Multilevel model order reduction

We present a multilevel Model Order Reduction scheme for enhancing numerical analysis of electromagnetic fields by means of grid based techniques. The scheme allows one to create nested macromodels and combine macromodels with the Fast Frequency Sweep. The implementation of the method is illustrated on the Finite Difference Frequency Domain technique and efficient nodal order reduction algorithm (ENOR) but the concept can easily be applied also for other mesh based methods and other order reduction schemes.     

Computationally efficient and stable order reduction methods for a large-scale model of MEMS piezoelectric energy harvester

In this work, we present novel model order reduction approaches for a large-scale multiport model of a MEMS-based piezoelectric energy harvester. These techniques are computationally efficient and generate stable reduced order models. The first method proposed combines model reduction based on Krylov subspaces and a Schur complement transformation of the resulting system. The second method includes structure preserving Krylov subspaces based model order reduction. We demonstrate an excellent match between the full-scale and the reduced order models of the harvester device during harmonic simulation and the co-simulation of the reduced harvester model together with the power management circuitry.     

Model order reduction using spline-based dynamic multi-point rational interpolation for passive circuits

The efficient modeling of integrated passive components and interconnects is vital for the realization of high performance mixed-signal systems. In this paper, we develop a dynamic multi-point rational interpolation method based on Krylov subspace techniques to generate reduced order models for passive components and interconnects that are accurate across a wide-range of frequencies. We dynamically select interpolation points by applying a cubic spline-based algorithm to detect complex regions in the system's frequency response. The results indicate that our method provides greater accuracy than techniques that apply uniform interpolation points.     

Sensitivity reduction in feedback eigenvalue controller design

The problem of reducing sensitivity to variations of the open-loop system parameters is considered for the case where the objective is to design a feedback controller which drives the open-loop eigenvalues to desired positions. The results are based on the assumption that the open-loop multivariable system is transformed to a phase-variable canonical form prior to the application of the control design procedure.     

Least-squares model order reduction enhancements

Two enhancements to the least-squares (LS) discrete-time model order reduction (MOR) method are presented: scaling and frequency response matching. Scaling generally improves the low-frequency fit between the reduced-order model (ROM) and the original model. For exact gains at specific frequencies, optional frequency response constraints can easily be added to the LS MOR method. An example is presented that illustrates these enhancements. The example model is reduced with the Hankel norm, weighted impulse response gramian, and LS MOR methods. Plots of error versus frequency are given for each of the three MOR methods     

Sensitivity analysis in multivariable-system design

A technique which makes the eigenvalue analysis of a class of systems much simpler, more accurate and more meaningful is presented. The given problem is split into a few smaller problems, and the sensitivity analysis of these subproblems is carried out independently. This approach provides deeper insight into the behaviour of the physical system.     

An efficient terminal and model order reduction algorithm

The paper proposes an efficient terminal and model order reduction method for compact modeling of interconnect circuits with many terminals. The new method is inspired by the recently proposed terminal reduction method, SVDMOR [P. Feldmann, F. Liu, Sparse and efficient reduced order modeling of linear subcircuits with large number of terminals, in: Proceedings of the International Conference on Computer Aided Design (ICCAD), 2004, pp. 88-92]. But different from SVDMOR, the new method considers higher order moment information for terminal responses during the terminal reduction and separately applies singular value decomposition (SVD) on both input and output terminals for low-rank approximations. This is in contrast to the SVDMOR method where input and output terminal responses are approximated by SVD at the same time, which can lead to large errors when the numbers of inputs and outputs are quite different. We analyze the passivity requirements for SVD-based terminal and model order reduction and show that the combined passive terminal and MOR using SVD method will not lead an effective terminal reduction in general. Our experimental results show that the proposed ESVDMOR method outperforms the SVDMOR method in terms of accuracy for the same reduced model sizes when the numbers of input and output terminals are quite different.     

MEMS隧道加速度计的系统分析与设计

主要论述了一种新型体硅工艺MEMS隧道加速度计的系统分析与设计 ,对加速度计敏感头与伺服反馈电路组成的系统进行系统建模 ,其中包含了结构的模型和反馈控制电路的模型。以系统模型作为基础 ,分析了器件工作所必须的条件 ,对器件的结构参数和反馈控制电路的参数进行了设计 ,并给出了系统的静态与动态输出。另外 ,本文提出了参数敏感度因子的概念及其计算方法 ,利用这种方法可以对每一个参数计算其对应的敏感因子 ,从而为参数容差设计提供了依据     

MEMS电热微驱动器的设计与仿真分析

本文介绍了一种基于双金属膜受热膨胀原理的面外电热微驱动器。采用聚合物SU-8和镍材料分别作为驱动器的功能材料和结构材料。给电阻丝通电使其发热,驱动器发生垂直于轴线的面外运动,使偏置层与基座接触,完成信号的输出。利用Coventorware软件建立模型,并对器件的性能进行仿真与分析。通过电热分析,驱动器在5V电压作用下,响应时间为5ms,产生18μm的位移,温度由300K上升到440K;在加速度场中,给驱动器施加10000g加速度,产生20μm的位移;在耦合场中施加3V电压和5000g加速度时,驱动位移为23μm,温度由300K升高到400K。最后在不同场源下对驱动器分别进行应力校核,最大应力均小于许用应力,有较高的可靠性。     

MEMS隧道加速度计的系统分析与设计

主要论述了一种新型体硅工艺MEMS隧道加速度计的系统分析与设计，对加速度计敏感头与伺服反馈电路组成的系统进行系统建模，其中包含了结构的模型和反馈控制电路的模型。以系统模型作为基础，分析了器件工作所必须的条件，对器件的结构参数和反馈控制电路的参数进行了设计，并给出了系统的静态与动态输出。另外，本文提出了参数敏感度因子的概念及其计算方法，利用这种方法可以对每一个参数计算其对应的敏感因子，从而为参数容差设计提供了依据。     

以工艺为主线的MEMS设计工具IMEE

IMEE是一个自主研发的MEMMS CAD系统，它包括结点化的系统设计功能、快速的力电耦合性能分析功能、参数化版图单元的版图设计功能、工艺编辑设计和三维模拟功能等。该系统的最大特点是以工艺为主线、贯穿整个设计过程，重点解决MEMS设计与工艺脱节的问题、实现MEMS工艺设计和在线模拟。另外、该系统是跨平台的，适用于UNIX和Windows操作系统，兼容其他MEMS CAD软件，还支持用户自主扩展其他功能模块。     

Sensitivity analysis in computer-aided design of linear circuits

An approximate linear relation is established between the transfer function of a linear network and the component deviations. This can reduce the time consumed by a Monte Carlo sensitivity analysis. Little work is involved in evaluating the relationship beyond that already required for a conventional transient analysis.     

人体头部过载模型阶次的辨识与降阶研究

针对在系统辨识过程中面临的人体头部过载模型阶次辨识问题,介绍了常用的模型阶次辨识方法及利用残差平方和即损失函数J估计模型阶次的原理,并基于20组试验数据开展人体头部过载模型阶次辨识研究。通过系统辨识获得了人体头部过载模型后,采用Gram阵对Hankel奇异值分解方法实施模型简化和降阶处理。通过比较降阶前后模型,表明模型降阶方法是有效和正确的。     

Motor car acoustic response modelling and order reduction viabalanced model truncation

A novel practical application of the balanced model truncation (BMT) technique for the accurate and reduced order/complexity magnitude and phase modelling of the acoustic response of a motor car is described and demonstrated. The effectiveness and viability are illustrated through a sample car response modelling example     

热红外高光谱成像仪的灵敏度模型与系统研制

热红外谱段是对地观测高光谱遥感中非常有用的波段,受限于技术发展,热红外谱段的高光谱成像系统在国内的空间光电系统中并不多见,近年来在国家相关部门的支持下发展迅速,取得了较大进展。结合十二五期间研制的机载热红外高光谱成像仪系统,建立了信号流模型,对系统背景辐射进行了建模仿真,并对红外焦平面组件等效暗电流进行了分析测量,在此基础上得出了影响系统的探测灵敏度的关键因素,给出了系统设计低温光学100K制冷的设计依据。机载热红外高光谱成像仪研制完成后,还进行了探测灵敏度实际测量并与仿真结果进行了对比分析,对未来进一步发展热红外高光谱成像技术积累了重要数据。     

An aggregating based model order reduction method for power grids

Simulation of power girds has become increasingly computationally expensive. In this paper, we propose a Model Order Reduction (MOR) method for power grids by extending the existing Aggregating based MOR (AMOR) method. In the proposed method, besides resistors and capacitors, current sources are also aggregated to improve MOR efficiency. Moreover, pre-partition and parallelization techniques are employed to decrease reduction time. Numerical results demonstrate that compared to original circuits, the scale of power grids is greatly reduced without much loss of accuracy. The reduced-order models are especially useful in the multiple simulations of different working modes or different environment corners.     

FIR filter order reduction: balanced model truncation andHankel-norm optimal approximation

Two different algorithms for approximating FIR by IIR filters are treated: truncation of the balanced model and the Hankel-norm optimal approximation. Both are assessed for approximation fidelity, as well as for intrinsic computational efficiency. Examples show surprisingly good relative performance of the balanced model truncation, suggesting that frequently this method will be operationally preferable