Energy Self-Sufficient Wireless Sensor Node for Inertial Measurements on Wind Turbine Blades

In this paper an energy-autonomous system for wind turbine blade deflection measurement is presented. Monitoring the blade deflection enables the possibility to avoid tower striking, reduce maintenance costs and optimize control parameters. The system consists of one or multiple nodes for motion tracking using inertial measurements and a stationary receiver. The nodes are designed to continuously measure acceleration and angular rate. The raw measurements are transmitted periodically to a base station where further signal processing takes place. The sensor node is developed for application inside a wind turbine blade without accessibility to external power supply. Therefore, an electromagnetic energy harvester has been developed to make use of the wind turbine blade rotation. The requirement of low power consumption is fulfilled by using the latest MEMS sensor technology in combination with an optimized wireless communication protocol based on IEEE 802.15.4 standard and a low power microcontroller. A 100Hz sample rate of the inertial measurement unit (IMU) results in a wireless data stream of 10.8kBits−1 and a total power consumption less than 1.5mW. The blade trajectory can be reconstructed using an algorithm based on Extended Kalman Filters.