Harness low frequency vibrations to power miniature devices
A team of researchers from A*STAR's Institute of Microelectronics (IME) has looked into low frequency vibrations, the most abundant and ubiquitous energy source in the surroundings, to power small-scale electronic devices. The energy harvester, according to them, has the ability to continuously convert the vibrations across a wide frequency range in different environments into electricity. This presents a green, economical and sustainable long-term solution to eliminate the manual re-charging or replacement of power sources in miniature devices, the researchers noted.
To use low frequency vibrations efficiently, common attempts focus on expanding the size of the device in order to attain maximum power output, which limit the applications of these energy harvesters. In addition, most reported designs can only operate at one fixed frequency, which significantly reduces the power generation efficiency in practical environments.
Figure 1: Fully integrated EH device.
To address these design challenges, IME researchers have demonstrated an aluminium nitride (AlN) based energy harvester with record-high power density of 1.5 x 10-3W/cm3 capable of generating electricity equivalent to three commercial implantable batteries over a 10-year period. As an inexorable power supply, the remarkable power density feature translates into massive savings as costs and logistics associated with power source servicing will no longer be relevant.
The energy harvester also extends the flexibility of low frequency vibrational sources that can be harvested by offering the widest sampling range of 10th - 100Hz. The wide sampling range makes it now possible to more productively harness real-world vibrational sources in spite of their irregularity and randomness.