VECTOR CONTROL OF GRID CONNECTED DFIG BASED WECS USING BACK-TO-BACK CONVERTER

Author

AKBAL RAIN, Southern Illinois University CarbondaleFollow

Date of Award

9-1-2021

Degree Name

Master of Science

Department

Electrical and Computer Engineering

First Advisor

Hatziadoniu, Constantine

Abstract

Wind Energy is one of the promising forms of energy in 21st century in the fight of humankind to the global warming. There has been a lot of research in this field from last 30 years and still there is a lot more to achieve in this field in order to make it more reliable and promising form of energy. In this research, wind turbine which is connected to the DFIG is used to harness the energy from the wind. The DFIG is connected to the grid and because of which active and reactive power control becomes must as it need to synchronize the power at a standard frequency and voltage of the grid. A back-to-back converter is used to decouple and control the active and reactive power from the DFIG to the grid. This paper deals with a variable speed variable pitch model of the WECS where it is able to operate at various wind speed and to regulate the power, it is able to operate at various pitch. Optimal Torque Control algorithm is used to capture maximum energy in MPPT mode.In this thesis, a detailed simulation model of 2 MW DFIG with variable speed variable pitch control scheme is developed which is interconnected to the grid. All the basic calculation regarding the designed speed, dc link voltage, capacitance, DC choke link, aerodynamics of the wind turbine, control of the rotor and grid side converter is designed. In addition to that wind turbine modelling is also done and the required pitch and the MPPT control is done. A steady state modelling of the model is done in order using the characteristics equation of the DFIG is done to analyze the aerodynamics, electrical and the mechanical operating characteristics. The study in this model provides most of the explanation for the DFIG wind turbine model system for the optimum power extraction and the output power control or regulation. Steady state modelling and simulations results are placed in the report which verifies the model operation and control of the WECS system. Various wind speed is set to test the system for different operating zones and from the results, it is clear that the model can regulate the power in the variable speed region and extract the maximum power during MPPT mode and control the power output during pitch control model by varying the pitch of the turbine.