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Study and prototyping of power supplies and klystron modulators. Carlos A. Martins Instituto Superior Técnico (IST) – Technical University of Lisbon Centre for Innovation in Electrical and Energy Engineering (CIEEE) (formerly a section leader at CERN in the power converters group). Summary.
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Study and prototyping of power supplies and klystron modulators Carlos A. Martins Instituto Superior Técnico (IST) – Technical University of Lisbon Centre for Innovation in Electrical and Energy Engineering (CIEEE) (formerly a section leader at CERN in the power converters group) Towards a Portuguese participation in the ESS project, 29th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE
Summary 1.- Introduction on Power Supplies for particle accelerators - Classifications; 2.- Main issues to be considered in the design - Load Regime (topology), Precision, EMC compliance, Remote controls, Safety, Reliability/maintenability; 3.- Examples of magnet power supplies (CERN case study) - “Of the shelf”; - Custom made; 4.- Solid state klystron modulators for proton Linac´s 5.- Potential contributions from CIEEE / IST 6.- Conclusions Towards a Portuguese participation in the ESS project, 29th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE
INTRODUCTIONPower supplies for particle accelerators Classification based on the load type 1.- Power Supplies for magnets - beam bending magnets; - beam correction magnets (steerers, quadrupoles, solenoids, sextupoles, etc.); - beam kicking magnets (septa, kickers); - “special purpose” (gamma transition, beam scope meters, etc.); 2.- Power Supplies for RF tubes - Tetrodes for RF generators in particle sources; - Klystron / IOT modulators for accelerating structures; Towards a Portuguese participation in the ESS project, 29th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE
INTRODUCTIONPower supplies for particle accelerators Classification based on load regime V, I t(s) V, I 0 t(s) 0 V, I t(ms) 0 Towards a Portuguese participation in the ESS project, 29th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE
Main Design considerations • Load regime (power) • selection of topology (DC, function tracking, pulsed); • nº of quadrants; • Cabling and AC feeders; • Cooling (air natural or forced; water); • Precision • Stability (over one year ?, one day ?, half an hour ?); • Reproducibility (pulse to pulse); • “Precision budget” should be established together with beam dynamics specialists; • Impact mostly from the choice of DCCT’s (magnets supplies) or HV voltage dividers (RF tube supplies); • These complex sensor devices are manufactured by very few companies (i.e. Danfysik, Hitec, North Star,...); • 3. EMC compliance • All power supplies should be compliant with international standards in terms of EMC emissions and immunity. Specific testing campaigns shall be planned and executed during prototyping and production acceptance; • The guarantee that all systems (power supplies, instrumentation electronics, ...) will perform correctly once integrated together in the machine Towards a Portuguese participation in the ESS project, 29th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE
Main Design considerations – cont. • Remote Control System • Selection of the fieldbus (WorldFIP?, ScienceFIP?, Ethernet?, WhiteRabbit?, ...); • Interface with the low-level controller part in the power supplies; • Physical layout of the controller (single board?, cassette?, chassis?,...); • Should be UNIQUE to all power supplies in the physics complex; • Online monitoring, diagnosis and “post mortem” facilities; • Reliability and maintainability • MTBF – Mean Time Between Failures (should be ~ 10 years, individually; if total power supplies = 1000 -> Total MTBF = 4 days); • Lifetime should be ~20 years by design (ageing of components like capacitors, obsolescence, thermal cycling of semiconductors must be taken into account); • MTTR – Mean Time to Repair (should be ~1 hour); • Spare parts and spare power supplies policy (shall be foreseen from the very early stage of the project and included in call for tenders; inventory data-base created and updated); • 6. Safety • Fire risks (special cables?); • Access for operation (Grounding equipment, capacitor discharge systems,...); • Presence of oil in HV equipments (leakage retainers, fire prevention systems, ...); Towards a Portuguese participation in the ESS project, 29th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE
Examples of power supplies(“Of the Shelf”) Danfysik Heinzinger • Low voltage DC • Low voltage DC; • High Voltage DC; • Capacitor Chargers FUG Technix Delta Elektronika • High Voltage DC; • Medium Voltage DC; • Capacitor Chargers • High Voltage DC; • Capacitor Chargers • Low voltage DC Towards a Portuguese participation in the ESS project, 29th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE
Examples of power supplies(custom made - CERN case study) PS Pole Face Windings (+/-250A, +/-1.2kV) PS Gamma Transition (500Apk, +/-6kVpk) PS Pole Face Windings (+/-1600A, +/-600V) Function tracking type Developed for CERN PS Consolidation program Towards a Portuguese participation in the ESS project, 29th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE
Examples of power supplies(custom made - CERN case study) Electronics crate 19”, 3U Power crate 19”, 6U 20A 7 ms 19”,3U PS injection / extraction Septa (Pulsed: 20kApk, 300Vpk, 0.6ms/1 Hz) 500V voltage Septa current current 300A 1 ms Linac2 & PSB TL Steerers (Pulsed: 20Apk, 600Vpk, 5ms/5 Hz) Linac2 & Linac3 Quads (Pulsed: 300Apk, 1kVpk, 1ms/5 Hz) Pulsed type CERN Linac2, PS Booster & PS Consolidation programs Also foreseen for Linac4 Towards a Portuguese participation in the ESS project, 29th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE
Solid state klystron modulators for proton linac’s Collector (GND) ~ hundred kV + - Cathode (-) Typical Requirements • Klystron power supply • Pulse width: ~2 ms • Flat-top duration ~1.5 ms • Precision at flat-top: < 1% • HF ripple at flat-top: < 0.1% • Repetition rate: 2..50 Hz • Nominal voltage: ~120 kV • Nominal current: ~20..100 A • Nominal power (peak): ~10 MW • Rise/fall times (99% / 1%): ~10% of Pulse width • Maximum energy in case of arc: < 20 J V Rise time Fall time time Flat-top Pulse width Shape of High Voltage Pulses Towards a Portuguese participation in the ESS project, 29th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE
Solid state klystron modulators for proton linac’s • The FERMILAB / DESY type modulator Simplified schematic, with pulse transformer 120 kV, 140A, 2.3ms, 10 Hz (Without pulse transformer) Also foreseen for: - Project X @ Fermilab; - XFEL @ Desy; Towards a Portuguese participation in the ESS project, 29th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE
Solid state klystron modulators for proton linac’s • CERN Prototype (3-MeV Test Stand & Linac4) 100 kV, 20A, 0.8ms, 2 Hz Simplified schematics Towards a Portuguese participation in the ESS project, 29th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE
Solid state klystron modulators for proton linac’s • SLAC Prototype Also a candidate for: - ILC; 115 kV, 135A, 1.5 ms, 5 Hz Towards a Portuguese participation in the ESS project, 29th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE
Solid state klystron modulators for proton linac’s 140 kV, 70A, 1.6ms, 60 Hz (9.8 MWpk, 940 kWav) • Oak Ridge (SNS) modulators AC/DC input converter not shown Towards a Portuguese participation in the ESS project, 29th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE
Solid state klystron modulators for proton linac’s • J-PARC modulators Towards a Portuguese participation in the ESS project, 29th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE
Potential contributions fromCIEEE / IST On Power Supplies and Klystron Modulators: • Carry on Studies for the Technical Design Report and Work-Package Description • Define main parameters, types and quantities for each application (in close collaboration with magnets team (magnet power supplies), RF team (klystron modulators) and beam dynamics team; • Propose topologies/references taking into account the market availability; • Define remote control system (in close collaboration with controls people); • Estimate costs, volumes, auxiliary requirements (water cooling, AC electrical feeders, AC and DC cables); • Planning; • Studies on Klystron Modulator Topologies • Evaluate in detail the existing topologies; • Propose the most suited topology for ESS (High power, High repetition ratio); • Study in detail the adopted topology by simulation and small scale prototyping (~same voltage, ~10% of rated power); • Synergy with CERN possible; Or alternatively (consulting): • Participate in writing-up of technical specifications and test protocols; • Evaluate commercial offers; follow-up of contracting milestones; participate in the testing campaign; • Realization of prototypes for “custom made” power supplies • Write-up technical specifications, test protocols. Follow-up of construction and validation Towards a Portuguese participation in the ESS project, 29th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE
conclusions • Power Supplies and Klystron Modulators are key technologies in accelerators • “Klystron modulators are probably the second most challenging sub-systems in high duty-cycle Linac’s, just after accelerating structures…” – Maurizio Vretenar, CERN Linac4 Project Leader; • Very few European and Worldwide companies are able to develop and produce such specific equipment (particularly for klystron modulators) • “Of the Shelf” versus “customized” solutions should be carefully evaluated • At least 2 solid companies (preferably 3) shall be able to provide the same or equivalent “Of the shelf” product (double source), to avoid risks of bankruptcy, monopoles in the long term future; • The project team shall have a “word to say” on the selection of the topology (technology); Do not delegate entirely this responsibility to companies; • Careful about functional specifications (technical specifications would be preferable…): - Too much freedom given to companies on “turn-key” solutions may put the whole project dependent on a single company in terms of delays, performance, long term reliability and maintainability; • Close follow-up of companies’ technical activities is essential • Single contracts (not a long term based commercial exchange); • Companies main objective: Profit (which is perfectly fair and honourable); • Project main objectives: Systems ready on time according to specifications; Reliable and maintainable in long term (20 years); • Be sure to get all documentation, knowledge and relevant information about the equipment; • Before placing a contract:- cross-check all parameters and technical details with the other partners of the project; • Be sure the specifications are clear and cover all pertinent technical details. Companies will challenge you on this capability… Towards a Portuguese participation in the ESS project, 29th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE