Development Of Vibration Monitoring System For Wind Turbine Blades Based On LabVIEW

Wind turbine is always used in a broad and remote area. As a result of the harsh natural environment and interactions among the whole unit, the unit is easy to appear some faults of the wind turbine blade, gearbox, generator and yaw system, which lead to the vibration of blade.The vibration characteristics of wind turbine blade were studied and analyzed by the method combining the theoretical calculation with the experimental research in this thesis, and a blade vibration monitoring system was developed.First of all, vibration types and mechanism of wind blade were analyzed and researched. At the same time, the mechanism of vibration was further studied in terms of aerodynamic force, mechanical force and systematical resonant. Secondly, on the basis of basic equations for structural dynamics, a wind turbine blade was treated as a free cantilever beam which was entirely fixed on the root. Then the physical and mathematical models of wind turbine blades were built. Blades of a 15kW wind turbine were modeled in the AutoCAD. With the aid of the finite element analysis (FEA) software ALGOR, the models of blades were analyzed on the vibration modes under the state of irrotational and different rotational speeds. Thus the natural frequencies and mode shapes were calculated, and the relation graph of wind speed - mode shape– frequency was obtained.In the paper, a wind turbine blade with the length of 1.5m was taken as the test object, and a laboratory bench for vibration testing of the wind blade was set up. The hardware system of signal acquisition was set up according to the arrangement of the laboratory bench and the measurement method. Meanwhile, the vibration detecting and analyzing system for wind turbine blade was developed based on LabVIEW. There are two functions were designed besides the time and frequency domain analysis. One is fuzzy fault diagnosis functions based on the maximum membership principle, the other is modal analysis of the collected data. Finally, the vibration test for wind turbine blade was respectively made by using strain gauge vibration test system and single point laser vibrometer. The relative error of the two test system is less than 5% obtained from the analyzing of experimental results and error analysis, which shows that the strain gauge vibration test system is correct and feasible.