Study On Converter Control Strategy Based On Fuzzy Reference Adaptive Permanent Magnet Wind Turbine

It are very important that accurate speed and rotor position of permanent magnet synchronous generator used in the direct drive wind turbine for field oriented control.Mechanical sensors are used in traditional detection methods,which increases the cost of the system and the accuracy of the detection is easily affected by the environment.The speed sensorless control method can be realized by software programming,which displaces the mechanical sensor to reduce the cost of the system and enhances the reliability of the system.In this paper,the speed sensorless of the permanent magnet direct drive wind turbine is analyzed and improved based on model reference adaptive system(MRAS).The fuzzy MRAS algorithm is designed to improve the accuracy of speed estimation and solve the problem of the delay in the rotor position estimation.This paper firstly discusses the significance of wind power generation to change energy structure,and describes the application of the speed sensorless in the wind power generation.Based on the characteristics of wind energy,the mathematical model of wind turbine is established,and the principle of maximum wind energy capture is also explained.Mathematical models of components of permanent magnet direct drive wind power system are established,including permanent magnet synchronous generator,machine side converter,grid side converter and SVPWM technology,which provides a theoretical basis for sensorless algorithm of permanent magnet direct drive wind turbines.Secondly,the principle of the model reference adaptive system(MRAS)algorithm is introduced,and the theory is applied to PMSG speed sensorless vector control system.However,the traditional MRAS method not only has a problem of high frequency jitter when running at low speed,but also has the problem of rotor position estimation delay.In order to solve the above problems,a fuzzy model reference adaptive observer is proposed in this paper.By adjusting PI parameters of adaptive law,the wind burbine has good performance under low wind speed and high wind speed.The jitter problem of speed estimation is eliminated and the precision of rotor position detection is improved.Finally,according the fuzzy MRAS control method proposed in this paper,the Matlab/Simulink simulation model is built and compared with the traditional MRAS.The results show that the speed estimation accuracy of the wind turbine based on fuzzy MRAS is higher and the problem of position estimation delay is greatly avoided.under the condition of the gradual wind and abrupt wind.The stator current waveform of the motor is sinusoidal and the harmonics are very few.The dynamic performance of the system can meet the grid-connected operation requirements of the convertor.