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According to emergency grid rule requirements, wind farm should has the ability to stay connected and continue generation under external voltage failure conditions, that is, wind turbines have to keep in connection with grid and own continue power supply. Consequently, the dynamic model of double fed wind turbines, converter model and grid model were established to study the transent chatacters of DFIG. Also, current vector control method oriented by the stator flux was applied in converter control. Based on these, PSCAD was used in building models and simulating. Finally, the results shows that vector control is able to fulfill decoupled active and reactive power control of double fed generators and improve system low voltage ride through ability.

For the variable speed operation of large scale wind turbine, the vibrations become key problem that can not be ignored. In this paper, the active vibration control based on Neural Network PID control strategy was researched. Firstly, PID control algorithm was analyzed. Then, the PID control based on Neural Network was described especially BP Network and its algorithm. In the end, this control method was verified using simulation and prototype test. Keywords-Control; PID; Neural Network; Bladed I.INTRODUCTION The more complicated of controlled system, the higher of people requirements, further, people need control system could adapt to uncertainty, time-varying objects and environment ability. Traditional control method based on exact model can hardly meet the requirements. Control is defined as concept including decision, planning and learning ability. The neural network is paid more and more attention because of these advantages mentioned above. The control diagram of wind turbine is shown in Figure 1.

For the consideration of the existing switching device power level, a converter circuit topology is proposed in this paper, which is accorded with the requirement of highpower direct-drive outer rotor permanent magnet generator. Particularly, a control method based on “non-controlled retification, boost chopper and SPWM inverter circuit” is proposed. Designs of the boost chopper circuit and the control system structure of SPWM inverter are mainly performed, then the block diagrams and control programs of the whole control system are set up. Finally Matlab/Simulink is used to carry on the simulation. The result of simulation showed that this method could meet the requirement of wind power generation system, and the feasibility and accuracy of the method are fully confirmed.