Author: King, Q.
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MOPGF090 Control of Fast-Pulsed Power Converters at CERN Using a Function Generator/Controller 281
 
  • R. Murillo-Garcia, Q. King, M. Magrans de Abril
    CERN, Geneva, Switzerland
  
  The elec­tri­cal power con­verter group at CERN is re­spon­si­ble for the de­sign of fast-pulsed power con­vert­ers. These gen­er­ate a flat-top pulse of the order of a few mil­lisec­onds. Con­trol of these power con­vert­ers is or­ches­trated by an em­bed­ded com­puter, known as the Func­tion Gen­er­a­tor/Con­troller (FGC). The FGC is the main com­po­nent in the so-called RegFGC3 chas­sis, which also houses a va­ri­ety of pur­pose-built cards. En­sur­ing the gen­er­a­tion of the pulse at a pre­cise mo­ment, typ­i­cally when the beam passes, is para­mount to the cor­rect be­hav­iour of the ac­cel­er­a­tor. To that end, the tim­ing dis­tri­b­u­tion and pos­te­rior han­dling by the FGC must be well de­fined. Also im­por­tant is the abil­ity to pro­vide op­er­a­tional feed­back, and to con­fig­ure the FGC, the con­verter, and the pulse char­ac­ter­is­tics. This paper pre­sents an overview of the sys­tem ar­chi­tec­ture as well as the re­sults ob­tained dur­ing the com­mis­sion­ing of this con­trol so­lu­tion in CERN's new Linac4.  
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WEC3O02 The Phase-Locked Loop Algorithm of the Function Generation/Controller 624
 
  • M. Magrans de Abril, Q. King, R. Murillo-Garcia
    CERN, Geneva, Switzerland
  
  This paper de­scribes the phase-locked loop al­go­rithms that are used by the real-time power con­verter con­trollers at CERN. The al­go­rithms allow the re­cov­ery of the ma­chine time and events re­ceived by an em­bed­ded con­troller through World­FIP or Eth­er­net-based field­buses. Dur­ing nor­mal op­er­a­tion, the al­go­rithm pro­vides less than 10 μs of time pre­ci­sion and 0.5 μs of clock jit­ter for the World­FIP case, and less than 2.5 μs of time pre­ci­sion and 40 ns of clock jit­ter for the Eth­er­net case.  
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WEPGF106 CCLIBS: The CERN Power Converter Control Libraries 950
 
  • Q. King, K.T. Lebioda, M. Magrans de Abril, M. Martino, R. Murillo-Garcia
    CERN, Geneva, Switzerland
  • A. Nicoletti
    EPFL, Lausanne, Switzerland
  
  Ac­cu­rate con­trol of power con­vert­ers is a vital ac­tiv­ity in large physics pro­jects. Sev­eral dif­fer­ent con­trol sce­nar­ios may co­ex­ist, in­clud­ing reg­u­la­tion of a cir­cuit's volt­age, cur­rent, or field strength within a mag­net. De­pend­ing on the type of fa­cil­ity, a cir­cuit's ref­er­ence value may be changed asyn­chro­nously or syn­chro­nously with other cir­cuits. Syn­chro­nous changes may be on de­mand or under the con­trol of a cyclic tim­ing sys­tem. In other cases, the ref­er­ence may be cal­cu­lated in real-time by an outer reg­u­la­tion loop of some other quan­tity, such as the tune of the beam in a syn­chro­tron. The power stage may be unipo­lar or bipo­lar in volt­age and cur­rent. If it is unipo­lar in cur­rent, it may be used with a po­lar­ity switch. De­pend­ing on the de­sign, the power stage may be con­trolled by a fir­ing angle or PWM duty-cy­cle ref­er­ence, or a volt­age or cur­rent ref­er­ence. All these dif­fer­ent cases are sup­ported by the CERN Con­verter Con­trol Li­braries (CCLIBS), which are open-source C li­braries that in­clude ad­vanced ref­er­ence gen­er­a­tion and reg­u­la­tion al­go­rithms. This paper in­tro­duces the li­braries and re­views their ori­gins, cur­rent sta­tus and fu­ture.  
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