Adaptive power management of energy autonomous structural health monitoring systems for wind turbines

Structural health monitoring systems of wind turbines with autonomous energy harvesting can extend lifetime, avoid blade corruption and improve energy efficiency. Their sensor measurement unit and wireless transmission are supplied from an energy harvester which transforms mechanical rotation into electrical energy. The wide dynamic range of the rotational speed of the rotor and the blade pitch angle result into a variable power demand of the sensor and transceiver, which must be adapted to the power generation. The electrical energy is generated twice in a complete rotation and has a pulse shaped waveform. It is stored in a capacitor followed by a DC/DC converter. An on board measurement system observes the charge status and can predict the remaining operation time. The wireless sensor node is reconfigured to prevent an approaching energy shortage in case of a shrinking energy budget. This paper introduces an adaptive power management by means of low latency wireless reconfiguration. It enables high flexibility under all operating conditions of a variable speed wind turbine.