Tunable Piezoelectric Energy Harvester for Vibration Matching
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Solution Overview
Problem
Battery-powered sensor assemblies in industrial settings require frequent battery replacements, especially in remote locations, leading to high labor costs and limited recyclability, making them commercially unviable.
Innovation Solution
A tunable vibration energy harvester using a piezoelectric cantilever beam with a proof mass and adjustable springs to match resonance frequency with the driving vibration frequency, converting mechanical vibrations into electrical power, and an automatic tuning mechanism to optimize power output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If battery-powered sensor assemblies are used in remote industrial locations, then sensors can be deployed for monitoring, but frequent battery replacements are required leading to high labor costs and limited recyclability
Solution Approach 1:
The energy harvester enables the sensor system to power itself by converting ambient vibrations into electrical energy. The piezoelectric cantilever beam continuously converts mechanical vibrations from the monitored machinery into electrical power, eliminating the need for external battery replacements and making the system self-sufficient.
Solution Approach 2:
The patent replaces the chemical energy storage system (batteries) with a mechanical energy conversion system (piezoelectric cantilever beam). The piezoelectric material directly converts mechanical vibrations from the industrial environment into electrical energy, substituting the need for chemical batteries with a mechanical-to-electrical energy conversion mechanism.
2Productivity
If fixed resonance frequency energy harvesters are used, then the system is simpler to design, but the harvester cannot adapt to varying vibration frequencies reducing power generation efficiency
Solution Approach 1:
The energy harvester incorporates a dynamic tuning mechanism that allows the resonance frequency to be adjusted in real-time. The piezoelectric cantilever beam's resonance frequency can be modified by changing the proof mass position or adding/removing mass, enabling the system to adapt to varying vibration frequencies from different machinery operations.
Solution Approach 2:
The system changes the physical parameters of the piezoelectric cantilever beam, specifically the proof mass, to adjust the resonance frequency. By modifying the mass parameter, the harvester can match different vibration frequencies from various industrial sources, optimizing power generation across different operating conditions.
3Power
If piezoelectric materials are subjected to high stress to generate more power, then energy output increases, but material durability decreases leading to faster wear
Solution Approach 1:
The system utilizes mechanical vibrations from the monitored machinery to induce oscillations in the piezoelectric cantilever beam. These vibrations naturally stress the piezoelectric material to generate electrical power while operating within the material's elastic limits, converting ambient mechanical energy into electrical energy without requiring excessive external stress.
Solution Approach 2:
The patent converts the ambient vibrations, which would otherwise be wasted mechanical energy, into useful electrical power. By harvesting energy from the natural vibrations of the machinery, the system generates power without imposing additional harmful stresses on the piezoelectric material beyond what is already present in the operating environment.
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 energy harvester efficiently generates power over a wide range of frequencies, reducing maintenance needs, minimizing wear, and enabling self-sufficiency of sensors, potentially eliminating the need for batteries and reducing environmental impact.
Implementation Method 1
Energy harvesting device 12 converts various types of mechanical vibrations into electrical power
Implementation Method 2
The resonance frequency of the piezoelectric device and the proof mass is mechanically tuned to substantially match the driving vibration frequency
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
An energy harvester (12) is provided which includes an energy conversion device (24) configured to convert vibrational energy to electrical energy, a mass (30) coupled to the energy conversion device, and at least one selectively adjustable biasing mechanism (32) coupled to the mass. Selectively adjusting the biasing mechanism (32) adjusts a resonance frequency of the energy conversion device (24) and the mass (30). Preferably, a piezoelectric cantilever (29) is used and the compression distance of a spring (60) is adjusted by an actuator (46).