swedish defence research agency (foi), defence & security, systems and technology presented at...

Swedish Defence Research Agency (FOI), Defence & Security, Systems and Technology Presented at The IET International Conference on Pulsed Power, CERN, Geneva, 21-25 September 2009

Overview of HPM as a Pulsed Power Application at FOI

Overview of HPM as a Pulsed Power Application at FOI

Sten E Nyholm , Mose Akyuz, Patrik Appelgren, Mattias Elfsberg, Tomas Hurtig, Anders Larsson , Cecilia Möller

Sten E Nyholm , Mose Akyuz, Patrik Appelgren, Mattias Elfsberg, Tomas Hurtig, Anders Larsson , Cecilia Möller


OverviewOverview

Introduction

High-voltage generators

Explosive flux compression generators

Cable based high-voltage generator

Repetitive Marx generator

Vircator studies

System simulation and propagation models

Summary

Introduction

High-voltage generators

Explosive flux compression generators

Cable based high-voltage generator

Repetitive Marx generator

Vircator studies


Summary


IntroductionIntroduction


HPM generation research

Electro-Thermal Chemical launch techniques

Electromagnetic launch techniques

Electric armour

Electrohydrodynamic flow control

Plasma-assisted combustion

HPM generation research

Electro-Thermal Chemical launch techniques

Electromagnetic launch techniques

Electric armour

Electrohydrodynamic flow control

Plasma-assisted combustion

Pulsed Power Applications at FOI Pulsed Power Applications at FOI


HPM research at FOIHPM research at FOI

HPM-susceptibility and protection 1988-2008

HPM-weapons technology 1993-2008

Joint project ”HPM” 2009-…

HPM-susceptibility and protection 1988-2008

HPM-weapons technology 1993-2008

Joint project ”HPM” 2009-…


Energy conversion efficiency

Compactness for usage on mobile platforms

Repetitive operation and durability

Output pulse parameter tuning

Energy conversion efficiency

Compactness for usage on mobile platforms

Repetitive operation and durability

Output pulse parameter tuning

Issues considered in HPM source research Issues considered in HPM source research


High-voltage generatorsHigh-voltage generators


Explosive flux compression generatorsExplosive flux compression generators

length = 300 mm, diam = 70 mm

Linitial = 23 µH, Lfinal = 0,2 µH

Seed current 5.7 kA, 11.2 kA

Peak current 269 kA, 436 kA

Current amplification 47, 39

length = 300 mm, diam = 70 mm

Linitial = 23 µH, Lfinal = 0,2 µH

Seed current 5.7 kA, 11.2 kA

Peak current 269 kA, 436 kA

Current amplification 47, 39


Cable based high-voltage generatorCable based high-voltage generator

to spark gap

powergui

Continuous

from spark gapSpark gapuBD=300 e3

Conn 1 Conn 2

R=2e3

Pulse formingLinear Switch

tBD=0

Conn 1 Conn 2

Capacitor bankVc=50e3

Cc=4.15 e-6Lc=250 e-9

Conn 1 Conn 2

Cable ending

Axial Vircator

1:12 Transformer(12 part segmentation)

Conn 1

Conn 2

Conn 3

Conn 4

Simulink model, top level

Measured and simulated pulses across 10 Ω load


Repetitive Marx generatorRepetitive Marx generator

25 stages of 100 nF and 55 nH each

length = 1.1 m (incl. charger), outer diameter = 0.3 m

Characteristic impedance 18.5 Ω

Repetition rate 10 Hz (burst mode)

25 stages of 100 nF and 55 nH each

length = 1.1 m (incl. charger), outer diameter = 0.3 m

Characteristic impedance 18.5 Ω

Repetition rate 10 Hz (burst mode)


Vircator studiesVircator studies


Initial experiments with a reflex triode and single shot Marx generator.

Axial vircator and repetitive Marx generator used in electrode material studies.

Coaxial vircator and Marx generator used in radiation mode control experiments.

Initial experiments with a reflex triode and single shot Marx generator.

Axial vircator and repetitive Marx generator used in electrode material studies.

Coaxial vircator and Marx generator used in radiation mode control experiments.

Vircator studies Vircator studies


Axial vircator - experimentalAxial vircator - experimental

VacuumPump

Waveguide

ResonanceCavity A

node

Marx Generator

Cat

hode

HV-

HV+

Emitter

Resonance cavity with anode

Cathode with graphite emitter


Axial vircator simulation in MagicAxial vircator simulation in MagicSimulation volume with small anechoic chamber representation

Simulated electric fields at one instant: TE21 dominant mode


Axial vircator geometries Axial vircator geometries

Selectable output window towards waveguide.

Cavity depth variation.

Selectable output window towards waveguide.

Cavity depth variation.


Coaxial vircator geometryCoaxial vircator geometryCoaxial vircator with sectioned emitter

Virtual cathodes oscillating in opposite phase =>

Recently verified in experiments !


Waveguide reflectorWaveguide reflector

Two-strip waveguide reflector

Simulations and experiments are performed this autumn.


Energy system simulationEnergy system simulationElectric circuit simulation models of

• FCG system

• Cable generator

• Marx generator

together with a vircator

model for comparison of

normalised voltage pulses.

Electric circuit simulation models of

• FCG system

• Cable generator

• Marx generator

together with a vircator

model for comparison of

normalised voltage pulses.


Energy system model in SimulinkEnergy system model in Simulink

WheelMotor

Vetronics PFN 3

Tri

g

PFN 2

Ctr

l

PFN 1

Tri

g

DC-ACconverter

Electrictransmission

DC-DCconverter

DC-DCconverter

MDS

HPMWcontrol

Gun firecontrol

FuelCells

HPMweapon

ElectricArmour

ETC gun

E-armouractiv ation

Driveprofile

DieselGenerator

2

DieselGenerator

1Capacitor

Bus bar and control system

Battery

Energy sources

Intermediate storages

Transmission and control

Adaptation units

Continuous consumers

Pulsed consumers


Simulated power flowsSimulated power flows

WheelMotor

Vetronics PFN 1

Tri

g

Gun firecontrol

Fuel cells

ETC gun

Driveprofile

DieselGenerator

Bus bar

Battery


HPM pulse propagationHPM pulse propagation

Wave propagation and attenuation

Microwave induced breakdown

Energy loss due to absorption

Energy loss due to pulse shortning

Wave propagation and attenuation

Microwave induced breakdown

Energy loss due to absorption

Energy loss due to pulse shortning



Electric field strength as function of distance for different systems

Critical electric field strength as function of the microwave pulse length for three atmospheric pressures



Radiation frequency 1 GHz 10 GHz

Energy input 1 kJ 1 kJ

Resistive losses in waveguide 0.4 J 13 J

Energy loss caused by microwave breakdown 0 0

Energy loss caused by rain (r=100 mm/h) 0.5 J 400 J

Energy loss caused by fog (visibility 30 m) 0.1 J 17 J

Energy loss caused by snow (r=10 mm/h) 0.2 J 1.7 J

Energy loss caused by ambient atmosphere 1.4 J 1.4 J

Energy budget calculation for a 1 GW, 1 μs, TE01 HPM pulse injected in rectangular copper wave guide, without microwave breakdown, but with microwave power absorption in atmosphere, primarily due to heavy rain.


SummarySummary


SummarySummary

Studies of pulsed power supplies for HPM includes explosive flux compression, cable based pulse forming line generator, and repetitive Marx generator.

The Marx generator has been used extensively in various vircator studies.

The work focuses on means to improve the energy efficiency of HPM generation, compactness for mobile use, and on repetitive operation combined with dynamic parameter tuning.

Studies of pulsed power supplies for HPM includes explosive flux compression, cable based pulse forming line generator, and repetitive Marx generator.

The Marx generator has been used extensively in various vircator studies.

The work focuses on means to improve the energy efficiency of HPM generation, compactness for mobile use, and on repetitive operation combined with dynamic parameter tuning.

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