An official website of the United States government
Motivated to run a self-powering monitoring sensor on a wind turbine blade, this paper proposes a pendulum based frequency-up converter that effectively captures a low-speed mechanical rotation into high-frequency vibration of a piezoelectric cantilever beam. A system of governing equations for the proposed concept is developed to describe the motion of the pendulum, the vibration of the beam, and the voltage output of the harvester. Design optimization is performed to improve the power generation performance, and the simulation results are verified experimentally. We demonstrate the improved power density from the proposed concept compared to the disk driven frequency-up converters.
more »
« less
On a self-tuning sliding-mass electromagnetic energy harvester
Prior research has investigated resonators capable of self-tuning through the use of a sliding mass. This passive tuning mechanism can be utilized to improve vibration control; however, little is known about the nonlinear dynamic interactions between the vibrating beam and sliding mass, particularly as these apply to vibration energy harvesting applications. This paper investigates this problem by numerically and experimentally examining the response of an electromagnetic self-tuning energy harvester. We present the governing equations of this electromagnetic cantilever beam with a sliding mass using the extended Hamilton principle. These equations are then discretized using the Galerkin method and solved numerically. An experiment is carried out to validate the numerical analysis. Parametric studies are conducted to examine the effect of different system parameters on the performance of the self-tuning harvester.
more »
« less
- Award ID(s):
- 1944032
- PAR ID:
- 10596909
- Publisher / Repository:
- American Institute of Physics
- Date Published:
- Journal Name:
- AIP Advances
- Volume:
- 10
- Issue:
- 9
- ISSN:
- 2158-3226
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
More Like this
-
-
Creating self-sustaining wireless sensor networks to power the Internet of Things requires universal energy harvesting systems. MEMS energy harvesters are in particular demand as they can be batch fabricated to meet the large supply demands. However, currently silicon MEMS kinetic energy harvesters are fabricated with a narrow bandwidth of 1–2 Hz, so each application requires a custom designed device which limits the advantages of batch fabrication. This paper investigates the development of a passive tuning MEMS vibration energy harvesting method that is based on distributing the load to various locations along the proof mass using a liquid load. A 3D printed proof mass with an array of cavities was developed, where each cavity could be filled with liquid to alter the resonant frequency as desired. Cavities were filled with silicone oil to validate the concept. The results illustrate tuning of the frequency with a resolution of < 1 Hz and a range of approximately 50 Hz. This method represents a passive tuning method as no power is required and the tuning can be accomplished during manufacturing so that one single universal energy harvester could be made and then tuned to meet the end user’s frequency specification.more » « less
-
Abstract Recently, vibration energy harvesting has been seen as a viable energy source to provide for our energy dependent society. Researchers have studied systems ranging from civil structures like bridges to biomechanical systems including human motion as potential sources of vibration energy. In this work, a bench-top system of a piecewise-linear (PWL) nonlinear vibration harvester is studied. A similar idealized model of the harvester was previously looked at numerically, and in this work the method is adjusted to handle physical systems to construct a realistic harvester design. With the physically realizable harvester design, the resonant frequency of the system is able to be tuned by changing the gap size between the oscillator and mechanical stopper, ensuring optimal performance over a broad frequency range. Current nonlinear harvester designs show decreased performance at certain excitation conditions, but this design overcomes these issues while also still maintaining the performance of a linear harvester at resonance. In this investigation, the system is tested at various excitation conditions and gap sizes. The computational response of the resonance behavior of the PWL system is validated against the experiments. Additionally, the electromechanical response is also validated with the experiments by comparing the output power generated from the experiments with the computational prediction.more » « less
-
Vibration energy is becoming a significant alternative solution for energy generation. Recently, a great deal of research has been conducted on how to harvest energy from vibration sources ranging from ocean waves to human motion to microsystems. In this paper, a theoretical model of a piecewise-linear (PWL) nonlinear vibration harvester that has potential applications in variety of fields is proposed and numerically investigated. This new technique enables automatic frequency tunability in the energy harvester by controlling the gap size in the PWL oscillator so that it is able to adapt to changes in excitations. To optimize the performance of the proposed system, a control method combining the response prediction, signal measurement and gap adjustment mechanism is proposed in this paper. This new energy harvester not only overcomes the limitation of traditional linear energy harvesters that can only provide the maximum power generation efficiency over a narrow frequency range but also improves the performance of current nonlinear energy harvesters that are not as efficient as linear energy harvesters at resonance. The proposed system is demonstrated in several case studies to illustrate its effectiveness for a number of different excitations.more » « less
-
Vibration energy harvesting is increasingly being seen as a viable energy source to provide for our energy-dependent society. There has been great interest in scavenging previously unused or wasted energy in a large variety of systems including vibrating machinery, ocean waves and human motion. In this work, a bench-top system of a piecewise-linear nonlinear vibration energy harvester is studied. A similar idealized model of the system had previously been studied numerically, and in this work the method is adjusted to better account for the physical system. This new design is able to actively tune the system’s resonant frequency to match the current excitation through the adjustment of the gap size between the oscillator and mechanical stopper; thus maximizing the system response over a broad frequency range. This design shows an increased effective frequency bandwidth compared with traditional linear systems and improves upon current nonlinear designs that are less effective than linear harvesters at resonance. In this paper, the physical system is tested at various excitation conditions and gap sizes to showcase the new harvester design’s effectiveness.more » « less
