Perpetuum advances battery-free wireless condition monitoring

London - Perpetuum and CAP-XX Ltd have reported on how a Perpetuum vibration energy-harvesting micro-generator, together with a CAP-XX supercapacitor, can allow wireless sensor system manufacturers to design battery-free condition monitoring systems that collect and report data on machinery for improved asset management.  The companies also presented the results of a field trial at a Norwegian gas plant to evaluate the system in a challenging industrial environment.

Output from the micro-generator can cover the power needs of intermittent radio sensor systems such as Wireless HART, SP-100 and Wi-Fi in industrial applications, but its output impedance is too high to supply the 10s to 100s of milliwatts required by sensor nodes during data collection and transmission, explains Perpetuum. The high capacitance and low equivalent series resistance (ESR) of the supercapacitor provides approximately 1 second of peak power to transmit data.

The supercapacitor stores the energy harvested by its PMG17 micro-generator - a low but steady source of between 0.5mW and 50mW-  and then delivers the peak power needed to transmit sensor condition data over wireless networks such as IEEE 802.15.4 (Zigbee) and 802.11 (WLAN). “The micro-generator and supercapacitor combination eliminates battery reliability issues and time-consuming maintenance, while enabling significant savings in operational costs and energy use,” said Dr. Stephen Roberts, technical manager for Perpetuum.

The companies went on to highlight use of the PMG17 and CAP-XX supercapacitors  during a field trial at the Nyhamna gas plant in Norway to power wireless sensor nodes in its network. "Operating faultlessly despite a wide range of temperatures, the sensors monitored the condition of rotating equipment, the main culprit in production shutdowns, reporting temperature and overall vibration every five minutes," according to a Perpetuum statement.