Design and Experiments of a Galloping-Based Wind Energy Harvester Using Quadruple Halbach Arrays

Hai Dang Le,Soon-Duck Kwon

doi:10.3390/en14196094

Abstract

This study aims to develop a device for harvesting electrical energy from low-speed natural wind. Four linear Halbach arrays are adopted to design a high-performance galloping harvester with the advantage of high durability and efficiency at low-frequency vibrations. The results of magnetic field analysis reveal that there are optimal sizes of the main and transit magnets of the Halbach arrays and coil to obtain the maximum magnetic flux density normal to the coil. The experimental and simulation results show that the electrical external load resistance significantly affects the vibration amplitude and the galloping onset velocity of the harvester. The results also reveal that the performance of the original design using the quadruple Halbach array was lower than that of the existing harvester because of the heavy magnet mass embedded in the tip prism. The modified design, reducing mass, improved the performance by four times compared to the original design.

Highlights

Most wireless sensors are currently powered by batteries, which require regular charging or replacement
Galloping is a widely used wind energy source because it readily occurs at low wind speeds
Where U is the wind speed, ρ is the air density, A is the frontal area of the tip prism, L is the cantilever length, and a1 and a3 are the empirical galloping coefficients associated with

Summary

Introduction

Most wireless sensors are currently powered by batteries, which require regular charging or replacement. Electromagnetic generators are highly durable and are efficient at low frequency. They generate a low output voltage and are bulky in size due to their magnets and pick-up coil. Successful miniature wind energy harvesters use fluid-induced vibrations such from galloping [4,5], flutter [3,8] vortex-induced vibration [9,10], and wake galloping [11]. The main drawback of vortex-induced vibration harvester is the narrow bandwidth of wind speed for generating electric power. Bandwidth of wind speed for generating electric power. Galloping is a widely used wind energy source because it readily occurs at low wind speeds.

F Fwind ρ12Uρ2 UA2

Findings

20 Experiment Simulation