A hybrid electrostatic micro-harvester incorporating in-plane overlap and gap closing mechanisms

Abstract

This paper presents a novel design, fabrication and characterization of an electrostatic micro-energy scavenger, converting the environmental vibration. The design incorporates MEMS comb-drive in-plane overlap as well as in-plane gap closing topologies into one hybrid structure. The device geometry and dimensions are optimized to maximize the energy harvesting efficiency. UV-LIGA process combined with nickel electroplating is utilized to fabricate the devices. A shaker platform in conjunction with a calibrated accelerometer is used to measure the harvested ac voltage with varying acceleration. Peak to peak value of 0.800 V is generated under external acceleration magnitude of 78.4 m s−2 at a vibration frequency of 1.90 kHz. Power predictions based on electromechanical and finite element method (FEM) simulations agree with the measured data.

Interface circuit with adjustable bias voltage enabling maximum power point tracking of capacitive energy harvesting devices

“…When V min across C var starts to increase, the diode D2 is blocking and Q Cvar + > Q Cvar − . In this case, when C var reaches its maximum value, the voltage relations can be expressed as (4) and (5), and the charge delivered by C bias can be expressed as (6). By comparing with (3), one can infer that V Cbias may saturate to a certain value.…”

“…Such relative displacement is induced by inertial forces resulting from ambient vibrations. Such electromechanical device can be profitably miniaturized using MEMS technology [1][2][3][4][5][6]. Contrary to piezoelectric, electromagnetic and electret-based electrostatic transducers that intrinsically generate voltage, current and energy, simple electrostatic transducers are passive devices.…”

Improvement of energy conversion effectiveness and maximum output power of electrostatic induction-type MEMS energy harvesters by using symmetric comb-electrode structures

“…Three types of conversion methods are known as the principle of vibrational energy harvesters, namely, piezoelectric, electromagnetic, and electrostatic [7][8][9][10][11][12][13][14][15][16][17][18][19][20]. To meet the low frequency range of the environmental vibrations, a piezoelectric type energy harvester needs to use a relatively large mass attached to a thin piezoelectric unimorph cantilever to intentionally lower the mechanical resonance.…”

Electromechanical analysis of an adaptive piezoelectric energy harvester controlled by two segmented electrodes with shunt circuit networks

“…Such micro-power harvesting devices can alleviate those essential technical issues by converting the vibration energy into the usable electrical energy so as to recharge battery and enable wireless sensor devices [1]- [3]. The most common micro-power harvester has been increasingly found in a wide range of applications using thermoelectric [4], electrostatic [5], electromagnetic [6]- [7], and piezoelectric [8]- [10] transductions. In terms of advantages over other competing transducers, the piezoelectric component has high sensitivity and power density, compact design, and scalability.…”