At the Techno-Frontier 2014 exhibition in Tokyo OMRON and IMEC's Holst Centre unveiled the prototype of an extremely compact vibrational energy harvesting DC power supply with what they claim is the worlds’ highest efficiency.
It combines OMRON’s energy harvester with a Holst Centre/imec power management IC to convert and store energy from vibrations in the µW range with high efficiency to the driving voltage of general sensors.
The prototype measures just 5 x 6 cm – with potential to shrink as small as 2 x 2 cm. Its small size, light weight (15.4 gram) and user-variable output voltage are ideal for a wide-range of autonomous wireless sensor node applications in the industrial and consumer domains, particularly in inaccessible locations.
According to René Elfrink, Senior Researcher Sensors & Energy Harvesters at Holst Centre/imec, small, autonomous wireless sensors that can simply be installed and then left to collect and share data are attracting huge interest.
“They are the foundation of the emerging, Internet of Things,” he said, “and they could enable new levels of automation and equipment monitoring in industrial applications. The ongoing miniaturization and reduction of power consumption of sensors and microelectronics make these devices possible.
However, a key question has been how to power them.
“Energy harvesting – extracting unused or waste energy from the local environment – is perfect for autonomous sensor nodes,” said Elfrink. “It does away with the need for cables and changing batteries, allowing true “fix-and-forget” systems.
He said the combination of OMRON’s robust electrostatic vibration harvester and IMEC's efficient power management technology enables an extremely compact design that can be installed in even the most inaccessible places – whereas today’s vibrational harvester power supplies are too large and too heavy.
“The vibration in the environment of customers are various and volatile,” said Daido Uchida, General manager of Technology Produce & Start-up division of OMRON Corporation.. “Under such an environment, our harvester can produce energy even just a little. But so far, we could not use our harvester as a stable DC power supply.
He said initial feedback from potential customers suggests this is already small enough for industrial application. However, the module has potential for further miniaturization down to 2 cm x 2 cm.
The supply’s output can be set to anything between 1.5 V and 5 V, giving users complete flexibility to replace any kind of battery in existing designs or create brand new products. The module contains an ON/OFF signal for efficient duty cycling with low power sensor systems.
Uchida said OMRON is currently putting the prototype through a number of field tests with customers to gather further input before entering volume production.