The scope of this workpackage is the delivery of the Power Converters needed for the powering of the HL-LHC circuits in IP1 and IP5. The circuits comprised in the High Luminosity upgrade are the ones of the inner triplets and the matching sections; there will be 43 circuits per IP side for a total of 172 new operational Power Converters. The new Power Converters will be requested to guarantee even superior performance with respect to the ones used in the LHC as it is going to be determined by WP2 studies outcomes. Together with potentially unprecedented accuracy and precision the HL-LHC Power Converters will also be requested to assure very high availability in order to maximize operation time. WP6B foresees two main phases: a first one driven by R&D activities spanning from 2016 to 2020 followed by a second one devoted to procurement 2020, production follow up 2021 - 2023, testing for overall quality assurance 2023 - 2024 and finally installation and commissioning in 2025.
- 1. WP Management: This task will guarantee the necessary coordination and communication on one side with Project Management, WP1, and on the other side with the other WPs involved in the upgrade of the circuits in the two IPs in particular WP2, WP3, WP6A, WP7, WP10, WP15, WP16 and WP17. In addition to the interface with other WPs the main goal is to establish the strategy to be implemented by the TE-EPC group: organization of the workpackage in suitable workunits, definition of deliverables and outline of the main planning. Monitoring of the progress and follow up of spending will also be guaranteed. Goal Directed Project Management methodology will be adopted.
- 2. R&D:
- 2.1 High Accuracy and Precision Control: Power Converters performance relies dramatically on the measurement and control technologies employed; some of these strategic components are always designed and implemented in house by TE-EPC. In order to match or exceed the LHC performance in terms of accuracy and precision different axes are going to be explored. One of them will consist in the upgrade of the ADC currently used for Class 1 accuracy in LHC converters, based on more recent, state of the art, technologies in terms of low frequency, high precision, Analog to Digital conversion. Another strategic axis of R&D is constituted by current to voltage conversion, in particular precision burden resistors such as the ones used in DCCTs.
- 2.2 Innovative 2-Q Very High Current Converters – 18kA: One of the most innovative and most challenging task is certainly the development of very high current two-quadrant switch-mode Power Converters for the IT quadrupole magnets MQXFA/B. 2-Q converters will dramatically speed up ramp-down times and therefore maximise beam time. Switch-mode technology will guarantee less disturbance to the magnetic field seen by the beam in the frequency range up to 1 kHz. A core R&D axis will be represented by the energy storage/recovery technologies to be adopted. A PhD project is ongoing in collaboration with EPFL.
- 2.3 Modular; 4-Q Converters: Powering most of the new circuits will require innovative 4-Q converters. Current ratings will go from 120A for the small correctors up to 2kA for the IT Q1 and Q3 orbit correctors and all of them will be requested to guarantee high availability while managing higher level of energy to be dissipated inside the power converter, compared to the case of the LHC, where the higher cable resistance was taking part of it. (HL-LHC Power Converters will indeed be closer to the magnets with respect to LHC). Furthermore maximum rating for 4-Q converters in LHC is 600A whereas for the new ones it will reach 2kA. A core R&D activity will be devoted to topologies assuring maximal availability by means of (partial) redundancy such as N+1 redundancy. In this way the new converters will still be able to run even if one of their modules is in fault. This design was proven very successful in 1-Q LHC converters so this approach is now going to be implemented for the 4-Q converters needed by HL-LHC. Strategy and technologies for energy recovery and storage will constitute other axes of this R&D task.
- 3. Circuits Definition: Given the high complexity of the future HL-LHC circuits that will involve sophisticated machine protection equipment and innovative SC links the main objective of this task will be the full definition of interface with the Power Converters. Efficient interactions with WP2, WP3, WP6A, and WP7 will be crucial for the achievement of this objective. Operational as well as integration aspects will also drive the final specification of the Power Converters.
- 4. Infrastructure: All the needs for the new Power Converters proper and safe operation will be specified; clear deliverables will be defined. Effective communication towards and from WP17 will be guaranteed.
- 5. Availability: Availability of the machine is of the outmost importance, this specific task is therefore devoted to the optimization of the powering in terms of availability, working in close collaboration with WP7. The scope of this task is not restricted to power handling, as for N+1 redundancy, but will also cover the control electronics aspects concerned by a modular approach. Furthermore, its scope will also cover availability maximization for LHC as well.
- 6. Control Electronics: LHC control electronics (FGC2 based) as well as the control electronics currently equipping TE-EPC converters (FGC3 based) will be obsolete by the time HL-LHC will be in operation. A new control electronics will need to be developed with the most recent, state of the art, components and fully validated by 2023. This electronics will need to guarantee stable operation of HL-LHC for at least a decade. At the core of this electronics will be the upcoming version of the FGC family: FGC4. The new electronics will also need to fully support in hardware the maximum availability strategy to be established by the dedicated task.
M. Martino (WP6B Leader) and J-P. Burnet (WP6B Deputy Leader)
High Accuracy and Precision Control: M. Cerqueira Bastos (leader), M. Martino (deputy leader)
Innovative 2-Q Very High Current Converters – 18kA: J-P. Burnet (leader)
Modular; 4-Q Converters: Y. Thurel (leader)
Circuits Definition: H. Thiesen (leader)
Infrastructure: C. Coupat (leader), J-P. Burnet (deputy leader)
Availability: Y. Thurel (leader), B. Todd (deputy leader)
Control Electronics: B. Todd (leader)