New prototype modulator for the European XFEL Project (DESY)

1. New prototype modulator for the European XFEL Project (DESY) Pulse Step Modulator (PSM) Technologyfor long pulse applications

2. Content • THOMSON Broadcast & Multimedia • A short company introduction • Brief introduction to the well known PSM technology • Topology and modulation • HV Modulator for the European XFEL • Challenges and Solutions • Conclusion • Gained benefits for future PSM application • Questions

3. Product Portfolio Radio Transmission Most comprehensive and innovative AM radio product portfolio

4. Solutions for various medical, research and industrial applications Customers on 4 Continents High Voltage Power Supplies (HVPS) up to 200 kV/130 A RF amplifiers up to 2 MW at frequencies up to 1300 MHz Industrial Fusion Medical Accelerator Applications Research Applications Research Labs Plasma Heating for Cancer treatment n Nuclear Waste Disposal n 3rd & 4th Generation n with heavy ion ICRH (Ion Cyclotron n Diamond Mining n Synchrotron Light acceleration Resonance Heating) Sources (electron Cancer treatment with proton acceleration n ECRH (Electron Cyclotron n acceleration) Resonance Heating) Particle Accelerators n NBI (Neutral Beam n Injection) LH (Lower Hybrid Heating and Current Drive) n Engagement in Science and Research NBI (Neutral Beam n

5. N S V D DC 3 S V D DC 2 S R V D LOAD DC 1 S Module V D DC PSM Technology • The system consists of N series- connected switched mode power supply modules • Each module consisting of • DC voltage source VDC • Switching Element S • Free-Wheeling Diode D • The voltage VDC is equal on all modules • With switch S the voltage VDC can be switched to the output • If switch S is open, the diode D provides a current path for the output current

6. V 4 4 3 3 2 2 2 1 1 1 PWM CSM t PSM Technology • The output voltage is controlled by a PWM modulation, distributed between all modules. This results in: • Equal loading of all modules • Allows high PWM frequency with low switching frequency of the individual module • => Small switching losses • High PWM frequency allows small filter size • Crowbarless operation

7. HV Modulator for European XFEL • The European XFEL Project at DESY (GER) requires 27 RF stations, capable of 10 MW RF Power each • Each RF station needs a HV Modulator with the following specifications: • 12 kV / 2‘000 Apulsed (via 1:12 pulse transformer => 144kV / 167A @ Klystron) • 0 - 1.7ms pulse width, 1-30Hz pulse repetition rate • Max allowed mains power variation (flicker): 10kVA • Pulse flatness and output ripple < +/- 0.3% • Pulse-to-Pulse stability < +/-0.1% • Rise time 20...70us • Cable length 1700m • Max allowed energy in to arc: 20J

8. System Overview Simplified RF system block diagram Four main issues: • Pulse flatness and flat top ripple => fast pulse control and higher order output filter network required • Max allowed mains flicker 10kVA => controller for constant power consumption required • Transformer demagnetisation => 2 Quadrant operation required • max. short circuit energy (1700m) => 2 Quadrant operation required

9. Solution to 1st issue Pulse voltage control • High dynamic • Pulse forming with PWM modulation frequency of 480kHz => leads to 20kHz per module • Higher order PSM output filter with 20dB damping at 20kHz • tuneable pre-compensation filter • Optimizing over-shoot and settling time, pulse forming • Compensation of mismatched loads Test result Pulse 10.5kV / 1000A (zoomed)

10. Solution to 2nd issue Design of Switching Power Module • Boost converter for constant power consumption 1200V / 400A IGBT • Main switching element: 1200V / 2400A IGBT module from Semikron • 20mF capacitor bank, charged up to 700VDC • Discharge during pulse down to 550VDC

11. Solution to 3rd and 4rd issue 2-Quadrant operation (patent pending) • Transformer demagnetisation • Reducing the arc energy Recharging of the pulse transformer magnetisation energy Output current in case of a short circuit

12. Solution to 3rd and 4rd issue Operation modes

13. System Design • Modulator Configuration • 480kVA Transformer • 20 switching modules • 4 pairs of 2-Q modules • 2 modules are for redundancy • Control System • Standard THOMSON PSM controller • Compact PCI computer running Win XP Embedded and TINE, touch screen • Pulse waveform sampling of 1MS/s

14. The HV Modulator test facility

15. HV Modulator in the factory

16. Gained benefits for future PSM Applications • Lower ripple • Higher order PSM filter leads to high damping at the PWM frequency and single module switching frequency • Thanks to the 2-Q operation mode, the L on the PSM output filter can be increased without increasing the energy into arc. • Increased reliability • Even with long cables and high inductance in the system, the energy into arc will stay below <20J. • Flexibility • The PSM technology has shown a very high flexibility in terms of pulse length, pulse shaping, high dynamic and modularity. • Extensions for the operation in all 4 quadrants are possible and are scalable according to the needs of the application.=> Pre-magnetization of Transformers would then be possible.

17. Thank you