Simulation And Analysis Of Double-Fed Variable-Speed Constant-Frequency Wind Turbine Timing System

Now, energy sources consume is increasing daily and environment pollution become more serious gradually. Because of its stand out merits, wind power is paid great attention in the exploitation of renewable energy source. The wind power generation technology has become the research hotspot of many country's scholars. The wind power generation system with variable-speed constant-frequency (VSCF) can capture energy as much as possible. In addition to the realization of VSCF control, reducing the capacity of the inverter, it can control active and reactive power flexibly; can play the role of reactive power compensation in terms of the power grids. In different wind speed, the wind turbine speed can make the corresponding modulation, and operating in the best working conditions, improve unit efficiency; shortcomings of the system is to increase the complexity and cost. Firstly, the research status of wind power generation technology and VSCF are summarized in this paper. Then, several wind power control technologies are reviewed in more detail. Vector control system implements the rotor current torque and exciting component of decoupling by the stator flux-oriented. The current closed-loop control inhibits the cross-coupling and the potential disturbance of the rotor two current; the torque closed-loop decouples the torque and the stator flux. And direct torque control gives up the thinking of decoupling and the rotating coordinate transformation, then to control by detecting the rotor current, voltage to calculate rotor flux and torque, and in accordance with a given value of the margin. As VSCF double-fed wind turbine works in the near synchronous speed, in this running region the rotor exciting current is very low, so large units usually uses VVVF.Finally, based on the analysis of the dynamic mathematical model of DFIG and its stator-flux-oriented vector control, a dual-closed-loop PI control scheme is developed and realizes decoupled control of the active and reactive power. Simulation study is carried out on the platform of MATLAB/SIMULINK and validates the proposed strategy, which will guide designing and debugging the practical software and hardware systems.