Transcript Marx P1 Slides LCWS 2011 - International Linear Collider

Marx Modulators
RF Controls P1 Marx
10 MW Klystron
• P1 Marx: has operated over 5 khr
although at half pulse length this year
due to capacitor lifetime problem –
will upgrade with zinc versions
• P2 Marx: has lower voltage cells with
individual droop control – being
assembled
• In FY12, no funding for new
development, but
– P1 and P2 will be long-term tested
– A SBIR funded DTI Marx will be
evaluated
– A new 10 MW MBK will be acquired
Toshiba 10 MW Multi-Beam Klystron (MBK)
Chris Adolphsen
ILC Klystron Modulator
• Performance requirements
– 120 kV peak voltage
– 140 A peak current
– 1.6 ms pulse width
– 5 Hz pulse repetition frequency
– +/- 0.5% flat top
– 134 kW average power
– <20 J deposited into klystron from gun
spark
P1 Marx +Toshiba 10 MW
MBK Performance
Kirk Bertsche
Operation History
750 ms Pulse Length
10 Months: Nov 2010 thru Aug 2011
Marx P1 System Faults
31 Total Faults Nov 2010 thru Aug 2011
• Majority of faults due to facilities interlocks (e.g.
waveguide pressure, cooling water flow)
• One modulator problem, June 2011
– Arc on backplane, induced by corona
– Corona prevention measures taken on new backplane
– No recurrence of problem
RF Pulse Flatness
Pulse flat to within 0.5%
Modulator Power Correlations
Modulator Voltage Correlations
Toshiba measured a mP of 3.16
P2 Marx Design Considerations
• Compatibility with two-tunnel design
• High availability
• Low-cost
• Ease of maintenance
• Portability of design to future
applications
Modulator Topology
• High Availability
– Each cell provides a regulated output
– Modulator has N+2 redundancy
• Low Cost
– Marx is inherently modular. Large quantities allow
for an economy of scale
• Portability of Design
– PEBB approach to allow cells (building blocks) to
be arranged differently for different output
requirements
RF System Overview
4.2kV
DC
3phase
480V
DC Power
Supply
DC
Rack
1.2kV
DC
Marx
Modulator
DC
32 Cells
pulsed
120kV
Klystron
DC
RF
out
Marx Basics
• Classic description:
+Vin
Marx “cell”
Charge in
Charge out
• SLAC P2 Marx Solid
State Implementation:
Cell in
Cell out
Voltage
SLAC P2 Marx Cell Schematic
Time
Correction Scheme
Cell Output Current
Cell Output Voltage
Main IGBT Vce
PWM Inductor Current
Ripple Cancelation
2 cells switching in phase
2 cells switching
180o out of phase
Switching
• High availability -> To simplify control, improve
protection, and enhance diagnostic access, the Marx
cells do not contain arrays of switches
• No need to push the device state-of-the-art with this
application. Operation is “within the datasheet”
6.5kV IGBT
half-bridge
1.7kV IGBT
half-bridge
6.5kV dual
diode module
Common
heat sink
Switching
• Switch (and cell) first level protection is accomplished
at the gate drive level
– Over voltage, over current, over di/dt
(b)
140 A
IGBT Ic
4 kV
(a)
IGBT Vce
(b)
IGBT Vge
•At left, load arc is triggered at (a). Current rises
through IGBT.
•After fault is detected, gate drive initiates turn-off.
•Active voltage clamping is achieved by partially turning
device back on, (b).
Controls
• High Availability
– System has abundant real-time diagnostic access
– Prognostics built into software
– Auto-reconfiguration possible
• Portability of design
– Controls hardware used on several projects
– High-level applications have potential use in
several areas
Modulator Control System
Application
Manager
Gigabit Ethernet + fiber optic trigger
Cell 1 Hardware
Manager
GD1
GD2
GD3
Cell 2 Hardware
Manager
GD1
GD4
GD2
GD3
Cell 32 Hardware
Manager
GD1
GD4
GD2
GD3
GD4
Control System
• Twelve 12-bit, 1 MS/s ADCs per cell
– 4 voltage monitors, 1-2 LEMs, 2 shunts, 3
temperature monitors, 1 spare
• Potential future addition of four 8-bit, 10 MS/s
ADCs per gate drive
– Vge, Vce, Ic, Vce,sat
• System-level monitoring
– Includes output voltage, current, system
temperatures
Packaging
• Ease of maintenance
– Oil-free design!
• Easy to get in and get out (low MTTR)
– Cells less than 50 lbs
– All cell parts easy to access
– Maintenance is at the shop, not at the modulator
• Portability of design
– Cells designed to be easily scalable
Packaging
P2 Being Assembled
Status
• Cell fabrication is finishing up
– Was delayed by 7 month capacitor delivery delay
• Cells have been tested in an array of six
• DC power supply rack is finished
• Switching to water load for larger arrays of cells
• Enclosure is 80% done
– Need to install air ducts, cooling system, and
remaining field shapers
Thompson Modulator for XFEL
Thompson Modulator
DTI MARX
MODULATOR
Rosa Ciprian
ARCHITECTURE
D1
Pulse
D2
Recharge
• High energy
• Recharge via switch
• Dual cell approach:
core = 6.5kV
corrector = 900V
• Minimize overall size and
possibly $ by using
electrolytic capacitors
• Pulse shaping via
feedback
CORE MODULES
• 6.5 kV cell
• 8.2 kJ electrolytic
capacitors
• 4 switches for
pulsing and 4 for
recharging
• All 20 modules
fired simultaneously,
(D1 is not needed)
CORRECTOR MODULES
• 900 V cell
• 340 J caps
• MOSFETs for
pulsing and
recharging
• Modules fire
for droop
remediation
(feedback)
ASSEMBLY
• Modulator tank footprint ~1.5m x 2.5m
• Height ~ 2 m including controls
(doghouse)
• Local controls in front panel and
remote in the rear panel.
Full Voltage/Current/PW Spec
Voltage:
120kV
Current:
130A
Pulse width:
1.5ms
Ch4: Command
Ch1: Pulse current 40A/V
Ch2: Voltage 15kV/V
Ch3: Feedback integrated
control
• Modulator has demonstrated full spec single pulsing into a resistive
load.
• Due to source and load limitations, full spec pulsing has been
demonstrated at 5Hz with a double full PW pulse, three 1ms pulses
and ten 150 us pulses.
VOLTAGE REGULATION
• User controls voltage regulation
set point with front panel
controls.
• User needs to adjust core and
corrector voltages (buck
regulators) to the pulse
requirement.
• Scope shot shows ability to
control the regulation point (blue
cursor).
• Green trace indicates sequencing
of pulse correction
CONTROLS AND FAULTS
• Controls provide protection from over-current, tank overheating, control power problems and invalid command
requests.
• A main interlock controls chopper power supplies, HV dump
relays and is in series with an external user interlock.
• Max rep rate: the limit is set at 5.1 Hz, after that limit it starts
skipping pulses.
• Max pulse width: at 1.542 ms, if commanded a wider pulse, the
pulse gets cut to the limit.
• Both these faults do not produce a hard fault, and pulsing
continues by skipping pulses to adjust to max rep rate or
cutting the pulse width. The error will show up just as a
flashing light in the front panel “pulse error”.
REMOTE CONTROLS
• Support of complete remote controls suitable for a PLC
interface
• Uses TTL level signals as well as analog signals
• Signals available for monitoring output parameters, run
status, and faults available in the rear panel.
QUALIFICATION
•
•
•
•
•
•
•
•
•
Performed by SLAC @ DTI Aug 22-26.
With and without correction at 120kV, 136A, 1.54mS. Experiments were performed
with just 15 correctors.
The load DTI had was about 910Ω which ask for more current than the original
requirement of 120kV/120A.
Output cable length: The output cable was about 20ft, emulating a longer cable
required installation of a 700pf 150kV capacitor, that was added to the resistive load.
No significant change at the output.
Regulation: The regulation feedback seems to be appropriate.
Calibration of the correctors was performed.
Because of the source and load limitations full rep rate cannot be tested at DTI.
Two pulses regulated at 120kV/130A, 1.5mS/5Hz, where the supply is still recharging
the caps, we could see a small degradation on the second pulse due to lack of supply
power. Also three pulses at 120kV/130V 1mS 5Hz and10 pulses 120kV/130A 150uS
5Hz.
Arc testing: Using a spark gap at 120kV/130A with regulation. After arc we validated
that all modules were firing as required, and the modulator was firing full specs
pulses.
DELIVERY AND INSTALLATION
DELIVERY
• The modulator will be shipped dry. It will be delivered with a 10m
output cable DS2077 (un-terminated at klystron end) and a 10m input
cable RG8 (un-terminated at the supply end).
• One assembled core and one corrector together with available spare parts
will be part of the delivery. DTI is working on the inventory of spares.
INSTALLATION REQUIREMENTS
• 10GPM cooling water, manifolds and water interlocks.
• 208VAC 3phase (30A breaker) for controls.
• 7-10kV rectified unregulated supply for main power.
• Oil: ~734 gallons Diala or mineral oil.
• Analysis of seismic compliance.
• Secondary oil containment.