Piezoelectric transformers(PT) are expected to be small, thin and highly efficient, and which are attractive as a transformer with high power density for step down voltage. For these reasons, we have attempted to develop a step-down PT for the miniaturized adaptor. We propose a PT, operating in thic...
Piezoelectric transformers(PT) are expected to be small, thin and highly efficient, and which are attractive as a transformer with high power density for step down voltage. For these reasons, we have attempted to develop a step-down PT for the miniaturized adaptor. We propose a PT, operating in thickness extensional vibration mode for step-down voltage. This PT consists of a multi-layered construction in the thickness direction. In order to develop the step-down PT of 10 W class and turn ratio of 0.1 with high efficiency and miniaturization, the piezoelectric ceramics and PT designs are estimated with a variety of characteristics. The basic composition of piezoelectric ceramics consists of ternary yPb(Zr$_{x}$Ti$_{1-x}$)O$_{3}$-(1-y)Pb(Mn$_{1/3}$Nb1$_{1/3}$Sb$_{1/3}$)O$_{3}$. In the piezoelectric characteristics evaluations, at y=0.95 and x=0.505, the electromechanical coupling factor(K$_{p}$) is 58$\%$, piezoelectric strain constant(d$_{33}$) is 270 pC/N, mechanical quality factor(Qr$_{m}$) is 1520, permittivity($\varepsilon$/ 0) is 1500, and Curie temperature is 350 $^{\circ}C$. At y = 0.90 and x = 0.500, kp is 56$\%$, d33 is 250 pC/N, Q$_{m}$ is 1820, $\varepsilon$$_{33}$$^{T}$/$\varepsilon$$_{0}$ is 1120, and Curie temperature is 290 $^{\circ}C$. It shows the excellent properties at morphotropic phase boundary regions. PZT-PMNS ceramic may be available for high power piezoelectric devices such as PTs. The design of step-down PTs for adaptor proposes a multi-layer structure to overcome some structural defects of conventional PTs. In order to design PTs and analyze their performances, the finite element analysis and equivalent circuit analysis method are applied. The maximum peak of gain G as a first mode for thickness extensional vibration occurs near 0.85 MHz at load resistance of 10 .The peak of second mode at 1.7 MHz is 0.12 and the efficiency is 92$\%$.
Piezoelectric transformers(PT) are expected to be small, thin and highly efficient, and which are attractive as a transformer with high power density for step down voltage. For these reasons, we have attempted to develop a step-down PT for the miniaturized adaptor. We propose a PT, operating in thickness extensional vibration mode for step-down voltage. This PT consists of a multi-layered construction in the thickness direction. In order to develop the step-down PT of 10 W class and turn ratio of 0.1 with high efficiency and miniaturization, the piezoelectric ceramics and PT designs are estimated with a variety of characteristics. The basic composition of piezoelectric ceramics consists of ternary yPb(Zr$_{x}$Ti$_{1-x}$)O$_{3}$-(1-y)Pb(Mn$_{1/3}$Nb1$_{1/3}$Sb$_{1/3}$)O$_{3}$. In the piezoelectric characteristics evaluations, at y=0.95 and x=0.505, the electromechanical coupling factor(K$_{p}$) is 58$\%$, piezoelectric strain constant(d$_{33}$) is 270 pC/N, mechanical quality factor(Qr$_{m}$) is 1520, permittivity($\varepsilon$/ 0) is 1500, and Curie temperature is 350 $^{\circ}C$. At y = 0.90 and x = 0.500, kp is 56$\%$, d33 is 250 pC/N, Q$_{m}$ is 1820, $\varepsilon$$_{33}$$^{T}$/$\varepsilon$$_{0}$ is 1120, and Curie temperature is 290 $^{\circ}C$. It shows the excellent properties at morphotropic phase boundary regions. PZT-PMNS ceramic may be available for high power piezoelectric devices such as PTs. The design of step-down PTs for adaptor proposes a multi-layer structure to overcome some structural defects of conventional PTs. In order to design PTs and analyze their performances, the finite element analysis and equivalent circuit analysis method are applied. The maximum peak of gain G as a first mode for thickness extensional vibration occurs near 0.85 MHz at load resistance of 10 .The peak of second mode at 1.7 MHz is 0.12 and the efficiency is 92$\%$.
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제안 방법
However, it does not be commercialized in the step-down transformer that is required as a de power supply such as dc-dc converter and adaptor. In order to develop the stepdown PTs of 10 W class and turn ratio of 0.1 with high efficiency and miniaturization, the piezoelectric ceramics and PTs designs are estimated with a variety of characteristics. The basic composition of piezoelectric ceramics consists of ternary yPb(ZrxTi i_x)O3-( 1 -y)Pb(Mni/3 Nbi/3Sb|/3)O3.
12 and the efficiency is 92%. In order to investigate the applications of designed PTs, the zero-voltage-switching, clamped-voltage (ZVS-CV) topologies are introduced and step-down PTs for an adaptor are designed and simulated. From the calculated results, the output power is about 10 W and efficiency is 85% at the switching frequency of 1.
Ferroelectric ceramics have Curie temperature that shifts from ferroelectric phase to para-electric phase with the change of temperatun?, and the permittivity has a peak at Curie temperature. In order to measure Curie temperature, the poled films fixed on holder in furnace, and the changes of capacitance were estimated with temperature by impedance/gain analyzer (HP 4194A). The thermocouple contacted on surface of ceramic film to measure possibly exact capacitance, and the rising velocity of temperature controlled below 1.
This paper proposes a step-down PT that has the turn rate of 10:1 and the output power of 10 W for the charger and adaptor of mobile phones, expecting the largest demand of various applications. The design of this transformer adopts the multi-layer method using a thickness extensional vibration mode for low impedance.
대상 데이터
). The disk-type films with 1 mm thickness and 12 mm diameter produced under the provision of EMAS 6001. Their dielectric and piezoelectric properties were measured under the low electric field.
There are 15 manufacturing industries for PT in Japan, taking the most technical lead in this field. Their PTs were used for LCD back light inverters of PDA, DVD players, car navigation system, camcorder, digital camera and notebook computers, and their capacities were around 10-50 W[2, 3]. PT is possible to make step-up and step-down voltages with the structure designs of vibration modes as in wire type transformers.
이론/모형
This paper proposes a step-down PT that has the turn rate of 10:1 and the output power of 10 W for the charger and adaptor of mobile phones, expecting the largest demand of various applications. The design of this transformer adopts the multi-layer method using a thickness extensional vibration mode for low impedance. Piezoelectric ceramic of step-down PT has the ternary composition as a modified PZT.
성능/효과
It means that the pinning effect is generated by addition of Mn in ternary PMNS. The kp of 0.95PZT-0.05PMNS composition proposed in this research is lower about 2% than that of 0.95PZT-0.05PMN, and Qm and Curie temperature increase around 50% and 10%, respectively. From these results, it is expected that piezoelectric PZT- PMNS ceramic may be available for high power piezoelectric devices such as PTs.
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