壓電變壓器應用於低壓直流電源轉換器時，一般採用厚度共振模態壓電變壓器以適應低阻抗負載，唯該型壓電變壓器之結構與製程較為複雜，且於商用化上有專利權問題。本文則係採用結構及製程均較為簡單之環型壓電變壓器，進行其應用於低壓直流電源轉換器之研究。文中首先推導環型壓電變壓器之等效模型，並使用Spice 與Matlab 軟體分析與模擬其特性。最後，配合相位檢測器及脈波寬度調變技術，利用半橋諧振式電路驅動環型壓電變壓器，令壓電變壓器確定工作於其諧振頻率，俾使其得以因應輸出端負載之變動，且達致較高輸出效率之目的。

When the piezoelectric transformer (PT) applies to DC-DC converters, it always uses thickness vibration mode PT for low impedance load. Because the structure and manufacture of the
above-mentioned PT is complex and there are patent problems in business, this thesis adapts simpler Annular-Type PT in structure and
manufacture to study DC-DC converters. First of all,the PT equivalent circuit and characteristics is introduced. And uses Spice and Matlab to
simulate and analyze. Later it uses the half bridge resonant circuit to drive the PT. A control strategy for DC-DC converters based on phase detector circuit. The control always tracks transformer resonance frequency. Voltage regulation is achieved by adopting the pulse width
modulation technique. Eventually, it will achieve the purpose of higher output efficiency.

[1] M. Rodahl and B. Kasemo, “On the measurement of thin liquid overlayers with the quartzcrystal microbalance,” Sensors and Actuators, A54, pp. 448-456, 1996.
[2] P. C. Y Lee and J. D. Yu, “Governing equations for a piezoelectric plate with graded properties across the thickness,” IEEE Trans. Ultrason., Ferroelec., and Frequency Contr., vol.45, no.1, pp. 236-250, Jan. 1998.
[3] T. Itoh and T. Suga, “Self-excited force-sensing micro- cantilevers with piezoelectric thin films for dynamic scanning force microscopy,” Sensors and Actuators, A54, pp. 477-781, 1996.
[4] V. L. Strashilov, J. I. Burov, and M. P. Nikolov, “Dynamic shear piezoelectricity of poly thin films,” IEEE Trans. Ultrason., Ferroelec., and Frequency Contr., vol.44, no.6, pp.1181-1190, Nov. 1997.
[5] Q. Zhang, P. A. Lewin, and E. Bloomfield, “PVDF transducers-A performance comparison of single-layer and multilayer structures,” IEEE Trans. Ultrason., Ferroelec., and Frequency Contr., vol.44, no5, pp. 1148-1156, Sep. 1997.
[6] 池田拓郎著,陳世春譯, 基本壓電材料學,復漢出版社pp.1-3, 1999.
[7] 許溢适, 壓電陶瓷新技術, 文笙書局, pp.1-90, 1994.
[8] C. A. Rosen, “Ceramic transformers and filters,” in Proc. of Electronic Comp. Symp., 1956.
[9] T. Zaitsu, O. Ohnishi, T. Inoue, M. Syoyama, and T. Ninomiya, “2MHz power converter with piezoelectric transformer,” in Proc. of IEEE. INTELEC, 1992, pp.430-437.
[10] C. Y. Lin and F. C. Lee, “Development of a piezoelectric transformer converter,” in Proc. of VPEC Power Electro. Seminar , 1993, pp.79-85.
[11] C. Y. Lin, “Design and analysis of piezoelectric transformer converters,” Ph. D Thesis, Virginia Polytechnic Institute and State University, USA, 1997.
[12] O. Ohnishi, H. Kishie, A. Iwamoto, T. Zaitsu, and T. Inoue, “Piezoelectric ceramic transformer operating in thickness extensional mode for power supply,” in Proc. of IEEE. Ultrasonics Symposium, 1992, pp.483-488.
[13] C. Y. Lin and F. C. Lee, “Piezoelectric transformer and its applications,” in Proc. of VPEC Power Electron. Seminar, 1995.
[14] T. Zaitsu, “Power conversion using piezoelectric transformer,” Ph.D. Dissertation, Kyushu University, Fukuoka, Japan, August 1997.
[15] S. H. Lee, J. I. Hong, J. H. Yoo, and S. G. Geon, “Characteristics of piezoelectric transformer for power supply,” in Proc. of IEEE. Ultrasonics Symposium, 1998, pp.971-975.
[16] R. L. Lin, F. C. Lee, E. M. Baker, and D. Y. Chen, “Inductor-less piezoelectric transformer electronic ballast for linear fluorescent lamp,” in Proc. of IEEE APEC, 2001,pp.664-669.
[17] K. Sakurai, S. Shindou, K. Ohnishi, and Y. Tomikawa, “Piezoelectric ceramic transformer using radial vibration mode disks,” in Proc. of IEEE. Ultrasonics Symposium, 1998, pp.939-944.
[18] C. Y. Lin and F. C. Lee, “Design of a piezoelectric transformer converter and its matching networks,” in Proc. of IEEE PESC’94, 1994, pp.607-612.
[19] H. W. Katz, Solid State Magnetic and Dielectric Devices, N.Y., Wiley, pp.94-126, 1959.
[20] D. A. Berngcourt, D. R. Curran, H. Jaffe, Piezoelectric and Piezomagentic Materials and Their Function in Transducers, In: W. P. Mason, ed., Physical Acoustics, vol. 1A, Academic Press, N.Y., pp.233-249, 1964.
[21] B. Jaffe, W. R. Cook, H. Jaffe, Piezoelectric Ceramics, N.Y., Academic Press, pp.7-47, 1971.
[22] 傅明宇, “應用壓電變壓器於冷陰極管驅動電路之研究”, 國立成功大學電機工程學系碩士論文, 1999.
[23] T. Zaitsu, T. Shigehisa, M. Shoyama, and T. Ninomiya, “Piezoelectric transformer converter with PWM control,” in Proc. of IEEE APEC, 1996, pp.279-283. [24] H. Kakehashi, T. Hidaka, T. Ninomiya, M. Shoyama, H. Ogasawara, and Y. Ohta, “Electronic ballast using piezoelectric transformers for fluorescent lamps,” in Proc. of IEEE PESC’98, 1998, pp.29-35.
[25] 馮若主編, 超聲手冊,南京,南京大學出版社pp.589-591, 1999
[26] 許書豪，“應用數位信號處理器建構之數位式波寬調變變 流器”， 國立成功大學電機工程研究所碩士論文，1997.