Study On The Wind Speed Determination Of Wind Power System Based On Time Delay Estimation

With conventional fossil fuels more and more rarer, which can not meet the requirements of sustainable development of national economy,the advancement of renewable energy becomes continuously important for us human, which requires higher demand of research and application of the renewable energy like wind power.Wind speed measurement for wind resource assessment and wind farm is an important parameter. Among variety of wind measurement technology, ultrasonic wind measuring technology, because of no moving mechanical parts, eliminating the need for regular maintenance, and by measuring the signal time delay from the transmitter to the receiver to calculate the wind speed value, meet the harsh environments of wind farms on request of the wind-measuring instrument.Time delay estimation is a fast and accurate method of measuring ultrasonic time of flight. Firstly, the alpha-stable distribution and time delay estimation problems are discussed and researched, from the perspective of modeling of random noise in the signal, the time delay estimation method has two major categories based on Gaussian model and Alpha-stable distribution, which lays a solid foundation for the subsequent theory research. However, for the pulses non-Gaussian signal that occurs in the ultrasonic signals, traditional Gaussian models could not be accurately modeled, to address the pulse signal of the proper modeling and improve the performance of algorithms based on the model problem,given an improved method of adaptive time delay estimation, specifically alpha-stable distribution is used to describe this type of pulse, redesignedin line with characteristics of optimization criteria. Through analysis of computer simulation, the new given method based on alpha stable distribution is better than the traditional algorithm based on Gaussian model in terms of performance and accuracy improved. Finally, through building the ultrasonic signal acquisition system, to complete the emission and collection of ultrasonic signal, get ultrasonic reference signal and ultrasonic echo signal respectively, give the experimental verification of the algorithm and solve the appearing theory problems. Through time delay estimate, based on the liner relation between wind speed and the time difference of ultrasonic downwind and upwind, real time wind speed is calculated. After a comparison of the measured wind speed values,ultrasonic anemometer system, relative to the mechanical wind measurement system, which has an advantage of higher accuracy and smaller relative error compared with calibrated wind speed, has good economic value.