E.P. James

Design and fabrication of a new vibration-based electromechanical power generator

A device is described for generating electrical power from mechanical energy in a vibrating environment. The design utilises an electromagnetic transducer and its operating principle is based on the relative movement of a magnet pole with respect to a coil. The approach is suitable for embedded remote microsystems structures with no physical links to the outside world. Simulation, modelling and test results following fabrication of a first prototype have demonstrated that generation of practical amounts of power within a reasonable space is possible. Power generation of more than 1 mW within a volume of 240 mm3 at a vibration frequency of 320 Hz has been obtained.

The Modelling of a Piezoelectric Vibration Powered Generator for Microsystems

As MEMS and Smart Material technologies advance, embedded and remote applications are becoming more widespread. Powering these systems can be a significant engineering problem, as traditional solutions such as batteries are not always appropriate. A method is described for modelling the power than can be produced from piezoelectric inertial generators. The method uses a combination of FEA and a complex stiffness model of a resistively shunted piezoelectric element. The model is verified with experimental results. Although the prototype produces only 3µW, the model reveals that orders of magnitude increase in power output are possible.

Planar signal extraction techniques for a self powered microsystem

Over the years there has been a growing interest in the field of micro-systems and their applications across a wide range of areas, including sensor based micro-systems able to operate with full galvanic isolation. Two significant issues to consider when designing such remote sensor systems are the supply of power and the method of signal extraction. This paper talks about using planar techniques to address both issues. The concept of a Self-Powered Micro-System is developed. This Eliminates the need for a battery with a finite service life. Current experimental work is explained and potential applications for such novel remote sensor systems are put forward.