The Research On Sensorless And Control Strategy Of Direct-driven Permanent Magnet Synchronous Wind Power Grid-connected

In today’s society,with the rapid development of power electronics technology,new energy is also increasing.Wind turbines are an indispensable power and source of clean energy,and the stability and reliability of wind power grid-connected control system are particularly important.Double-fed asynchronous wind turbines(DFIG,Doubly Fed Induction Generator)have the advantages of simple installation,low cost and high efficiency,so they have been widely used in the global wind power field.In the dual-fed asynchronous wind grid control system,the two-fed asynchronous turbine and the power grid via back-to-back AC,and the AC control strategy will directly affect the reliability,stability and the grid quality of the whole system,when the voltage of the grid fails,it will even break off the grid,causing the grid voltage again.In order to avoid double-fed asynchronous wind turbine units from the power grid failure and have good control performance,the control strategy of double-fed asynchronous wind turbine and low voltage crossing technology.The control strategy and low voltage crossing technology of two-fed asynchronous wind power grid-connected system(LVRT)are etc.Firstly,the wind power technology,the machine side and network control strategy of two-fed wind power grid system,the working principle and mathematical model of two-fed wind turbine set,machine side and network side,the operation characteristics of two-level back-to-back converter and output voltage equation,and the working principle of wind power maximum tracking control,and the mathematical simulation model of wind turbine in MATLAB software.Then,the To improve the control performance and grid quality of the double-fed asynchronous wind power grid control system,Using a model for predictive control(MPC,Model Predictive Control)Technology,A model prediction current control is proposed for the machine side and network side AC(MPCC,Model Predictive Current Control)Method,And build its simulation model;When the power grid voltage fluctuates,In contrast to the traditional PI controls,Model prediction current control method can control the reliable and stable operation of the system,And enhance the system’s low-voltage crossing capacity and the quality of the power grid;Finally,Add a super capacitance battery to the DC side bus terminal to keep the DC side bus voltage constant;The system builds on the super capacitance storage energy,Switching the operation mode with the STATCOM using the unit power factor,An optimable low voltage crossing control method is proposed,And build its simulation model and analysis;Simulation results show that,Low voltage crossing control method based on STATCOM operation mode can make the system stable and reliable operation,And can not only meet the reactive power compensation requirements of the national power grid,And improve the low voltage crossing capacity and power grid quality.