Low-Loss Piezoelectric Transformer Using Energy Trapping of Width Vibration

Abstract

Piezoelectric transformers proposed by Rosen have been studied for high-voltage step-up applications. A piezoelectric transformer using LiNbO3 proposed recently by Nakamura and Adachi has low loss and a simple structure. The plate of a conventional piezoelectric transformer was supported only at the node of vibration. Rigid support and loss suppression are required for high-power and high-voltage applications. To apply a piezo-electric transformer to a power circuit, we studied methods for supporting the piezoelectric plate and reducing loss. Based on these studies, we proposed a piezoelectric transformer using energy trapping of the width-shear vibration in a LiNbO3 plate.

Construction of a low-frequency high-power piezoelectric transformer with a specified step-up voltage transformation ratio using two identical bolt-clamped Langevin-type transducers

“…However, we should be aware that the voltage transformation ratio specified in the design cannot be obtained at a frequency near the total mechanical resonance under such optimum conditions for power-transfer efficiency. [20][21][22][23][24][25][26][27][28][29][30][31] On the other hand, the piezoelectric transformer proposed here can exactly realize the specified step-up voltage transformation ratio at a frequency very close to its total mechanical resonance. In addition, even in high-amplitude operation where the "jump" effect becomes significant, the transformer can realize the exact specified voltage transformation ratio by adjusting the driving frequency slightly as shown in Figs.…”

Power transmission through an unbounded elastic plate using a finite piezoelectric actuator and a finite piezoelectric power harvester

“…There are also other possible applications of the technology like data transmission [6] through a wall by acoustic waves. The procedure involves the generation and propagation of acoustic waves and energy harvesting from the waves using piezoelectric transducers, representing generalizations or combinations of piezoelectric generators (power harvesters) [7][8][9][10][11][12] in which energy changes from mechanical to electrical, and piezoelectric transformers [13][14][15][16][17][18][19] in which energy changes from electrical to mechanical and then back to electrical.…”

High-Power, Multioutput Piezoelectric Transformers Operating at the Thickness-Shear Vibration Mode

“…Compared with a conventional electromagnetic transformer, a piezoelectric transformer has many advantages such as high-power density, high efficiency, low profile, small size, light weight, no windings, electromagnetic noise-free operation, and noninflammability. Since the Rosen-type transformer [1], many piezoelectric transformers have been proposed and developed [2]- [13]. However, up to now, the piezoelectric transformers mainly have been used to generate high voltage for the cold cathode fluorescent lamps in notebook computers.…”