Research On Permanent Magnet Direct-drive Wind Power Generation Backstepping Control System

In the current global context of energy scarcity and severe pollution,wind energy has gained increasing attention as a clean and pollution-free renewable energy source.The permanent magnet direct-drive wind power generation system(D-PMSG)has a high generator energy density,eliminates the gearbox,and lowers the system failure rate.In the sector of wind power generation,it has a lot of development potential and its own special benefits.The permanent magnet directdrive wind power generation system,however,is an effective way to increase the conversion and utilization efficiency of wind energy by studying an effective control method for the system.This is because the permanent magnet direct-drive wind power generation system has the characteristics of high nonlinearity and strong coupling,and it operates in a highly random wind speed environment.This paper uses the backstepping control strategy to thoroughly examine the permanent magnet direct-drive wind power generation control system in an effort to increase the wind energy absorption and utilization rate.The backstepping control strategy is based on a detailed analysis of the working principle and structure of the permanent magnet direct-drive wind power generation system.According to the Back-stepping Control(BSC)strategy,a backstepping speed and current controller based on the Lyapunov function is designed,taking into account the highly nonlinear and strong coupling characteristics of permanent magnet direct-drive wind power generation systems.This achieves the best control of the output power of wind power generation systems while ensuring global gradual stability of permanent magnet direct-drive wind power generation systems.This paper designs an extended sliding mode observer to estimate the unknown disturbance of the system and suppresses the influence of torque fluctuation and parameter perturbation by feedforward compensation,which improves the robustness of the system to some extent.The unknown parts of PMSG,such as parameter perturbation and torque variation,will affect the control effect.In order to further enhance the robustness of the system,the Sliding Mode Control(SMC)has the advantages of insensitivity to parameter changes,good stability and strong robustness when being disturbed by the outside world.The sliding mode control is combined with backstepping control,and a sliding mode backstepping speed controller is designed to enhance the antiinterference ability of wind power system when tracking the ideal speed.The non-singular fast terminal sliding mode surface(NFTSMS)is constructed to optimize the controller design,and the speed error can converge quickly in different stages.A new reaching law,which can dynamically change the gain with the system state,is designed to optimize the extended sliding mode observer,avoiding the use of large switching gain and weakening the sliding mode chattering phenomenon of the system.By establishing a simulation model in Matlab/Simulink and comparing it with traditional PI control and sliding mode control,it is verified that the designed control strategy can improve the robustness of the system,quickly track the ideal speed and optimize the power output of the system.