Research On Fault Ride.through Of Doubly Fed Wind Power Generation System Based On Matrix Converter

With the rapid development of wind power generation technology,new requirement for the generation system is put forward by the wind farm grid regulation,that when the power grid breaks down,the system must not go off.line and should provide voltage support for the grid to make sure the electrical power system is in safe and steady operation.The doubly.fed wind generation system based on matrix converter has drawn wide attention for its compact structure.But given that matrix converter doesn't have energy storage links,its fault ride.through capability is weaker compared to systems based on back.to.back converter under the circumstance of adding no hardware.Therefore,this paper takes the doubly.fed wind generation system based on matrix converter as studies to propose a new type of matrix converter topology helping improve the low voltage ride.through capability of wind power generation systems.First of all,this paper analyzed the basic operating principle of double.fed wind power system and established a detailed systematical mathematical model,which achieves the controlling goal for the system in the condition of the grid functioning,laying the foundation of the study of the double fed induction generator's fault ride.though control.Then,aiming at the dip of three.phase and single.phase voltage in the grid,the paper analysed the behavior characteristics and harm of the doubly.fed wind generation system,based on which it proposes a new type of matrix converter topology.If the grid breaks down,the topology can separate the rectifier stage and inverter stage through its affiliated hardware circuit,and works respectively by current.mode STATCOM and voltage source inverter,insisting the system accomplish the fault ride.through.Based on that,a simple and reliable double closed.loop PI control is adopted to make sure the wind power system wouldn't go off.line when the three.phase symmetrical voltage drop occurs in power grid;and a fault ride.through scheme based on finite set model predictive control is adopted to deal with asymmetric faults in the grid,which omits the complicated positive and negative sequence decomposition,consequently simplifies the control method.At last,the paper used matlab/simulink model to simulate and verify the reliability of the low voltage ride.through control strategy proposed in this paper and successfully proved its correctness.