Improvement In Low Voltage Ride Through Capability Of Doubly Fed Induction Generator

Wind energy is a clean and renewable energy, under the global concern for environmental protection. The developed countries are focused on the development of the use of non-polluting or less polluting renewable energy and new energy, both to protect the environment and energy conservation. Wind power generation technologies, including large-scale wind turbine and grid-connected technology have been basically mature. The installed capacity of the wind farm is also increasing. Because of the increase in the capacity of the wind turbine, stable operation of the wind farm is more important to the power system. When the grid fault occurs, it also requires the wind turbines to be able to continue working. So, the study on low voltage ride-through capability of doubly-fed wind turbine is of great significance.1. This paper studies the structure and principle of double-fed wind power generation system, and analyzes the mathematical model in static three-phase ABC coordinate system of the doubly-fed wind power generator and in two-phase rotating dq coordinate system of the mathematical model, which provides theoretical guidance For the low voltage ride-through technology research of DFIG.2. According to the mathematical model of the generator, it analyzes the DFIG transient electromagnetic relation, and gives further analysis of the DFIG rotor overvoltage and overcurrent.3. Then, based on the mathematical analysis, the method to choose the appropriate value of Crowbar resistor was introduced. Furthermore, a modified Crowbar protection circuit with resistance in series with a capacitor was proposed to shorten the transition process of the rotor over current. Finally, based on the platform of MATLAB/SIMULINK, a DFIG simulation model is built, which is used in various simulations in the studies.