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Power Converter Characteristics
Involved Peoples
Power Converter ArchitectureThis Power Converter is used for powering HL-LHC Superconductive Magnets, and for DC applications. Different parts were designed and produced separately, with the option of a 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 positive current only, operating in 1 quadrants. Constructed from a modular architecture composed of 07..08 x [+2 kA; +08 V] power modules (active redundancy in a n+1 configuration). Primary use is in HL-LHC particle accelerator. 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. Additionnal free wheeling diodes located in the Power Rack always provide a current path, independent of the converter status.
Power Converter is normally assembled using a n+1 Power Bricks [+2 kA; +08 V] to provide active redundancy in case of one subconverter is lost. A [+14 kA; +08 V] is composed of 8x [+2 kA; +08 V] Power Bricks, working as current source being controlled by a Voltage Source main control. [2 kA; 08 V] Sub-Converter simplified Architecture / Topology .vsd Power Brick is actually a high frequency current source (7-8 kHz) controlled by a 1 kHz bandwidth voltage loop, even if voltage source capacitors are located in the current source block for mechanical reasons. Representation below gives a symbolic structure of the power converter, clarifying the cascade loops. ( Is1 & Is2 are actually assumed to be representative and equal to the current of each power transformer secondaries). The multiplication of rectifier stages in each output module gives the following advantages: easier design of magnetic parts, lower rating fuse (lower losses) to protect whole Power Converter being short-circuited by a faulty secondary (fuse would immediately blow in case one of the schottky dies, giving the possibility to the whole power converter to reconfigure the current level in other current sources to maintain required voltage level). [2 kA; +08 V] n+1 redundant Voltage Source simplified Architecture / Topology .vsd Redundance operation relies mainly on each [2 kA; 08 V] inner current source reactivity, so that load output current is not impacted by the loss of one sub. Of course a sudden short at the level of the output stage of a sub converter will likely lead to a converter global fault stop, despite the presence of output fuse. No fault - Sub Fault Transition - Sub Fault state Power converter redundance .vsd
Control PartControl & 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 schematic 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 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.
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. Power Converter is built through two Power Racks. One contains the six Sub-Converter Power Modules, when the second one includes the converter crowbar and DC-contactor systems, the converter power part control electronic, the FGC complete Electronic Chassis, the two DCCTs head and their electronics.
Magnet Types
Machine Installation
Production Contract & Contact History
Converter Circuit Names
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