The energy-harvesting devices, created at U-M's Engineering Research Center for Wireless Integrated Microsystems, are highly efficient at providing renewable electrical power from arbitrary, non-periodic vibrations. This type of vibration is a byproduct of traffic driving on bridges, machinery operating in factories and humans moving their limbs, for example.
The Parametric Frequency Increased Generators (PFIGs) were created by Khalil Najafi, chair of electrical and computer engineering, and Tzeno Galchev, a doctoral student in the same department.
Most similar devices have more limited abilities because they rely on regular, predictable energy sources, said Najafi, who is the Schlumberger Professor of Engineering and also a professor in the Department of Biomedical Engineering.
"The vast majority of environmental kinetic energy surrounding us everyday does not occur in periodic, repeatable patterns. Energy from traffic on a busy street or bridge or in a tunnel, and people walking up and down stairs, for example, cause vibrations that are non-periodic and occur at low frequencies," Najafi said. "Our parametric generators are more efficient in these environments."
The researchers have built three prototypes and a fourth is forthcoming. In two of the generators, the energy conversion is performed through electromagnetic induction, in which a coil is subjected to a varying magnetic field. This is a process similar to how large-scale generators in big power plants operate.
The latest and smallest device, which measures one cubic centimeter, uses a piezoelectric material, which is a type of material that produces charge when it is stressed. This version has applications in infrastructure health monitoring. The generators could one day power bridge sensors that would warn inspectors of cracks or corrosion before human eyes could discern problems.
The generators have demonstrated that they can produce up to 0.5 milliwatts (or 500 microwatts) from typical vibration amplitudes found on the human body. That's more than enough energy to run a wristwatch, which needs between one and 10 microwatts, or a pacemaker, which needs between 10 and 50. A milliwatt is 1,000 microwatts.
"The ultimate goal is to enable various applications like remote wireless sensors and surgically implanted medical devices," Galchev said. "These are long lifetime applications where it is very costly to replace depleted batteries or, worse, to have to wire the sensors to a power source."
Batteries are often an inefficient way to power the growing array of wireless sensors being created today, Najafi said. Energy scavenging can provide a better option.
"There is a fundamental question that needs to be answered about how to power wireless electronic devices, which are becoming ubiquitous and at the same time very efficient," Najafi said. "There is plenty of energy surrounding these systems in the form of vibrations, heat, solar, and wind."
These generators could also power wireless sensors deployed in buildings to make them more energy efficient, or throughout large public spaces to monitor for toxins or pollutants.
The research is funded by the National Science Foundation, Sandia National Laboratories, and the National Institute of Standards and Technology.
The university is pursuing patent protection for the intellectual property. Galchev and a team of engineering and business students are working to commercialize the technology through their company, Enertia. Enertia recently won first place in the DTE/U-M Clean Energy Prize business plan competition and second place in the U-M Zell Lurie Institute for Entrepreneurial Studies' Michigan Business Challenge. Other members of the team are Erkan Aktakka, and Adam Carver. Aktakka is an electrical engineering doctoral student. Carver is an MBA student at the Ross School of Business.
For more information:
Khalil Najafi: http://www.eecs.umich.edu/najafi/
Engineering Research Center for Wireless Integrated Microsystems: http://www.wimserc.org/
Nicole Casal Moore | Newswise Science News
Stanford researchers develop a new type of soft, growing robot
21.07.2017 | Stanford University
Team develops fast, cheap method to make supercapacitor electrodes
18.07.2017 | University of Washington
Physicists have developed a new technique that uses electrical voltages to control the electron spin on a chip. The newly-developed method provides protection from spin decay, meaning that the contained information can be maintained and transmitted over comparatively large distances, as has been demonstrated by a team from the University of Basel’s Department of Physics and the Swiss Nanoscience Institute. The results have been published in Physical Review X.
For several years, researchers have been trying to use the spin of an electron to store and transmit information. The spin of each electron is always coupled...
What is the mass of a proton? Scientists from Germany and Japan successfully did an important step towards the most exact knowledge of this fundamental constant. By means of precision measurements on a single proton, they could improve the precision by a factor of three and also correct the existing value.
To determine the mass of a single proton still more accurate – a group of physicists led by Klaus Blaum and Sven Sturm of the Max Planck Institute for Nuclear...
The research team of Prof. Dr. Oliver Einsle at the University of Freiburg's Institute of Biochemistry has long been exploring the functioning of nitrogenase....
A one trillion tonne iceberg - one of the biggest ever recorded -- has calved away from the Larsen C Ice Shelf in Antarctica, after a rift in the ice,...
Physics supports biology: Researchers from PTB have developed a model system to investigate friction phenomena with atomic precision
Friction: what you want from car brakes, otherwise rather a nuisance. In any case, it is useful to know as precisely as possible how friction phenomena arise –...
21.07.2017 | Event News
19.07.2017 | Event News
12.07.2017 | Event News
21.07.2017 | Earth Sciences
21.07.2017 | Power and Electrical Engineering
21.07.2017 | Physics and Astronomy