Power Quality Analysis of Multilevel Inverters for HVDC Transmission Systems

Abstract

This dissertation is comprised of seven chapters. Exclusive summary of each chapter is described as following: • Chapter 1 includes a brief background of the dissertation topic, problem statement, aims, objectives, description of work done and achieved results. • Chapter 2 provides a literature review of the conventional inverter, multilevel inverter and three most common types (NPC, FC, and CHB) of the multilevel inverter along with some advantages, disadvantages, and applications. • Chapter 3 describes different types of control and modulation strategies that are required to control the switching of power semiconductor devices. • Chapter 4 is comprised of simulations of seven and nine levels of CHB inverter based on SPWM and SHE methods. Comparison Table of SPWM and SHE based simulation results show that the SHE method provided better results. • Chapter 5 includes the calculation of power losses for symmetric and asymmetric structures of seven and nine levels of CHB inverter. Asymmetric seven-level CHB inverter caused less power losses. • Chapter 6 is based on the results and discussion of simulated results. • Chapter 7 concludes the work done during this dissertation while indicating extensions of current research work for the upcoming future.