Electrostatic energy harvesting device with dual resonant structure for wideband random vibration sources at low frequency

Abstract

In this paper, we present design and test of a broadband electrostatic energy harvester with a dual resonant structure, which consists of two cantilever-mass subsystems each with a mass attached at the free edge of a cantilever. Comparing to traditional devices with single resonant frequency, the proposed device with dual resonant structure can resonate at two frequencies. Furthermore, when one of the cantilever-masses is oscillating at resonance, the vibration amplitude is large enough to make it collide with the other mass, which provides strong mechanical coupling between the two subsystems. Therefore, this device can harvest a decent power output from vibration sources at a broad frequency range. During the measurement, continuous power output up to 6.2-9.8 μW can be achieved under external vibration amplitude of 9.3 m/s at a frequency range from 36.3 Hz to 48.3 Hz, which means the bandwidth of the device is about 30% of the central frequency. The broad bandwidth of the device provides a promising application for energy harvesting from the scenarios with random vibration sources. The experimental results indicate that with the dual resonant structure, the vibration-to-electricity energy conversion efficiency can be improved by 97% when an external random vibration with a low frequency filter is applied.

An electrostatic energy harvester with sandwiched structure of two electret layers

“…The sandwich device with two electret layers was also tested when driven by a random vibration with the bandpass of 135±25 Hz at the average accelerations of 7.63 m/s 2 and 10.2 m/s 2 , as shown in Figure 5(a). At 10.2 m/s 2 , we got the output power of 3.96 μW, which is higher than the result in our previous single device [16] with the same device size. The new device can also work in a broader bandwidth (135±25 Hz) than before (160±12.5 Hz).…”

“…Figure 2 shows the circuit diagrams of two types of devices based on the sandwich structure. Based on the work principle of the pre-charged electret vibration energy harvester [16], [25], induced charges are obtained on both sides of the proof mass. When the proof mass is driven to move, there will be two kinds of current flow through the external load at the same time.…”

Nonlinear gyrokinetic simulations of the I-mode high confinement regime and comparisons with experimenta)

“…16 Experimental evidence for profile stiffness and critical gradients is also found in several tokamaks. [17][18][19][20][21][22][23] As a consequence of stiff transport in the plasma core, the edge temperature provides the key boundary condition dictating overall plasma performance. 10,14,24 This means that in very stiff core plasmas, like many H-modes, small decreases/increases in local temperature gradients can lead to large decreases/increases in local diffusivity.…”

Recent progress on piezoelectric energy harvesting: structures and materials

“…The electromagnetic vibration energy harvesting with the benefit of larger output power and dispense with additional power supply in use, however, is difficult to compatible with modern industrial production technology of higher output voltage due to the developing tendency for device miniaturization [5]. Electrostatic vibration energy harvesting, also called capacitor vibration energy harvesting, mainly forms the potential difference above the capacitor plate to generate a stable voltage under external power [6]. And charges will come into forming due to the change of capacitance between electrode plates.…”