Multilevel inverters for renewable energy systems

dc.contributor.advisorBarendse, Paul
dc.contributor.authorChiwaridzo, Pride
dc.date.accessioned2022-08-30T07:32:01Z
dc.date.available2022-08-30T07:32:01Z
dc.date.issued2018
dc.date.updated2022-07-14T10:35:18Z
dc.description.abstractVoltage source inverters have become widely used in the last decade primarily due to the fact that the dangers and limitations of relying on fossil fuel based power generation have been seen and the long term effects felt especially with regards to climate change. Policies and targets have been implemented such as from the United Nations climate change conference (COPxx) concerning human activities that contribute to global warming from individual countries. The most effective way of reducing these greenhouse gases is to turn to renewable energy sources such as the solar, wind etc instead of coal. Converters play the crucial role of converting the renewable source dc power to ac single phase or multiphase. The advancement in research in renewable energy sources and energy storage has made it possible to do things more efficiently than ever before. Regular or 2 level inverters are adequate for low power low voltage applications but have drawbacks when being used in high power high voltage applications as switching components have to be rated upwards and also switch between very high potential differences. To lessen the constraints on the switching components and to reduce the filtering requirements, multilevel inverters (MLI's) are preferred over two level voltage source inverters (VSI's). This thesis discusses the implementation of various types of MLI's and compares four different pulse width modulation (pwm) techniques that are often used in MLI under consideration: three, five, seven and nine level inverters. Harmonic content of the output voltage is recorded across a range of modulation indices for each of the three popular topologies in literature. Output from the inverter is filtered using an L only and an LC filter whose design techniques are presented. A generalized prediction algorithm using machine learning techniques to give the value of the expected THD as the modulation index is varied for a specific topology and PWM switching method is proposed in this study. Simulation and experimental results are produced in five level form to verify and validate the proposed algorithm.
dc.identifier.apacitationChiwaridzo, P. (2018). <i>Multilevel inverters for renewable energy systems</i>. (). ,Faculty of Engineering and the Built Environment ,Department of Electrical Engineering. Retrieved from http://hdl.handle.net/11427/36740en_ZA
dc.identifier.chicagocitationChiwaridzo, Pride. <i>"Multilevel inverters for renewable energy systems."</i> ., ,Faculty of Engineering and the Built Environment ,Department of Electrical Engineering, 2018. http://hdl.handle.net/11427/36740en_ZA
dc.identifier.citationChiwaridzo, P. 2018. Multilevel inverters for renewable energy systems. . ,Faculty of Engineering and the Built Environment ,Department of Electrical Engineering. http://hdl.handle.net/11427/36740en_ZA
dc.identifier.ris TY - Master Thesis AU - Chiwaridzo, Pride AB - Voltage source inverters have become widely used in the last decade primarily due to the fact that the dangers and limitations of relying on fossil fuel based power generation have been seen and the long term effects felt especially with regards to climate change. Policies and targets have been implemented such as from the United Nations climate change conference (COPxx) concerning human activities that contribute to global warming from individual countries. The most effective way of reducing these greenhouse gases is to turn to renewable energy sources such as the solar, wind etc instead of coal. Converters play the crucial role of converting the renewable source dc power to ac single phase or multiphase. The advancement in research in renewable energy sources and energy storage has made it possible to do things more efficiently than ever before. Regular or 2 level inverters are adequate for low power low voltage applications but have drawbacks when being used in high power high voltage applications as switching components have to be rated upwards and also switch between very high potential differences. To lessen the constraints on the switching components and to reduce the filtering requirements, multilevel inverters (MLI's) are preferred over two level voltage source inverters (VSI's). This thesis discusses the implementation of various types of MLI's and compares four different pulse width modulation (pwm) techniques that are often used in MLI under consideration: three, five, seven and nine level inverters. Harmonic content of the output voltage is recorded across a range of modulation indices for each of the three popular topologies in literature. Output from the inverter is filtered using an L only and an LC filter whose design techniques are presented. A generalized prediction algorithm using machine learning techniques to give the value of the expected THD as the modulation index is varied for a specific topology and PWM switching method is proposed in this study. Simulation and experimental results are produced in five level form to verify and validate the proposed algorithm. DA - 2018_ DB - OpenUCT DP - University of Cape Town KW - Harmonics KW - machine learning KW - multilevel inverter KW - PWM LK - https://open.uct.ac.za PY - 2018 T1 - Multilevel inverters for renewable energy systems TI - Multilevel inverters for renewable energy systems UR - http://hdl.handle.net/11427/36740 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/36740
dc.identifier.vancouvercitationChiwaridzo P. Multilevel inverters for renewable energy systems. []. ,Faculty of Engineering and the Built Environment ,Department of Electrical Engineering, 2018 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/36740en_ZA
dc.language.rfc3066eng
dc.publisher.departmentDepartment of Electrical Engineering
dc.publisher.facultyFaculty of Engineering and the Built Environment
dc.subjectHarmonics
dc.subjectmachine learning
dc.subjectmultilevel inverter
dc.subjectPWM
dc.titleMultilevel inverters for renewable energy systems
dc.typeMaster Thesis
dc.type.qualificationlevelMasters
dc.type.qualificationlevelMSc
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