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de Lira, A. C.

Paper Title Page
MOPAS059 ILC - ATF2 DC-Magnet Power Supplies 569
  • B. Lam, P. Bellomo, D. Macnair, A. C. de Lira
    SLAC, Menlo Park, California
  Funding: The development and commissioning of DC magnet power supplies for ATF2 is supported by KEK and SLAC.

In 2008 KEK is commissioning ATF2 - an extension to the existing ATF. ATF2 is a mockup of the final focus test beam accelerator envisioned in the ILC. SLAC is designing the power supply systems for the dc magnets in the ATF2, which will require 38 power supplies ranging from 1.5 to 6 kW, currents from 50 to 200 A, all rated at output voltages not higher than 30 V. Because of the extensive quantities of magnets required for the ILC, high availability is paramount to its successful operation, so the power supply topology chosen for the ATF2 uses N+1 redundancy, with 50-A power modules to construct each power supply. These power modules are current-mode buck regulators, which operate in parallel with each other and one redundant module. One bulk power supply provides off-the-line regulated dc input to a number of the power supplies. Current stability requirements for the magnets range from 10 to 1000 ppm. A precision current transductor and a recently developed SLAC-built 20-bit Ethernet Power Supply Controller will provide the current regulation required. In this paper we present the conceptual design, prototype results, and the status of the power supply systems for the ATF2.

MOPAS070 The DC-Magnet Power Supplies for the LCLS Injector 590
  • A. C. de Lira, P. Bellomo, K. Luchini, D. Macnair
    SLAC, Menlo Park, California
  Funding: This work was performed in support of the LCLS project at SLAC and funded by Department of Energy contract DE-AC02-76SF00515

The LCLS injector at SLAC requires 100+ dc-magnet power supply systems for its operation. Power supplies are divided into two main groups: intermediate rack-mounted type for output powers up to 20 kW at 375 A, and bipolar units rated 6 A, 12 A, and 30 A for corrector magnets and small quadrupoles. The intermediate power supplies are controlled by a 20-bit Ethernet power supply controller, specially developed at SLAC to be used in this project. The bipolar units are controlled via 12-bit DACs and ADCs housed in a VME crate. EPICS is the controls interface to all systems. For all systems, stability requirements are better than 1000 ppm. The Power Conversion Department at SLAC, in close cooperation with the LCLS Controls group, was responsible for defining the major characteristics of the power supply systems, their specification, procurement, installation, and commissioning. In this paper we describe the main characteristics of the power supply systems for the LCLS injector, including results from their successful commissioning early this year.

WEPMS028 Converter-Modulator Design and Operations for the ILC L-band Test Stand 2397
  • W. Reass
    LANL, Los Alamos, New Mexico
  • C. Adolphsen, T. G. Beukers, C. Burkhart, R. L. Cassel, M. N. Nguyen, G. C. Pappas, R. Swent, A. C. de Lira
    SLAC, Menlo Park, California
  • D. E. Anderson
    ORNL, Oak Ridge, Tennessee
  Funding: This work supported by Stanford Linear Accelerator Center, Oak Ridge National Laboratory, and the Department of Energy.

To facilitate a rapid response to the International Linear Collider (ILC) L-Band development program at SLAC, a spare converter-modulator was shipped from Los Alamos. This modulator was to be a spare for the Spallation Neutron Source (SNS) accelerator at ORNL. The ILC application requires a 33% higher peak output power (15 MW) and output current (130 Amp). This presents significant design challenges to modify the existing hardware and yet maintain switching parameters and thermal cycling within the semiconductor component ratings. To minimize IGBT commutation and free-wheeling diode currents, a different set of optimizations, as compared to the SNS design, were used to tune the resonant switching networks. Additional complexities arose as nanocrystalline cores with different performance characteristics (as compared to SNS), were used to fabricate the resonant "boost" transformers. This paper will describe the electrical design, system modifications, modeling efforts, and resulting electrical performance as implemented for the ILC L-band test stand.