Increasing the operating area of shunt active filters by advanced nonlinear control

(整期优先)网络出版时间:2015-02-12
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ThisworkisaimedtorigorouslymanagevoltagesaturationandmaximumcurrentconstraintsinShuntActiveFilters.Inthisrespect,assuming'unconstrained'controlalgorithmshavealreadybeendefinedtoachievestandardobjectivesforsuchdevices(i.e.currenttrackingforharmoniccompensationandDC-busvoltageboundness),aplug-inunit,orientedtoextendthesystemoperatingregionandatthesametimepreservinggoodperformanceunderlargetransientsandoverloadconditions,ispresented.Thissolutionallowstoimproveavailability,robustnessandcomposabilityofShuntActiveFilters,whichareexpectedtobekeyfeaturesinpresentandnextgenerationcomplexandpossibly'smart'powergrids.Theproposedunitiscomposedbytwoparts.First,asuitableanti-windupstrategyisdefinedinordertodealwithcontrolinputsaturation.Itsmainpurposeistopreservetheoriginal'unconstrainederrordynamics',infaceofinputsaturation,whileguaranteeinglowcomputationalburdenandreducedperformanceimpairment(thelattergoal,inharmoniccompensationcontext,leadstorathernon-standardproblemformulation).Tothisaim,theanti-windupactsonthecurrentreferencesthroughasuitably-designedadditionaldynamics.Then,inordertocopewithcurrentlimitations,anadditionalstrategyhasbeendesigned;againthecurrentreferencesissuitablyshapedtocomplywiththefeaturesandboundsofthesystem,augmentedwiththeabove-mentionedanti-windupsolution.TheproposedschemecanbesimplyjoinedtoanykindofunconstrainedcontrolleradoptedtosteerShuntActiveFilters.Inthiswork,anInternal-Model-basedcurrentcontrollerisadoptedasabenchmarkcase.Theproposedapproachisvalidatethroughextensivesimulationtests.