1 EBM 2016, Estoril, Portugal, 18-22/09/2016 /15
Investigation on a high power solid-state
pulse generator
Jingming Gao, Hanwu Yang, Song Li, Baoliang Qian,
Jun Zhang, Jiande Zhang
National University of Defense Technology, Changsha, China
September, 2016
2 EBM 2016, Estoril, Portugal, 18-22/09/2016 /15
Outline
Introduction
System design
Circuit and Electromagnetic simulation
Experimental test
Conclusions
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Introduction
• Solid-state PPS characterized by high repeatability, high
reliability, long lifetime, free maintenance and easy-to-use
• Such systems with moderate peak power (sub GW) are
widely applied in high average power region
• Pursuing higher peak power with quasi square waveform for
HPM, X-ray and more industrial applications…
10GW/160 ns/20 Hz OSU 60 kV/75kW bipolar pulser S-3N 400kV 16kW (Burst)
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Introduction
• Switch
- high power capability
- large power compression ratio
- high switch speed
- low switch impedance
- high repetition rate and long lifetime
• Insulation
- components still restricted to relatively low rated voltage
- finish the power compression under lower voltage
- fully profit the insulation rules
• Energy transfer efficiency
- reducing energy lost is essential
- important for thermal management
magnetic switch
low impedance pulse forming
close-loop pulse transformer
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System design
Primary
unit
Pulse
transformer
Magnetic
compression
Low impedance
PFN
Magnetic
switch
Charging
unit
Reset
unit
Control
unit
IVA
14MW/25ms 350MW/1ms 2GW/160ns 14MW/25ms 350MW/1ms Power net
Load
2GW/160ns
A High Power, Low Impedance and Long Pulse Generator Voltage Adder
• High power magnetic switch based pulse modulation
• Low impedance pulse forming network
• Induction voltage adder for voltage step-up
• Modularization RHEPP-II & ETIGO-IV
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Circuit simulation
Circuit model
Schematic of a high power solid-state pulse generator
Schematic of a high power, low impedance and long pulse generator
• Three magnetic switches for pulse modulation
• IVA performs dual functions of charging inductor and adder
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Circuit simulation
Output pulse voltage on the load
Simulation results
29000 29500 30000 30500 31000
-80
-40
0
40
80
PF
N v
olta
ge
(kV
)
Time (ns)
PFN charging voltage
PFN discharging voltage
30000 30400 30800
-400
-300
-200
-100
0
100
V(l
oa
d)
(ns)
Time (ns)
PFN charging and discharging voltage
• IVA completes the dual functions well
T_FC Z_FC LC Lm_IVA Ls_IVA Rload
20ns 12Ω 29nH 18μH 100nH 50Ω
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Electromagnetic simulation
0 50 100 150 200
0.0
0.5
1.0
Source voltage
Load voltage with single feed
Load voltage with symmetrical feed
Load voltage of one cell (10ohm)
Time [ns]
So
urc
e v
olta
ge
0
1
2
3
4
Lo
ad
vo
lta
ge
Simulation results of the IVA Four-stage IVA
Symmetrical feeding structure of the cell
IVA response characteristics
• Symmetrical feeding responses much faster
• IVA with fewer stages performs better
core material outer diameter inner diameter height thickness
2605SA-1 406 mm 274 mm 20 mm 25μm
width Bs Br Insulation stacking factor
20 mm ~1.56 T ≥1.4 T 120 V/layer ~0.82
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Experimental test
Key sub-systems
• HVPS: AC-link, 0-30 kV/60 kJ/s
• Transformer: 0-150 kV/15μH
• MPC: 2-stage/20:1, Fe-based amorphous
HVPS Close-loop pulse transformer
-20000 -10000 0 10000 20000 30000 40000
0
1
2
3
4
B
[T]
H [A/m]
Amo_S @ 25m s
BH curve measurement
Magnetic pulse compressor
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Experimental test
Key sub-systems
• Magnetic switch: coaxial winding and output ports
• Low impedance PFN: symmetrically circumferential structure
• IVA: symmetrical fed modules with v-s product of 24mV·s
Magnetic switch Low impedance PFN(1.6Ω/60kV) Four-stage IVA
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0 20 40
0
20
40
60
Vo
lta
ge
(kV
)
Time (ms)
Normal status
Capacitor broken
Experimental test
Ceramic capacitor test
Transformer
Test cell with
PFN, PSS2
and water
resistor
Magnetic switch
HVPS input
Primary CapacitorReset circuit
PSS1
Trigger unit
Transformer
Test cell with
PFN, PSS2
and water
resistor
Magnetic switch
HVPS input
Primary CapacitorReset circuit
PSS1
Trigger unit
PSS2 Water resistor
PFN
• Rep. test in μs region
• 40nF/80kV/10Hz/60s
• Further analysis of
failure mechanism
Test platform
Test cavity Test waveforms Broken capacitors
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Experimental test
0 1000 2000 3000 4000 5000
-400
-300
-200
-100
0
100
Lo
ad
vo
lta
ge
(kV
)
Time (ns)
50ms interval
-500 0 500 1000 1500
-400
-300
-200
-100
0
100
Lo
ad
_vo
lta
ge
(kV
)
Time (ns)
1st
2nd
3rd
Primary test results
• On-line DC reset condition
• 2.1GW/170ns/20Hz
• Risetime~50ns
• Prepulse~10%
• Energy transfer ratio~45%
Overlap mode Sequential mode
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Experimental test
voltage
current
voltage
currentHVPS
2-stage MPCLoad
Low impedance
PFN
Magnetic
switch
IVA
P.T.
F.C.
HVPS
2-stage MPCLoad
Low impedance
PFN
Magnetic
switch
IVA
P.T.
F.C.
Upgraded test results
• Magnetic switches and PFN upgraded
• 5.5GW/170ns/20Hz/5s
• Showing good repeatability and stability
Upgrade system Overlap of 100 pulses
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Conclusions
A scheme for GW-level solid-state generator is
put forward based on magnetic switch, low
impedance PFN and IVA
The latest results are 5.5GW/170ns/20Hz/5s,
showing good repeatability and stability
The primary switch would be replaced with
semiconductor for all solid-state system
SMART: Solid-state Magnetic switched
Accelerator for Repetitive Test
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EAPPC & Beams & Megagauss 2016
Thanks for
your attention!
