热声直线发电机系统阻抗匹配机理及最大声功捕获控制策略研究

There are three core problems in the development of the thermoacoustic electricity generation technology, which are the resonant frequency shifting from thermoacoustic engine, the subsystem impedance no matching between the linear alternator and the thermoacoustic engine, the improving energy conversion efficiency in system, respectively. The dominant innovativeness in this project embodies three key aspects. First, basing on the thermoacoustics two-phase flow theorem, adopting acoustoelectric analogy analysis method, we explore the impedance matching mechanism of thermoacoustic electricity generator system, even further optimize the design of new transverse flux linear alternator to match thermoacoustic engine, while the alternator applied in thermoacoustic electricity generator system we have obtained patent. Secondly, a resonant structure of linear alternator of stiffness force controllable and an optimal control combining the stiffness force of system and the output characteristic from alternator are put forward, in order to solve those problems such as the off-resonance state and the reduction largely of energy conversion efficiency in the thermoacoustic electricity generator system resulting in the resonant frequency shifting from thermoacoustic engine. Simultaneously ，it is provided that the control of synergy and autonomous starting oscillation without resonance pipe in order to improve the energy conversion efficiency. It means that the thermoacoustic electricity generator system is driven into resonance by the linear alternator in motoring meanwhile it starts with autonomous oscillation. Because the resonance pipe consumes a great quantity acoustic power to make energy conversion efficiency drop dramatically. It is noted that we have obtained patent of the starting control strategy. In this project, the important achievements innovative will be obtained, which are the impedance matching mechanism in thermoacoustic system, the new method for the optimization design of transverse flux generator, the control of synergy and autonomous starting oscillation, the acoustic power maximization capturing control and so on.

热声发动机谐振频率漂移、和发电机子系统之间阻抗特性不匹配、提高热声发电效率是热声发电领域研究的核心问题。本课题主要创新性研究有三个方面：首先，提出根据热声学两相流定理，采用声电类比分析方法，探索出热-声-电系统阻抗匹配规律，并优化设计新型横向磁通直线发电机（自有专利)与之匹配；其次，针对热声发动机谐振频率漂移、导致系统失谐、热声发电效率显著降低问题，提出一种刚度力可控的直线发电机谐振结构，并采用最大声功捕获控制策略对刚度力和发电机输出特性进行综合最优控制；同时，针对热声发动机自激起振用谐振管在运行时消耗大量声功、导致系统效率降低的问题，提出取消谐振管、控制发电机电动运行将系统牵入谐振的自主协同起振控制策略（自有专利)，提高系统发电效率。课题将在热声发电系统阻抗匹配特性规律研究、新型横向磁通发电机优化设计方法、热声发电系统自主协同起振控制策略和最大声功捕获控制策略等方面取得创新性成果。

热声发电技术一种新兴的热电转换装置，能够将低品质热源转换为电能。热声发动机谐振频率漂移、和发电机子系统之间阻抗特性不匹配、提高直线发电机捕获的声功是热声发电领域研究的核心问题。.本课题主要研究内容：.（1）根据声学两相流定理、交变流动热机的介观热力循环理论、声学线性理论和热声流源理论，采用声力电类比的分析方法，系统地分析了发电机声学阻抗结构及其与热声发动机的耦合特性，建立热声发电系统的数学模型。. (2) 为提高热声发电系统捕获的声功，提出一种直线发电机弹簧机械阻抗和负载容抗双阈值设计方法。该方法通过优化弹簧刚度系数、负载电容和负载电阻阈值，实现系统捕获声功最大的设计目标。此方法易于工程设计，可控性好，实时性强，可以有效地提高整机的匹配性。.（3）考虑到热声发电系统声学柔性运动特性，分别提出叠片单元交错初级圆筒型永磁直线发电机设计方案、“Ω”型叠片初级圆筒型永磁直线发电机设计方案，基频与二倍频混合型双定子圆筒永磁直线振荡发电机设计方案。.（4）提出基于三维磁路的横向磁通永磁直线电机空间穿片磁场分析方法，计算穿片磁场区间，基于子域模型法对横向磁通永磁直线电机初级铁心中穿片磁感强度进行计算。计算由穿片磁场所产生的附加涡流损耗，推导计算得到不同饱和状态下穿片磁场所形成的涡流损耗及经典铁耗与电机主磁密的幂函数关系，并给出综合考虑空载铁耗及功率密度的设计的横向磁通永磁直线电机设计依据。.（5）设计并搭建三个实验平台：拼装式穿片磁场等效实验平台；热声发电系统刚度力可控谐振结构实验平台；以热声发动机、直线发电机、检测系统、控制系统和电负载为主要组成设备的热声直线发电系统实验平台。.申请发明专利2项；发表相关学术论文15篇，其中SCI检索1篇，EI检索8篇，培养博士（生）3人、硕士（生）4人；项目成果转化：为中国工程物理研究院机械制造工艺研究所开发研制国内首台15kW大功率直线振荡发电机及其控制系统。