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Title:Three-Phase load current reconstruction using singleshunt current measurement and modified vector modulation for three-level DC-AC converter : doctoral dissertation
Authors:ID Kovačević, Haris (Author)
ID Milanovič, Miro (Mentor) More about this mentor... New window
Files:.pdf DOK_Kovacevic_Haris_2022.pdf (12,21 MB)
MD5: 6760A676DA4DB17D4A493599C4EF73A3
 
Language:English
Work type:Doctoral dissertation
Typology:2.08 - Doctoral Dissertation
Organization:FERI - Faculty of Electrical Engineering and Computer Science
Abstract:This doctoral thesis focuses on the development of Space Vector Modulation (SVM) techniques adjusted for single-shunt current measurement and applied to the three-level three-phase voltage source inverter. Based on the single-shunt current measurement, three-phase load currents are then reconstructed. An overview of existing multilevel topologies and their main operating principles is provided within the thesis. To evaluate proposed SVM techniques adjusted for single-shunt current measurement, a three-level three-phase diode clamped voltage source inverter topology is selected. The main advantages of the selected topology are high efficiency, reduced semiconductor stress, the low capacitance of DC-link capacitors, etc. To reconstruct the three-phase load currents, a single-shunt is positioned inside the middle branch of the DC-link. An overview of existing modulation techniques for two-level and multilevel inverters is provided within the thesis. To reconstruct three-phase load currents, three SVM methods are proposed within the thesis. Due to the lack of a current measurement window, while the voltage vector is positioned near sector or region boundary areas, additional modifications are required. The first SVM method shifts the SVM signals to ensure the minimum current measurement window needed for measurement with minimum additional vector injection. Such an approach ensures the high modulation index values greater than 0.8 with the smallest current ripple due to the SVM signal symmetry. The second method intentionally injects the colinear voltage vector into the existing vector combination to ensure the minimum time window required for current measurement. As a drawback, a smaller modulation index compared to the first method can be achieved. As an advantage, a very low modulation index of less than 0.2 can be achieved. The third method simplifies the second method by using a single SVM pattern. Such a method can be used only for very low modulation indexes and can be applied for two-level and three-level inverters. The proposed SVM methods are implemented within the Digital Signal Processor (DSP). Experimental results confirm the proper operation of the proposed methods applied to the three-level diode clamped voltage source inverter.
Keywords:single-shunt, three-level inverter, SVM modification, current reconstruction, vector injection
Place of publishing:Maribor
Place of performance:Maribor
Publisher:[H. Kovačević]
Year of publishing:2022
Number of pages:[ILV], 166 str.
PID:20.500.12556/DKUM-81473 New window
UDC:621.317.3:314.222(043.3)
COBISS.SI-ID:144864771 New window
Publication date in DKUM:09.03.2023
Views:396
Downloads:64
Metadata:XML DC-XML DC-RDF
Categories:KTFMB - FERI
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Licences

License:CC BY-ND 4.0, Creative Commons Attribution-NoDerivatives 4.0 International
Link:http://creativecommons.org/licenses/by-nd/4.0/
Description:Under the NoDerivatives Creative Commons license one can take a work released under this license and re-distribute it, but it cannot be shared with others in adapted form, and credit must be provided to the author.
Licensing start date:31.03.2022

Secondary language

Language:Slovenian
Title:Rekontrukcija trifaznih tokov bremena z meritvijo toka na souporu in uporabo modificirane vektorske modulacije za trinivojski DC-AC pretvornik
Abstract:Ta doktorska disertacija se osredotoča na razvoj tehnik prostorske vektorske modulacije (SVM), ki so prilagojene za merjenje enojnega bočnega toka in se uporabljajo za tristopenjski trifazni napetostni pretvornik. Na podlagi merjenja enojnega bočnega toka se nato rekonstruirajo trifazni tokovi bremena. V diplomskem delu je podan pregled obstoječih večnivojskih topologij in njihovih glavnih načel delovanja. Za oceno predlaganih tehnik SVM, prilagojenih za merjenje enojnega bočnega toka, je izbrana tristopenjska topologija trifaznega napetostnega izvornega inverterja z diodno sponko. Glavne prednosti izbrane topologije so visoka učinkovitost, manjša obremenitev polprevodnikov, majhna kapacitivnost kondenzatorjev DC-link itd. Za rekonstrukcijo trifaznih bremenskih tokov se v srednjo vejo povezave DC-link namesti enojni šunt. V disertaciji je podan pregled obstoječih modulacijskih tehnik za dvonivojske in večnivojske inverterje. Za rekonstrukcijo trifaznih bremenskih tokov so predlagane tri metode SVM. Zaradi pomanjkanja okna za merjenje toka, medtem ko se vektor napetosti nahaja v bližini mejnih območij sektorjev ali regij, so potrebne dodatne spremembe. Prva metoda SVM premakne signale SVM, da se zagotovi minimalno okno za merjenje toka, ki je potrebno za merjenje z minimalno dodatno injekcijo vektorja. Tak pristop zagotavlja visoke vrednosti modulacijskega indeksa, večje od 0,8, z najmanjšim valovanjem toka zaradi simetrije signalov SVM. Druga metoda namerno injicira kolinearni vektor napetosti v obstoječo kombinacijo vektorjev, da se zagotovi minimalno časovno okno, potrebno za merjenje toka. Kot pomanjkljivost je mogoče doseči manjši modulacijski indeks v primerjavi s prvo metodo. Prednost je, da se lahko doseže zelo majhen modulacijski indeks, manjši od 0,2. Tretja metoda poenostavi drugo metodo z uporabo enega samega vzorca SVM. Takšno metodo je mogoče uporabiti le za zelo nizke modulacijske indekse in jo je mogoče uporabiti za dvo- in tristopenjske inverterje. Predlagane metode SVM se izvajajo v digitalnem signalnem procesorju (DSP). Eksperimentalni rezultati potrjujejo pravilno delovanje predlaganih metod, uporabljenih za tristopenjski diodno vpet napetostni pretvornik.
Keywords:soupor, trinivojski razsmernik, modificirana vektorska modulacija, rekonstrukcija trifaznih tokov, injektiranje vektorjev


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