Airflow-driven rotary electret energy harvester

Harvesting energy from physical resources in the environment is an effective way to solve the micro power issues in micro system. Gas flow as a clear and renewable physical resource has a great potential in the field of micro energy harvester. In this work, we design an efficient rotary electret energy harvester driven by gas flow with a high output power. the key parameters of structure design are analyzed, and the prototype is fabricated using a 3D printing technology. The surface potential of electret on the rotor structure is up to 1000 V by a classic corona charging method. Our designed energy harvester could be driven by a low air flow speed of 2.5 m/s. The output voltage of 17 V and output power of 3.6 µW are obtained with external resistance of 10 MΩ at the speed of 3 m/s, which corresponds to a rotation speed of 300 rpm.