State Recognition for Main Bearing of Wind Turbines Based on Multi-Fractal Theory

The main bearing dynamic characteristics of megawatt wind turbines are complex system with strong non-linearity, strong coupling and time-varying. The vibration signals are mixed with background noise, so it is difficult to extract the characteristics of week signals. Based on the dynamic characteristics, multi-fractal theory is put forward to detect and recognize the working status of the main bearing of megawatt wind turbines. Different working states are recognized intuitively by different dimensions of multi-fractural which are sensitive to variety of working state. The paper justifies the method can detect and recognize different working states of main bearings quickly and accurately through the experiments on the main bearings of 3 WM wind turbines.