the same time

24. Emmanuele Ravaioli TE-MPE-TM 14-07-2011 24 RQ circuit – Fast Power Abort – Details No opening of the extraction switches

25. Emmanuele Ravaioli TE-MPE-TM 14-07-2011 25 RQ circuit – Fast Power Abort – Details One RQ extraction switch opened without delay

26. Emmanuele Ravaioli TE-MPE-TM 14-07-2011 26 RQ circuit – Fast Power Abort – Details Both RQ extraction switches opened without delay at the same time