Sensor-less Direct Torque Control Of Doubly Fed Induction Wind Generator

At the present,low-carbon, environment protection, energy saving and emission reduction become the theme, new energy are given rise to more and more attention, wind power for its special advantage rapidly develops, so it's important to study how to maximize the use of wind energy and improve the efficiency of plant operation.Doubly fed induction wind generator is taken as the main object of study, The sensor-less technology and direct torque control technology are used in doubly fed induction wind generator in order to improve its reliability and stability, improve overall system dynamic performance at the same time.Firstly, starting from the component of wind power system, the model of double-fed wind generator is separately created under two-phase stationary coordinate system and the rotating coordinate system, then the theories of the wind turbine are analyzed, its mathematical model is created.Secondly, the basic principle of direct torque control for doubly fed induction wind generator is illuminated, the fundamental difference between the traditional DTC and its are mainly analyzed, elaborated on the voltage space vector is how to influence the rotor's flux and torque in detail. Based on the model reference adaptive system, sensor-less technology will be introduced into wind generation group, and a complete block diagram of sensor-less direct torque control is set up, as well as the whole working principle is explained.Thirdly, the function of each model is analyzed, in the meanwhile, the corresponding model is set up based on Matlab / Simulink, such as the model of wind speed, wind turbine and transmission part, observation of flux, the rotor flux zone judgment, a complete simulation platform for sensor-less doubly fed induction wind generator direct torque control is also built.Finally, in the study of simulation, the simulation waveform of current, flux, torque, speed and position angle is analyzed, the result showed that the application of combining sensor-less with direct torque control technology is feasible. In the low and middle speed range, the rotor speed and rotor position is precisely identified based on improved model reference adaptive system, which has a good dynamic and static performance.