A nonlinear MEMS electrostatic kinetic energy harvester for human-powered biomedical devices

Abstract

International audienceThis article proposes a silicon-based electrostatic kinetic energy harvester with an ultra-wide operating frequency bandwidth from 1 Hz to 160 Hz. This large bandwidth is obtained, thanks to a miniature tungsten ball impacting with a movable proof mass of silicon. The motion of the silicon proof mass is confined by nonlinear elastic stoppers on the fixed part standing against two protrusions of the proof mass. The electrostatic transducer is made of interdigited-combs with a gap-closing variable capacitance that includes vertical electrets obtained by corona discharge. Below 10 Hz, the e-KEH offers 30.6 nJ per mechanical oscillation at 2 grms, which makes it suitable for powering biomedical devices from human motion. Above 10 Hz and up to 162 Hz, the harvested power is more than 0.5 μW with a maximum of 4.5 μW at 160 Hz. The highest power of 6.6 μW is obtained without the ball at 432 Hz, in accordance with a power density of 142 μW/cm3. We also demonstrate the charging of a 47-μF capacitor to 3.5 V used to power a battery-less wireless temperature sensor node

Enhanced Bandwidth Nonlinear Resonance Electromagnetic Human Motion Energy Harvester Using Magnetic Springs and Ferrofluid

“…And this idea has attracted a lot of research interesting recently. In general, the harvesting of human motion energy is achieved through various transfer mechanisms such as piezoelectric [1]- [3], electrostatic [4]- [6], electromagnetic [7]- [15], and hybrid [16], [17], which convert human motion energy into electrical energy [18]. However, the piezoelectric energy harvesters has a disadvantage of low generation efficiency in low frequency and electrostatic energy harvesters require very high processing technologies.…”

Design and Simulation of Bistable Microsystem with Frequency-up conversion effect for Electrostatic Energy Harvesting

“…Numerous examples of the energy harvesters operating with such input parameters had already been proposed, but generally they are not compatible with biomedical applications due to the size [2] and use of magnetic elements [3]. However, introducing the non-linearity in electrostatic energy harvester could produce a dramatic effect on its performance [4].…”

“…Numerous examples of the energy harvesters operating with such input parameters had already been proposed, but generally they are not compatible with biomedical applications due to the size [2] and use of magnetic elements [3]. However, introducing the non-linearity in electrostatic energy harvester could produce a dramatic effect on its performance [4].In the bistable system, the switching between stable positions depends only on the value of the external applied force [5], and it could be used to access the low frequencies keeping the bandwidth high for the external excitation.It had been clearly demonstrated that maximum power that can be converted by an inertial power generator is proportional to the operational frequency of the transducer [6]. So, the frequency-up conversion is a promising strategy to increase the output power value.…”

High Figure of Merit Nonlinear Microelectromagnetic Energy Harvesters for Wideband Applications

“…Thus in order to address this problem, a number of strategies has been reported in recent literature to improve the efficiency of the energy harvesters under frequency varying environment. Resonant frequency tuning [17]- [20], activating multiple modes [21]- [23] and nonlinear energy harvesting [24]- [32] have emerged as the prospective solutions. However not all of these techniques are suitable for integration in a Micro Electro Mechanical System (MEMS) based energy harvesting device.…”

“…Employing multiple MEMS cantilevers with different physical dimensions to achieve separate resonance frequencies [21] or activating multiple fundamental modes of a linear structure within a close frequency range [22], [23] through design modulations are popular methods to operate under multi-frequency input. Nonlinear oscillation based on stretching strain of specially designed beams [28], [29], [31] and frequency up conversion using mechanical impacts [11], [32] are potential methods to develop wideband VEHs at MEMS scale.…”