Research On Response Characteristics And Control Method Of DFIG Under Grid Frequency Fluctuations

In recent years, every countrie has stepped up the development and utilization of new energy sources, wind power technology in the actual production has been rapid development and widely application. Among them, the Variable Speed Constant Frequency(VSCF) Doubly Fed Induction Generator(DFIG) model of fastest development. With the wind and the continuous improvement of network scale, conventional generators gradual decline in the proportion, the ability to regulate the system frequency will inevitably be affected. So research the wind turbine power system frequency regulation in recent years has gradually become a hotspot. In this paper, for the grid frequency fluctuations DFIG response characteristics and control methods to expand research, the new method involved in the power system frequency regulation of DFIG is established. The main research work is as follows:Firstly, based on the analysis of the basic research background and significance of research status at home and abroad on the subject, analyzes the components and working principle of the DFIG, study the wind turbine and the DFIG mathematical model of the grid frequency is constant, using the controlled voltage source instead of the network side and the rotor side pulse-width modulation(PWM) converter, building the maximum wind energy tracking control strategy, the correctness of the DFIG model and the effectiveness of the control strategies can be verified by the MATLAB/Simulink simulation.Secondly, study the DFIG response characteristics under the grid frequency fluctuations. The first step establishment of a common induction motor steady-state equivalent circuit and dynamic model were plotted response characteristics of three-dimensional map and dynamic simulation map under grid frequency fluctuation, description of induction motor response to grid frequency fluctuation effects. The second step through simulation verification DFIG response characteristics under the grid frequency fluctuations, in-depth analysis of the frequency response characteristics of DFIG.Finally, simplified the DFIG model, constructs single-area power system automatic generation control(AGC) dynamic model containing DFIG, improved the frequency adjustment method that DFIG participating in the system, called coordinated control method. Analysis of the power system controller parameters for frequency affecting, at different wind speeds and different wind power penetration verify the effectiveness of coordinated control mode. After that, establish a double area power system dynamic model of AGC containing DFIG. In the two regions with different wind power penetration, through the system sudden increase in load and sudden load shedding in both cases analysis the frequency adjustment effect of the coordination control method between the two regions. Simulation results show the feasibility and effectiveness of the coordinated control method.