Piezoelectric Generator Wideband Energy Recovery
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Solution Overview
Problem
Current piezoelectric generators are limited to operating at a narrow frequency range around their resonance frequency, making them inefficient for applications where vibration frequencies vary significantly, as they experience increased losses and reduced efficiency when operating away from resonance.
Innovation Solution
A wideband piezoelectric generator system that includes a piezoelectric element, a switching circuit, and an inductive converter, where the switching is controlled based on the deformation and voltage of the piezoelectric element to optimize energy transfer across a range of frequencies, using sequential shorting, open-circuit, and connection phases to maximize energy transfer to a load.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a piezoelectric generator operates at resonance frequency, then energy conversion efficiency is maximized, but the operating frequency range is limited to a narrow band
Solution Approach 1:
The patent implements dynamic switching between different circuit configurations (series and parallel connections of piezoelectric elements) to adapt the system's electrical characteristics to varying vibration frequencies. The switching circuit dynamically adjusts the impedance matching between the piezoelectric elements and the load, allowing efficient operation across a wide frequency range rather than being fixed at resonance frequency only.
Solution Approach 2:
The patent changes electrical parameters (impedance, voltage, current distribution) by switching between different circuit topologies. By altering the connection configuration of piezoelectric elements and adjusting the operating voltage levels, the system maintains optimal energy conversion efficiency across varying frequency conditions, effectively decoupling efficiency from a fixed resonance frequency requirement.
2Adaptability or versatility
If switching circuitry is added to expand frequency range, then operating frequency range increases, but device complexity increases
Solution Approach 1:
The patent divides the piezoelectric generator into modular elements that can be independently switched and reconfigured. This segmentation allows the system to achieve wide frequency adaptability through combinatorial switching of individual elements, rather than requiring a completely complex control system. The modular approach simplifies the switching logic while expanding operational capabilities.
Solution Approach 2:
The switching circuit is designed to perform multiple functions: impedance matching, voltage regulation, and frequency adaptation all through the same circuit topology. This multi-functionality reduces the need for separate dedicated circuits for each function, thereby limiting the increase in overall device complexity while achieving wide frequency range operation.
3Duration of action of moving object
If continuous extraction technique is used, then energy recovery is continuous, but efficiency is limited by resistive impedance matching
Solution Approach 1:
The patent employs periodic switching between different circuit configurations rather than continuous extraction. The switching occurs in synchronized cycles with the vibration pattern, alternating between charging phases (energy storage in capacitors) and discharging phases (energy transfer to load). This periodic action reduces resistive losses by minimizing the time the circuit spends in high-current discharge states while maintaining continuous overall energy recovery.
Solution Approach 2:
The patent introduces intermediate energy storage capacitors that buffer between the piezoelectric elements and the load. These intermediaries allow the system to decouple the charging and discharging processes, enabling continuous energy recovery while reducing the peak currents and associated resistive losses that would occur with direct continuous extraction to the load.
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
Enables efficient energy recovery over a wide frequency range, optimizing energy transfer and reducing losses by dynamically adjusting the switching phases to match the varying vibration frequencies, thereby improving the overall efficiency of the energy recovery process.
Implementation Method 1
a piezoelectric element
Data Source
AI summary
A piezoelectric generator including: a piezoelectric element; a circuit for shorting and placing in open circuit the piezoelectric element; and an inductive converter.