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Power Converter Characteristics
Design & Operation Responsibles
Power Converter ArchitectureThis Power Converter is used in LHC Machine to power superconductive magnets. It is located in the LHC underground installation, close to the loads to limit cable losses in the underground installation. Different parts were designed and produced separately, Power Converter being finally integrated in a housing rack, with 3 main parts:
Power Converter simplified Architecture .ppt
Power PartA high current switch mode power converter, designed for powering of superconducting loads requiring only positive current and positive voltage control (1 quadrant). The converter is constructed from a modular architecture composed of 3.25kA power modules. The converter is water cooled, and is thus ideally suited to situations where air losses must be carefully managed. Designed for underground operation, extensive remote diagnostics have been foreseen to allow efficient monitoring and fault diagnostics without requiring being present locally.
Power Converter is normally assembled using a n+1 Power Bricks [+3.25kA +18V] to provide active redundancy in case of one subconverter is lost. [+20.5kA +18V] Power Converter is composed of 8x [+3.25kA +18V] Power Brick, working as current source being controlled by a Voltage Source main control. [3.25kA 18V] Sub-Converter simplified Architecture / Topology .vsd Power Brick is actually a high frequency current source (7-8kHz) controlled by a 1kHz bandwidth voltage loop. One can notice that Power Brick is actually a current cource in its structure, even if voltage source capacitors are located in this block for mechanical reasons. Representation below gives a symbolic structure of the power converter, clarifying the cascade loops. [20.5kA 18V] Voltage Source simplified Architecture / Topology .vsd
Control PartControl & regulation principles are summarized in a detailled schematics representating only the part involved in the output current regulation scheme. 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).
Magnet ProtectionPower 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:
Power Converter Components .vsdA power converter is actually a sum of different equipments under several different sections in the SY-EPC group. The modularity is a key factor for easier maintenance with regards to LHC tunnel access conditions.
Magnet Types
Machine Installation
Production Contract & Contact History
Converter Circuit Names
To be completed ...
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