engAguglia, D2 MW Active Bouncer Converter Design for Long Pulse Klystron ModulatorsAccelerators and Storage RingsCERN-ATS-2012-015This paper presents some design issues of a 2 MW interleaved buck converter which is used as an active bouncer droop compensator for a 5.5MW long pulse klystron modulator. This novel design concept presents many challenges in terms of voltage ripple versus pulse rise-time. Issues related to the voltage ripple specification versus output filter design are discussed in detail. The design study is analyzed analytically, simulated numerically and is validated by experimental results obtained from a full power prototype.2012-01-30http://cds.cern.ch/record/1419793http://cds.cern.ch/record/1419793oai:cds.cern.ch:1419793 engSiemaszko, DPittet, SFailure Tolerant Operation and Trimming Principle in the CLIC Main LinacAccelerators and Storage RingsCERN-ATS-2012-017A powering strategy for a high number of magnets disposed in a radiated and confined area is presented for a particle accelerator application. One power converter supplies the main current in series connected magnets. Then, for adjusting each current individually, small active trimmers are implemented together which each magnet. The trimmers are only dissipative, implemented as MOSFETs operated in their linear region and controlled by analog PI controllers. The reliability of the whole powering system is ensured with failure tolerance that complies with beam physics. The steady state operation and dynamic response in case of failures are experimentally studied in a reduced scale prototype.2012-01-30http://cds.cern.ch/record/1419792http://cds.cern.ch/record/1419792oai:cds.cern.ch:1419792 engSiemaszko, DSpeiser, MPittet, SReliability Models Applied to a System of Power Converters in Particle AcceleratorsAccelerators and Storage RingsCERN-ATS-2012-016Several reliability models are studied when applied to a power system containing a large number of power converters. A methodology is proposed and illustrated in the case study of a novel linear particle accelerator designed for reaching high energies. The proposed methods result in the prediction of both reliability and availability of the considered system for optimisation purposes.2012-01-30http://cds.cern.ch/record/1419790http://cds.cern.ch/record/1419790oai:cds.cern.ch:1419790 engAguglia, DAntoszczuk, PBenedetti, MGarcia Retegui, RMaestri, SNisbet, DImproved Control Strategy for Active Bouncers used in Klystron ModulatorsAccelerators and Storage RingsCERN-ATS-2012-058This paper introduces a closed-loop control system for klystron modulators. The system is based on the discharge of a capacitor into a step-up voltage transformer and an active bouncer implemented with a multiphase buck converter. In order to obtain a constant Klystron voltage at the at-top, the active bouncer must compensate both the capacitor discharge and the pulse transformer characteristic. The proposed control includes an inner voltage regulation loop that controls the active bouncer output voltage and an outer one that controls the klystron voltage. The primary side current and main capacitor voltage are included in the regulation loops to simplify the controllers. Simulations demonstrate that the strategy adopted allows to obtain a precision better than 0:1% on a 110 kV klystron. Experimental tests have shown that the multiphase converter is able to track a high dynamics reference even under variable output voltage conditions.2012-03-15http://cds.cern.ch/record/1432949http://cds.cern.ch/record/1432949oai:cds.cern.ch:1432949