Analysis of power converter topologies to improve the power quality of wind energy conversion systems

Abstract

In order to prevent the natural environment on the earth, the development of clear energy without pollution has the major representative role in the last decade. By accompanying the of Kyoto protocol, clear energies, such as Fuel Cell (FC), photovoltaic (PV), wind energy, etc., have been rapidly promoted. Nowadays wind energy systems have been used for electricity generation from small house hold consumers to large factories. Investors have started to prefer the establishment of large wind energy systems due to cost, performance and power requirements advantages. There are two types of Wind Energy Conversion Systems (WECS) such as variable speed WECS and fixed speed WECS. The normally used type is fixed speed WECS. But it needs excitation and bi-directional power flow controller. Nowadays, variable speed WECS associated with Power Electronic Converter (PEC) is preferred because of its ability to control the wind power efficiently and effectively. The WECS use various types of generators viz the Permanent Magnet Synchronous Generator (PMSG), Doubly Fed Induction Generator (DFIG) and Squirrel Cage Induction Generator (SCIG) etc. Among the different type of generators, the PMSG combined with PEC is more suitable for variable speed WECS. This thesis deals with PMSG fed with different types of power converter topologies and their control techniques to boost the output voltage and reduce the Total Harmonic Distortion (THD) of WECS. Traditional power converter circuits have three stages of power conversion and are the rectifier, DC-DC boost converter, and Pulse Width Modulation (PWM) inverter. Normally, the WECS have used the three stage power conversion system to achieve the required load voltage and load frequency from the continuously varying generated voltage. The main focus of this research is on reducing the power conversion stages of variable speed WECS using the efficient power converter. newline