Potential of electrostatic micro wind turbines

TL;DR

This paper explores electrostatic micro wind turbines based on drag and lift aerodynamic forces, demonstrating ultralow speed operation with high efficiency and analyzing different polarization and circuit options for energy harvesting.

Contribution

It introduces the physical principles of electrostatic micro wind turbines and demonstrates ultralow speed operation with high efficiency, a novel achievement in the field.

Findings

Power flux densities up to 150 μW/cm² at low wind speeds

Achieved 9% efficiency at 1 m/s wind speed

Compared different circuit configurations for energy harvesting

Abstract

This paper presents the physical operating principles of several micro wind turbines based on different aerodynamic forces: drag-type Vertical Axis Wind Turbine (VAWT) and lift-type Horizontal Axis Wind Turbine (HAWT). All these devices share the similarity of exploiting the same mechanical-to-electrical conversion: the electrostatic conversion. This type of conversion is based on capacitance variations induced by the motion between a rotor and a stator and requires a source of polarization. We will focus our study on two technologies to polarize the capacitive structure: the use of electrets and the exploitation of triboelectricity. Some experiments conducted in a low-speed wind tunnel between 0 and 20m.s-1 have highlighted power flux densities from 0 to 150{\mu}W.cm-2 corresponding to power coefficients of 0 and 9% respectively. Among these results, we can especially retain an ultralow speed operation, which has never been reached until now, in terms of speed and efficiency (9% of efficiency at 1m.s-1). Finally, we will end up comparing different types of circuits to supply a temperature/acceleration sensor, in order to complete the energy harvesting chain.