• Proceedings of the KIPE Conference
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• 2002.07a
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• pp.701-706
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• 2002

Typically, dimensions of the power circuit depend on magnetic components, heat sink, and smoothing capacitor, etc. For the miniaturization of the power circuit, one of the solutions is that bulky magnetic transformer in previously used is replaced by a piezoelectric transformer. Therefore, since many systems are attempted to apply the piezoelectric transformers, a new piezoelectric material is tending to be developed continuously. In this paper, an analysis of neon tube inverters with piezoelectric transformers are presented by Pspice modeling. Simulation results show that it is possible to apply a piezoelectric transformer to neon tube inverters with high conversion efficiency

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04b
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• pp.195-198
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• 2004

In this paper, the disk-type piezoelectric transformer for the high power was investigated with the variation of road resistance. The diameter and thickness of a disk-type piezoelectric transformer was 50mm and 4.5mm, respectively. The piezoelectric transformer was composed to PZT-PMN-PSN. The ratio of driving electrode and generating electrode ranges from 1.4:1 to 3:1. The poling direction of driving part and generating part are the same. A voltage step-up ratio increased with increasing the load resistance, $R_L$, so it reached 60 times under no road resistance. also, the maximum efficiency of 97% was obtained.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.48 no.9
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• pp.611-615
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• 1999

Piezoelectric properties of PMN-PZT ceramics with $CeO_2$ impurity were investigated. Mechanical quality factor, $Q_m$ of 1792, 1285 and the electromechanical coupling coefficient, $k_p$ of 0.52, 0.54 were obtained from the specimen with 0.25 and 0.5 mole % $CeO_2$ respectively. Curie temperature was decreased with the addition of $CeO_2$ while the electric coercive field was proportional to the amount of impurity. Based on the system ceramics with 0.5 mole % cerium oxide, a Rosen type piezoelectric transformer was fabricated and tested. Voltage step-up ratios of 230 and 13 were obtained from the transformer at no load and $100 k\Omega$ resistance, respectively. Experimental results showed a potential of the transformer for the practical use coupled with the expected strength increase by the grain size refinement.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.7 no.3
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• pp.350-357
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• 2006

In this paper, a PSPICE model of piezoelectric transformer and CCFL using an electrical equivalent circuit was presented. The parameters of CCFL for PSPICE were derived by the least square method. The computer simulations were performed and the results are compared on the PSIPCE model of piezoelectric transformer driven by push-pull inverter and CCFL.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.11 no.10
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• pp.849-854
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• 1998

The load characteristics on the voltage gain and efficiency were analyzed using a lumped constant equivalent circuit of the piezoelectric transformer. These analytical results were confirmed by experiments. Theoretical values of voltage gain were nearly constant with experimental ones. However, It was shown that theoretical values of efficiency is higher than experimental ones.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 1998.06a
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• pp.183-189
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• 1998

In this paper, The load characteristics on the voltage gain and efficiency were analyzed sing an lumped constant equivalent circuit of the piezoelectric transformer. These analytical results are confirmed by experiments. Theoretical values of voltage gain were nearly constant with experimental ones. However, It was shown that theoretical values of efficiency had higher values than experimental ones.

• The Transactions of the Korean Institute of Power Electronics
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• v.9 no.2
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• pp.171-177
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• 2004

Piezoelectric transformer(PZT) can be used advantageously in high output voltage power supply. Recently, it also can be used in AC/DC Converter for miniaturizing size nd lightening weight. The modeling of PZT was performed by the calculation method through the physical and electrical constants of the material. The attributes of PZT were derived by an approximate analysis for output voltage gain, and resonant frequency. The proposed method is verified by computer simulation and experiment.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.469-470
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• 2006

Piezoelectric transformers based on lead zirconate titanate(PZT) have been received considerable interest because of their wide potential applications in transformer, oscillator, resonance sensor, actuator, acoustic transducer, as well as active slider for hard disk drives. However, for the applications which need a small power supply such as thin and flat displays, micro-robot, micro-system, it is especially necessary to integrate the passive components because they typically need more than 2/3 of the space of the conventional circuit. So, we have fabricated the piezoelectric micro-transformer to supply energy for micro-systems using PZT thin films and MEMS technologies.

• Proceedings of the KIEE Conference
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• 2006.07b
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• pp.1031-1033
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• 2006

In this study, in order to solve these problems, a new type of electronic ballast, which is composed of rectifier, active power factor corrector, series resonant half bridge inverter and piezoelectric transformer, was proposed for driving T5 fluorescent lamp. Driving of piezoelectric transformer was carried out with input region for the ring electrode and output region for the dot electrode. A 35W (T5) fluorescent lamp was successfully driven by the fabricated ballast with piezoelectric transformer.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.03a
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• pp.1-1
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• 2010

In this study, electrical properties of multilayer piezoelectric transformer sintered at $900^{\circ}C$ using pure Ag internel electrode was investigated. This multilayer piezoelectric transformer was fabricated as a ring-dot type. The multilayer piezoelectric transformer should have hight electromechanical coupling factor ($k_p$) and electromechanical qualiy factor ($Q_m$) in order to increase the efficiency of energy conversion between electrical and mechanical energy. The maximum values of $k_p$ and $Q_m$ showed 0.552 and 1320, respectively.