topPower Converter Characteristics

Picture of the converter
MIDIDISCAP Medium size DIScharge CAPacitor converter
Power In 3 ~ 230V/2.75A
Power Out 5ms max (+/- 50A +/-600V)
Converter Type Capacitor Discharge
Control type FGC3 / Ethernet+
Current Accuracy 200 ppm@ 30 mn
200 ppm@ 24 h
1000 ppm@ 1 year
(1 ppm=50uA=0.05mA)
Voltage Ripple 10 mVrms@ f=20Hz-1kHz
60 mVrms@ f=1kHz-130kHz
7 mVrms@ f=130kHz-5MHz

topDesign & Operation Responsibles

Serge PITTET Serge PITTET Technical referee, designer
Christophe MACHADO Christophe MACHADO Responsible 1
Ludovic CHARNAY Ludovic CHARNAY Responsible 2
Design History
Antoine GIRALDI Antoine GIRALDI digital control studies (2015-2016)

topPower Converter Architecture

Simplified Schematic

Power Part simplified Architecture / Topology .vsd

Simplified Operation Overview

Simplified cylce

  • Simplified Operationnal chronograms
    • pre-warning starts charging the capacitor bank.
    • warning indicates that the discharge will soon start.
    • Start discharging the capacitor bank into the magnet.
    • Meas indicates when the current value must be sampled.
    • Stop the capacitor discharge. Note that this is a new proposed signal and that it should be optional (the converter will limit the pulse to an internal maximum).

topPower Part

Voltage Source is based on a full bridge phase shifted topology followed by a linear stage in series with a fulle bridge to allow the 4 quadrant operation.

One precision resistor is used for the high precision current loop (FGC), and is located directly in the converter.

Converter is compatible with 19'' standard dimensions.

Power In 3 ~ 230V/2.75A
Power Out 5ms max (+/- 50A +/-600V)
Cooling type Fans
Converter Weight Power Module ............ 27 kg (FGC Included)
Simplified Schematic

Power Part simplified Architecture / Topology .vsd


Typical Curves

Output Voltage Ripple TBD

topControl Part

topMagnet Protection

Power Converter is part of magnet protection scheme, even if not directly fully responsible of the monitoring and diagnostic of the magnet status. WIC (Warm 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.
  • Stop powering the load in safe way (handling the magnet energy even when stopping, through dedicated system called crowbar). This active system provides a safe resistive discharge path for magnet current (energy).
  • Monitor Earth current of the total circuit: converter + load (magnet and its DC cables), and take the right action if threshold reached.


  • Earth System

    Detection system is an active / passive system, since relying on a converter state-controlled 100mA current source powering a 100Ohms resistor connected between earth and negative polarity of the Power Converter. A common mode voltage is then created, (100mA x 100Ohms = 10V) making possible to detect an earth fault even with converter being OFF (not condamned). Active system is disabled when Power Converter is set STANDBY or ON, with a 10 Ohms resistance series a fuse only being connected between negative polarity and earth.

    Simplified Schematic

    Earthing System simplified schematic .vsd


topPower Converter Components

Components layout

A power converter is actually a sum of different equipments under several different sections in the TE-EPC group. The modularity is a key factor for easier maintenance with regards to MTTR reduction.


topMagnet Types

corrector TBD


topMachine Installation

Air losses Module @ P.nom (incl. FGCs) 350 Watts
Linac 4 Use 4 Power Converters: DTL
8 Power Converters: CCDDTL
12 Power Converters: PIMS
26 Power Converters: TRANSFER Line
Booster Use 0 Power Converters
PS Use 0 Power Converters
AD Use 0 Power Converters


topProduction Contract & Contact History

Developped LPC icon CERN TE-EPC-LPC
Manufactured Denmark
Production 60 Pc

topConverter Circuit Names