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

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 2 6/18/2016

Product Portfolio Radio Transmission 3 Most comprehensive and innovative AM radio product portfolio March 10

Engagement in Science and Research 4 March 10  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 Fusion Research Plasma Heating for ICRH (Ion Cyclotron Resonance Heating) ECRH (Electron Cyclotron Resonance Heating) NBI (Neutral Beam Injection) Industrial Applications Nuclear Waste Disposal Diamond Mining 3rd & 4th Generation Synchrotron Light Sources (electron acceleration) Particle Accelerators Accelerator Research Labs Medical Applications Cancer treatment with heavy ion acceleration Cancer treatment with proton acceleration LH (Lower Hybrid Heating and Current Drive) NBI (Neutral Beam

PSM Technology  The system consists of N series- connected switched mode power supply modules  Each module consisting of DC voltage source V DC 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 5 March 10

PSM Technology 6 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 V t CSM PWM March 10

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 A pulsed (via 1:12 pulse transformer => 144kV / Klystron)  ms 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 us  Cable length 1700m  Max allowed energy in to arc: 20J 7 6/18/2016

System Overview Four main issues: (1) Pulse flatness and flat top ripple=> fast pulse control and higher order output filter network required (2) Max allowed mains flicker 10kVA => controller for constant power consumption required (3) Transformer demagnetisation=> 2 Quadrant operation required (4) max. short circuit energy (1700m)=> 2 Quadrant operation required 8 6/18/2016 Simplified RF system block diagram

Solution to 1 st 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 9 6/18/2016 Pulse 10.5kV / 1000A (zoomed)

Solution to 2 nd 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 10 6/18/2016

Solution to 3 rd and 4 rd issue 2-Quadrant operation (patent pending) Transformer demagnetisation Reducing the arc energy 11 6/18/2016 Recharging of the pulse transformer magnetisation energy Output current in case of a short circuit

Solution to 3 rd and 4 rd issue 12 6/18/2016 Operation modes

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 13 6/18/2016

The HV Modulator test facility 14 6/18/2016

HV Modulator in the factory 15 6/18/2016

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. 16 6/18/2016

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