Power Systems Krzysztof Sozański Digital Signal Processing in Power Electronics Control Circuits Second Edition Power Systems More information about this series at http://www.springer.com/series/4622 ń Krzysztof Soza ski Digital Signal Processing in Power Electronics Control Circuits Second Edition 123 Krzysztof Sozański Institute of Electrical Engineering University of ZielonaGóra ZielonaGóra Poland ISSN 1612-1287 ISSN 1860-4676 (electronic) Power Systems ISBN978-1-4471-7331-1 ISBN978-1-4471-7332-8 (eBook) DOI 10.1007/978-1-4471-7332-8 LibraryofCongressControlNumber:2017938127 ©Springer-VerlagLondonLtd.2013,2017 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpart of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission or information storage and retrieval, electronic adaptation, computer software, or by similar or dissimilarmethodologynowknownorhereafterdeveloped. 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Theregisteredcompanyaddressis:236Gray'sInnRoad,LondonWC1X8HB,UnitedKingdom This book is dedicated to my dear parents Maria and Kazimierz, and my darling children, Anna, Mateusz and Andrzej. Preface Preface to the Second Edition The first edition of the book was one of the elements of my habilitation (a quali- fication above a Ph.D., which is a necessary step for obtaining the title of a professor in Poland and other European countries), and as a result it was subse- quently very carefully reviewed by four reviewers. The habilitation was a success. Using the insightful comments from my reviewers, I have improved the current version and eliminated some typographic errors that were initially overlooked. Thisbookisbased onthefirst edition ofthebookandbesidessomechangesto thepreviousmaterial,therearesomenewelementsIincludeinthenewedition.In particular, I add more MATLAB listings, which would further complement and enrich the text by providing worked examples of the solutions proposed in the book. More figures are added and all the existing ones are revised and in color. Mynewsolutionforashuntactivepowerfilterisalsoincludedinthenewedition. All those changes are introduced in the Chapters from the first edition. This book also includes a new Chapter considering selected problems of sim- ulation of power electronic systems together with digital control circuits. These simulations are conducted using MATLAB and PSIM. In the case of the PSIM programs, the considered methods use C code for describing the digital control algorithm. I have written this book in his endeavor to abide by the following maxim nulla dies sine linea $ nie ma dnia bez kreski $ not a day without a line drawn (Apelles, Greek painter, flourished 4th century bc). However, this is not always easily achieved. Zielona Góra, Poland Krzysztof Sozański February 2017 vii viii Preface Preface to the First Edition Powerelectronicscircuitsarebecomingincreasinglyimportantinthemodernworld due to the rapid progress in developments of microelectronics in areas such as microprocessors, digital signal processors, memory circuits, complementary metal-oxide-semiconductors, analog-to-digital converters, digital-to-analog con- verters and power semiconductors—especially metal-oxide-semiconductor field-effect transistors and insulated gate bipolar transistors. Specifically, the development of power transistors has shifted the range of applications from a few amperes and hundreds of volts to several thousands ofamperesandafewkilovolts,withaswitchingfrequencymeasuredinmillionsof hertz. Power electronics circuits are now used everywhere: in power systems, industry, telecommunications, transportation, commerce, etc. They even exist in suchmodernpopulardevicesasdigitalcameras,mobilephones,andportablemedia players.Powerelectronicsarealsousedinmicropowercircuits,especiallyinenergy harvesting circuits. In the early years of power electronics, in the sixties and seventies, analog control circuits were most commonly used, meaning that only the simplest control algorithms could be applied. Some years later, in the eighties and early nineties, hybrid control circuits were used, which consisted of both analog and digital components. In subsequent years there followed a slow transition to fully digital- ized control systems, which are currently widely used and enabled the application of more complex digital signal processing algorithms. In this book the author considers signal processing, starting from analog signal acquisition, through its conversion to digital form, methods of its filtration and separation, and ending with pulse control of output power transistors. The author has focused on two applications for the considered methods of digital signal pro- cessing: an active power filter and a digital class-D power amplifier. Bothapplicationsrequireprecisedigitalcontrolcircuitswithveryhighdynamic range of control signals. Therefore, in the author’s opinion these applications will provide very good illustrations for the considered methods. In this book the author’s original solutions for both applications are presented. In the author’s opinion the adopted solutions can also be extended to other power electronics devices. The discussion of the first application, APF, starts with the analysis of first harmonicdetectorsbasedon:IIRfilter,wavedigitalfilters,slidingDFTandsliding Goertzel,movingDFT.Followingthat,author’simplementationofclassicalcontrol circuits based on p(cid:2)q algorithm is presented. Next, the dynamics of APF is considered. Dynamic distortion of APF makes it impossible to fully compensate line harmonics. In some cases, the line current THD ratio for systems with APF compensation canreach avalue ofadozenor sopercent.Therefore theauthor has dealt with this problem by proposing APF models suitable for analysis and simu- lation of this phenomenon. For predictable line current changes, it is possible to develop a predictable control algorithm to eliminate APF dynamics compensation Preface ix errors.Inthefollowingsectionstheauthor’smodificationusingapredictivecircuit toeliminatedynamiccompensationerrorsisdescribed.Inthisbookcontrolcircuits withfilterbankswhichallowtheselectionofcompensatedharmonicsaredescribed. The considered filter banks are based on sliding DFT, sliding Goertzel, moving DFT and p(cid:2)q algorithm. ForunpredictablelinecurrentchangestheauthorhasdevelopedamultirateAPF. The presented multirate APF has a fast response for sudden changes in the load current. So, using multirate APF, it is possible to decrease the THD ratio of line current even for unpredictable loads. The second application is a digital class-D amplifier. Both APFs and the amplifiersareespeciallydemandingintermsofthedynamicsofprocessedsignals. However, in the case of a class-D amplifier, the dynamics reach 120 dB, which resultsinhighrequirementsforthetypeofalgorithmusedanditsdigitalrealization. The author has proposed a modulator with a noise shaping circuit for a class-D amplifier. Interpolators are also considered that allow for the increasing of the sampling frequency whilst maintaining a substantial separation of signal from noise.Theauthoralsopresentsanoriginalanalogpowersupplyvoltagefluctuation compensation circuit for the class-D amplifier. The class-D amplifier with digital clickmodulationisgivenspecialconsiderationtoo.Finally,two-wayandthree-way loudspeaker systems, designed by the author, are presented, where the signal from input to output is digitally processed. The great majority of the presented methods and circuits is the original work oftheauthor.ListingsfromMATLABorinClanguageareattachedtosomeofthe considered algorithms to make the application of the algorithms easier. The pre- sentedmethodsandcircuitscanbesuccessfullyappliedtothewholerangeofpower electronics circuits. Theissuesconcerningdigitalsignalprocessingarerelativelywidelydescribedin the literature. However, in the author’s opinion, there are very few publications combiningdigitalsignalprocessingandpowerelectronics,duetothefactthatthese two areas of knowledge have been developed independently over the years. The author hopes that this book will, to some extent, bridge the gap between digital signalprocessingandpowerelectronics.Thisbookmaybeusefulforscientistsand engineers who implement control circuits, as well as for students of electrical engineering courses. It may also be of some value to those who create new topologies and new power electronics circuits, giving them some insights into possible control algorithms. Zielona Góra, Poland Krzysztof Sozański December 2012 Acknowledgements I would like to thank the reviewers of my habilitation (in alphabetical order) Andrzej Dzielinski from Warsaw University of Technology, Boguslaw Grzesik from Silesian University of Technology, Gliwice, Adam Kempski from the University of Zielona Góra, Jan Mucko from University of Science and Technology, Bydgoszcz. Many thanks also to my English consultants, Peter Preston from the University ofZielonaGóraandmydaughterAnnaSozanskawhoisstudyingattheUniversity of Cambridge. I hope that I successfully applied all of your comments and corrections. Iwouldalsoliketothankeveryonewhosupportedmeduringthewritingofthis book. xi