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EDMS No.: 1460238
Group Code: TE/EPC
MS-4094 /TE
Market Survey
Technical Description
for the supply of three 18 MW power converters
for the Booster 2 GeV project
Abstract
This technical description concerns the design, manufacturing, testing and
delivery to CERN of three identical 18 MW, 6000 A / 3000 V power
converters for the Booster 2 GeV project.
This market survey will be followed by the issue of an invitation to tender to
qualified and selected firms in April 2015 for a contract to be awarded in
September 2015.
February 2015
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EDMS No.: 1460238
MS-4094 /TE
Table of Contents
1.
1.1
1.2
1.3
2.
3.
3.1
3.1.1
3.1.2
3.2
3.3
3.3.1
3.3.2
3.3.3
3.4
3.5
3.6
4.
4.1
4.2
5.
INTRODUCTION ........................................................................................................................... 1
Introduction to CERN ....................................................................................................................... 1
Introduction to the Technology Department and Electric Power Converter group ........................... 2
Introduction to the PS Booster accelerator ........................................................................................ 2
SCOPE OF THIS MARKET SURVEY ........................................................................................ 2
TECHNICAL DESCRIPTION OF THE SUPPLY ...................................................................... 2
New Main Power System for PS Booster.......................................................................................... 3
Main Power Converter standard load cycle ..................................................................................... 3
Energy exchange ............................................................................................................................... 4
Scope of the supply ........................................................................................................................... 5
Main Power Converter topology ....................................................................................................... 5
AFE and DC/DC topology ................................................................................................................ 7
Control system ................................................................................................................................... 7
Cooling system .................................................................................................................................. 8
Technical Requirements .................................................................................................................... 8
Ratings .............................................................................................................................................. 9
Testing requirements ......................................................................................................................... 9
PROVISIONAL DELIVERY SCHEDULE .................................................................................. 9
Provisional delivery schedule ............................................................................................................ 9
Contract Follow-up and Progress Monitoring ................................................................................. 10
CERN CONTACT PERSONS ..................................................................................................... 10
List of Acronyms / Abbreviations
AFE
Active Front End
DTR
Dipole Trim power converter
IEGT
Injection-Enhanced Gate Transistor
IGBT
Insulated-Gate Bipolar Transistor
IGCT
Integrated Gate-Commutated Thyristors
LIU
LHC Injectors Upgrade
MPC
Main Power Converter
MPS
Main Power Supply (include MPC and QTR and DTR)
NPC
Neutral Point Clamped
QTR
Quadrupole Trim power converter
PSB
Proton Synchrotron Booster
PWM
Pulse Width Modulation
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1.
INTRODUCTION
1.1
Introduction to CERN
CERN, the European Organization for Nuclear Research, is an intergovernmental organization with
21 Member States 1.
Its seat is in Geneva but its premises are located on both sides of the French-Swiss border
(http://cern.ch/fplinks/map.html).
CERN’s mission is to enable international collaboration in the field of high-energy particle physics
research and to this end it designs, builds and operates particle accelerators and the associated
experimental areas. At present more than 11 000 scientific users from research institutes all over the
world are using CERN’s installations for their experiments.
The accelerator complex at CERN is a succession of machines with increasingly higher energies.
Each machine injects the beam into the next one, which takes over to bring the beam to an even
higher energy, and so on. The flagship of this complex is the Large Hadron Collider (LHC) as
presented below:
Figure 1: CERN Accelerator Complex
Further information is available on the CERN website: http://cern.ch
1 The CERN Member States are currently Austria, Belgium, Bulgaria, Czech Republic, Denmark, Finland, France, Germany, Greece,
Hungary, Israel, Italy, Netherlands, Norway, Poland, Portugal, Slovakia, Spain, Sweden, Switzerland and United Kingdom. In
addition: Serbia is Associate Member State in the pre-stage to Membership and Romania is Candidate for Accession.
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1.2
Introduction to the Technology Department and Electric Power Converter group
The Technology (TE) Department is composed of the groups responsible for technologies which are
specific to existing particle accelerators, facilities and future projects. The main domains of
activities cover: magnets (superconducting, normal conducting, fast pulsed magnets, electrostatic
and magnetic septa), their machine integration and protection, power converters, cryogenics, high
and ultra-high vacuum systems, coatings and surface treatments.
The Electric Power Converter (EPC) group, part of the TE department, is responsible for design,
development, procurement, construction, installation, commissioning, operation and maintenance of
all power converter systems for the present and future accelerators, including experimental areas
and tests facilities at CERN.
1.3
Introduction to the PS Booster accelerator
The Proton Synchrotron Booster (PSB) is the smallest circular proton accelerator in the accelerator
chain at the CERN Large Hadron Collider injection complex. The accelerator has been constructed
in 1972 and it is composed of four superimposed synchrotron rings with a radius of 25 m.
The accelerator currently takes protons with energy of 50 MeV from the linear accelerator
Linac 2/3/4 and accelerates them up to 1.4 GeV, ready to be injected into the Proton Synchrotron.
The PS Booster is controlled with a pulse modulation with 1.2 s cycle length (repetition time
of 1.2 s).
With a circumference of 157 m, the PS Booster contains 264 magnets of 15 different types,
including 32 dipole magnets (192 mH / 500 mΩ) and 48 quadrupole magnets (8.8 mH / 83.6 mΩ).
2.
SCOPE OF THIS MARKET SURVEY
The purpose of this market survey is to identify potential bidders for the supply of three 18 MW
main power converters (hereinafter referred to as MPC). The new power systems will supply the
dipole magnets of PS Booster accelerator.
Only firms qualified by CERN after analysis of their reply to this market survey and after having
proven their capability to manufacture medium voltage high power converters in accordance with
the conditions of this technical description will be included in the forthcoming invitation to tender.
The selection criteria under which companies will be assessed are defined in the document entitled
“Qualification Criteria”, and in the appended document “Selection and Adjudication Criteria for
Supply Contracts”. CERN reserves the right to visit the bidder premises and its sub-contractors.
3.
TECHNICAL DESCRIPTION OF THE SUPPLY
As part of the LHC accelerator chain and in the frame of the Large Hadron Collider Upgrade
project, an increase of the particle energy from the present 1.4 GeV to 2 GeV of the Booster has
been foreseen. This increase in energy of the particles requires a proportional increase of the power
ratings of the main power supply.
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3.1
New Main Power System for PS Booster
A consolidation program for the main power supply (MPS) has been launched (known as
Booster 2 GeV project), with the objective to design and build a new MPS.
To accommodate the energy upgrade and to keep the existing dipole magnet isolation levels, the
existing magnet ring will be split into two separate and independent circuits. The two new magnetic
circuits are identical and represent inductive loads of 96 mH and 250 mΩ each.
The MPS is constituted by three identical sets of main power converters (MPC) (Figure 2). Two are
used to supply the magnet strings and one is kept as spare system. Each MPC block is based on
medium voltage drive technology and consists of the Active Front End (AFE) rectifier and the
DC/DC output converter. This market survey refers to the supply of the three MPC.
MPS
MPC 1
DC/DC
DC
AFE
AC
DC
AC
DC
MPC 2
DC/DC
AFE
PS Booster
magnets – ring 1
PS Booster
magnets – ring 2
DC
AC
DC
AC
DC
MPC S
DC/DC
DC
AFE
AC
DC
AC
DC
Figure 2: Booster 2 GeV new main power system
3.1.1
Main Power Converter standard load cycle
The operating conditions of the MPC are reported in Figure 3. The current in the load magnets runs
from 500 A to 6000 A and back to 500 A in 1.2 s.
The cycle is used for dimensioning of the main power converters. The cycle is executed every 1.2 s,
non-stop around the clock, 11 months per year.
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Magnet current
Magnet voltage
Figure 3: MPC standard load cycle
3.1.2
Energy exchange
In order to limit the instantaneous power (peak power) taken from the 18 kV AC network, a DC
storage capacitor will be used as energy storage. The capacitors provide the energy required by the
Booster magnets during pulsed operation (Figure 5). During this energy exchange voltage across
capacitors varies from 3000 V to 5000 V during each cycle as depicted in Figure 4.
With this approach, the peak power drawn from the AC network is limited to 3 MW compared to
the instantaneous peak power of 18 MW.
Magnet current
Capacitor voltage
Magnet voltage
Figure 4: MPC storage capacitor discharge cycle
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Magnet power
AFE power
Storage power
Figure 5: MPC power flow conditions
3.2
Scope of the supply
The supply shall include the design, manufacture, factory tests and delivery of three identical
18 MW medium voltage power converters required to supply the Booster 2 GeV dipole magnets.
In addition, 20% of spare components shall be provided as part of the contract.
For each converter the following (indicated by red dotted rectangles in Figure 6) shall be supplied:
•
AFE converter with associated filtering elements;
•
DC/DC converters with associated filtering elements;
•
AC inductor;
•
Decoupling inductors;
•
Output filter.
The supply shall not include:
•
DC storage capacitor;
•
Power transformer;
•
Control system;
•
Cooling system;
•
Installation on site.
3.3
Main Power Converter topology
The proposed topology for the three Booster 2 GeV MPC is shown in Figure 6.
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AFE Converter
DC Storage
Capacitors
DC/DC Converter
Positive
DC/DC Converter
Negative
Ldiff
Ldiff
AC Inductor
In1
In2
In3
Ip1
Ip2
Ip3
Decoupling
Inductors
Lfilter
Lfilter
Power
Transformer
Rcc
C EMI
2xCf
2xCf
Rfx
Cfx
Output
Filter
L crowbar
Figure 6: MPC topology of one converter
Each of the three converter units shall be composed of the following components:
a) One power transformer 18/2 kV 2.5 MVA (not included in the scope of supply)
b) One AC/DC Active Front End (AFE) sinusoidal rectifier.
This converter will rectify the AC voltage and control the power flow from AC to DC side with
unity power factor. The AC current harmonic distortion will be kept very low by means of the input
AC inductors. In addition the inductors shall limit/reduce the dv/dt generated by the AFE converter.
c) One DC storage capacitor required for energy exchange with the Booster magnets (not
included in the scope of supply)
The DC storage capacitor will provide energy to the magnets during the current rise and operate as
an energy sink when the current decreases. This strategy decouples the instantaneous power
required by the magnets from the AC network (see § 3.1.2).
d) One DC/DC converter that controls the output voltage across the magnets
The DC/DC converter shall consist of two identical power modules, each of them consisting of
a 3-leg H-bridge. The legs will be interleaved in order to reduce the output voltage/current ripple
and increase the current capability of the DC/DC converter. The three legs shall be connected by
coupling inductors.
e) One output filter and crowbar protection
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The output filter shall have a second order parallel damped structure. This shall reduce the voltage
ripple, and hence the current ripple in the dipole magnets. A crowbar protection system shall be
employed to discharge the magnet energy in case of emergency.
3.3.1
AFE and DC/DC topology
The three-level Neutral Point Clamped (NPC) topology shall be used as the internal power structure
both for the AFE and DC/DC power modules as shown in Figure 7.
Power Module
Power leg
G1
D1
G2
D2
G3
D3
G4
D4
Dp
AC/DC
DC
AC
Dn
Figure 7: MPC power module - leg topology
3.3.2
Control system
CERN will provide the control system (hardware and software) for both AFE and DC/DC
converter. The control system will be centralized and will provide the Pulse Width Modulated
(PWM) gating signals to all required switching components (converters and crowbar). The
simplified schematic of the CERN control system is shown in Figure 8.
The voltage reference will be generated by the Function Generator Controller FGC3 using
measured magnetic field or current. The voltage regulation is then implemented in the DSP part of
the CERN regFGC3 control crate. The IGBT switching signals are then generated on the DSP board
and transmitted to the IGBT transceiver card.
The interface with the power converter will be agreed with the contractor at a later stage.
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BOOSTER 2GeV POWER PLANT
VS_REGULATION_DSP AFE
GPS TIME
Voltage
Regulation
VS_IGBT_TRANSCEIVER AFE
PWM
Logic
Fibre
Optics
AFE IGBT pulses
AFE IGBT
Driver Interface
DCDC IGBT pulses
DCDC IGBT
Driver Interface
SYNCHRONIZATION
FGC3
Remote
Control
VS_REGULATION_DSP DCDC
B-field/ Current
Regulation
Voltage
Regulation
PWM
VS_IGBT_TRANSCEIVER DCDC
Logic
Fibre
Optics
Measurements
INTERLOCK
STATE CONTROL
LOCAL HMI
PLC
MCB,
PRECHARGE,
FAST LOOP,
Digital I/O
Figure 8: MPC control system
3.3.3
Cooling system
CERN will provide the cooling of the MPC converters. Direct cooling of the converters (pumps are
not required as part of the converter) will be provided by CERN. The standard demineralised water
with conductivity of 0.5 µS/cm will be used as a coolant (as normally required for a converter of
similar power range).
3.4
Technical Requirements
The power system (all elements specified in the scope of supply) shall be designed, produced and
tested by the contractor, based on the working load specified by CERN.
This power system shall be built with a modular concept to facilitate the operation and exploitation
of the system.
The supply shall be in conformity with the following requirements:
•
Connection of switches in series or parallel is not allowed. Therefore one switch shall be
represented by one component;
•
The switches shall use press-pack technology: namely IGBT, IEGT or IGCT.
The power converters will be installed indoors in a dedicated building.
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3.5
Ratings
The converter design shall be rated based on the parameters as given in Table 1:
Parameter
Value
Rated voltage of power transformer
18 kV / 2 kV
Rated power of power transformer
2.5 MVA
Rated voltage of DC storage capacitor (max/min)
5 kV / 3 kV
Rated DC/DC converter output voltage
± 3 kV DC
Rated DC/DC converter output current peak/rms
6 kA / 2.4 kA
Converter leg rated current peak/rms
2 kA / 0.8 kA
Insulation level
7.2 kV AC RMS (1 min)
Rated capacitance of each DC storage capacitor
0.3 F
PS Booster dipole magnet resistance
250 mΩ
PS Booster dipole magnet inductance
96 mH
Table 1: MPC design parameters
3.6
Testing requirements
The contractor shall perform all routine and type tests, and provide the corresponding test
certificates.
The tests shall include the following:
Routine test:
•
Drive test on inductive load at nominal current;
•
Stack/leg nominal current and voltage test at power factor 1;
•
Insulation tests of the MPC.
Type tests:
•
Heat run test;
•
Short circuit test.
4.
PROVISIONAL DELIVERY SCHEDULE
4.1
Provisional delivery schedule
The contract is scheduled to be awarded in September 2015. Further to notification of the award of
contract, the supply shall be delivered to CERN according to the following provisional schedule:
1st batch (1st MPC):
nd
nd
June 2017
2 batch (2 MPC):
August 2017
3rd batch (3rd MPC):
October 2017
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4.2
Contract Follow-up and Progress Monitoring
The contractor shall assign a person responsible for the technical execution of the contract and its
follow-up, as well as a person responsible for the commercial follow-up, throughout the duration of
the contract. They shall be able to communicate in one of the official languages of CERN (English
or French).
5.
CERN CONTACT PERSONS
Persons to be contacted for technical matters:
Name/Department/Group
Gregory Skawinski TE/EPC
Fulvio Boattini TE/EPC
Tel-Fax
Tel:
+41 22 767 3085
Fax:
+41 22 767 5300
Tel:
+41 22 767 8542
Fax:
+41 22 767 5300
Tel:
+41 22 767 3474
Fax:
+41 22 767 5300
Email
[email protected]
[email protected]
In case of absence:
Karsten Kahle TE/EPC
[email protected]
Persons to be contacted for commercial matters:
Name/Department/Group
Ivo Lobmaier
Tel-Fax
Tel:
+41 22 767 2025
Fax:
+41 22 766 9948
Tel:
+41 22 766 2532
Fax:
+41 22 766 9279
Email
[email protected]
In case of absence:
Boi-Lan Nguyen Lemoine
[email protected]