Design, status and first operations of the spallation neutron source polyphase resonant converter modulator system

Conference · Wed Jan 01 00:00:00 EST 2003

DOI:https://doi.org/10.1109/PAC.2003.1288975· OSTI ID:976666

Reass, W A ^[1]; Apgar, S E ^[2]; Baca, D M ^[3]; Doss, James D; Gonzales, J ^[4]; Gribble, R F ^[5]; Hardek, T W ^[6]; Lynch, M T ^[7]; Rees, D E ^[8]; Tallerico, P J ^[9]; Trujillo, P B ^[10]; Anderson, D E ^[11]; Heidenreich, D A ^[12]; Hicks, J D ^[13]; Leontiev, V N

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1. William A.
2. Sean E.
3. David M.
4. Jacqueline
5. Robert F.
6. Thomas W.
7. Michael T.
8. Daniel E.
9. Paul J.
10. Pete B.
11. David E.
12. Dale A.
13. Jim D.

The Spallation Neutron Source (SNS) is a new 1.4 MW average power beam, 1 GeV accelerator being built at Oak Ridge National Laboratory. The accelerator requires 15 converter-modulator stations each providing between 9 and 11 MW pulses with up to a 1 .I MW average power. The converter-modulator can be described as a resonant 20 kHz polyphase boost inverter. Each converter modulator derives its buss voltage from a standard substation cast-core transformer. Each substation is followed by an SCR pre-regulator to accommodate voltage changes from no load to full load, in addition to providing a soft-start function. Energy storage is provided by self-clearing metallized hazy polypropylene traction capacitors. These capacitors do not fail short, but clear any internal anomaly. Three 'H-Bridge' IGBT transistor networks are used to generate the polyphase 20 kHz transformer primary drive waveforms. The 20 kHz drive waveforms are time-gated to generate the desired klystron pulse width. Pulse width modulation of the individual 20 lcHz pulses is utilized to provide regulated output waveforms with DSP based adaptive feedforward and feedback techniques. The boost transformer design utilizes nanocrystalline alloy that provides low core loss at design flux levels and switching frequencies. Capacitors are used on the transformer secondary networks to resonate the leakage inductance. The transformers are wound for a specific leakage inductance, not turns ratio. This design technique generates multiple secondary volts per turn as compared to the primary. With the appropriate tuning conditions, switching losses are minimized. The resonant topology has the added benefit of being deQed in a klystron fault condition, with little energy deposited in the arc. This obviates the need of crowbars or other related networks. A review of these design parameters, operational performance, production status, and OWL installation and performance to date will be presented.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE
• OSTI ID: 976666
• Report Number(s): LA-UR-03-3219; TRN: US1006523
• Resource Relation: Conference: Submitted to: IEEE PAC-2003, Portland, OR, May 12-16, 2003
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
ACCELERATORS
ALLOYS
CAPACITORS
DESIGN
ENERGY STORAGE
FEEDBACK
INDUCTANCE
KLYSTRONS
MODULATION
NEUTRON SOURCES
ORNL
PERFORMANCE
POLYPROPYLENE
PRODUCTION
SPALLATION
TOPOLOGY
TRANSFORMERS
TRANSISTORS
TUNING