Design of modular multi-level converter and permanent magnet synchronous generator-based wind energy conversion system

Wind is the important type of clean energy originated from sun. Wind energy conversion systems are important actors in developing smartgrids and microgrids. On the other hand, wind energy is a premier resource which has been one of the world's fastest growing renewables for producing clean electrical energy. Due to higher efficiency, reliability, and controllability, nowadays, variable speed wind turbines employing permanent magnet synchronous generators (PMSG) have been extensively adopted as the major source for power generation in wind energy conversion systems. As the power and voltage levels increase, utilizing multi-level converters are inevitable due to the salient features such as redundancy, high flexibility, low switching losses, low harmonic content, and less electromagnetic interference. Among multi-level converter topologies, modular multi-level converter (MMC) topology is a promising candidate which has been originally proposed for high voltage direct current transmission systems. The purpose of the thesis is to design, simulate, and validate a three-phase wind energy conversion system connected to the electric power grid. The overall system consists of a full-scale MMC and PMSG with no gearbox. In MMC topology, the capacitor voltage balancing problem is solved by a closed-loop control. Various case studies have been conducted in a simulation platform to verify the overall model of the proposed system.