Most powerful millimeter-scale energy harvester generates electricity from …

April 26, 2011
By

April 25, 2011

Most powerful millimeter-scale energy harvester generates
electricity from vibrations


Click on image for higher
resolution

ANN ARBOR, Mich.—Electrical engineers at
the University of Michigan have built a device that can harness
energy from vibrations and convert it to electricity with five to
ten times greater efficiency and power than other devices in its
class. And it’s smaller than a penny.

“In a tiny amount of space, we’ve been able to
make a device that generates more power for a given input than
anything else out there on the market,” said Khalil Najafi, one of
the system’s developers and chair of Electrical and Computer
Engineering.

This new vibration energy harvester is
specifically designed to turn the cyclic motions of factory
machines into energy to power wireless sensor networks. These
sensor networks monitor machines’ performance and let operators
know about any malfunctions.

The sensors that do this today get their power
from a plug or a battery. They’re considered “wireless” because
they can transmit information without wires. Being tethered to a
power source drastically increases their installation and
maintenance costs, said Erkan Aktakka, one of the system’s
developers and a doctoral student in Electrical and Computer
Engineering.

Long-lasting power is the greatest hurdle to
large-scale use of pervasive information-gathering sensor networks,
the researchers say.

“If one were to look at the ongoing life-cycle
expenses of operating a wireless sensor, up to 80 percent of the
total cost consists solely of installing and maintaining power
wires and continuously monitoring, testing and replacing
finite-life batteries,” Aktakka said. “Scavenging the energy
already present in the environment is an effective solution.”

The researchers have built a complete system
that integrates a high-quality energy-harvesting piezoelectric
material with the circuitry that makes the power accessible.
(Piezoelectric materials allow a charge to build up in them in
response to mechanical strain, which in this case would be induced
by the machines’ vibrations.)

“There are lots of energy sources surrounding
us. Lightning has a lot of electricity and power, but it’s not
useful,” Najafi said. “To be able to use the energy you harvest you
have to store it in a capacitor or battery. We’ve developed an
integrated system with an ultracapacitor that does not need to
start out charged.”

The active part of the harvester that enables
the energy conversion occupies just 27 cubic millimeters. The
packaged system, which includes the power management circuitry, is
in the size of a penny. The system has a large bandwidth of 14
Hertz and operates at a vibration frequency of 155 Hertz, similar
to the vibration you’d feel if you put your hand on top of a
running microwave oven.

“Most of the previous vibration harvesters
operated either at very high frequencies or with very narrow
bandwidths, and this limited their practical applications outside
of a laboratory environment,” Aktakka said.

The new harvester can generate more than 200
microwatts of power when it is exposed to 1.5g vibration amplitude.
(1g is the gravitational acceleration that all objects experience
by Earth’s gravity.) The harvested energy is processed by an
integrated circuitry to charge an ultracapacitor to 1.85 volts.

In theory, these devices could be left in place
for 10 or 20 years without regular maintenance. “They have a
limitless shelf time, since they do not require a pre-charged
battery or an external power source,” Aktakka said.

A novel silicon micromachining technique allows
the engineers to fabricate the harvesters in bulk with a
high-quality piezoelectric material, unlike other competing
devices.

The market for power sources for wireless
sensor networks in industrial settings is expected to reach $450
million by 2015, Aktakka said.

These new devices could have applications in
medicine and the auto industry too. They could possibly be used to
power medical implants in people or heat sensors on vehicle motors,
Najafi said.

The researchers will present this work next at
the 16th International Conference on Solid-State Sensors,
Actuators, and Microsystems (TRANSDUCERS 2011) in Beijing in June.
This research is funded by the Defense Advanced Research Projects
Agency and National Nanotechnology Infrastructure Network. The
university is pursuing patent protection for the intellectual
property, and is seeking commercialization partners to help bring
the technology to market.

SOURCE

Article source: http://www.rdmag.com/News/Feeds/2011/04/general-sciences-most-powerful-millimeter-scale-energy-harvester-ge/ The feed :

Tags:

Sponsored By:

The Deeter Group

Deeter Electronics Ltd. | Deeter Electronics Inc | Deeter Group Asia | Deeter Group Germany | Deeter Group Corporate

Head & Registered Office:
Deeter Electronics Ltd.
Deeter House,
Valley Road,
Hughenden Valley,
Bucks. HP14 4LW

Tel: +44 (0) 1494 566 046
Fax: +44 (0) 1494 563 961
E-mail: [email protected]


The Deeter Group with products ranging from: , , , continuous , 4-20mA , , , , , , , a , wireless sensor and much more.

If you want a standard or a custom level switch, float switch, level sensor, or wireless sensor, contact us via email [email protected] or call us now on 01494 566 046.

Company Name: The Deeter Group

Location: Hughenden Valley, UK

Deeter Electronics USA
Deeter Electronics USA
Wireless sensor system | Radio telemetry | Level switches | Level sensors | Liquid level sensor | Float switches | Controllers & indicators | Industrial weighing equipment | Electronic circuit design & manufacture | Software design | Reed relays | Ultrasonic level flow sludge & proximity sensors | Proximity sensors & switches | Reed switches | Litz wire | Wago Terminals | Mechanical & magnetic floats | Boiler control |

Deeter Electronics UK
Wireless sensor system | Radio telemetry | Level switches | Level sensors | Liquid level sensor | Float switches | Controllers & indicators | Industrial weighing equipment | Electronic circuit design & manufacture | Software design | Reed relays | Ultrasonic level flow sludge & proximity sensors | Proximity sensors & switches | Reed switches | Litz wire | Wago Terminals | Mechanical & magnetic floats | Boiler control |

Deeter Electronics Europe
Wireless sensor system | Radio telemetry | Level switches | Level sensors | Liquid level sensor | Float switches | Controllers & indicators | Industrial weighing equipment | Electronic circuit design & manufacture | Software design | Ultrasonic level flow sludge & proximity sensors | Proximity sensors & switches | Reed switches | Litz wire | Wago Terminals | Mechanical & magnetic floats | Boiler control |

Sensor Magazine Websites
Explosion Proof Sensors UK | Explosion Proof Sensors | Water Level Measurement | Liquid Level Sensing | Liquid Level Measurement | Liquid Level Sensors UK | Liquid Level Sensors Europe | Wireless Sensors | Sensor Magazine | Industrial Sensors



Water use