An efficient harvester with an autoregulatory driving arm to capture random wind energy

The wind energy is a type of renewable energy widely distributed in nature, but conventional wind generator faces a challenge in efficiently harnessing this energy due to their large and constant rotational inertia, which results in a relatively high start-up wind speed requirement. To address this issue, the paper proposes a concept of autoregulatory driving arm (ADA), which consists of a spring and a stretchable arm for each wind cup to achieve adjustable rotational inertia and low start-up wind speed. The arm length of the wind cup changes autonomously with wind speed due to the interaction between the elastic force of the spring and the centrifugal force of the wind cup, which contributes to the self-adjustable rotational inertia of the harvester. With a small rotational inertia at the idle state, a low start-up wind speed of 1.6 m/s can be achieved by the proposed ADA harvester. As the wind speed increases, the enlarged centrifugal force brings about stretched driving arms, which enables the ADA harvester to generate improved power as compared with the corresponding harvester with a constant driving arm (CDA). Moreover, the ADA harvester is capable of generating power for a longer duration after the wind ceases compared to the CDA harvester. Therefore, the ADA harvester can be utilized as a sustainable energy source to power certain sensors in natural breeze environment.