The Study, Based On Wind Power Generation System Of The Doubly-fed Induction Motor

The energy crisis and environmental pollution makes people attach importance to the wind power technology. In this paper, variable speed and constant frequency wind power generation system (VSCF-WPGS) of doubly-fed induction generator(DFIG) operational control and no-load grid-connection control as the theme, the theory analysis and simulation studies. Different with most literature based on the field oriented control(FOC), this paper control DFIG based on the direct torque control (DTC), together with the wind turbines on the pitch angle adjustment, realize from the low wind speed to the high wind speed of wind power to the whole running smoothly. Enlightened by DTC, DFIG attempts to put forward a kind of direct electromotive-force control (DEC) strategy to realize the control of DFIG no-load grid-connection. The simulation results show that the proposed operation control strategies and grid control strategy is effective for engineering application, has certain reference value.The paper mainly complete work:(1) Introduces the current several VSCF-WPGS and gives the wind speed, wind turbines and DFIG drive system of the mathematical model.Established the DFIG dynamic mathematical model in different coordinates system,super-synchrony and sub-synchrony operation in DFIG (electric power state and power state) and the relationship between the energy flow were described.(2) Established the simulation platform of the wind turbines and drive system by Matlab/Simulink, gives the overall control framework and its mainly control methods of the doubly-fed VSCF generation system, including the vector control, direct torque control and direct power control, the details of their specific control strategies are describled.(3) Based on the wind, wind turbine and DFIG drive system , joint debugging the three models established a doubly-fed wind power control system mathematical model. Based on the theoretical knowledge, try to give an approach based on direct torque control (DTC) of the overall control strategy theory. Using Matlab/Simulink simulation platform,the doubly-fed wind power generation system from low wind speed to high wind speed operation process was studied, the simulation results show the feasibility of the proposed strategy.(4) With the wind generator capacity increasing,wind power generation system will be relatively large impact on power grids, so adopting rational grid technology is a problem that nots allow to ignore. By direct torque control (DTC) thought inspiration, tried to put forward a kind of direct electromotive-force control (DEC) strategy. Simulation results show that this control strategy for the impact of power grid, is a feasible scheme.