Piezoelectric Transformer Impedance Reduction via Phase-Inverted Vibration
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Solution Overview
Problem
Piezoelectric transformers face challenges in reducing impedance while maintaining resonant frequency, as increasing the surface area of vibration films leads to undesirable changes in resonant frequency, and existing solutions for reducing impedance in vibrators are not suitable for extracting transformed voltage.
Innovation Solution
A piezoelectric transformer design featuring a base and an upper layer with a vibration portion assembly including multiple piezoelectric layers and electrodes, where voltages of opposite phases are applied to odd and even-numbered vibration portions, allowing for impedance reduction without significantly altering the resonant frequency, and enabling voltage extraction using an intermediate electrode as a reference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the surface area of the vibration film is increased to reduce impedance, then the impedance is reduced, but the resonant frequency is undesirably changed
Solution Approach 1:
The vibration film is divided into multiple vibration portions (first vibration portion and second vibration portion) that are connected in parallel. Each vibration portion has its own piezoelectric layers and electrodes, allowing independent control of vibration phases while maintaining a compact overall structure that preserves resonant frequency characteristics.
Solution Approach 2:
Adjacent vibration portions are driven with opposite phases by applying voltages of opposite phases to the piezoelectric layers. This phase inversion approach allows the vibration portions to vibrate in opposite directions, effectively reducing the overall impedance while maintaining the resonant frequency through careful design of the vibration mode.
2Adaptability or versatility
If a multilayer structure with piezoelectric layers is used to create a piezoelectric transformer, then voltage transformation is enabled, but the impedance per element becomes high and matching with external circuit is difficult
Solution Approach 1:
Multiple vibration portions with piezoelectric layers are connected in parallel to form a single piezoelectric transformer element. This merging of multiple high-impedance elements into a parallel configuration reduces the overall impedance while maintaining the voltage transformation capability through the combined piezoelectric effect across all vibration portions.
Solution Approach 2:
The patent transitions from a single vibration mode to a multi-mode vibration structure where multiple vibration portions operate simultaneously in parallel. This dimensional expansion from one vibration element to multiple parallel elements provides both impedance reduction and voltage transformation functionality.
3Object-affected harmful factors
If a vibration device with multiple vibration portions connected in parallel is used to reduce impedance, then the impedance is reduced, but the device cannot extract transformed voltage for piezoelectric transformer implementation
Solution Approach 1:
The piezoelectric transformer structure serves multiple functions simultaneously: it reduces impedance through parallel connection of vibration portions, enables voltage transformation through the piezoelectric effect in multiple layers, and provides voltage extraction capability through properly configured output electrodes. This multi-functional design resolves the limitation of single-function vibration devices.
Solution Approach 2:
The patent introduces an intermediate electrode structure that facilitates both the input and output of voltages in the multi-layer piezoelectric configuration. This intermediary electrode arrangement enables proper voltage extraction from the transformed energy while maintaining the impedance-reducing parallel vibration structure.
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 design effectively reduces impedance and allows for voltage transformation with a boosting ratio of several tenfold, maintaining resonant frequency stability and achieving efficient power transfer.
Implementation Method 1
a first piezoelectric layer that is arranged so as to include a part of the upper layer that is interposed between the output electrode and the intermediate electrode and a second piezoelectric layer that is arranged so as to be superposed with the first piezoelectric layer
Implementation Method 2
n vibration portions arrayed in one direction, where n is an integer greater than or equal to 2... adjacent vibration portions vibrate with opposite phases
Implementation Method 3
maintaining resonant frequency stability
Data Source
AI summary
A piezoelectric transformer that includes a base and an upper layer supported by the base. The upper layer includes a first piezoelectric layer that includes the portion of the upper layer that is interposed between an output electrode and an intermediate electrode, and a second piezoelectric layer that is superposed with the first piezoelectric layer and includes the portion of the upper layer interposed between the intermediate electrode and an input electrode in at least n vibration portions. Moreover, the input electrode includes multiple input electrode pieces and the output electrode includes multiple output electrode pieces. In addition, wiring lines are routed such that voltages of opposite phases can be respectively applied to a first input electrode piece group and a second input electrode piece group with the potential of the intermediate electrode serving as a reference.