Research On Control Strategy Of Wind Turbines Individual Variable Pitch Based Improving PID

With the large-scale wind turbine, the tower height and the length of the blade is also a substantial increase, adding to the factors such as wind shear and tower shadow and turbulence for the wind turbine key components fatigue loading, at this stage the installed wind turbines most use a uniform pitch control, compared with the previous fixed pitch control, although fluctuations in wind power and unbalanced forces of the wind turbines can be reduced to a certain extent, but still can not meet the requirements of wind power integration. Therefore, this subject through the theoretical analysis of the independent variable pitch control, is put forward based on wind speed subarea-subsection PID independent variable pitch control, the main work is as follows:(1)According to the composition of wind turbines, has established the mathematical model of wind turbine parts, on the basis of momentum-blade theory, established the wind speed model considering wind shear,tower shadow effect and turbulent wind conditions, and verifying the validity of the model by Matlab simulation platform.(2)Puting the established wind speed model respectively into united variable pitch control system and the common PID independent variable pitch control system,to research the relationship between the power and wind speed model. The simulation results show that the power fluctuations of common PID independent variable pitch control system is smaller.(3)For the lack of Normal PID independent pitch system In the control the output power stability, andWind energy utilization coefficient, etc.This paper proposes the partition segment PID independent pitch control method on the basis of wind speed. According to the given error using the gold optimum method to zone the wind speed area reasonably from the rated wind speed to cut out wind speed,and design controllers of different partition.The simulation results show that the proposed control strategy can make the generator power output more stable.(4)In view of the problem that nonlinear wind turbines cannot found the model accurately, this topic proposes a method that Matlab and GH Bladed realize interaction design to analyze the load of wind turbine components.Import the blade aerodynamic parameters and pneumatic loads calculated by GH Bladed into the controller simulation system built by Matlab,and the results obtained with GH Bladed system joint debugging to get the aerodynamic load in different locations during the rotating blade. The results show that compared with the general PID independent variable pitch control,the piecewise PID control based on wind speed partition reduce each of the three propeller under load 12.45%, 11.76%, 11.63%; Wave bending moment decrease 20.86%, 21.00% and 20.86% respectively; Wheel fixed coordinates Y, and Z direction load decreased 14.14% and 11.25% respectively; Wheel rotation coordinates Y, and Z direction load decreased 13.06% and 15.08% respectively; Y and Z direction of the tower load decreased 26.43% and 22.92% respectively. The simulation results show that the proposed control strategy can decrease the unbalanced load of wind wheel.