1. Power Supply System for DRFS
Accelerator Laboratory
Power Supply System for DRFS
Mitsuo Akemoto(KEK)
LCWS2010 Workshop in Beijing
March 27, 2010

2. Design of Power Supply System for DRFS Parallel Connection System
Accelerator Laboratory
Failure rate ~13 times go up
Parallel Connection System
for 13 Klystrons
Low Availability
To realize high available system capable of continuous operation,
which should be high-reliability and low cost
Main Features
Use of switching Power Supply to charge the capacitor bank
2. One common dc power supply with a bouncer circuit
and one common modulation anode modulator
3. Redundancy of one unit for switching power supply and
modulation anode modulator (Backup system)
4. Individual HV relay and CT monitor for all klystrons
to separate the failed klystron from the system

3. PS system for DRFS (one unit)
Accelerator Laboratory
VCB
Capacitor Bank
MA modulator
Oil Tank
(0V)
Klystron（１3） LC
Bouncer
Circuit
50kW
Switching PS
4 units +
1 unit
Back-up
Switch
Drive
circuit
Crowbar Circuit HV
(-68kV)
-2kV
Bias PS A HK
Heater PS H
6.6kV/420V TRNS
Control System
HV Relay
6.6 kV 3ø
Main AC Line CT

4. Design Parameters of PS system for DRRF
(one unit)
Accelerator Laboratory
Cathode Power Supply per 3 cryomodules
In Case of a droop of 10%.
MA L-band Klystron
# of Klystron 13
Cathode voltage
68 kV
Average Current
2.3 A
Output Power
165 kW
Peak Pulse Current
254 A
Pulse Width
1.7 ms
Repetition Rate
5 Hz
Capacitor Bank
67.2 µF
Frequency
1.3 GHz
RF Peak　Power
750 kW
RF Pulse Width
1.5 ms
Repetition Rate
5 Hz
Efficiency
60%
Beam Perveance
1.2 µP
Cathode Voltage
64.1 kV
Cathode Current
19.5 A
M Anode Modulator
Switching Power Supply
# of MA Modulator 2
Anode Voltage
53 kV
Anode Bias Voltage
-2 kV
Pulse width
1.5 ms
# of Switching PS 5
Output Power
50 kJ/s
Output Voltage
70 kV

5. Droop compensation using a Bouncer Circuit
Accelerator Laboratory
LC Bouncer Circuit
Reduce total size of dc and ac capacitors
10 % droop design is 20% lower
than 20 % droop design
Inductance
8.9 mH
Capacitance
33.8 µF
Period
6.4 ms
Peak Current
750 A
Peak Voltage
+-6 kV
Flat-top Flatness = 0.5%
Cathode voltage
Bouncer Voltage
Bouncer Current

6. DRFS Tunnel Layout VCB 3 Cryomodule unit (38 m) MA modulator +1
Accelerator Laboratory
3 Cryomodule unit (38 m)
MA modulator +1
Bouncer circuit
DC Capacitors
4 Switching PSs +1
6.6 kV/420V Trans.
VCB

7. PS System for S1-Global DRFS
Accelerator Laboratory
Demonstration of DRFS system with 2 klystron loads.
To rapidly study the system and reduce its cost,
No Bouncer circuit
Use of a thyratron switch as a crowbar circuit
Five Switching PSs are used as a capacitor charger.
A droop of 5% is designed for 2 klystron loads.
MA modulator is based on J-Parc design.
MA switch uses series IGBTs.

8. PS System for S1-Global DRFS
Accelerator Laboratory
MA modulator
Capacitor Bank
Oil Tank
Klystron
5.2µFx3
Switching PS
Max-80kV
6.4 kW x 5units
Input
AC 200V 3ø
Switch
Drive
circuit
Crowbar Circuit
-2kV
Bias PS A
Cathode
(-72kV) HK
Heater PS H
Control System
HV Relay CT

9. PS Set-up for S1-Global DRFS at STF
Accelerator Laboratory
Switching PS
Cathode PS
HV Cable
MA modulator
MA Klystron

10. R&D of Power Supply for DRFS
Accelerator Laboratory
HV Relay Test and Development
70kV HV Relay
SF-6 gas filled
Max current 10 A
Operate time 20 ms
Life 0.5 million
Weight 336 g
Coil 28Vdc, 1A
Long HV Cable test
GIGAVAC G71L
Crowbar circuit
Cost down using gap switch

11. Summary Proposal of PS system for DRFS is presented.
Accelerator Laboratory
Proposal of PS system for DRFS is presented.
A prototype power supply for S1-Global is under construction
and will be completed in October.
The first PS system for DRFS will be evaluated in S1-Global test.