A high-efficiency wind-flow energy harvester using micro turbine

There are emerging applications for standalone embedded systems where devices are required to operate for very long time with the minimum battery maintenance after the deployment. Examples include wireless sensor networks, environmental monitoring, surveillance, civil infrastructure and industrial control. Energy harvesting has emerged as an innovative way to keep small stationary hardware platforms running unattended for years or even decades. This paper analyzes wind flow as feasible energy source to meet the energy needs of a wireless sensor network node. We provide a detailed model and characterization of the micro wind turbine and an effective power-saving architecture to control the harvesting circuit. The optimized design of the wind flow harvester outperforms the ones proposed in literature within an overall volume below 300 cm3. A highly efficient buck-boost converter is the core of the optimal power point tracking circuit and experimental results show that the wind generator works at its maximum efficiency over a wide range of operating conditions.