Centro de Electrónica Industrial (CEI) | Universidad Politécnica de Madrid | [email protected] | Design,...
1
Centro de Electrónica Industrial (CEI) | Universidad Politécnica de Madrid | [email protected] | www.cei.upm.es Design, prototype and manufacture of a large series of 10V/50A DC/DC power converters for driving superconducting magnets into the 4km X-Ray free-electron laser tunnel, located in the research facilities of DESY, Hamburg Project sponsored by Glosary Cold magnet: Electromagnet whose superconductivity comes from its low temperature (<10K). The low temperature is achieved by using liquid He cryostats. Hot magnet: Superconducting electromagnet at “much higher temperature” (>77K) Quench: A quench is an abnormal termination of magnet operation that occurs when part of the superconducting coil enters the resistive state, mainly due to magnetic field excess. That part sinks power which increases T in the surroundings, making them enter the resistive state as well. High-current and low-voltage step-down converter for feeding cold superconducting magnets P. Varela The Power Supply A DC/DC SMPS intended for cutting-edge research is under development in CEI-UPM. Its main singularity is the load nature to be fed: a superconducting magnet, which makes necessary to provide very high current output at low voltage. For that reason, variable switching frequency is applied, in order not to drive very short on times in steady-state (low duty cycle). Planar transformer design is applied as long as current-doubler with 4 SR for low losses under free-wheeling operation mode allowing bipolar output. XFEL Project: the Application Magnets What for? Smaller, faster, more intense: The European XFEL will open up areas of research that were previously inaccessible. Using the X-ray flashes of the European XFEL, scientists will be able to map the atomic details of viruses, decipher the molecular composition of cells, take 3D images of the nano-world, film chemical reactions and study processes such as those occurring deep inside planets. How it works? To generate the X-ray flashes, bunches of electrons will first be accelerated to high energies and then directed through special arrangements of magnets. In the process, the particles will emit radiation that is increasingly amplified until an extremely short and intense X-ray flash is finally created. Conclusions 1. Design Design inputs η, size, T, … Bipolar output Redundancy (2 power modules per power PCB) THE LOAD: ELECTROMAGNET Normal operation: L (2H) + very low R TRANSFORMER ±10V / 50A TOPOLOGY Usual operation: free- wheeling ≈0V/50A Current-doubler rectifier Saves transformer losses when running at almost 0V 1/2 Redundant module Planar technology Enhances repeatability & reduces assembling cost (500 units) Interwinding Low R AC Low Cu loss (50A) Low L leak For low ringing Bipolar Synchronous Rectification (4 MOSFETs) 2 LF switches (define polarity) 2 HF switches (rectify Vsec waveform) V s e c 2. Initial prototype 0.00 5.00 10.00 15.00 70.00% 75.00% 80.00% 85.00% 90.00% 95.00% Vout η (%) Planar transformer RM transformer 1st prototype with FPGA open-loop control η up to 92,5% (planar transformer, no driving nor control losses) IL1 Vgs3 Vds3 IL2 Vout Vgs3 Vds3 Iout 50A/10V, detail of the current share among both inductors in a module 50A/1.4V, detail of a secondary MOSFET turn-on Control PCB 3. Adaptation to control interface Power PCB v2 i ref , PI param. T, i out , V out … Vgs T, i out , V out … (raw data) CONTROL Outer loop: i out control, which creates the field Inner loop: V out control, which defines the magnet di/dt Variable f sw control for optimal losses balance (switching vs on) 2 nd version of the power PCB 4 . P r o t e c t i o n s Quench transient evolution (voltage across the magnet) External detection PCB QUENCH Failure in the magnet, detected by a voltage rise in the magnet terminals
-
Upload
daniella-harrison -
Category
Documents
-
view
217 -
download
1
Transcript of Centro de Electrónica Industrial (CEI) | Universidad Politécnica de Madrid | [email protected] | Design,...
Centro de Electrónica Industrial (CEI) | Universidad Politécnica de Madrid | [email protected] | www.cei.upm.es
Design, prototype and manufacture of a large series of 10V/50A DC/DC power converters for driving superconducting magnets into the 4km X-Ray free-electron laser tunnel, located in the research facilities of DESY, Hamburg
Project sponsored by
GlosaryCold magnet: Electromagnet whose superconductivity comes from its low temperature (<10K). The low temperature is achieved by using liquid He cryostats.
Hot magnet: Superconducting electromagnet at “much higher temperature” (>77K)
Quench: A quench is an abnormal termination of magnet operation that occurs when part of the superconducting coil enters the resistive state, mainly due to magnetic field excess. That part sinks power which increases T in the surroundings, making them enter the resistive state as well.
High-current and low-voltage step-down converter for feeding cold superconducting magnets
P. Varela
The Power Supply
A DC/DC SMPS intended for cutting-edge research is under development in CEI-UPM. Its main singularity is the load nature to be fed: a superconducting magnet, which makes necessary to provide very high current output at low voltage. For that reason,
variable switching frequency is applied, in order not to drive very short on times in steady-state (low duty cycle). Planar transformer design is applied as long as current-doubler with 4 SR for low losses under free-wheeling operation mode allowing bipolar output.
XFEL Project: the Application
Magnets What for?Smaller, faster, more intense: The European XFEL will open up areas of research that were previously inaccessible. Using the X-ray flashes of the European XFEL, scientists will be able to map the atomic details of viruses, decipher the molecular composition of cells, take 3D images of the nano-world, film chemical reactions and study processes such as those occurring deep inside planets.
How it works?To generate the X-ray flashes, bunches of electrons will first be accelerated to high energies and then directed through special arrangements of magnets. In the process, the particles will emit radiation that is increasingly amplified until an extremely short and intense X-ray flash is finally created.
Conclusions
1. D
esi
gn
Design inputs
η, size, T, …
Bipolar output
Redundancy (2 power modules per power PCB)
THE LOAD: ELECTROMAGNET
Normal operation: L (2H) + very low R
TRAN
SFO
RMER
±10V / 50A
TOPOLOGYUsual operation: free-wheeling≈0V/50A
Current-doubler rectifierSaves transformer losses when running at almost 0V
1/2 Redundantmodule
Planar technology
Enhances repeatability & reduces assembling cost (500 units)
Interwinding Low RAC
Low Cu loss (50A) Low Lleak
For low ringing
Bipolar Synchronous Rectification (4 MOSFETs) 2 LF switches (define polarity) 2 HF switches (rectify Vsec waveform)
Vsec
2. In
itia
l pro
toty
pe
0.002.00
4.006.00
8.0010.00
12.0014.00
70.00%
75.00%
80.00%
85.00%
90.00%
95.00%
Vout
η (%
)
Planar transformerRM transformer
1st prototype with FPGA open-loop control
η up to 92,5% (planar transformer, no driving nor control losses)
IL1 Vgs3 Vds3IL2
Vout Vgs3 Vds3Iout
50A/10V, detail of the current share among both inductors in a module
50A/1.4V, detail of a secondary MOSFET turn-on
Control PCB
3. Adaptation to control interface
Power PCBv2
iref, PI param.
T, iout , Vout…
Vgs
T, iout , Vout…
(raw data)
CONTROL Outer loop: iout control, which creates the field Inner loop: Vout control, which defines the magnet di/dt Variable fsw control for optimal losses balance (switching vs on)
2nd version of the power PCB
4. P
rote
ctions
Quench transient evolution(voltage across the magnet)
External detection PCB
QUENCH
Failure in the magnet, detected by a voltage rise in the magnet terminals
