SYSTEMS CORPORATIONPulse Sciences Division

FAST MARX-CHARGED

ONE-STAGE MPC CONCEPT

FOR KrF LASER IFE

Doug Weidenheimer

Titan Pulse Sciences Division

Candidate Topologies Studied to Date

SYSTEMS CORPORATIONPulse Sciences Division

System Description Cost$/E-beam

Joule

RiskFactors

OtherFactors

Baseline 3-stage w/SOTA solid-state primary switch

11.30 81% Components -- noneMaterials -- moderate

(1)

3-stage mag pc w/laser-gatedprimary switch

10.03 84% Components -- moderateMaterials -- moderate

(1)

2-stage mag pc w/advanced laser-gated solid state switched Marxcharging

7.65 85% Components -- highMaterials -- moderate

(2,5)

1-stage MPC, Marx-charged,laser-gated thyristor switched

8.66-8.69 86-87% Components -- highMaterials -- moderate

(2,4,5)

XFMR charged PFL w/MV-classsolid state switch/magnetic hybridor solid state switch

8.35-8.75 87.5% Components -- highMaterials -- moderate

(3)

(1) Alternative XFMR design(s) may reduce cost (.60/J), improve efficiency (1%).(2) Reduced charge voltage eliminates XFMR in charging system -- cost saving in charging, improve

efficiency (1%).(3) Alternative XFMR may reduce cost (.30/J), improve efficiency (.5%).(4) Cost and reliability issues related to reduced liquid dielectric volume, stressed area and floor space yet

to be quantified.(5) Further efficiency improvement possible with continuous optical pumping of solid state switch (1%).

Efficiency Wall Plug/ E-beam (J)

Marx-Charged 1-Stage MPC (Mag. Pulse Compressor) - System Parameters

SYSTEMS CORPORATIONPulse Sciences Division

• Load: space charge limited e-beam diode, 800 kV, 176 kA, 600 ns.

• Vacuum Bushing: 2 parallel inside-out, 72 nH equivalent inductance.

• Transit time Isolator: T (1 way) = 300 ns, water dielectric, 4.55 impedance,

stainless steel coax.

• Output Mag Switch: single-turn, Lsat = 110 nH, 291 mV-sec, post-winding anneal,

2605SC or equivalent.

• Output Reset: multi-turn, saturating.

• PFL: stainless steel coax, center-charged, peaking section, 4.55 (151.5 ns) -

4.65 (148.5 ns) - 2.8 (10 ns), water dielectric at 15oC.

• Marx: erected capacitance = 69.4 nF, erected voltage = 1.6 MV, series equiv. L =

1.76 H, Ipk = 228 kA, non-resonant inductive charge, laser-gated thyristor switched.

• Charging System: assumed polyphase rotating machine at 1000 Hz or greater, 13.8 kV

RMS class insulation, phase-controlled rectifier.

System Energy Audit (kJ)SYSTEMS CORPORATIONPulse Sciences Division

( ) = with saturating inductors

Charging Main Pulse ResetLoad Usable - 600 ns, 176 kA, 800 kV

(> 90% Pavg)

Rise/Fall

84.5

4.8

Magnetics Output SwitchDownstream ResetCharging InductorsLaser Charging Inductors

(.001)(.002)

.634

.065(.013)(.052)

.013

.003

Resistances Water dielectric (assume 15oC water)Skin Losses (stainless)Downstream ResetStray Capacitance (with stage)Capacitor ESRMarx Switch ESRCharging InductorsLaser Charging Inductors

.011 (.003).03 (.012)

.25

.13.004.03.10

1.73.40 (.000).80 (.000)

.05

Power Supply (assume 5% of stored energy) 4.672 (4.615)

Totals: with standard inductors with saturating inductors

4.7734.633

93.44392.308

.067

.067Efficiency: with standard inductors 86% with saturating inductors 87%

Marx-Charged 1-Stage MPC

SYSTEMS CORPORATIONPulse Sciences Division

10 m10 m

3.5 m

Output Reset

PFL

Transit-Time Isolator Output Switch

Marx Tank

Fast Marx ParametersSYSTEMS CORPORATIONPulse Sciences Division

• Erected Capacitance: 69.4 nF• Series Equivalent Inductance: 1.76 H• Peak Current: 228 kA• Erected Voltage: 1.63 - 1.64 MV • Stored Energy: 92.3 - 93.4 kJ• Charge Transfer Time (T/2): 783 nsec• No. of Stages: 50• Working Voltage/Stage: 32.8 kV ( 16.4 kV)• Full Stage Capacitance: 3.47 F• Inductance per Full Stage: 31.63 nH• Stage Capacitor Configuration: 2 parallel @ -Vchg, 2 parallel @ +Vchg• Current Path Width (thru Marx): 108 cm each side • Switches: laser-gated thyristors (± 16.4 kV working) • Inductance of Connections (ground and output): 117 nH• Charging: inductive (non-resonant)• Full Stage Dimensions: 100 cm x 140 cm x 7 cm• Marx Envelope Dimensions: 100 cm wide x 140 cm high x 355 cm long

Place holder for Marx tank vugraph -- see workshop 2

10.1nH 3.47F

75

10.1nH3.47F

75

10.1nH 10.1nH3.47F 3.47F

75 75

3.5pF 3.5pF

3.5pF3.5pF

CtankCtankLconn

Lconn

9.16nH 9.16nHCstray

.56nF

.50nFCstray

16.9nH

Cstray

Cstray.56nF

.50nF1.71m

Full Marx Stage Schematic

SYSTEMS CORPORATIONPulse Sciences Division

Laser-Gated Thyristor

Marx CapacitorsSYSTEMS CORPORATIONPulse Sciences Division

• Dielectric System: multi-layer polypropylene film, impregnant• Construction: floating foil, 5 kV rated per section, 4 sections per winding,

multiple windings in parallel• Rated Voltage: 20 kV• Rated Reversal: 10%• Working Voltage: 16.4 kV• Peak Current: 114 kA• RMS Current: 161 Amps• Capacitance: 3.47 F• Energy at Working Voltage: 467 Joules• Energy Transfer Time: 783 nsec• Repetitive Service: 5 pps• Life Time: 99% survival @ 5x108 charge/discharge cycles• Dimensions: 42 cm x 108 cm x 3.5 cm• Case Type: welded polypropylene, buss bar terminals each end• Environment: oil immersion, 40oC max

Laser Gated Thyristor Specifications

SYSTEMS CORPORATIONPulse Sciences Division

• Single Device Working Voltage: 16.4 kV

• Peak Current: 228 kA forward, 10% current reversal max

• Action: 20.8 x 103 A2-sec

• Max di/dt: 895 kA/sec

• Ipk /Area: 4.07 kA/cm2

• Service: 5 pps continuous, RCT (reverse conducting thyristor), 56 cm2 thyristor - 6 cm2 diode

• Life Time: 99% survival at 5 x 108 shots

• Environment: oil immersion, 40oC max

• Lasers: on-board 1120 nm CWL laser diode mini-bars at 500 watts for 1.0 sec,

laser duty factor = 5 x 10-6

• Laser Sites: 8 mini-bars/cm2 active silicon, 4 kW optical/cm2

• Laser Drives: integral with end electrodes, optical trigger isolation

• Silicon Device: advanced fabrication techniques, passivation, etc.

• Full Stage Switch Dimensions: 108 cm x 11 cm x 6 cm

SYSTEMS CORPORATIONPulse Sciences Division

Projections based on current component development efforts and conformal component packaging have shown that improvements in pulse compressor efficiency, cost and reliability are possible. A solid-state switched-Marx charging a single stage magnetic pulse compressor has been identified as a candidate topology with this study. This approach will be investigated further through careful modeling and benchmarking of component characteristics and interactions.

Conclusion