Chinese Academy of Sciences Institute of High Energy Physics Accelerator Center Power Supply Group Status of BEPCII and CSNS Power Supply System Qi Xin May DESY

2of38 Outline Introduction BEPCII Power Supply System CSNS Power Supply System Prototyping R&D for CSNS PS

3of38 BEPC II BEPC II is a two-ring e+e- collider running in the tau- charm energy region (Ecm = GeV), which, with a design luminosity of 1 *10 33 cm-2s-1 at the beam energy of 1.89 GeV, is an improvement of a factor of 100 over its successful predecessor, BEPC. Its installation was completed in the summer of 2005 and it has reached most of the design specifications. The collider consists of two m long storage rings, one for electrons and one for positrons. They collide at the interaction point with a horizontal crossing angle of 11 mrad and a bunch spacing of 8 ns. Each ring holds 93 bunches with a beam current of 910 mA. The machine will also provide a high flux of synchrotron radiation at a beam energy of 2.5 GeV.

4of38 General layout for BEPCII BESIII Double Storage Ring Transport Line Injector BSRF

5of38 BEPCII Power Supply System Total 650 sets, DC PS, 2 kinds: SCR power supply 1000A/300V, 4 sets, dipole magnet PS Switch power supply 200A/70V, chopper, 152 sets, quadrupole and sextupole magnet PS 1700A/120V, 3 sets, insertion quadruple magnet PS …… All for analog control PS

6of38 BEPCII Power Supply System

7of38 CSNS -China Spallation Neutron Source Baseline Schedule February 2001 idea of CSNS discussed prototyping R&D January 2006 – detail design January 2011 – December 2011 construction start September 2011 civil construction December 2012 – March 2017 component fabrication September 2011 – September 2015 installation & tests June 2013 – March 2017 RCS commissioning start March 2016 first beam on target March 2017 project complete/operation start March 2018 (6.5 years from start) The site of CSNS has been selected at Dongguan, Guangdong Province

8of38 CSNS Power Supply System MEBT DC PS LEBT DC PS DTL DC PS LRBT DC PS RTBT DC PS 6 sets Resonant PS Programmable Pulse PS Corrector DC PS Injection DC PS Extraction DC PS

9of38 CSNS Power Supply System Total 303 sets, three operation modes: DC mode from 10A to 1700A, 239 sets AC+DC mode(frequency 25Hz) 2200A/6000V, 1set 1700A/4000V, 1set 1700A/1500V, 1set 1700A/1000V, 3sets Programmable Pulse mode 28A/400V, 36 sets Full digital control PS

10of38 RCS PS system PSNo. Peak Current （ A ） Peak Voltage （ V ） Power Ratio （ kW ） Tracking error RCS-BPS % RCS-QPS % RCS-QPS % RCS-QPS % RCS-QPS % RCS-QPS % RCS-SPS DC RCS-Trim BH % RCS-Trim BV %

11of38 Dipole Magnet and Quadrupole Magnet MagnetNumber Dipole(BM)24 Quadrupole(QM) Q1(272) Q2(253) Q3(222) Q4(206)

12of38 Resonant network structure for BM &QM Serial resonant network

13of38 Dipole Resonant network Magnet Parameters Number of Dipole Magnet24 Gap （ mm ） 160 Effective length (mm)2100 Frequency (Hz) 25 AC Peak Current (A)877 DC Current (A)1227 Total power loss (kW)45 Inductance (mH)38.2 Resonant Network Parameters Power Supply for Dipole Magnet1 Magnet No./Cell2 Resonant cell12 Magnet inductance (Lm)/cell (mH)76.4 Capacitance /cell (  F) Choke inductance/cell (mH)76.4 Peak Voltage/cell (V)10519

14of38 Quadrupole resonant networks QPSQ265Q253Q222Q206 Magnet Parameters Total No DC Current (A) AC Current (A) Peak Voltage (V) Total Loss (KW) Inductance (mH) Resonant Network Parameters Magnet No./cell48888 Resonant cell No Capacitance (  F) L ch (mH) Peak voltage/cell (V)

15of38 Power Supply Topology Diode rectifier + H type PWM inverter

16of38 Prototyping R&D for CSNS Prototype for Dipole Power Supply( ); Choke and capacitor bank( ); Prototype for Quadrupole Power Supply( ); Prototype for Trim-B Power Supply( ); Digital Power Supply Control Module(2005- ;

17of38 Specification of the B-PS prototype Output current: 1260A+900sin  t; Output Peak Voltage : 230V; Extraction current stability:  100ppm/8H; Injection current stability:  500ppm/8H; Frequency stability:  100ppm/8H; THD: 0.02%;

18of38 Test result Extraction current long term stability: 3.7  /8H; Injection current long term stability: 2.2  /8H; Frequency stability: 2  /8H.

19of38 Choke and Capacitor Choke is design with multi-gaps, oil cooling tank. The winding is used the copper strip, the core is used in steel rolling direction; Capacitor is a single-phase power capacitor of all film type, with very low dielectric losses and long lifetime.

20of38 Specification of the Q-PS prototype DC mode: Output: 2000A/120V; Long term stability: 50ppm; AC mode: Output current: 1150A+820sin  t; Output peak voltage: 300V; DC current stability: 100ppm/8H; AC current stability: 100ppm/8H; Frequency stability: 100ppm/8H; Tracking error:  0.1%

21of38 Power Supply prototype for QM Diode rectifier +Boost+ H type PWM inverter

22of38 Test result DC mode Current stability: 3.99  /8H

23of38 Test result AC mode, sinwt A; DC current stability: 5.05  /8H; AC current stability: 8.09  /8H; Frequency stability: 1.27  /8H; Tracking error:  0.07%

24of38 Specification of the Trim-B PS prototype Any programmable pulse waveform; Output peak current: ±28 A; Output peak voltage: 400V; Maximum di/dt: ≥5.6A/mS; Tracking error:  3%. parallel resonant half-bridge rectifier +H type chopper

25of38 Test result Trapezoidal wave: removal of the inflection point; Maximum di/dt: 5.6A/mS; Tracking error: 0.7%.

26of38 Test result Arbitrary waveform: reference to ISIS Trim-B; Maximum di/dt: 6.5A/mS; Tracking error: -2.5% / 2%.

27of38 Digital Power Supply Control Module(DPSCM) Based on FPGA; Physical connection: optical fiber; Communication protocol: RS-232;

28of38 DPSCM

29of38 DPSCM for Trim-B PS

30of38 DPSCM for B-PS

31of38 Problem both in B-PS and Q-PS Magnet inductance non-linearity( test result) BM: ≈ 14% QM: ≈7% Choke: ≈ 1.4% Power supply output voltage

32of38 Magnet Field TrackingCurrent Tracking Perfect sinusoidal field High order harmonic current vector control Digital Control for B-PS and Q-PS Change control strategy

33of38 Digital Control for B-PS and Q-PS In ensuring perfect sinusoidal magnetic field under the premise, the real time calculation method replaces the look-up table method. Through precisely controlling the current amplitude and 25Hz phase to obtain the B/Q magnet field tracking. A 100kHz clock signal is used the synchronize the digital Power Supply Control Module (DPSCM). A 25 Hz trigger signal is used to synchronize for BM and QM.

34of38 Digital Control for B-PS and Q-PS High order harmonic current vector control one with the original harmonic magnetic field of similar amplitude, phase contrast harmonic field is injected to reverse the original harmonic field, which makes the harmonic field small enough.

35of38 Harmonic injection before and after contrast Current (after injection) Current-BCurrent-Q 1 st (25)100% 2 nd (50)0.882%0.583% 3 rd (75)0.513%0.324% 4 th (100)0.224%0.133% 5 th (125)0.106%0.058% 6 th (150)0.038%0.016% 7 th (175)0.022%0.008% Field (before injection) B(BL)Q(GL) 1 st (25)100% 2 nd (50)0.524%0.713% 3 rd (75)0.112%0.135% 4 th (100)0.042%0.094% 5 th (125)0.015% th (150)0.010%0.006% 7 th (175)0.003%0.015% Current (before injection) Current-BCurrent-Q 1 st (25)100% 2 nd (50)1.301%1.061% 3 rd (75)0.527%0.327% 4 th (100)0.202%0.054% 5 th (125)0.114%0.025% 6 th (150)0.047%0.021% 7 th (175)0.021%0.020% Field (after injection) B(BL)Q(GL) 1 st (25)100% 2 nd (50)0.003%0.005% 3 rd (75)0.005%0.002% 4 th (100)0.002%0.006% 5 th (125)0.002%0.008% 6 th (150)0.001%0.002% 7 th (175)0.003%0.001%

36of38 Compare with J-PARC CurrentBL 1st (25Hz) 100% 2nd (50Hz)1.335%0.003% 3rd (75Hz)0.841%0.002% 4th (100Hz)0.475%0.001% 5th (125Hz)0.256%0.002% CurrentBL 1st (25Hz) 100% 2nd (50Hz) 0.882%0.003% 3rd (75Hz) 0.513%0.005% 4th (100Hz) 0.224%0.002% 5th (125Hz) 0.106%0.002% CurrentGL 1st (25Hz) 100% 2nd (50Hz) 1.948%0.006% 3rd (75Hz) 1.197%0.006% 4th (100Hz) 0.672%0.008% 5th (125Hz) 0.333%0.003% CurrentGLGL 1st (25Hz) 100% 2nd (50Hz) 0.583%0.005% 3rd (75Hz) 0.324%0.002% 4th (100Hz) 0.133%0.006% 5th (125Hz) 0.058%0.008% CSNS J-PARC

37of38 Summary Control strategy New control strategy solves the technical problem and DPSCM work well. Power supply Not too much consideration of the magnet inductance nonlinearity. Pay more attention to the current stability, the DC ripple and the bandwidth. Pay more attention to high voltage insulation, energy feedback protection, grounding protection, module generalization and safety interlock protection.

Chinese Academy of Sciences Institute of High Energy Physics Accelerator Center Power Supply Group Mailing address 19B Yuquan Lu/ Shijingshan District / Beijing/ China