Base Mounted Piezoelectric Transducer for Low-Frequency Vibration Harvesting
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Solution Overview
Problem
Piezoelectric energy harvesters based on cantilevered beams face limitations in size and resonant frequency due to the properties of piezoelectric materials, restricting their effectiveness in harvesting low-frequency vibrations and requiring complex manufacturing processes.
Innovation Solution
A Base Mounted Piezoelectric (BMP) harvester design where the piezoelectric transducer is mounted beneath the base of a cantilevered beam, decoupling the beam's mechanical properties from the transducer, allowing for a wide range of material choices and independent resonant frequency settings, enabling efficient low-frequency energy harvesting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If piezoelectric materials are used in cantilevered beam energy harvesters, then power density at small scale is improved, but size and resonant frequency are restricted
Solution Approach 1:
The piezoelectric transducer is segmented from the cantilevered beam structure, mounted independently at the base rather than being integrated into the beam. This segmentation allows the beam's mechanical properties and the transducer's electrical properties to be optimized independently, enabling a wider range of resonant frequencies while maintaining high power density.
Solution Approach 2:
The piezoelectric transducer is positioned specifically at the base of the cantilevered beam where stress concentration occurs during vibration. This local placement maximizes the conversion efficiency of mechanical energy to electrical energy at the most critical location, improving power density without constraining the overall beam design.
2Power
If piezoelectric materials are used in cantilevered beam energy harvesters, then power density at small scale is improved, but manufacturing complexity increases
Solution Approach 1:
The piezoelectric transducer is extracted from the integrated cantilevered beam structure and mounted separately at the base. This extraction simplifies manufacturing by allowing the beam and transducer to be fabricated and optimized independently, then assembled together, reducing the overall manufacturing complexity while maintaining high power density performance.
3Power
If piezoelectric transducer is mounted beneath the base of cantilevered beam, then power output per unit area is improved, but device complexity increases
Solution Approach 1:
The piezoelectric transducer is merged with the base structure of the cantilevered beam, utilizing the existing base as the mounting platform. This merging approach maximizes power output per unit area by concentrating the active piezoelectric material at the most efficient location without requiring additional structural components, thus minimizing the increase in device complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The BMP harvester achieves higher power output per unit area compared to traditional designs, is cost-effective, and suitable for small-scale, low-power devices, particularly in applications with space constraints, while maintaining flexibility in material selection and manufacturing ease.
Implementation Method 1
Transducers made from piezoelectric materials use the direct piezoelectric effect, electric polarization as a result of external applied load, to convert mechanical energy to electrical energy.
Data Source
AI summary
An energy harvester apparatus, system and method. A cantilevered beam resonator includes a cantilever beam and a base defined by the ends of the cantilever beam. The cantilevered beam resonator further includes a piezoelectric transducer composed of one or more piezoelectric components. The piezoelectric transducer is generally mounted beneath the base of the cantilevered beam resonator. In some example embodiments, the piezoelectric component can be configured in a split electrode configuration composed of a single split arrangement or more than one split (e.g., two splits, three splits, four splits, and so on).