Using a Z-Source Inverter as Rotor Side Converter in Doubly-Fed Induction Generator Wind Energy Conversion System

Due to the increasing need of electrical energy and environmental issues corresponding to fossil fuels such as global warming, renewable energy sources attracted a lot of engineers and researchers to themselves. Among renewable energy sources, wind energy as the most accessible energy source, has been among the most popular research topics in recent years. Doubly-Fed Induction Generator (DFIG) is a commonly used configuration for variable speed Wind Energy Conversion Systems (WECSs) because of its independent control of active and reactive powers and extensive range of wind speed variations. In this paper, a Pulse Width Modulation (PWM) rectifier and a Z-Source Inverter (ZSI) are used as Grid Side Converter (GSC) and Rotor Side Converter (RSC), respectively. Z-Source Inverter is a newly proposed power electronic converter which has solved the limitations and disadvantages of conventional voltage source and current source inverters. A modified Space Vector Modulation (SVM) technic based on Sliding Mode generator power control is used to control the switching pattern of the ZSI. To verify the effectiveness of the proposed control system, simulations result in MATLAB/Simulink software are presented. Different wind speeds as well as independent control of active and reactive powers are examined through these simulations.