Remote area wind energy harvesting for low-power autonomous sensors

A growing demand for deployment of autonomous sensors and sensor networks is leading to a subsequent increase in the demand for localized, independent energy harvesting capabilities for each node. In this paper, a method of remote area wind energy harvesting is presented, with a focus on an anemometer-based solution. By utilizing the motion of the anemometer shaft to turn a compact alternator, small amounts of power can be harvested from otherwise unavailable sources. Energy harvested is converted to battery potential via a pulsed buck-boost converter operating in discontinuous conduction mode (DCM). It is found that maintaining a constant input resistance at the input port of the converter biases the alternator to operate at its peak power point over a wide range of wind speeds. Results show that power harvesting capability using the discussed alternator and power converter solution are in the range of tens to hundreds of microwatts up to approximately one milliwatt. This power is passed to the central system batteries, providing a trickle-charge. As a result, sensor nodes incorporating this harvesting solution have an increased field lifetime. High overall efficiency is maintained over a wide range of potential wind speeds, with little impact on anemometer measurement accuracy.