Study of Variable Pitch Control for Direct-drive Permanent Magnet Wind Turbines Based on Fuzzy Logic Algorithm

摘要

Due to the complex structure of direct-drive permanent magnet wind turbines and the high nonlinearity of wind speed, the effect of the conventional PID variable pitch control to maintain the output power unchanged is often less than ideal when the wind speed is above the rated. This paper proposes a new pitch control method based on fuzzy logic algorithm, combining the fuzzy adaptive PID control with the fuzzy feed forward control after analyzing the operating characteristics of direct-drive permanent magnet wind turbines. The fuzzy adaptive PID controller can ensure the unit to have a better control result than the conventional PID controller at a wider range of wind speed. The fuzzy feed forward controller can improve the response rapidness of the variable pitch control system. The effectiveness and superiority of the proposed method are verified with the simulation of a 1.5 MW direct-drive permanent magnet wind turbines using PSCAD/EMTDC and MATLAB. The results show that the new compound variable pitch control method can effectively ensure the rapid response and stability of the wind turbines when the wind speed is above the rated.