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The control of a back-to-back power converter for small-scale reluctance synchronous generators in grid-connectedwind turbine systems
Thesis (MScEng)--Stellenbosch University, 2017.
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| Format: | Thesis |
| Language: | en_ZA |
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Stellenbosch : Stellenbosch University
2017
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| _version_ | 1867613898845192192 |
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| access_status_str | Open Access |
| author | Mitchell, Joshua Cole |
| author2 | Kamper, M. J. |
| author_browse | Kamper, M. J. Mitchell, Joshua Cole |
| author_facet | Kamper, M. J. Mitchell, Joshua Cole |
| author_sort | Mitchell, Joshua Cole |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (MScEng)--Stellenbosch University, 2017. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/101036 |
| institution | Stellenbosch University (South Africa) |
| language | en_ZA |
| last_indexed | 2026-06-10T12:43:27.297Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2017 |
| publishDateRange | 2017 |
| publishDateSort | 2017 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/101036 The control of a back-to-back power converter for small-scale reluctance synchronous generators in grid-connectedwind turbine systems Mitchell, Joshua Cole Kamper, M. J. Stellenbosch University. Faculty of Engineering. Dept. of Electrical and Electronic Engineering. Electric current converters Wind turbines Synchronous generators UCTD Thesis (MScEng)--Stellenbosch University, 2017. ENGLISH ABSTRACT: In this thesis several topics in the field of geared variable speed and fixed pitched wind turbine systems (WTS) are covered. The main focus is the layout of the power electronics and an alternative layout for small-scale WTS is introduced. This novel layout, implemented in both simulation and practice, is achieved by splitting the converters at their common DC bus and linking them through the wind turbine tower with a DC rated cable (DC-link). The grid-tie voltage source converter (VSC) is placed at ground level and the generator VSC is placed in the nacelle. DC bus voltage control is investigated in directly connected and DC-link-connected VSCs. Attention is paid to the DC bus dynamics, which is shown to be somewhat independent of the DC-link cable. Due to the strict standards for grid-tiedWT and PV systems the control, design and implementation of an LCL-filter grid-tie VSCs is detailed in this research and was used extensively in the practical measurements to inject the generated power into the grid. Although this DC-link topology can work with any back-to-back VSC-connected generator topology, a reluctance synchronous generator (RSG), which has great potential for small scale systems, was used in this thesis. A non-linear current controller and an energy efficient, finite element method-based, maximum torque per ampere (MTPA) strategy was implemented, along with a hybrid saliency-based position sensorless control (PSC) technique to allow operation over the entire speed range without an encoder. PSC and encoder control of the RSG with an output du/dt LC-filter was also investigated. A non-linear wind turbine controller that can operate seamlessly in both under-rated and above-rated wind conditionswas designed and implemented. This method uses maximum power point tracking (MPPT) and stall regulation to limit the systems power output without overloading the generator. AFRIKAANSE OPSOMMING: In hierdie tesis word verskeie onderwerpe i.v.m. geratte,wisselende gereelde windturbine sisteme (WTS) bespeek. Die hooffokus is die ontwerp van die elektronika en ’n alternatiewe ontwerp vir ’n kleinskaalse WTS word voorgestel. Hierdie nuwe ontwerp wat in die simulasie en die praktyk implementeer word, word moontlik gemaak deur om die omvormers by hulle gesamentlike gelykstroombus te splits en hulle deur middel van ’n gelykstroomkabel te verbind. Die netwerkgekonnekteerde kragbron-omvormer word op grondvlak geplaas, en die opwekker in die omhulsel. Die gelykstroom-busspanningsbeheer word ondersoek in die direkverbinde- en die gelykstroomverbinde omvormers. Aandag word geskenk aan die busdinamiekwat ietwat onafhanklik van die gelykstroomgeskakelde kabel is. Weens die streng standaarde vir die windturbines en die PV sisteme, word die beheer, ontwerp en implementering van die filter in netwerkgeskakelde omvormers in besonderhede beskryf en word dit gewoonlik gebruik om die opgewekte krag in die network in te spuit. Alhoewel hierdie gelykstroomskakel topologie met enige rug-aan-rug netwerkgeskakelde kragbron omvormer opwekker topologie kan werk, word ’n weerstands sinkroniese generator wat goeie potensiaal het in kleinskaalse sisteme in hierdie navorsing gebruik. ’n Nie-lineêre stroombeheerder en ’n doeltreffende (finite-element) metode met maksimum wringkrag per ampère strategie is geimplementeer, tesame met ’n (hybrid, saliency-based) sensorlose posisie beheer strategieomte verseker dat dit teen enige spoed sonder ’n enkodeerder kan werk. Sensorlose posisie- en enkodeerder beheer van die sinkroniese generatormet ’n opbrengs du/dt filter is ook ondersoek. ’n Nielineêre windturbine-beheerder wat goed onder alle wind-toestande kan werk is ontwerp en geïmplementeer. Hierdie metode maak gebruik van maksimum kragpuntopsporing sonder om die opwekker te oorlaai. 2017-02-14T10:02:02Z 2017-03-29T12:00:37Z 2017-02-14T10:02:02Z 2017-03-29T12:00:37Z 2017-03 Thesis http://hdl.handle.net/10019.1/101036 en_ZA Stellenbosch University 242 pages : illustrations application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Electric current converters Wind turbines Synchronous generators UCTD Mitchell, Joshua Cole The control of a back-to-back power converter for small-scale reluctance synchronous generators in grid-connectedwind turbine systems |
| title | The control of a back-to-back power converter for small-scale reluctance synchronous generators in grid-connectedwind turbine systems |
| title_full | The control of a back-to-back power converter for small-scale reluctance synchronous generators in grid-connectedwind turbine systems |
| title_fullStr | The control of a back-to-back power converter for small-scale reluctance synchronous generators in grid-connectedwind turbine systems |
| title_full_unstemmed | The control of a back-to-back power converter for small-scale reluctance synchronous generators in grid-connectedwind turbine systems |
| title_short | The control of a back-to-back power converter for small-scale reluctance synchronous generators in grid-connectedwind turbine systems |
| title_sort | control of a back to back power converter for small scale reluctance synchronous generators in grid connectedwind turbine systems |
| topic | Electric current converters Wind turbines Synchronous generators UCTD |
| url | http://hdl.handle.net/10019.1/101036 |
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