Research On Control Strategy Of Grid-side Converter For Permanent Magnet Direct Drive Wind Power System Based On LADRC

Facing the current situation of the increasingly serious energy crisis,people have begun to explore renewable energy.As a clean energy,wind energy provides a green and clean and practical way to alleviate the current energy tension and replace traditional energy generation methods.It is not only widely accepted by countries around the world,but the world ’s installed wind power capacity is also increasing year by year.Grid-connected converters,as the interface between wind energy and the power grid,play an important role in guaranteeing the quality and efficiency of grid-connected power.At the same time,wind turbines also need to be able to maintain non-grid operation under external disturbances such as voltage fluctuations.Ability.Therefore,this paper will study the control strategy of the grid-side inverter of the direct-drive permanent magnet synchronous wind power system,which has important engineering practical significance for improving the stable operation and fault ride-through capability of wind turbines.First of all,this article introduces the development trend and research significance of three-phase grid-connected inverters based on the research background and the current status and trends of wind power generation.Through a brief analysis of the topology of the wind turbine,the control strategy and modulation method of the inverter,it is understood Control theory foundation.While laying the foundation for the subsequent chapters,the double-closed-loop control structure of the grid-side converter of the direct-drive permanent magnet synchronous wind turbine is mainly analyzed.Based on the topology of the grid-side converter,a three-phase stationary coordinate system and a two-phase are established.The mathematical model in the rotating coordinate system,combined with the voltage-oriented vector control strategy of the power grid,respectively designed the voltage outer loop and the current inner loop PI controller,and carried out parameter tuning.Then,in response to the traditional PI controller’s short response speed,prone to overshoot,and poor anti-interference performance,this paper improves the outer loop of the DC bus voltage,and designs the first-order LADRC and second-order LADRC controllers for the bus voltage.Control and analyze the convergence of the corresponding second-order LESO and third-order LESO at the same time,and use the frequency domain method to analyze the anti-interference performance of LADRC,which not only improves the transient process of the bus voltage of the wind power system,but also improves The ability of the system to run stably.A MATLAB / Simulink digital simulation software was used to build a simulation model of a three-phase grid-connected system of a 1.5 MW direct-drive permanent magnet synchronous wind turbine.Finally,physical experiments were performed with the help of the company ’s 3.6MW-class full-scale wind field simulation experimental platform to simulate the fault of the DC bus voltage under the conditions of power grid voltage drop,sudden load loading,and load shedding.The effectiveness and feasibility of the proposed control strategy are verified.