Design, fabrication, and testing of a low frequency MEMS piezoelectromagnetic energy harvester

Abstract

This paper details a power solution for smart grid applications to replace batteries by harvesting the electromagnetic energy from a current-carrying wire. A MEMS piezoelectromagnetic energy harvester has been fabricated using PZT screen-printing technology with a centrally-supported meandering geometry. The energy harvesting device employs a symmetric geometry to increase its power output by reducing the effects of the torsional modes and the resultant overall strain nodes in the system subsequently reduce the complexities for the electrode fabrication. The unit is modelled using COMSOL to determine mode shapes and frequency response functions. A 12.7 mm by 14.7 mm unit is fabricated by screen-printing 75 μm-thick PZT on a stainless steel substrate and then experimentally tested to validate the FEA results. Experimentally, the harvester is shown to produce 9 μW from a wire carrying 7 A while operating at a distance of 6.5 mm from the wire. The design of the current work results in a greater normalized power density than other MEMS based piezoelectromagnetic devices and shows great potential relative to larger devices that use bulk or thin film piezoelectrics.

Key features in the development of unimorph stainless steel cantilever with screen‐printed PZT dedicated to energy harvesting applications

“…For cantilever structures, lower electromechanical coupling and piezoelectric coefficients are obtained, as confirmed by finite element simulation analysis for the zig‐zag cantilever 22 . Overall, lower properties are expected for cantilever multilayer structure due to the presence of the passive metallic substrate supporting the active PZT layers.…”

“…A stainless steel substrate (SS301) with a Young Modulus of 193 GPa 22 is selected according to its compatibility with the high firing temperature of the screen‐printed layers (900°C). This substrate is laser cut into the selected geometry.…”

“…Ag wires of diameter 100 µm are glued on the Au electrodes with Ag epoxy paste. Additional ultrasonic wire bonding of 20 µm Au wires is led for the zig‐zag cantilevers as detailed in previous work 22 . Maximum voltages chosen to avoid dielectric breakdown are respectively of 0.25, 0.35, and 1 kV for cantilevers, disks, and ceramics.…”

“…Recently, PZT layers supported on metallic substrates and its interface circuitry were developed, in order to collect and regulate the energy for smart grid applications 22,23 . Power output tests results were presented, showing an improved performance compared to other MEMS‐based piezo‐electromagnetic devices.…”

Electromechanical Modeling of a Piezoelectric Vibration Energy Harvesting Microdevice Based on Multilayer Resonator for Air Conditioning Vents at Office Buildings

“…For this, the conventional batteries will must be replaced by novel power sources. An alternative solution is the development of energy harvesting devices that can convert the environment energy (e.g., mechanical vibrations, thermal energy, solar radiation, wind energy and movement of the human body) into electrical energy [3,4,5,6,7,8,9]. For instance, the kinetic energy caused by the mechanical vibrations in the environment could be transformed into electrical energy through vibration energy harvesting (VEH) devices.…”