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چكيده انگليسي :

Application of Finite States Predictive Control Technique in Hybrid Active Filters Mehrdad Chapariha chapariha@ec iut ac ir Date of Submission 2009 05 9 Department of Electrical and Computer Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language FarsiSupervisor Hamidreza Karshenas karshen@cc iut ac irAbstract In this thesis after a survey on harmonic problems and different harmonic mitigation techniques Hybrid Active Power Filters HAPFs are studied HAPFs are a newer kind of filters used to controlharmonics in power systems These filters are made by combining passive and active filters to preventresonance of passive filter while obtaining better filtering quality with a small rated inverter Anintroduction to passive and active filters is given and some methods used to combine these filters arediscussed There are two commonly used types of HAPFs the first is an active part in series with powersource in addition to a parallel passive filter the second one or parallel HAPF is a series combination of anactive and a passive part installed in parallel to the load Different control approaches for these commontypes are presented With mathematical equations using circuit theory in addition to time based simulations these common HAPFs are compared together Reasons for more trends in using the parallel HAPF arediscussed The parallel HAPF is chosen for more studies especially in control methods Since in most casesparallel filters are used to inject or sink current harmonics a current control technique which is based oncurrent prediction by using the load model is studied There is a chapter on this approach which is namedFinite States Predictive Current Control This current control technique has been used in different powerelectronics and electric drives applications and has shown very good performance The method is discussedfor current control of single and three phase loads A laboratory model is used to verify the method inpractice by using a TMS320F28016 Digital Signal Processor DSP unit Some methods are proposed tosimplify calculations for the DSP unit In addition a technique to estimate the unknown model in practice isproposed and implemented The method can estimate the model by applying test signals inverter outputvoltage and reading the output load current Signal filtering is an indispensable part of active filtering There are two common filters used to extracta single frequency from a signal Single frequency filtering by using the Synchronous Rotating Frame SRF and the Instantaneous p q Theory are the most commonly used methods that are discussed andcompared together also their similarities are shown in block diagrams After that a control approach for theparallel HAPF is proposed This method controls the filter current directly similar to a pure active powerfilter but only for harmonic frequencies The approach is simply using aforementioned filters to removefundamental frequency from feedback loop By this method similar to the common control method whichis used by most authors a small rated inverter is enough for current control The simulation results showthat this approach has almost the same result as the common control approach The proposed controlmethod is more developed in a way that full filter current is feed back in the current control loop Thismethod can provide better results if the aforementioned predictive control approach is used as currentcontroller While this developed direct current control is simpler than the other direct current controlmethod proposed by some other authors it can provide similar or better quality than common controlmethod Time based simulations on a 6 3KV system with a combination of a linear load and a none linearload are used to verify the idea and the performance of proposed control methods by using proportional andpredictive controllers Furthermore a unified control approach based on finite states predictive control is

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كاربرد كنترل پيش بين با حالات محدود در فيلترهاي اكتيو هيبريد موازي

پردازنده هاي سيگنال ديجيتال ﴿DSP ﴾ , كنترل يكپارچه , تئوري p-q لحظه اي , فيلتر كردن با دستگاههاي گردان , آلودگي هاي هارمونيكي