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topPower Converter(s) Characteristics

Picture of the converter

topCommon Power Converters Characteristics

Power In 3 ~ 230 V / 32 A
Converter Type 1 Quadrant + *Pol. Switch
Control type FGC3 / FGCEther
Current Accuracy 10 ppm@ 30 mn
20 ppm@ 8 h
50 ppm@ 24 h
500 ppm@ 1 year
(1 ppm=0.8mA)

topDipole Power Converter Characteristics

Machine Name RPADC.EHN2.RDIP.COMPASS
FGCEther Address 1
Power Out +700 A, +14 V *
-700 A,  -14 V *
(700 A limited by polarity switch)

topSolenoid Power Converter Characteristics

Machine Name RPADC.EHN2.RSOL.COMPASS
FGCEther Address 2
Power Out +700 A, +14 V *
-700 A,  -14 V *
(700 A limited by polarity switch)

topDesign & Operation Responsibles

Yves THUREL Yves THUREL Interface EPC <=> Compass
Benoit FAVRE Benoit FAVRE Rack + Polarity Switch, Integration, Commissioning, Operation
Edwin ROHRICH Edwin ROHRICH COMBO-Technical manager
Nicolas KUCZEROWSKI Nicolas KUCZEROWSKI COMBO-Expert designer

topPower Converter Architecture

Control & regulation principles are summarized in a detailled schematics representating only the part involved in the output current regulation scheme. FGC3 control can adapt quite easily with different possible scenarios.

Detail FGC Regulator Vol.Sour.

I.Loop, I.sensor = power    -    I.Loop=fgc, I.sensor=power    -    I.Loop=fgc, I.sensor=external

Regulation Control simplified schematic .vsd

High precision current control loop is managed by the digital controller called FGC (Function Generator Controller). This unit includes a high precision Sigma Delta Analog to Digital Converter which digitalize the analog current measurement coming from 1 or 2 Current sensors (DCCTs: DC current Transducer). Precision is then directly relying on sensor precision: current sensors, the ADCs, and the algorithm being used for the regulation loop. Voltage source is then used as a power amplifier, powering the load through a high bandwidth voltage loop.

Converter SKINTLK Connector Pin Assignment

topPower Part

The system proposed is capable to handle a resetable fault, or also AC mains cut for several seconds, not loosing too much current in the magnet (then saving time for de-ramping + ramping again). The capability of restarting with the converter while the load is in free-whell mode has to be proved to ensure scenario is valid, and magnet protection scheme is adequate. REE system can be launched in case of a Quench requiring energy discharge, or in case Power Converter is definitively dead and to save time. A safety crowbar is placed between the polarity switch and the load, to prevent any severe crash in case of a DC Contactor malfunction.

Power In 3 ~ 230 V / 32 A.max @ 2 x 14 V x 700 A
Power Out 2x (+700 A +14 V) = 19 600 Watts
Cooling type Forced air ventilation
Rack Power Losses [200; 2000] Watts (depending on load operation conditions)
Converter Weight Bare Rack ........................... TBD kg (Power Modules and full equipped electronic chassis excluded)
Delta Power Module ........... 27 kg
Polarity Switch A1.700 ....... 25 kg
Electronic Chassis .... xx kg (FG3 Chassis + 2x FGC3s + 2x PSUs + 2 V2V DCCT Cards)

 

topSolenoid

Normal Operation Ramping Up or DC  |  Ramping Down
Fault Cases           Fast Discharge  |  very long discharge

Powering System simplified schematic .vsd & .xls
(Ramping Down sequence detailed proposal .pdf)

topDipole

Normal Operation Ramping Up or DC  |  Ramping Down
Fault Cases           Fast Discharge                                           

Powering System simplified schematic .vsd & .xls

Typical Curves / Measurements

Output Voltage Ripple .txt [  5A     50mV  ] V 150MHz: 10us / 1ms - 30MHz: 2ms - I [9; 150] kHz / [150 kHz; 30 MHz]
[ 700A    3.6V ] V 150MHz: 10us / 1ms - 30MHz: 2ms - I IAB: std, FFT
Output Currrent Ripple .txt [ 700A    3.6V ] I Spy: Ripple / FFT
Output Currrent Tracking .txt 600A → 700A, di/dt = 5A/s I Spy: End of ramp
EMC: AC Conducted Noise .txt 2x (700 A; 4 V) [9; 150] kHz / [150 kHz; 30 MHz]
EMC: AC Burst Effect on I.out .txt 2x (700 A; 4 V) [0,1,2,4] kV applied on AC 3Ph-Side (.xls)
Earth to DC Neg Pol. FFT .txt 5ADC Floating , 700ADC Floating
Voltage source bandwidth Vout/Vref Voltage Bandwidth
Voltage Source Efficiency vs Output Power Efficiency Graph, (.xls)

topControl Part

Control & regulation principles are summarized in a detailled schematics representating only the part involved in the output current regulation scheme.

Control & regulation principles are summarized in a detailled schematics representating only the part involved in the output current regulation scheme.

Detail FGC Regulator Vol.Sour.

Regulation Control simplified schematic .vsd

High precision current control loop is managed by the digital controller called FGC (Function Generator Controller). This unit includes a high precision Sigma Delta Analog to Digital Converter which digitalize the analog current measurement coming from 2 DCCTs (DC current Transducer). Precision is then directly relying on sensor precision: DCCT, the ADCs, and the algorithm being used for the regulation loop. Voltage source is then used as a power amplifier, powering the load through a high bandwidth voltage loop (>500Hz).

 

topMagnet Protection

Power Converter is part of magnet protection scheme, even if not directly fully responsible of the monitoring and diagnostic of the superconductive magnet status. Dedicated systems QPS (Quench Protection System) + PIC (Power Interlock Controller) can interlock Power Converter if magnet safety requires it.

Power Converter is then expected to:

  • Always ensure that external protection system can stop the Power Converter through a safe signal called Fast Abort. This redundant signal uses 2 paths to interlock and stop the converter and its redundancy is checked each time it acts. It directly acts on AC Contactor bobbin, ensuring their opening as required.
  • Always ensure a safe path exists, on the power converter side, even if experience ensure this at the level of the magnet side. It is important to notice that Free Wheeling Diode provided in the Polarity Switch cannot handle the complete and very long discharge of the superconductive magnets.

topEarthing Circuit

Earth Detection system is managed by experience. DC Output Lines are delivered being floating.

topPower Converter Fault Events

Power magnet protection strategy shall not lead to Power Converter failure. Principal risk can be to over-stress the free-wheeling diode of the Polarity Switch, in case the converter is stopped without fault, while at maximum current. The Energy Extraction System using both POWERING FAILURE (SKINTLK) and POLSW_FAULT1 or POLSW_FAULT2 (SKPOLINTLK1/2) shall prevent dramatic consequences by protecting the power converter. Other powering units faulty standard cases are covered in the table below.

Case Power Converter Polarity Switch Energy Extraction System Load Operation
State Powering Failure State Fault CP(1&2) CL CR
Normal Operation Safe 0 Safe 0 Closed Opened Closed Powered
Fault on Power Units Fault 1 Safe 0 Opened Closed Closed Very Long Discharge. It is possible that Power Units failed on AC Phase loss, and experience can recover them without discharging the magnet. Load is disconnected from the powering system.
Fault on Pol. Switch Safe 1 Fault 1 Opened Closed / Opened Opened Fast Discharge. A polarity switch fault can be internal free wheeling diodes being close to being destroyed, requiring an immediate disconnection from the load current. Since a polarity switch is a main event, and has to be analyzed, magnet is completly discharged with a Fast Discharge.

Interfaces between Power Converter and Energy Extraction System in case of Power Units or Polary Switch Faults

topPower Converter Components .vsd

A power converter is actually a sum of different equipments under several different sections in the TE-EPC group. Proposed solution is based on a Power Rack + Control & Meas Rack; main reason behind this technical choices comes from physical constraints (DCCT Heads location) + fact high precision DCCT electronics are better located in a cool environement (not the case of the power rack, since converters are air cooled).

  • EPC Power Rack of 2 power converters including Front View  |  Rear View

    EPC Power Rack

    • 1x Rack 45U
      • Datasheet Rack Atos Evolution Series .pdf

    • 4x Delta-Electronika Power Module 15V 400A
      • 1x Power Converter = 2x Power Module in //.
        Datasheet .pdf, Manual .pdf, Application Note .pdf

    • 2x Polarity Switches A1.700
      • 1x Power Converter = 1x Polarity Switch

    • 1x Rack AC distribution Front Panel providing:
      • 1x AC Breaker per Power Converter (2x in total)
      • 1x AC Breaker for Global Rack electronic crate.

    • 1x Rack A.U.E. (UPS Stop) Panel providing:
      • A push button to stop the UPS powered system with the capability
        to also cut the Power AC departure (contactor at AC Dist. level)

    • 1x Rack DC Grounding System (rear view) providing:
      • A way to easily ground DC Connexion to earth in a safe way.

    • 1x Rack Config Front Panel providing:
      • A central Power Rack Equipment Stop Button
      • Individual earthing system configuration for up to 4x Power Converters.

    • 1x Controller / Electronic Chassis (Type x) including cards:
      • 2x Digital Controllers                        FGC3 + FGC3-dongle (1x FGC3 / Power Converter)
      • 2x VS V2V (1x V2V for 2x DCCTs)       HCRAKAB EDA-02710
      • 1x VS PSU (1x PSU for 2 FGC3)           HCRFAAB EDA-02322

    • 1x COMBO Config Panel (Type 2cvs2&2):

    • 1x Dual Earthing Detection System:
      • 2x detection system in 1 2U-unit provided by experience.

    • A Rack Bottom Panel including:
      • Interlock System Connections to be reviewed.
  • EPC Measurement Rack including EPC Control & Measurement Rack
    • 1x Rack 18..22U
      • Datasheet Rack Atos Evolution Series .pdf

    • 1x Rack AC distribution Front Panel providing:
      • 1x AC Breaker per Odd DCCT of each Converter
      • 1x AC Breaker per even DCCT of each Converter

    • 1x Rack A.U.E. (UPS Stop) Panel providing:
      • A push button to stop the UPS powered system with the capability
        to also cut the Power AC departure (contactor at AC Dist. level)

    • 4x DCCT Electronics
      • 2 DCCTs per Power Converter

  • EPC Control Units to be integrated in experience IT-rack EPC Control & Measurement Rack
    • 1x Gateway

    • 1x FGC3 Switch

    • 1x FGC3 Pulse Injector

topMagnet Types

Compass Experience xxxxxx

topMachine Installation

Compass Use 1 Complete Rack including 2 Power Converters (solenoid + dipole)

topProduction Contract & Contact History

Developped Designed & built @ CERN
2013
Upgraded Modified to fit with COMBO parts
2017

Old Design Compass Typical Curves / Measurements

Output Voltage Ripple .txt [  5A     50mV  ] V 150MHz: 10us / 1ms - 30MHz: 2ms - I [9; 150] kHz / [150 kHz; 30 MHz]
[ 700A    3.6V ] V 150MHz: 10us / 1ms - 30MHz: 2ms - I IAB: std, FFT
Output Currrent Ripple .txt [ 700A    3.6V ] I Spy: Ripple / FFT
Output Currrent Tracking .txt 600A → 700A, di/dt = 5A/s I Spy: End of ramp
EMC: AC Conducted Noise .txt 2x (700 A; 4 V) [9; 150] kHz / [150 kHz; 30 MHz]
EMC: AC Burst Effect on I.out .txt 2x (700 A; 4 V) [0,1,2,4] kV applied on AC 3Ph-Side (.xls)
Earth to DC Neg Pol. FFT .txt 5ADC Floating , 700ADC Floating
Voltage source bandwidth Vout/Vref Voltage Bandwidth
Voltage Source Efficiency vs Output Power Efficiency Graph, (.xls)

Rack Thermal Characterization

topConverter Circuit Names