Experimental Study of the Vibration Coupling Characteristics Between Wind Turbine Tower and Blades

Wind turbine blades are critical components for energy conversion but are susceptible to fatigue damage due to complex environmental and loading conditions. Traditional blade vibration monitoring methods, which rely on sensors installed on the blade surface, face challenges in terms of placement, signal transmission, and maintenance costs. To address these limitations, this study explores a cost-effective method to monitor blade conditions via tower vibrations. It establishes a four-degree-of-freedom lumped mass model, revealing that blade vibrations can transmit to tower through the nacelle. This finding establishes tower vibrations as a viable indirect measurement approach for blade dynamics. To validate this theory, an experimental study was conducted based on a small-scale wind turbine. The test system consists of accelerometers, laser displacement sensors, and video measurement technology. Offline tests were performed to determine how the natural frequency of the blade varies with added mass whereas online tests demonstrated corresponding changes in tower vibration frequency. The results showed that as the blade mass increased, its natural frequency decreased, which was reflected in the tower’s vibration response correspondingly. Moreover, remote video-based monitoring results closely match the accelerometer data, confirming the feasibility of a non-contact blade vibration measurement method. This study bridges theoretical analysis and experimental validation, proving that tower vibrations can effectively reflect blade dynamics. The findings provide a foundation for remote and cost-effective blade health monitoring, enhancing the practical applications of wind turbine condition monitoring technology.