Research On Control Technology Of Permanent Magnet Direct Drive Wind Power Generation System Based On ESO

As the global annual electricity consumption continues to increase,the status of sustainable renewable energy is becoming more and more important.Wind energy plays a very important role in clean energy as a green and non-polluting energy source,so various types of wind turbines are gradually coming onto the historical stage of the new energy industry.The permanent magnet direct-drive wind power generation system has the characteristics of low operating cost,high power generation efficiency and high stability,which has become the main force in the field of wind power generation system.At present,one of the popular research directions of this system is converter control technology.In this paper,the maximum utilization of wind energy and high quality transportation of electric energy are achieved by improving the control algorithms inside the machine side rectifier and network side inverter of the system,and the main research contents are as follows:(1)Aiming at the problems of slow convergence speed and poor anti-disturbance performance of PI controller for speed outer loop control in machine side rectifier vector control technology,this paper designs a fast terminal sliding mode controller based on High-Order Extended State Observer to improve the control accuracy of speed and achieve maximum power tracking.In order to accurately obtain the real-time disturbance effect of wind speed on D-PMSG,a HOESO is designed to accurately estimate the disturbance changes brought by sudden changes in wind speed to the system torque,which is used as the input of the fast terminal sliding mode controller for feedforward compensation to enhance the system robustness.By comparing the simulation with Linear Extended State Observer in MATLAB/Simulink,it is verified that HOESO is superior to LESO in terms of observation performance.(2)To address the problem of large jitter in the PI controller for voltage outer-loop control in the vector control technology of the network-side inverter.In this paper,we design a fast double power convergence law with variable coefficients to adjust the control rate of the controller according to the distance between the system state and the equilibrium point to reduce the system jitter.For D-PMSG load voltage variation features,the Generalized Extended State Observer is proposed to real-time estimation of perturbations caused by grid voltage fluctuations and nonlinear loads.And use them as the input of the variable coefficient fast terminal sliding mode controller to offset the disturbances to the system.MATLAB/Simulink emulation outcome illustrate that the new convergence law has a quicker convergence speed compared to other conventional convergence laws.GESO has a higher observation accuracy compared to LESO.(3)A permanent magnet direct-drive wind power generation system is modeled in MATLAB/Simulink.The simulation outcome explains that the fast terminal slid-mode controller based on higher-order expansive state observer has higher control accuracy for rotational speed and stronger anti-interference capability,which can maximize the utilization of wind energy and achieve maximum power tracking compared with the traditional PI control and other control algorithms.The fast terminal slid-mode controller with variable coefficients build on the generalized dilated state observer regulates the DC bus voltage faster and with less voltage jitter.This verifies the effectiveness of the two control strategies proposed in this article.