Thesis
Multilevel Voltage-Sourced Converters for Grid Applications
Washington State University
Master of Science (MS), Washington State University
12/2015
Handle:
https://hdl.handle.net/2376/103141
Abstract
The growing demand for the integration of power electronic converters to the electrical power systems necessitates the development of multilevel power electronic converters with high-quality output voltages that can meet the grid codes. This thesis studies the commercial multilevel converter structures and introduces a new multilevel converter topology that consists of a traditional two-level converter and an asymmetrical cascaded H-bridge (A-CHB) converter. The proposed granular multilevel converter (GMC) needs only one DC voltage source and has a scalable structure. Scalability allows for an easy change in the voltage rating of the GMC or the number of the voltage steps it can construct. Addition of H-bridge modules to a GMC results in an exponential increase in the number of the steps of its output voltage. Thus, with a small number of components, a GMC can offer a highquality AC voltage that meets the grid codes. Two switching strategies are proposed to control the output voltage and the voltages of H-bridge capacitors. An algorithm for sizing the H-bridge capacitors is also proposed, which minimizes the ripple on the output voltage of the GMC. This thesis also studies two possible applications of the proposed GMC. In the first application, the GMC is used as the power electronic interface of a renewable energy resource and a variable-frequency vehicular power system. The proposed controller structure facilitates a smooth transition of the GMC from one operating mode to the other. In the second application, the GMC is used as a static synchronous compensator (STATCOM) which injects specifies values of the reactive power to the grid. A simplified GMC structure that is specifically suitable for STATCOM applications is suggested, and the controllers of the simplified GMC-based STATCOM are proposed.
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Details
- Title
- Multilevel Voltage-Sourced Converters for Grid Applications
- Creators
- Saleh Ziaieinejad
- Contributors
- Ali Mehrizi-Sani (Chair)Anjan Bose (Committee Member) - Washington State University, Electrical Engineering and Computer Science, School ofANURAG K. SRIVASTAVA (Committee Member) - Washington State University, Electrical Engineering and Computer Science, School of
- Awarding Institution
- Washington State University
- Academic Unit
- Electrical Engineering and Computer Science, School of
- Theses and Dissertations
- Master of Science (MS), Washington State University
- Publisher
- Washington State University; [Pullman, Washington] :
- Number of pages
- 96
- Identifiers
- 99900525032001842
- Language
- English
- Resource Type
- Thesis