压电变压器的研究进展

压电变压器利用压电陶瓷材料自身的压电和逆压电效应来实现升降压，同传统的电磁变压器相比较，具有体积小、无电磁污染、升压比随工作频率和阻抗变化的特点。本文详细评述了用于压电变压器的铁电陶瓷材料的电畴特性、性能参数和掺杂改性的方法，以及压电变压器的变压原理、一般等效电路图和各种各样的压电变压器，分析了现阶段压电变压器存在的问题，并展望了压电变压器的发展方向。     

压电陶瓷变压器的发展——回顾与展望

文章简要介绍了压电变压器的工作原理 ,给出了压电变压器几个重要工作特性的数学表达式 ,并对压电变压器的发展过程进行了简要的回顾。在此基础上 ,文章着重对压电变压器在研发过程中所涉及的五个方面的问题进行了详细的探讨与说明 ,作者讨论了压电变压器等效电路模型的改进措施及压电变压各个特性的研究状况 ,分析和对比了各种用于制作压电变压器的压电材料的优缺点及其性能的改进方法 ,探讨了各种振动模式作用于压电变压器的效果 ,总结了压电变压器的制作工艺及结构对其特性的影响效果 ,给出了压电变压器的具体应用的例子 ,并指出了压电变压器今后的发展方向及有待解决的问题     

压电陶瓷变压器材料的研究与发展

从压电变压器材料的角度叙述了:压电变压器材料研究与发展;压电变压器对其材料性能的要求;现有常用的各系列压电陶瓷变压器材料及其特点;今后的发展。     

压电陶瓷变压器研究和发展现状

概述了压电陶瓷变压器的原理和分类，介绍了各种振动模式的压电陶瓷变压器，并重点叙述了两种电极设计精巧的压电陶瓷变压器，对体型和膜型压电陶瓷变压器的研究进展现状进行了分析。     

压电陶瓷变压器CCFL背光电源研究

以压电陶瓷变压器为升压器件，以脉宽调制器（PWM）和MOSFEET管所组成的开关振荡器为驱动电．路，研制出适用于液晶显示器的压电陶瓷变压器背景光高压电源。由于压电陶瓷变压器具有体积小、重量轻、不会打火、不会燃烧、不怕短路等优点，不仅提高了液晶显示器整机的可靠性，而且能适应当前电子产品小型化、轻型化的发展需要。     

大功率压电变压器用压电陶瓷材料发展现状

随着科学技术的进步和压电变压器在生产中的应用，压电陶瓷变压器逐渐向“大功率”、“小型化”方向发展，对压电陶瓷材料提出了更高的要求，简而言之就是“双高”及“双低”，即高“Qm”、高“Kp”和低“tanδ”、低“TCf，”。同时为降低生产成本，压电陶瓷材料应具有尽可能低的烧结温度。本文即以此为中心，对我国大功率压电材料的生产及发展现状、各项性能的影响因素及其成份选择原则做出了相应的讨论。     

PLMN、PLN、PMN体系压电陶瓷性能与结构的对比研究

在ＰＬＮ－ＰＺＴ、ＰＭＮ－ＰＺＴ两个三元素基础上制备的ＰＬＭＮ－ＰＺＴ四元素系压电陶瓷综合了两个三元素材料的优点，既具有良好的压电性能又具小的损耗，是一种优良的压电变压器材料。通过三个体系的比较，ＰＬＭＮ－ＰＺＴ四元材料适中的四方度、晶粒尺寸及晶界处锰的析出是它具有良好压电、介电性能的结构基础。     

功能陶瓷材料研究的若干进展

本文介绍了几种典型铁电、压电陶瓷及其多层片式元件应用研究的若干新进展。基于过渡液相烧结机制的压电陶瓷材料具有烧结温度低、压电常数和介电常数高，介质损耗低等诸多优点。低烧多层压电变压器(MPT)以其低驱动电压、小体积、高升压比、薄型片式化等优点在液晶显示背光电源等方面获得应用。多层压电变压器及其背光电源具有高功率密度、高转换效率、薄型化和低成本等特点，通过有限元分析和多普勒激光扫描测振仪对MPT的振动模态与机电谐振特性等进行了分析与测定，为结构与性能优化提供了理论与实验依据。研究了钛酸钡基高介电常数温度稳定型多层陶瓷电容器(MLCC)及薄层贱金属内电极MLCC的关键材料组成以及制备技术，基于缺陷化学原理和无晶粒长大的致密化烧结动力学，通过调控受、施主掺杂和两段法烧结工艺，制备了在还原气氛烧结亚微米／纳米晶钛酸钡基陶瓷及其细晶化贱金属内电极MLCC。研究了多层复合功能陶瓷共烧行为、异质界面互扩散、致密化速率调控机制及共烧匹配技术，借助于差热膨胀仪研究了铁电陶瓷介质和内电极共烧失配的动力学根源，为制备高可靠的MLCC等多层元器件提供实验与理论依据。介绍了压电陶瓷超声微马达的结构与特性。     

功能陶瓷材料研究的若干进展

本文主要介绍几种典型的铁电、压电陶瓷及其多层片式元件应用研究的若干新进展.基于过渡液相烧结机制的压电陶瓷材料具有烧结温度低、压电常数和介电常数高,介质损耗低等诸多优点.低烧多层压电变压器(MPT)以其低驱动电压、小体积、高升压比、薄型片式化等优点在液晶显示背光电源等方面获得应用.多层压电变压器及其背光电源具有高功率密度、高转换效率、薄型化和低成本等特点,通过有限元分析和多普勒激光扫描测振仪对MPT的振动模态与机电谐振特性等进行了分析与测定,为结构与性能优化提供了理论与实验依据.研究了钛酸钡基高介电常数温度稳定型多层陶瓷电容器(MLCC)及薄层贱金属内电极MLCC的关键材料组成以及制备技术,基于缺陷化学原理和无晶粒长大的致密化烧结动力学,通过调控受、施主掺杂和两段法烧结工艺,制备了在还原气氛烧结亚微米/纳米晶钛酸钡基陶瓷及其细晶化贱金属内电极MLCC.研究了多层复合功能陶瓷共烧行为、异质界面互扩散、致密化速率调控机制及共烧匹配技术,借助于差热膨胀仪研究了铁电陶瓷介质和内电极共烧失配的动力学根源,为制备高可靠的MLCC等多层元器件提供实验与理论依据.介绍了压电陶瓷超声微马达的结构与特性.     

锰掺杂对PMN-PT陶瓷介电和压电特性的影响

采用氧化物固相反应法制备了Mn掺杂0.67Pb（Mg1/3Nb2/3）O3-0.33PbTiO3陶瓷，研究了锰掺杂量对陶瓷相结构、介电和压电性能的影响。实验发现，随着锰掺杂量的增加，陶瓷焦绿石相含量的逐渐较少，材料变“硬”。即当锰掺杂量少于1.5mol％时，介电系数ε、压电常数d33和机械品质因数Qm逐渐增加，介电损耗tanδ减少。随着锰掺杂量的进一步增加，弛豫程度变得更加明显。当压电陶瓷组分中锰掺杂量为1.5mol％时，其介电和压电性能各为：ε=2300，kp=0.54，Qm=900，tanδ=0.004，d33=400pC/N，适于制作大功率压电陶瓷变压器。     

Penny shaped crack in a three-dimensional piezoelectric strip under in-plane normal loadings

Summary The singular mechanical and electric fields in a three-dimensional piezoelectric ceramic strip containing a penny shaped crack under in-plane normal mechanical and electrical loadings based on the continuous electric boundary conditions on the crack surface are considered here. The potential theory and Hankel transforms are used to obtain a system of dual integral equations, which is then expressed as a Fredholm integral equation. All sorts of field intensity factors of Mode I are given, and numerical values for PZT-6B piezoelectric ceramic are graphically shown.     

加层压电条界面裂纹的稳态扩展

研究当压电条同时与两个不同材料的弹性条粘接在一起,在反平面机械载荷及面内电载荷联合作用下,长度不变的有限Griffith 界面裂纹沿加层压电条界面以常速稳态扩展时裂尖的动态断裂问题。应用Fourier积分变换将问题化为以第二类Fredholm积分方程表示的对偶积分方程,导出了相应的动应力强度因子表达式。给出了动应力强度因子与裂纹传播速度、裂纹长度、压电条及弹性条厚度、电荷载大小及方向的关系曲线。研究结果对结构设计及结构失效的预防具有理论和应用价值。     

Contact zone models for an interface crack in a piezoelectric material

Summary A plane strain problem for an interface crack along the fixed edge of a piezoelectric semi-infinite space is examined. Electrically conducting and electrically insulated crack surfaces are considered. By using Fourier transforms the systems of singular integral equations are formulated for both cases. It was found that in the second case for the most commonly used piezoelectric materials instead of oscillating singularity the real singularity of general power type occurs. The dependence of this singularity on the piezoelectric parameters has been investigated. The contact zone model is considered as an alternative one for the case of the oscillating singularity, and the way this model can be used for the investigation of interface cracks in finite size piezoelectrics is suggested.     

Scattering of antiplane shear waves by a finite crack in piezoelectric laminates

Summary Following the dynamic theory of linear piezoelectricity, we consider the scattering of horizontally polarized shear waves by a finite crack in a composite laminate containing a piezoelectric layer. The piezoelectric layer is bonded between two half-spaces of a different elastic solid. The crack is normal to the interfaces and is placed at an equal distance away from them. Both cases of a partially broken layer and a completely broken layer are studied. Fourier transforms are used to reduce the problem to the solution of a pair of dual integral equations. The solution of the dual integral equations is then expressed in terms of a singular integral equation. The propagation of symmetric first mode is studied numerically, and the dynamic stress intensity factor and the dynamic energy release rate are obtained for some piezoelectric laminates.     

Cylindrical interface cracks in 1-3 piezocomposites

1-3 Piezocomposites are made by embedding piezoelectric fibers/rods in polymer matrix materials. Fiber–matrix interface fracture can affect the performance of piezocomposites. In this paper, axisymmetric interfacial cracks in piezocomposites are studied by considering an idealized model of a single piezoelectric fiber in a matrix material. The displacement discontinuity method is used to formulate the Mode I and II crack problems. The fundamental solutions required for DDM are derived explicitly by using the electroelastic field equations and Fourier integral transforms. The dependence of Mode I and II stress intensity factors of single and multiple interface cracks on fiber and matrix material properties, crack length and distance between cracks are investigated.     

Singular stress and electric fields of a piezoelectric ceramic strip with a finite crack under longitudinal shear

Summary Following the theory of linear piezoelectricity, we consider the problem of determining the singular stress and electric fields in an orthotropic piezoelectric ceramic strip containing a Griffith crack under longitudinal shear. The crack is situated symmetrically and oriented in a direction parallel to the edges of the strip. Fourier transforms are used to reduce the problem to the solution of a pair of dual integral equations. The solution of the dual integral equations is then expressed in terms of a Fredholm integral equation of the second kind. Numerical values on the stress intensity factor and the energy release rate for piezoelectric ceramics are obtained, and the results are graphed to display the influence of the electric field.     

加层压电半空间界面裂纹力电联合冲击动态响应

基于线性压电弹性理论,研究电绝缘和电接触两种电边界条件下,任意多个任意排列的压电加层半空间界面裂纹在力电联合冲击作用下的动态响问题。通过引进Laplace变换和 Fourier 变换及位错密度函数,将问题首先转化为Cauchy 奇异积分方程,进而转化为代数方程进行数值求解。数值算例表明,电载荷、加层厚度及材料参数对动能量释放率具有重要的但不同的影响。研究结果对结构设计及结构失效的预防具有理论和应用价值。     

Impact response of a finite crack in an orthotropic piezoelectric ceramic

Summary The transient dynamic stress intensity factor and dynamic energy release rate were determined for a cracked piezoelectric ceramic under normal impact in this study. A plane step pulse strikes the crack and stress wave diffraction takes place. Laplace and Fourier transforms are employed to reduce the transient problem to the solution of a pair of dual integral equations in the Laplace transform plane. The solution of the dual integral equations is then expressed in terms of a Fredholm integral equation of the second kind. A numerical Laplace inversion technique is used to compute the values of the dynamic stress intensity factor and the dynamic energy release rate for some piezoelectric ceramics, and the results are graphed to display the electroelastic interactions.     

Impact response of an anti-plane crack in a FGPM bonded to a homogeneous piezoelectric strip

A finite crack under transient anti-plane shear loads in a functionally graded piezoelectric material (FGPM) bonded to a homogeneous piezoelectric strip is considered. It is assumed that the electroelastic material properties of the FGPM vary continuously according to exponential functions along the thickness of the strip, and that the two layered strips is under combined anti-plane shear mechanical and in-plane electrical impact loads. The analysis is conducted on the electrically unified crack boundary condition. Laplace and Fourier transforms are used to reduce the mixed boundary value problems to Fredholm integral equations of the second kind in the Laplace transform domain. Then, a numerical Laplace inversion is performed and the dynamic intensities are obtained as functions of time and geometric parameters, which are displayed graphically.