Definition of Power Converters

The paper is intended to introduce power conversion principles and to define common terms in the domain. The concepts of sources and switches are defined and classified. From the basic laws of source interconnections, a generic method of power converter synthesis is presented. Some examples illustrate this systematic method. Finally, the commutation cell and soft commutation are introduced and discussed.Comment: 29 pages, contribution to the 2014 CAS - CERN Accelerator School: Power Converters, Baden, Switzerland, 7-14 May 201

Novel Topology for Four-Quadrant Converter

Particle accelerators, like the LHC (Large Hadron Collider), make use of true bipolar power converters to feed superconducting magnets. Moreover, the LHC imposes that most converters must be installed underground. This constraint leads to the necessity of a high efficiency and a reduced volume for all the power converters. In this paper, the authors present a novel four-quadrant topology composed by an association of a ZVS-inverter and a ZCS-rectifier. This DC-AC-DC converter is fully reversible and a soft-switching operation mode is achieved for all switches over the full operating range. After a thorough analysis of the prototype design [±600A, ±10V], simulation and experimental results confirm the general performance of this power structure

Machine Protection for the LHC: Architecture of the Beam and Powering Interlock Systems

The superconducting Large Hadron Collider under construction at CERN is an accelerator with unprecedented complexity. Its operation requires a large variety of instrumentation, not only for control of the beams, but also for the control and protection of the complex hardware systems. Sophisticated protection systems are mandatory to minimise the risk for serious damage caused by a failure. Each proton beam will have an energy of more than 300 MJ, and the energy stored in the magnet system amounts to about 1.2 GJ for each sector. Ideas for the architecture of the interlocks linking the protection systems are presented here

First Powering of the LHC Test String 2

String 2 is a full-size model of a regular cell in an LHC arc. In the first phase, three dipole magnets and two quadrupole magnets have been assembled in String 2 and commissioning started in April 2001. By the beginning of 2002 three pre-series dipole magnets will be added to complete the cell. As for its predecessor String 1, the facility was built to individually validate the LHC systems and to investigate their collective behaviour for normal operation with the magnets at a temperature of 1.9 K, during transients as well as during exceptional conditions. String 2 is a precious milestone before installation and commissioning of the first LHC sector (1/8 of the machine) in 2004, with respect to infrastructure, installation, tooling and assembly procedures, testing and commissioning of individual systems, as well as the global commissioning of the technical systems. This paper describes the commissioning, and retraces the first powering history

The Commissioning of the LHC Test String 2

String 2 [1,2] is a full-size model of an LHC cell of the regular part of the arc. It is composed of six dipole magnets with their correctors, two short straight sections with their orbit and lattice corrector magnets, and a cryogenic distribution line running alongside the magnets. The commissioning of String 2 Phase 1, with one half-cell and the following quadrupole, has started in April 2001. As for String 1 [3], the facility was built to individually validate the LHC systems and to investigate their collective behaviour during normal operation (pump-down, cool-down and powering) as well as during exceptional conditions such as quenches. String 2 is a stepping stone towards the commissioning of the first sector (one eight of LHC) planned for 2004. It is expected to yield precious information on the infrastructures, the installation, the tooling and the procedures for the assembly, the testing and the commissioning of the individual systems, as well as the global commissioning of the technical systems. This paper describes the procedures followed for the commissioning and details the preparation for the first cool-down and for the powering

A Storage Ring based Option for the LHeC

The LHeC aims at the generation of hadron-lepton collisions with center of mass energies in the TeV scale and luminosities of the order of $10^{32}-10^{33} cm^{-2} sec^{-1}$ by taking advantage of the existing LHC 7 TeV proton ring and adding a high energy electron accelerator. This paper presents technical considerations and potential parameter choices for such a machine and outlines some of the challenges arising when an electron storage ring based option, constructed within the existing infrastructure of the LHC, is chosen

First Results and Status of the LHC Test String 2

After the commissioning of String 2 Phase1 and the powering of the main circuits in autumn 2001, a short yet vigorous experimental program was carried-out to validate the final design choices for the technical systems of LHC. This program included the investigation of thermo-hydraulics of quenches quench propagation, power converter controls and tracking between power converters, as well as the measurement of currents induced in the beam screen after a quench and crossing the interconnects. Parameters significant for the LHC, such as heat loads, were also measured. During the winter shutdown the String was completed to a full cell with the addition of three pre-series dipoles (Phase 2). After a short description of the layout of Phase 1 and Phase 2, the results of the experiments are presented and the future experimental program is outlined

The LHC Prototype Full-Cell: Design Study

As a continuation of the experimental program carried-out with String 1, project management decided toward the end of 1995 to construct an LHC prototype Full-Cell, also known as String 2. The present document reports on the outcome of the one-year design effort by the community of specialists contributing to the LHC Prototype Full-Cell: it informs specialists on the boundary areas with other syste ms and conveys to the general public a description of the facility